Effect of Vitamin D3 on Improvement of Learning and Spatial Memory Following Demyelination induction in hippocampal CA1 Area of rat

Consumption of vitamin D3 is effective to reduce intensity of autoimmune diseases such as multiple sclerosis. Neurons of the central nervous system are constantly exposed to reactive oxygen species and these factors play a key role in the destruction of myelin and damage of axons. The hippocampus is a vital center for learning and memory in central nervous system. This area is extremely vulnerable to neurodegenerative diseases and oxidative damage. In the present study the effects of vitamin D3 on learning, spatial memory and lipid peroxidation following demyelination of rat hippocampal CA1 neurons was investigated. For demyelination induction, 2μl lysolecithin was injected into the CA1 area of rat brain using stereotaxic surgery. After induction of demyelination, animals received 5 μg/kg vitamin D3 for 7 days. The learning and spatial memory of rats were investigated by radial maze. The extent of demyelination in hippocampus was studied using myelin specific Luxol fast blue staining. On day 7, lipid peroxidation was evaluated by Esterbauer and cheeseman methods. The results of this study showed that administration of vitamin D3 caused significant improvement of spatial learning and memory compared to the group receiving lysolecithin alone (p<0.001). Levels of lipid peroxidation in group treated with vitamin D3 showed significant reduction compared to the group receiving lysolecithin alone (p<0.01). Vitamin D3 acts as an antioxidant agent and caused improvement in learning and spatial memory through reduction of demyelination and lipids peroxidation products.