Vitamin E ameliorates histological and immunohistochemical changes in the cerebellar cortex of alloxan-induced diabetic rats

Introduction :Diabetes mellitus causes a variety of functional and structural disorders in the central nervous system. Objectives :To describe structural, ultrastructural, and immunohistochemical changes in the cerebellar cortex of alloxan-induced diabetic rats and to determine the possible protective effect of vitamin E. Materials and methods: The rats were divided into three equal groups at random: group A (control), group B (alloxan-induced diabetic rats), and group C (alloxan-induced diabetic rats that received vitamin E). In rats of groups B and C, diabetes was induced by a single intraperitoneal injection of alloxan monohydrate. After 8 weeks, the rats of all groups were sacrificed and the cerebellum was dissected immediately and subjected to H E stain, and immunostaining for glial fibrillary acidic protein (GFAP), and thin strips from the cortex were prepared and examined by transmission electron microscopy. Results :Diabetic untreated rats showed shrunken Purkinje cells and apoptotic cells in the granular layer. Ultrastructurally, the nuclei of Purkinje cells were irregular and the cytoplasm contained numerous lysosomes, abnormal mitochondria, and dilated Golgi saccules. Myelinated nerve fibers showed splitting of myelin sheaths and wide axonal spaces. Immunohistochemically, a significant increase in the number of GFAP-positive astrocytes in diabetic untreated rats was found as compared with the control. These histological and ultrastructural alterations were ameliorated in vitamin E-treated diabetic rats. Moreover, a significant decrease in the number of GFAPpositive astrocytes was found in animals that received vitamin E as compared with diabetic untreated rats. Conclusion :Vitamin E can be used as an adjuvant therapy for the prevention and treatment of the central nervous system complications of diabetes.