Abstract
PURPOSE: To investigate the effects of intraperitoneal melatonin administration on the optic nerve and retina following acute methanol exposure. MATERIALS AND METHODS: Twenty-four female albino Wistar rats weighing 200-300 g and aged between 3 and 6 months were utilized. The rats were divided into three groups, each consisting of eight rats: healthy control (C), methanol (M), and methanol + melatonin (MM) groups. Initially, rats in groups M and MM were administered intraperitoneal methotrexate at a dose of 0.3 mg/kg. One week later, the same groups were orally given methanol at a concentration of 20% and a dose of 3 g/kg to induce methanol toxicity. To ensure survival, four hours after oral methanol administration, ethanol was orally administered at a concentration of 20% and a dose of 0.5 g/kg. Additionally, starting from the next day, the MM group received intraperitoneal melatonin at a dose of 20 mg/kg/day for 14 days. On the 14th day, rats were sacrificed, and their eyes, including the optic nerves, were enucleated for histopathological examinations. Myelin basic protein (MBP), retinal ganglion cell (RGC), glial cell degeneration and optic nerve thickness were evaluated. RESULTS: The experiment was completed with a total of twenty-four rats, with each group consisting of eight rats. When evaluating RGC, glial cell degeneration, and optic nerve thickness, the results for Group MM were significantly better than those for Group M (p < 0.0001, p < 0.0001, p < 0.0001, respectively). There was no significant difference between Group MM and Group C, which was not subjected to alcohol intoxication (p: 0.89, p: 0.82, p: 0.77, respectively). There was no significant difference in MBP values between the groups (p: 0.44, p: 0.17, p: 0.80, respectively). CONCLUSION: Intraperitoneal administration of melatonin has a significant positive effect on the structure of the retina and optic nerve resulting from methanol exposure. Melatonin should be considered in future studies as a potential therapy for methanol-induced toxic optic neuropathy.