The Superoxide Dismutase Mimetic TEMPOL and Its Effect on Retinal Ganglion Cells in Experimental Methanol-Intoxicated Rats

INTRODUCTION: The incidence of blindness due to methanol intoxication is higher in males of productive age. The management of methanol-induced toxic optic neuropathy is yet to produce satisfactory results. Antioxidant therapy is now used as an alternative method of preventing methanol intoxication. The aim of this study was to observe the effect of TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidinyl-1-oxyl), a superoxide dismutase (SOD) mimetic, on retinal ganglion cells in methanol-intoxicated rats. METHODS: This experimental study was conducted with 20 male Wistar rats that were 10–12 weeks old and weighed 300–350 g. The rats were divided into four groups that each received a different treatment: a negative control group, a positive control group, a methanol group, and a methanol + TEMPOL group. Enucleated eyes from all groups were sliced and stained using hematoxylin–eosin (HE). Retinal layer and ganglion cells were assessed based on cellular structure, cellular swelling, and vacuole formation in the ganglion cell layer as observed at × 200 magnification. The Kruskal–Wallis test and the Mann–Whitney test were used, with significance taken to correspond to p < 0.05. RESULTS: Retinal ganglion cells of the control group had fewer vacuoles and a more well-organized cellular structure compared to those of the methanol group. The histopathologic scores of the methanol-intoxicated group were lower than those of the TEMPOL therapy group; p = 0.011 (i.e., p < 0.05). CONCLUSIONS: TEMPOL had a positive impact on the cellular structure of retinal ganglion cells in methanol-intoxicated rats.