Co-Administration of Vitamins E and D3 on Spatial Learning and Memory of Hippocampal Formation of Rat Following Ethidium Bromide- Induced Demyelination

The hippocampus as part of the limbic system has a major role in the formation of several types of memory including spatial memory. Cognitive and memory impairment have been reported in patients with multiple sclerosis (MS) by several studies and vitamins have antioxidant role for neuro-regeneration. The present study investigates the effects of combined administration of vitamins E and D3 on spatial learning and memory in the demyelinated hippocampus of rat following administration of ethidium bromide. Male Wistar rats were anesthetized with intraperitoneal injection of chlorate hydrate. The animal head was fixed in a stereotaxic apparatus and 3 microliter of ethidium bromide was injected into the dentate gyrus of hippocampus for 7 days. Behavioral tests after intra-peritoneal administration of vitamin E (mg/kg100) and D3 (μg/kg5) were carried out. Animals were subjected to 5 days of training in the Morris water maze; 4 days with the invisible platform to test spatial learning and the 5th day with the visible platform to test sensory-motor coordination. The results showed that co-administration of vitamins E and D3 significantly decreased the total traveled distance to the platform compared to the lesion group. However, the indexes of escape latency and swimming speed did not decrease significantly. The co-administration of vitamins E and D3 slightly enhanced spatial learning and memory impairment probably through its neuro-protective effect in the hypocampus.