Abstract
Despite the growing concerns about the relationship between exposure to radiofrequency radiation (RFR) and detrimental health effects due to the changes in biological processes of experimental animals, there is still ongoing debate on the significance of these findings in causing significant public health problems with the growing advancement in internet technology. The aim of this study is to review existing literature on the effects of high RFR on wistar rats.
A search was conducted on Google scholar and PubMed to identify relevant peer-reviewed articles to be included into the review. Studies eligible for inclusion included free full text articles on wistar rats exposed to ≥ 2.45GHz RFR conducted in the past 5 years. Studies included in this review were written or transcribed in English language. From 286 titles, 36 eligible studies were included in the review and assessed for quality using the Strengthening the Report of Observational Studies in Epidemiology - Veterinary Extension (STROBE-Vet) quality assessment tool.
Studies included in this review generally had good quality (>60%) based on the STROBE-Vet assessment. This review identified numerous biological changes in wistar rats exposed to high RFR including variations in biochemical, cholinergic, genetic, histopathologic, psychological, optical, and dermatological parameters. In this review, studies identified variations in protein and liver enzymes while high RFR was found to induce oxidative stress and cellular damage of exposed wistar rats compared to the unexposed groups. This was seen in the changes in protein, lipids, enzymatic and non-enzymatic antioxidants. Studies also identified changes in expression of genes and neurotransmitters with imbalance in hormones. In addition, this review identified structural changes of cells, tissues and organs indicative of apoptosis, damage and death. Exposed rats were identified to have behavioral changes indicative of anxiety and memory decline while studies identified optical and dermatologic changes in exposed rats compared to the unexposed.
With numerous biological changes identified in wistar rats exposed to high RFR, there is an increasing risk of detrimental health events giving the advancement in internet technology and limited regulations to control exposures to RFR. Therefore, studies should be conducted to identify strategies to mitigate human exposure to RFR while policies are developed and enforced to protect human health.
Author Contributions
Copyright© 2022
A. Attah Timothy, et al.
License
This work is licensed under a Creative Commons Attribution 4.0 International License.
This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Competing interests The authors have declared that no competing interests exist.
Funding Interests:
Citation:
Introduction
Over the past two decades, the utilization and expansion of Wireless Fidelity (Wi-Fi) communication has rapidly grown, Worldwide there is an exponential growth of wireless communication. As a result, Wi-Fi communication devices and technology have been largely utilized to transmit or access information from the internets, cell phones, computers and other appliance, hence the emission of large degrees and magnitudes of radiofrequency radiation (RFR) With rapid expansion in this non-ionizing radiation considering its significance role in enhancing communication, there have been growing concerns about the potential public health impact Two major countries (France and Russia) have the world’s longest research history on the harmful effects of microwaves and have come out with laws to minimize exposure to Wi-Fi among school children 7.8. These policies have been proposed by the council of Europe, to restrict the use of cell phones and accessibility of Wi-Fi internet devices in schools in order to protect the young ones from the possible harmful effect of radiation The globe continues to advance in wireless technology with little or no actions to prevent and eliminate its harmful impact on human health and the environment. Although recent findings have linked RFR exposure to detrimental health effects in experimental animals, the globe continues to experience immense development and increase in wireless networks with high radiofrequencies and increased levels of exposure to RFR
Results
Out of 1870 outputs from Google Scholar and PubMed, a total of 268 titles were selected for screening of abstract. After removal of duplicates, 256 titles were retrieved for the screening of abstracts of which 178 were excluded and 78 were retrieved from screening of full text. After screening of full-text, 38 articles eligible for selection into the review of which 2 were excluded and 36 were finally included in the review
1
Polyakova et al. 2016
61.43
41.67
64.52
92.86
260.48
65.12
2
Bas et al. 2018
71.43
77.62
80
94.29
323.34
80.835
3
Ali et al. 2017
62.38
59.05
59.52
95.23
276.18
69.045
4
Iheme et al. 2018
68.57
61.42
45.24
77.62
252.85
63.2125
5
Yu¨ksel, et al. 2015
79.05
76.19
68.1
100
323.34
80.835
6
Afolabi et al. 2019
50.95
59.52
50
95.24
255.71
63.9275
7
Rui et al. 2021
88.57
61.9
55.24
94.29
300
75
8
Gupta et al. 2019
61.9
70.48
64.76
98.57
295.71
73.9275
9
Varghese et al. 2018
95.24
74.29
76.67
97.62
343.82
85.955
10
Kamali et al. 2018
84.76
51.9
92.86
89.52
319.04
79.76
11
91.9
42.38
40.47
80.95
255.7
63.925
12
Zhu et al. 2021
84.62
44.76
45.24
94.29
268.91
67.2275
13
Owolabi et al. 2021
50.95
37.62
54.76
60.48
203.81
50.9525
14
Hassanshahi et al. 2017
91.43
58.1
61.9
97.62
309.05
77.2625
15
Fahmy & Mohammed 2020
78.09
54.29
68.57
87.62
288.57
72.1425
16
78.1
46.67
65.71
80.48
270.96
67.74
17
Ibitayo et al. 2017
79.52
39.52
50
64.29
233.33
58.3325
18
Kumar et al. 2021
91.9
61.9
45.33
85.71
284.84
71.21
19
Chauhan et al. 2016
88.57
53.81
43.33
90.48
276.19
69.0475
20
Yorgancliar et al. 2017
92.38
52.38
54.29
60.95
260
65
21
Sharaf et al. 2019
88.1
62.38
48.57
81.43
280.48
70.12
22
Bayat et al. 2021
91.43
42.86
80
84.76
299.05
74.7625
23
Akkaya et al. 2019
92.38
48.1
92.38
90.48
323.34
80.835
24
Haifa et al. 2021
89.05
46.67
78.1
89.52
303.34
75.835
25
Bilgici et al. 2018
94.29
46.67
86.67
76.19
303.82
75.955
26
Haifa et al. 2021
92.38
58.1
79.05
70.95
300.48
75.12
27
Oyewopo et al. 2017
96.19
71.43
73.33
74.29
315.24
78.81
28
Saygin et al. 2016
92.38
58.57
65.24
95.24
311.43
77.8575
29
Kuybulu et al. 2016
49.05
53.33
43.81
95.24
241.43
60.3575
30
Kesari et al. 2017
80.48
45.24
67.62
90.48
283.82
70.955
31
Obajuluwa et al. 2017
86.67
71.9
158.57
79.285
32
Aderemi et al. 2019
85.24
73.33
158.57
79.285
33
Vamsy et al. 2021
86.67
73.81
100
260.48
86.82667
34
Tan et al. 2017
43.81
43.81
43.81
35
Delen et al. 2021
88.1
46.67
72.85
95.24
302.86
75.715
36
Akdag et al. 2016
74.76
53.33
59.52
77.14
264.75
66.1875
S/No
1
(Polyakova et al. 2016) Moscow
Study Sample: 15 Male Wistar rats; control (n=5), intact (5) and exposure group (n=5)
Weight: 250– 300 g
Radiofrequency: 53.57–78.33 GHz
Duration of Exposure: daily for 7 days Distance:
SAR:
Power Density:
Determine the effect of millimeter wavelengths on the intensity of free radical-mediated oxidation and antioxidant properties in Wistar rats
Significant changes total antioxidant reserves, catalase (CAT) activity of blood blood, lipid peroxidation (LPO), free radical mediated oxidation, superoxide dismutase (SOD) activity and malondialdehyde (MDA) concentration.
2
(Baş et al. 2018)
Turkey
Study Sample: 18 Female Sprague-Dawley rats control group (n=6), the EMR group (n=6) and the EMR + vitamin C group (n=6)
Weight: 250-300g Radiofrequency: 2.45GHz
Duration of Exposure: 1 h / day 9:00 a.m.-12:00
p.m. for 30 days Distance of Exposure: SAR: 2.63 mW/kg
Power Density: >80db 0.1-4.45V/m
To assess the effect of 2.45 GHz radiofrequency (RF) emissions on renal damage
Significant pathological changes upon exposure to 2.45Ghz RFR with higher tubular and glomerular damage in EMR group.
3
(Ali et al. 2017)
Pakistan
Study Sample: 40 Sprague dawley rats, Control (n=10), Experimental 2G (n=10), Experimental C 3G (n=10), Experimental D 4G (n=10).
Age: 3-4 months Weight:250-350g Radiofrequency: 2.1- 2.6GHz
Duration of Exposure: 60 mins daily for 2 months
SAR:
Power Density:
To determine the histomorphological changes induced by mobile phones electromagnetic fields on Purkinje cell layer of cerebellum
Significant alteration in the organization of Purkinje cell layer of cerebellum.
4
(Iheme et
al. 2018) Nigeria
Study Sample: 60 Male
Wistar Albino Rats
Age: 32 days
Weight: 42.6-78.8g Radiofrequency: 2.4GHz Duration of Exposure: 24 hrs/day exposure for 90 and 180 days
Distance of Exposure:
5m
SAR: ?
Power Density: ?
Effects of Mobile
Phone Frequencies and Exposure Durations on Selected Oxidative Stress Biomarkers
Significant duration mediated changes in enzyme activities (CAT,
SOD, MDA concentration and LPO)
5
(Yu¨ksel, et al. 2015)
Study Sample: 32 Female Wistar Albino Rats and 40 newborns Age: 12 weeks old Weight: 180 ± 21 g
Radiofrequency: 2.45 GHz
Duration of Exposure: 60 mins/day from four generations (5 days/week) Distance of Exposure: SAR: 0.1 W/kg
Power Density: 20 dB and 11 V/m
Determine the effects of mobile phone (900 and
1800 MHz) and
Wi-Fi (2450
MHz)-induced electromagnetic radiation (EMR) exposure on uterine oxidative stress and plasma hormone levels in pregnant
rats and their offspring.
Time dependent significant changes in LPO, glutathione peroxidase (GSH-Px) and variation in dorsal temperature compared to controls
6
(Afolabi et al. 2019)
Study Sample: 16 Male Wistar Albino Rats
Age: 12-week old
Weight: ? Radiofrequency: 2.5GHz Duration of Exposure: 4,6 & 8 weeks
Distance of Exposure:
10 cm
SAR: ?
Power Density: ?
Evaluate effects of EMF radiation from WiFi on biochemical and hematological parameters
Significant difference in hematology mean corpuscular volume (MCV) major histocompatibility complex (MHC) packed cell volume (PCV) and hemoglobin, protein concentration and liver enzymes aspartate aminotransferase (AST) and alanine aminotransferase (ALT), MDA concentration in the liver, testes and heart
7
(Rui et al. 2021)
Study Sample: 75 Male Sprague-Dawley Rats Age: days
Weight: 258±5g Radiofrequency:
5.8 GHz
Duration of Exposure: 2h and 4hrs daily for 15 days
Distance of Exposure: SAR: 2.33 W/kg
Power Density:
74.25 W/m2
Determine the effects of exposure to 5.8 GHz microwave on learning and memory ability of rats
No significant difference in the spatial learning, memory ability, scene memory ability, % rigidity time (emotional memory ability), Neuron specific enolase (NSE) and S100 calcium-binding protein B (S110B), content of mitochondrial JC-1 monomer in hippocampal neurons, density of apical and basal dendritic spines in CA1 region of hippocampus, synaptic ultrastructure in hippocampus and hippocampal synaptic plasticity
8
(Gupta et al. 2019)
Study Sample: 24 Inbred Charles-foster albino male rats
Age: ?
Weight: 180 ± 20 g Radiofrequency: 2.45GHz
Duration of Exposure: 1hr/day for 28 days Distance of Exposure: SAR: 0.042 W/kg
Power Density: s 0.1227 W/ m
Determine the effects of long- term exposure of 2.45GHz EMF on
stress induced anxiety in experimental
animals
Significant inducement of anxiety-like behaviors with variation in stress markers plasma corticosterone levels corticotrophin releasing hormone in amygdala.
Significant impairment in mitochondria function and integrity (changes in the expression of Bcl2 and Bax and Bcl2) in mitochondria and cytoplasm and expression of cytochrome-c, caspase-9 and neuronal
cells in amygdala. Necrotic and apoptotic amygdalar cell death
9
(Varghese et al. 2018)
Study Sample: 12 Female Sprague Dawley rats
Age: ?
Weight: 180–220 g Radiofrequency: 2.45GHz
Duration of Exposure: 4 hrs/day for 45 days Distance of Exposure: SAR: 0.04728 W
Power Density: 7.88 W/m2
Investigate and explore the effects of NI-EMR
especially the radiation frequency used in Wi-Fi devices, on the brain of rats focusing on some of the parameters of oxidative stress and apoptosis
Memory decline and anxiety behavior in exposed rats.
Significant variation in SOD, O2 anions, CAT and MDA, with variation in apoptotic marker capase 3, number of dendritic branching and intersections indicative of alteration in dendritic structure of neurons and affected neuronal signaling
10
(Kamali et al. 2018)
Study Sample: 20 male rats
Age: 3 months
Weight: 160 ± 10 g Radiofrequency: 2.45GHz
Duration of Exposure: 24 hrs/day for 10 weeks Distance of Exposure: 30cm
SAR: ?
Power Density: ?
Determine the effect of exposure of WiFi signal on oxidative stress
Significant variation in Ferric reducing ability of plasma (FRAP) assay (FRAP) value, total antioxidant capacity, plasma and RBC CAT, SOD, Glutathione- Px (GSH-Px) and glutathione S-transferase (GST)
11
(Ozdemir et al. 2021)
Study Sample: 32 Male Wistar Albino Rats
Age: days Weight: 200-250 g Radiofrequency: ?
Duration of Exposure: 2hrs/day for 6 weeks Distance of Exposure: 23 cm and 37 cm
SAR: 0.01 W / kg
Power Density:?
investigate the effect of mobile phone working with LTE- Advanced Pro (4.5 G) mobile network on the optic nerve
Significant morphometric variation in axonal diameter and myelin sheath thickness and G-ratio. Variations in visual evoked potential (VEP) recordings and mean VEP amplitude and relationship with oxidative stress markers. Significant variation in MDA, SOD and CAT activities
12
(Zhu, et al. 2021)
Study Sample: 140 Male Wistar Albino Rats
Age: 8-week-old Weight: 180–220 g Radiofrequency:
4.3 GHz
Duration of Exposure: 6 mins and 12 mins/day daily for 28 days Distance of Exposure:
0.85 m
SAR: 0-10 mW/cm2
Power Density: 10 mW/cm2
Evaluate the effects of 1.5 and 4.3 GHz microwave radiation (single- frequency effects and combined effects) on irradiated groups, Evaluate the frequency-specific effects of 1.5 and
4.3 GHz microwaves Evaluate possible
combined effects of irradiation with
1.5 and 4.3 GHz microwaves.
Compromised learning, memory decline, hippocampal structural damage, prolonged average escape latency and cognition. Microstructural hippocampal, neuronal and synaptic damage. Vascular changes and variations in PSD thickness.
13
(Owolabi et al. 2021)
Study Sample: 42 pregnant Wistar Albino Rats
Age: ?
Weight: ? Radiofrequency: Duration of Exposure: 6, 12 and 24 hrs/day for 21 days of pregnancy and 35 post-natal days
Distance of Exposure: ? SAR: ?
Power Density: ?
Determine intrauterine and postnatal exposure to RFR on brain structures, functions and behaviors in Wistar rats.
Significant changes in neurotransmitters and enzyme neurochemistry (Cytochrome C oxidase enzyme dopamine, gamma-amino butyric acid, serotonin glutamate and serotonin) in tissue and brain
14
(Hassansha hi et al. 2017)
Study Sample: 80 Male Wistar Albino Rats
Age: ?
Weight: 200–250 g
Radiofrequency: 2.4 GHz
Duration of Exposure: 12 h/day for 30 days Distance of Exposure: 50 cm
SAR: ?
Power Density: ?
investigate the effect of 2.4 GHz Wi-Fi radiation on multisensory integration in rats
Insignificant Increased in expression of muscarinic receptor 1 (M1 mRNA).
15
(Fahmy & Mohamme d. 2020)
Study Sample: 24 Female Wistar Albino Rats
Age: 40 days Weight: 101 + 3.00g Radiofrequency: 2.45 GHz
Duration of Exposure: 24 h/day for 40 days Distance of Exposure: 25 cm
SAR: 0.01 W kg-1
Power Density: ?
Impact of standard
2.45 GHz radio frequency on the liver of Wistar female rat
Significant difference in SOD, glutamic pyruvic transaminase (GPT) levels, increase in MDA
16
(Almášiová et al. 2017)
Study Sample: 20 male Wistar Albino Rats Age: ?
Weight: ? Radiofrequency: 2.45 GHz
Duration of Exposure: 3h/day for 21 days Distance of Exposure: ? SAR: ?
Power Density: f 28 W/m2
Determine the potential thermal and/or non-thermal effects of immediate, whole body electromagnetic irradiation of rat testes
Significant difference in local temperature of testes
Dilation of the testes, congestion of blood vessels within tunica albuginea and interstitium. Degeneration of seminiferous epithelium and ultrastructural changes in developing sex cells, sertoli cells and endotherlial cells, spermatozoa motility
17
(Ibitayo et al. 2017)
Study Sample: 20 male Wistar Albino Rats
Age: ?Weight: 80–120 g Radiofrequency: 2.5 GHz
Duration of Exposure: 30, 45, 60 days Distance of Exposure: 10 cm
SAR: ?
Power Density: ?
Investigate the
injurious effect of radiofrequency emissions from installed Wi-Fi devices in brains of young male rats
Progressive DNA fragmentation in the band pattern with larger band
size in prolonged duration indicative of apoptosis. Alteration in harvested brain tissues and DNA damage in brain with prolonged RFR exposure.
Histopathological alterations in harvested brain tissues, vascular congestion and perivascular congestion and tissue damage
18
(Kumar et al. 2021)
Study Sample: 96 male Wistar Albino Rats Age: ?
Weight: 100±10 g Radiofrequency: 0.9GHz, 1.8GHz, 2.45
GHz
Duration of Exposure: 2 h/day for 6 months Distance of Exposure: 1m
SAR: 6.4 × 10− 4 W/kg
Power Density: 1 mW
Determine the effect of mobile phone signal radiation on epigenetic modulation in the hippocampus of Wistar rat
Duration of exposure dependent variation in DNA methylation, histone methylation in the hippocampus, epigenetic modulations in the hippocampus and gene expression
19
Chauhan et al. 2016
Study Sample: 24 male Wistar Albino Rats Age: 60 days
Weight: 180 ± 10 g
Radiofrequency: 2.45 GHz
Duration of Exposure: 2 hrs/day for 35 days Distance of Exposure: 10 cm
SAR: 0.14 W/kg
Power Density: 0.2 mW/cm2
Explore the effect of 2.45 GHz microwave radiation on histology and the level of lipid peroxide (LPO) in Wistar rats
Significant LPO and histological changes in liver, brain, kidney and spleen.
20
(Yorgancli ar et al. 2017)
Study Sample: 16 male Wistar Albino Rats Age: ?
Weight: 313 ± 25 g
Radiofrequency: 2.4 GHz
Duration of Exposure: 24 h/day for one year Distance of Exposure: 50 cm
SAR: ?
Power Density: 0.00036 mW/cm2
long-term effects of radiofrequency radiation (RFR) emitted from Wi-Fi systems on hearing
Significant distortion product otoacoustic emissions (DPOAE) values and hearing frequency
21
(Sharaf et al. 2019)
Study Sample: female Wistar Albino Rats Age: 3 months Weight: 120±5g Radiofrequency: 2.4 GHz
Duration of Exposure:
24 h/day for 6 months
Distance of Exposure:
25 cm
SAR: 0.091 W/kg
Power Density: 0.00036 mW/cm2
Determine impact of Wi-Fi signals exposure on cognitive function and its relevant brain biomarkers
The possible role of designed Bio-Geometrical forms in restoring the neurobehavioral alterations resulting from the exposure
to the emerging radiation
Elevated anxiety level and impaired spatial memory with variations in dopamine, serotonin, acetylcholine and melatonin levels in the brain, cortex, striatum and hippocampus. Depleted heat shock protein in the cortex.
22
(Bayat et al. 2021)
Study Sample: 30 male Sprague-Dawley rats Age: 8-9 week
Weight: 200–250 g Radiofrequency: 2.45GHz
Duration of Exposure: 2 h/day for 45 days Distance of Exposure: 35 cm
SAR: 0.0346-0.0060
W/Kg
Power Density: 0.018-
0.0032 mW/cm2
Assess the effects of 2.45 GHz Wi-Fi signal on learning memory and synaptic plasticity in y vascular dementia( VaD) rat model induced by permanent occlusion of bilateral common carotid artery (2- VO)
Impairment in spatial learning and memory associated with long-term potentials impairment, variation in basal synaptic transmission, neurotransmitter release-probability, hippocampal cell loss and GABA transmission.
23
(Akkaya et al. 2019)
Study Sample: 30 male Wistar Albino rats
Age:
Weight: 230−250 g Radiofrequency: 2.4GHz Duration of Exposure: 12hrs/day for 30 days Distance of Exposure: 60 cm
SAR: ?
Power Density: ?
Investigate the effect of Wi-Fi on melatonin anticonvulsive effect and oxidative damage in pentylene tetrazole induced epileptic seizures in rats
Significant difference in Total Oxidant Status (TOS) and Oxidative Stress Index (OSI). Behavioral changes associated with epilepsy and reduction in anticonvulsive and antioxidant effects of melatonin.
Significant variation in the percentage of dark neurons in CA1, CA3, and DG regions.
24
(Haifa et al. 2021)
Study Sample: 24 male Wistar Albino rats
Age: ? Weight: 120 g
Radiofrequency:
2.45GHz
Duration of Exposure: 2hrs/day for 14 days Distance of Exposure: 25 cm
SAR: ?
Power Density: ?
Evaluate the neurological effects of exposure to WiFi radiation on wistar rats
Significant difference in center entries and time indicative of anxiety, cerebral MDA, SOD levels, brain Iron , lead and cadmium
25
(Bilgici et al. 2018)
Study Sample: 22 male Wistar Albino rats
Age: ?
Weight: 250-300 g Radiofrequency: 2.45GHz
Duration of Exposure: 1 hour/day for 30 days Distance of Exposure: 15 cm
SAR: 0.0233W/kg
Power Density: ?
Determine the inflammatory effect and testicular damage on rats exposed to low level of electromagnetic fields (EMF)
Significant differnece in interleukin-6 and C-Reactive protein. Iindication of necrosis and changes in spermatogenesis with increase in necrosis score and slight damaged spermatogenesis
26
(Othman et al. 2017)
Study Sample: 24 female Wistar Albino rats and their offsprings
Age: ?
Weight: 230- 250g Radiofrequency: 2.45GHz
Duration of Exposure: 2 h per day for gestation period
Distance of Exposure:
25 cm
SAR: ?
Power Density: ?
Evaluate the effects of maternal concurrent exposure to stress and WiFi signal on the postnatal development and behavior of rat offspring
Detrimental effect of gestational progress, outcomes and neuromotor maturation. Gender dependent defect in physical development of pups and Inducement of anxiety like behavior, motor deficit and exploratory behavior impairment in both male and female progeny. Significant variation in MDA, CAT, SH, SOD phosphorus, and magnesium levels in male, and MDA, SH, CAT, Lactate dehydrogenase (LDH), glucose, triglycerides and magnesium level in female progenies.
27
(Oyewopo et al.2017) Nigeria
Study Sample: 20 sexually matured male Wistar rats; group A (control; n = 5), group B (n = 5), group C (n = 5) and group D (n = 5) Weight: 180-200 g Radiofrequency: Duration of Exposure: group A (switched off mode exposure), group B (1-hr exposure), group C (2-hr exposure) and group D (3-hr exposure).
Exposure for 28days
Distance:
SAR:
Mean power Density: 28 W/m2
Investigate the effects of the emitted radiation by cell phones on testicular histomorphometry and biochemical analyses
Significant alteration in lumen diameter, sera levels of MDA, SOD, follicle stimulating hormone (FSH), luteinizing hormone (LH) and testosterone. Uneven distribution of germinal epithelial cells
28
(Saygin et al. 2015)
Turkey
Study Sample: 48 Six- week-old male Sprague Dawley rats divided into four groups: Sham (n = 12), EMR only (n = 12), EMR+ gallic acid (GA) (n = 12), Gallic Acid (n = 12)
Weight: 150–170 g
Radiofrequency: 2.45 GHz
Duration of Exposure: Sham, EMR only (EMR, 3 h day−1 for 30 days),
EMR + GA (30
mg/kg/daily), and GA (30 mg/kg/daily) groups.
Distance: SAR:
Power Density:
Investigate electromagnetic radiation (EMR) transmitted by wireless devices (2.45 GHz), which may cause physio pathological or ultrastructural changes, in the testes of rats.
Significant difference in MDA, TOS and TAS activities. Insignificant variations in testosterone and vascular endothelial growth factor (VEGF) levels.
Changes in prostaglandin E2 (PGE2) and calcitonin gene related peptide (CGRP) staining in tubules of the testes. Fewer spermatozoa in most of the tubules of the testes.
29
(kuybulu et
al. 2016) Turkey
Study Sample: 12 3
months old female Wistar albino rats and 8 male offspring
Weight: ? Radiofrequency:2.45GH z
Duration of Exposure: Prenatal group: utero exposure for1hr/day during pregnancy and exposure of offspring at 16 days of life until the 12 week
Postnatal group:1hr/day from 18 days till the 12th week
Distance: ?
SAR: 0.1 W/kg
Power Density:?
Investigate
oxidative stress and apoptosis in kidney tissues of male Wistar rats that
pre- and postnatally exposed to wireless electromagnetic field (EMF) with an internet frequency of 2.45 GHz for a long time.
Significant difference in MDA, SOD levels in prenatal group,
significant variation in kidney TAS and TOS levels. Significantly higher ratio of spot urine N-acetyl-β-D-glucosaminidase (NAG)/creatinine in prenatal group.
Significantly higher Bcl-2 immunohistochemically staining intensity in the cortical and medullary areas in prenatal group and postnatal. Bax immunohistochemical staining intensity in the cortical area in the prenatal and postnatal groups were significantly lower with significant increase in Bcl-2/Bax staining intensity ratio in medullar and cortical areas.
30
Kesari et al. 2017
Study Sample: 60 days old male wistar rats Weight: 180±10g Radiofrequency: 2.45GHz
Duration of Exposure: 2 h per day for 35 days Distance: ?
SAR: 0.14 W/kg
Power Density: 0.2 mW/cm2
Explore the computational elucidation of melatonin in repair system induced by microwave radiation exposure
Statistically significant difference in lipid peroxidation, reactive oxygen species in brain tissues of exposed rats.
31
Tan et al. 2021
Study Sample: 120 male wistar rats
Weight: 200±20g Radiofrequency:2.856G Hz and 1.5GHz Duration of Exposure: 2.856 GHz microwave group: 6 mins/day for Distance:
SAR: 3.3 W/kg
Power Density: 10 mW/cm2
Evaluate the acute effects of 2.856
and 1.5 GHz microwaves on spatial memory and cAMP response element binding related pathways
Significant changes in the Average Escape Latency. Significant difference in the frequency of electroencephalogram, power amplitude of α, β, θ, and δ waves.
Significant Injuries in the dentate gyrus areas of the hippocampus indicative of karyopyknosis and cell edema with significant increase in the mean optical density of the nuclei in the hippocampus.Apoptosis of the neuron and significant difference in the expression of p- CaMKII/CaMKII and p-CREB/CREB
32
Obajuluwa et al. 2017
Study Sample: 24 male albino rats
Weight:? Radiofrequency: 2.5GHz Duration of Exposure: 24 h/d for 4, 6 and 8 weeks respectively Distance: 50 cm
SAR:?
Power Density: ?
Investigate the effect of 2.5 GHz band radio- frequency electromagnetic waves exposure on cerebral cortex acetylcholinesteras e activity, their mRNA expression level and locomotor function and anxiety-linked behavior of male
rats
Significant duration of exposure dependent variation in locomotive activity (line crossing frequency), acetylcholinesterase gene expression
33
Vamsy et al. 2021
Study Sample: 108 male Wistar rats of 30 days old Weight: Radiofrequency:2.4GHz Duration of Exposure: 96 min/day for 6 months Distance: ?
SAR: 1.6 W/kg
Power Density: ?
Examine the effects of mobile phone radiation on the histology of Wistar rats
Mild to moderate duration of exposure dependent inflammation and necrosis on the portal tract which worsens with duration of exposure. Observed congestion of the sinusoids and central vein, random clustering, congestion and inflammation of the Kupffer cell and formation of granuloma.
Gradual change in the shape of the nucleus from vesicular to pyknotic, increase in number of inflammatory cells in the liver parenchyma, portal and lobular areas. Significant difference in total bilirubin, SGOT and SGPT levels.
34
Tan et al. 2017
Study Sample: 175 Male Wistar Rats
Weight: 200 ± 20 g Radiofrequency: 2.856 GHz
Duration of Exposure: 6 mins
Distance:
SAR: 1.7 W/Kg
Power Density: 5 and 10 mW/cm2
the relationship between the effects and the power and frequency of microwave and analyzed the accumulative effects of two different frequency microwaves with
the same average power density
Significant dose-dependent prolonged AELs, karyopyknosis, irregular arrangement, cell edema, and broadening pericellular space distributed in hippocampus region (DG, CA1 and CA3). Decline in spatial learning and memory and fluctuations of brain electric activities. Features of cognitive dysfunction, protein-based metabolic disorder in neurons in exposure groups.
35
Akdag et al. 2015
Study Sample: 16 Male Wistar rats
Weight: 313 ± 25 g Radiofrequency: 2.4GHz Duration of Exposure: 24 h/d for 12 months Distance:
SAR: 1.41 W/kg and
71.27 W/kg
Power Density:
Effect of long term exposure of 2.4 GHz RF radiation on DNA damage of different tissues (brain, kidney, liver, and skin tissue and testicular tissues of rats).
Significant DNA damage in the testis of rats and insignificant for other tissues.
36
Delen et al. 2021
Study Sample: 36 Male Wistar albino rats Weight: 250–300 g Radiofrequency: 2.6GHz Duration of Exposure: 30 min, 5 days/week for 30 days
Distance:
SAR: 0.616 W/kg
Power Density:
Investigate the effects of 2.6 GHz RFR and melatonin on brain tissue biochemistry and histology of male rats
Significant difference in GSH, GSH-Px, SOD, myeloperoxidase (MPO), MDA, and NOx levels.
Dilated blood vessels, pyramidal neurons with abnormal morphology. Edema and apoptotic neurons were observed in the cortex and around neuroglia cells in the CA1 region of the hippocampus.
Lose of normal course and random placement in neurons of the hippocampus CA3 region, number of neurons decreased semi quantitatively and the number of astrocytes increased
Strong immunoreactivity of Glial fibrillary acidic protein (GFAP) in in the cortical astrocytes compared with the hippocampal regions. Large number of TUNEL-positive neurons and neuroglia cells in both cortex
and hippocampus in RFR group.
Discussion
This review study was conducted to synthesize existing knowledge on the health effect of exposure to high RFR in studies conducted on wistar rats as experimental models. The studies included in this review identified numerous biochemical, genetic, behavioral, histological, optical and behavioral patterns that have been influenced by exposure to high RFR in wistar rats. Findings from this review are also consistent with recent reviews and studies conducted to identify RFR effects Numerous findings identified exposure to high RFR to be associated with oxidative stress and cellular damage Generally, when antioxidant defense is compromised, the expected outcome is reduced activities of enzymatic antioxidant and an increased level of lipid peroxidation (MDA levels). This review identified duration of exposure dependent reduction in enzymatic antioxidant activities among exposed group and thus may be as a result of a compromised cellular defence or oxidative damage from consistent response to oxidative stress as a result of exposure to high RFR. There is evidence that oxidative stress could alter biological processes that can lead to apoptosis, necrosis and autophagy which could result to cancers and metabolic disorders Exposure to high RFR in wistar rats have been found to be associated with cholinergic effects which is observed in the decrease in ACh levels It is important to note that there is evidence of the relationship between decreased cholinergic activities and the occurrence of chronic health conditions such as Alzheimer s disease Behavioral changes have also been found to be influenced by exposure to high RFR EMF Organs, tissues and cells play very key roles in regulating the entire system. When they are altered, the normal functioning of the body is interfered resulting to effects that are detrimental to the entire body. Histopathological changes have been identified in this review. These changes are seen mostly in the liver, kidneys, testis, nervous system as well as the brain resulting in renal, metabolic, reproductive, neurologic and cognitive dysfunctions of exposed animals and based on exposure duration cell death This study synthesizes existing peer reviewed articles conducted in the past 5 years on the effects of high RFR on wistar rats. As a result, it provides a collection of more recent data on high RFR effects on health outcomes. While other reviews have been conducted for specific RFRs, this review is also the first to assess all RFR exposures and therefore provides more detailed information of the general effects of high RFR EMF on health outcomes. Also, this review only included studies conducted on wistar rats as the utilization of animal models can address certain variables that cannot be accounted for and may confound or modify the effects caused by exposure to high RFR. However, there are some limitations identified in this study. This review provided a summary of ≥ 2.45GHz RFR studies and did not consider comparing the radiation effects based on radiation type. This review identified a wide range of high RFR EMF effects and as a result, does not provide in-depth understanding of these effects and its public health significance. Rather, this review provides a summary of the effects of high RFR exposure on wistar rats. It is important to note that this study has the potential of promoting other systematic reviews and primary studies to assess RFR effects on specific study outcomes. This study also can potentially improve the awareness about the potential harmful effects of RFR on human health and can foster research and advocacy for public health actions to mitigate these effects on the population. While there has been consistent advancement and expansion in technology and access to wireless technology globally, downlink, broadcast, uplink and Wi-Fi devices have contributed significantly to the general RFR exposures in humans In this review, numerous effects of exposure to high RFR EMF on wistar rats were identified. With all studies being observational and conducted on this animal model which has similar genetic make-up with humans, the global population is at an increasing risk of poor health outcomes. It is recommended that while these effects have been identified, further experimental studies that measures periodic radiation exposure and its effects on human health should be conducted. Also, research should focus on adequately assessing the pathway between long-term high RFR EMF, occurrence of oxidative stress and the onset chronic health events such as organ damage, cognitive defects and cancers amongst others in exposed animals. Studies should explore plants that may be resistant to RFR as these plants could play a critical role in mitigating the level of exposure and the effects of exposure. Although advancement in wireless network technology is inevitable, it is important that studies are conducted to provide strategies and public health actions to mitigate or reverse these harmful effects. Also countries across the globe must take necessary actions to develop and enforce policies that set and monitor exposure limits to RFR EMF. This will help prevent the potential of poor health outcomes and promote a healthy population in a long run.
Conclusion
This review study identifies numerous health defects as a result of exposure to high RFR. This includes significant alterations in the biochemistry, genetics, histopathology, behavior and other changes in wistar rats.