ABSTRACT
Fifteen healthy adult male albino rats were used in this study aiming to demonstrate the structural changes occurring in the peripheral nerves as a result of chronic diabetes and to investigate the role of vitamin E as an antioxidant. The animals were equally divided into three groups [A, B and C] [5 animals each]. Group A served as a control. Group B animals were injected intra-peritoneally with 40 mg streptozocin/kg body weight for successive 5 days. Group C animals were injected with streptozocin as those of group B then they received a daily dose of vitamin E 70 mg/kg body weight orally for successive 6 weeks. At the time of sacrifice the animals of the all groups were anaesthetized with ether inhalation and their sciatic nerves were dissected out carefully and small pieces were taken and processed for light and electron microscope examinations. Light microscope examination of the diabetic group showed the sciatic nerve was formed of numerous axons with poor myelination and with different diameters. The intensity of the reaction of the nerve growth factor [NGF] was more at the periphery than the center. Ultrastructurally, the myelin sheath showed splitting in the lamellae. The endoneurium contained mast cells and infiltrating cells in close relation with the distorted myelin. Schwann cells nuclei appeared with much heterochromatin and their cytoplasm contained few scattered segments of rough endoplasmic reticulum and poorly developed Golgi. The nodes of Ranvier exhibited irregular neurolemmal terminations. Examination of the diabetic group which received vitamin E by light microscope revealed the sciatic nerve was formed of many well myelinated axons and few ones with poor myelination. The intensity of the reaction of [NGF] was intense in the center and weak in the periphery. Ultrastructurally, Schwann cells appeared with much euchromatic nuclei and their cytoplasm contained several segments of rough endoplasmic reticulum. The related axons appeared with closely packed myelin lamellae. Vitamin E as an antioxidant exhibited a protective role against structural changes in diabetic peripheral neuropathy