The effects of microwave radiation on rabbit's retina

Effect of 2.45 GHz Microwave Radiation on the Inner Ear: A Histopathological Study on 2.45 GHz Microwave Radiation and Cochlea

BACKGROUND

The present study aims to determine the possible low dose-dependent adverse effects of 2.45 GHz microwave exposure and Wi-Fi frequency on the cochlea.

METHODS

Twelve pregnant female rats (n=12) and their male newborns were exposed to Wi-Fi frequencies with varying electric field values of 0.6, 1.9, 5, 10 V/m, and 15 V/m during the 21-day gestation period and 45 days after birth, except for the control group. Auditory brainstem response testing was performed before exposure and sacrification. After removal of the cochlea, histopathological examination was conducted by immunohistochemistry methods using caspase (cysteine-aspartic proteases, cysteine aspartates, or cysteine-dependent aspartate-directed proteases)-3, -9, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). Kruskal-Wallis and Wilcoxon tests and multivariate analysis of variance were used.

RESULTS

Auditory brainstem response thresholds in postexposure tests increased statistically significantly at 5 V/m and above doses. When the number of apoptotic cells was compared in immunohistochemistry examination, significant differences were found at 10 V/m and 15 V/m doses (F(5,15)=23.203, P=.001; Pillai's trace=1.912, η2=0.637). As the magnitude of the electric field increased, all histopathological indicators of apoptosis increased. The most significant effect was noted on caspase-9 staining (η2 c9=0.996), followed by caspase-3 (η2 c3=0.991), and TUNEL staining (η2 t=0.801). Caspase-3, caspase-9, and TUNEL-stained cell densities increased directly by increasing the electric field and power values.

CONCLUSION

Apoptosis and immune activity in the cochlea depend on the electric field and power value. Even at low doses, the electromagnetic field in Wi-Fi frequency damages the inner ear and causes apoptosis.

Delayed Reaction of Radiation on the Central Nervous System and Bone System in C57BL/6J Mice

The aim of this study was to provide a suitable mouse model of radiation-induced delayed reaction and identify potential targets for drug development related to the prevention and treatment of radiation injury. C57BL/6J mice were subjected to singular (109 cGy/min, 5 Gy*1) and fractional (109 cGy/min, 5 Gy*2) total body irradiation. The behavior and activity of mice were assessed 60 days after ionizing radiation (IR) exposure. After that, the pathological changes and mechanism of the mouse brain and femoral tissues were observed by HE, Nissl, Trap staining micro-CT scanning and RNA sequencing (RNA-Seq), and Western blot. The results show that singular or fractional IR exposure led to a decrease in spatial memory ability and activity in mice, and the cognitive and motor functions gradually recovered after singular 5 Gy IR in a time-dependent manner, while the fractional 10 Gy IR group could not recover. The decrease in bone density due to the increase in osteoclast number may be relative to the down-regulation of RUNX2, sclerostin, and beta-catenin. Meanwhile, the brain injury caused by IR exposure is mainly linked to the down-regulation of BNDF and Tau. IR exposure leads to memory impairment, reduced activity, and self-recovery, which are associated with time and dose. The mechanism of cognitive and activity damage was mainly related to oxidative stress and apoptosis induced by DNA damage. The damage caused by fractional 10 Gy TBI is relatively stable and can be used as a stable multi-organ injury model for radiation mechanism research and anti-radiation medicine screening.

Safety profiles of terahertz scanning in ophthalmology

Terahertz (THz) technology has emerged recently as a potential novel imaging modality in biomedical fields, including ophthalmology. However, the ocular biological responses after THz electromagnetic exposure have not been investigated. We conducted a rabbit study to evaluate the safety profiles of THz scanning on eyes, at a tissue, cellular, structural and functional level. Eight animals (16 eyes) were analysed after excessive THz exposure (control, 1 h, 4 h, and 1 week after continuous 4-h exposure; THz frequency = 0.3 THz with continuous pulse generated at 40 µW). We found that at all the time points, the corneas and lens remained clear with no corneal haze or lens opacity formation clinically and histopathologically. No thermal effect, assessed by thermographer, was observed. The rod and cone cell-mediated electroretinography responses were not significantly altered, and the corneal keratocytes activity as well as endothelial viability, assessed by in-vivo confocal microscopy, was not affected. Post-exposed corneas, lens and retinas exhibited no significant changes in the mRNA expression of heat shock protein (HSP)90AB1), DNA damage inducible transcript 3 (DDIT3), and early growth response (EGR)1. These tissues were also negative for the inflammatory (CD11b), fibrotic (fibronectin and α-smooth muscle actin), stress (HSP-47) and apoptotic (TUNEL assay) responses on the immunohistochemical analyses. The optical transmittance of corneas did not change significantly, and the inter-fibrillar distances of the corneal stroma evaluated with transmission electron microscopy were not significantly altered after THz exposure. These results provide the basis for future research work on the development of THz imaging system for its application in ophthalmology.

[Acute ocular lesions after exposure to electromagnetic radiation of ultrahigh frequency (an experimental study)]

PURPOSE

To investigate the clinical and morphological manifestations of ocular lesions resulting from acute exposure to microwave radiation (MR).

MATERIAL AND METHODS

Twenty-four rabbits were included in the study and divided into four equal groups according to MR exposure time (15, 30, 45, 60 s). The right eyes of rabbits were exposed to MR of 3.97 GHz and energy density of 1.0 W/cm². The sham control group consisted of six animals. The exposed (right) and the paired (left) eye were studied for clinical and morphological changes, content of proinflammatory cytokines IL-1β, IL-6 and TNF-α in the anterior chamber and in the vitreous body after exposure to MR.

RESULTS

Significant dose-dependent changes in the structure of the exposed eye were revealed. Formation of microwave cataract was noted at the MR exposure time of 15 seconds and more. Partial or complete de-epithelialization, stromal edema, endothelial damage and inflammatory infiltration in the cornea, effusion of protein and cellular reaction in the aqueous humor were detected after MR exposure of 30, 45 and 60 seconds. Cellular reaction in the vitreous body was observed after exposure time of 45 and 60 seconds. Exposure to MR for up to 1 minute did not lead to visible clinical or morphological (traditional methods of examination) damage of the retina and optic nerve within 24 hours. Significantly higher content of proinflammatory cytokines IL-1ß, IL-6 and TNF-α in the aqueous humor and vitreous body was revealed in animals exposed to MR for 45 and 60 seconds.

CONCLUSION

Acute exposure of the organ of vision to electromagnetic microwave radiation can lead to adverse dose-dependent effects not only in the lens, but also in other structures of the eye.