Effects of 900 MHz electromagnetic field exposure on the optic nerve of pregnant rats: Evaluation of melatonin and omega-3

This study investigated the effects of 900 MHz electromagnetic field (EMF) exposure on the maternal optic nerve and evaluated the potential modulatory effects of melatonin and omega-3. Pregnant Wistar albino rats were divided into Control, Sham, EMF, EMF+melatonin (EMF+Mel), and EMF+omega-3 (EMF+ω3) groups. The EMF, EMF+Mel, and EMF+ω3 groups were exposed to 900 MHz EMF for 2 h/day throughout the 21-day gestational period. Optic nerves were examined using stereological and transmission electron microscopic methods. The number of myelinated nerve fibers was significantly higher in the EMF group compared to the Sham group, whereas axon diameter, myelin sheath thickness, and g-ratio did not differ significantly among groups. Ultrastructural examination of the EMF group revealed a common axoplasmic vacuolization, separation of myelin lamellae, and degeneration of axons and nerve fiber bundles. Most myelinated fibers in the EMF+Mel group exhibited relatively preserved ultrastructure, although some alterations remained. In contrast, balloon-like vacuolization of the myelin sheath and axoplasm persisted in the EMF+ω3 group. These findings indicate that gestational 900 MHz EMF exposure induces measurable quantitative and ultrastructural alterations in the maternal optic nerve, while melatonin, but not omega-3, appears to provide partial preservation of nerve fiber ultrastructure.