Vitamin E Does Not Modulate Insulin-Induced Memory Impairment Assessed Using Y Maze Test in Mice

• I.U Yarube

Induction of oxidative stress has been proposed as one of the mechanisms of the mechanisms through which insulin causes its negative effect. Vitamin E is known to counter oxidative stress in different biological systems. This study was aimed at evaluating the effect of insulin administration on long-term visuo-spatial and short-term working memory and brain histology in mice and to examine for any modulatory effects of vitamin E. A set of 24 naïve mice were grouped into four (n = 6) and treated for seven days as follows: Control group received distilled water; Insulin group received insulin (10 I.U./kg/day); Insulin+vitamin E group received insulin (10 I.U./kg/day) + vitamin E (100 mg/kg); Vitamin E group received vitamin E (100 mg/kg). Long-term spatial and short-term working memory was assessed using Y maze at the end of the treatment period. Brain tissue was examined for histological changes. Data was processed using IBM SPSS Statistics version 20.0 with p < 0.05 considered as significant. The insulin-treated mice showed reduced preference for the novel arm and performed less number of triads when compared to the controls. The performance of the insulin+vitamin E-treated and vitamin E-treated mice was similar in all the parameters, when compared with the insulin-treated. Normal histology of the cortex and absence of histological lesions were observed. It was concluded that sub-acute insulin treatment impairs long-term visuo-spatial and short-term working memory but does not affect brain histology in mice. Co-treatment with vitamin E does not modulate these insulin effects.

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