Possible protective effect of vitamin D on age related cognitive impairment and synaptic dysplasticity in rats.

Background: Brain aging is a natural process that affects all populations, leading to declines in both cognitive and biological functions. Consequently, promoting healthy brain aging has become a major public health priority. Vitamin D (Vit.D), a crucial hormone involved in calcium regulation, plays diverse roles across various tissues, including the brain, and has been implicated in mitigating age-related cognitive decline. Aim: To investigate the possible neuroprotective effects of Vitamin D in alleviating cognitive dysfunction in aged rat models. Method: Forty male albino rats were divided into 5 groups consisting of 8 rats in each group; control, D-galactose induced brain aging group, Vit.D 100,1000,10000 IU/kg groups respectively. Upon aging induction with D-galactose, Vitamin D therapy was sustained for eight weeks, and cognitive function was measured through the Novel Object Recognition Test (NORT) and the Barnes test. At the study’s endpoint, biochemical markers were measured; amyloid β (Aβ), MDA and GSH in hippocampal tissue. Results: Rats that received Vit.D at doses 1000 &10000 IU/Kg showed significant decrease in Aβ level and oxidative stress state and also showed improvement in memory impairment that was confirmed by histopathological examination of hippocampal tissue and rats’ performance in memory tasks. The same doses of Vit.D also improved synaptic plasticity which was confirmed by immunohistochemistry staining of synaptic proteins; post synaptic density protein 95 (PSD-95) and synaptophysin. Conclusion: Vit. D administration in high doses has a neuroprotective effect on cognitive impairment in aged rats through an antioxidant mechanism and by modulating synaptic plasticity.