Evaluation of histopathological effects of steroid and erythropoietin treatments on the optic nerve in experimental methanol intoxication rat

Purpose: We aimed to evaluate the histopathological effects of erythropoietin in methanol intoxication, which we experimentally created in rats, and compare it with the effects of steroid treatment. Materials-Methods: We used 60 eyes of 40 rats In our study. We formed four groups, each containing 10 mice, groups 0, 1, 2, 3. Group 0 was the control group, no agent was given. Group 1 was given methanol, ethanol, methotrexate. Steroid treatment was added to group 2, which was different from group 1. Unlike Group 2, recombinant human erythropoietin treatment was added to Group 3. In the study, oral methanol was given to the rats one week after intraperitoneal methotrexate administration to groups 1, 2, 3. Oral ethanol was given 4 hours later following oral methanol. In addition to all these, the second group received high dose intraperitoneal methyl prednisolone for 3 days, and the third group received intraperitoneal recombinant human erythropoietin for 3 days. At the end of the two-week period, the optic nerves of the rats were dissected and examined histopathologically. Results: In the electron microscopic examination of the methylprednisolone group, it was noted that the myelin sheath in the majority of myelinated nerve fibers and the mitochondria, neurotubules and neurofilaments in the axoplasm maintained their normal structures. It was observed that oligodendrocytes encircled the myelinated axons and generally maintained their normal thin structure. In the group 1, significant degenerative changes were observed in many areas of myelinated nerve fibers. It was noted that in oligodendrocytes there was an increase in heterochromatin in the nucleus and vacuolization in the cytoplasm. The number of myelinated axons was found to be significantly increased compared to the group 1. Although the degenerative changes seen in the group treated with erythropoietin were more limited compared to the untreated group 1, these changes were more severe than the group treated with methylprednisolone. Both in the erythropoietin-treated group (p<0,01) and in the methylprednisolone-treated group (p<0,001); It was seen that the number of axons with myelin was significantly higher compared to the experimental group. Conclusions: The neuroprotective effect of methylprednisolone and erythropoietin was found histopathologically effective in our experimental study. However, it was observed that methylprednisolone treatment preserved the structures of myelinated nerve fibers and the number of myelinated axons more than erythropoietin treatment. Key words: Methanol intoxication, toxic optic neuropathy, erythropoietin, steroid, neuroprotection