In the present study, a rat model of subacute methyl mercury (MeHg) intoxication was used to investigate possible MeHg-induced detrimental effects on cerebellar cortices. Thirty six adult male Sprague Dawley rats (aged 6 weeks) were randomly assigned into three equal groups viz. control group (group I), low Methyl mercury exposure group (group II - 2.5 ppm) and high Methyl mercury exposure group (group III - 5 ppm). Exposed rats were sacrificed at 14 and 35 days and cerebellar tissue samples were collected and examined the effect of the two levels of MeHg exposure for varying periods. Histological study of these samples revealed a reduced average thickness of molecular cell layer, granular cell layer, average number and size of Purkinje cells in both the treated groups and periods. Purkinje cell shape was altered in both exposure periods in 5 ppm group and loss of nucleoplasm and karyolysis in 2.5 ppm at 35 days post-exposure. Further, the granule cells were disoriented and a few altered their shape in both the treatment groups at 35 days post-exposure.
Key words: Cerebellum, Methylmercury Treatment, Purkinji Cells, Basket Cells, Granular Layer