Background: Diabetes mellitus (DM) is a chronic progressive metabolic illness and that is greatly associated with an increased risk of developing cognitive deficits. Numerous previous studies have indicated that vitamin D has neuroprotective effects.  However, the impact of vitamin D on type 2 diabetes mellitus (T2DM)-associated hippocampal damage in the brain and its protective mechanism remains unclear.
Objectives: We investigated the effect of vitamin D supplementation on diabetes-related apoptotic changes in the hippocampus of diabetic rats.
Materials and methods: Our study is an experimental randomized control trial conducted between November 2020 to March 2021in the Physiology Department, Faculty of Medicine, South valley university. We constructed a T2DM rat model on 24 Male albino Sprague Dowely rats; diabetes was induced by a high- fat diet and a single low dose of streptozotocin (STZ) (30mg/kg). Animals were divided into four groups; Normal control, Control receiving vitamin D (VD), Diabetic control, and Diabetic receiving vitamin D group.
Results: Compared with the control, results showed decreased spontaneous alternation T maze cognitive test, declined neural survival and increased immunohistochemistry expression of Synaptophysin in the hippocampus in diabetic rats. Vitamin D supplementation for six weeks can ameliorate diabetes-associated cognitive impairments by increasing neural cell survival and reducing neural apoptosis in the hippocampus.
Conclusion: The resulting data have the potential to provide vitamin D as a new type of adjuvant agent for anti-diabetic lines of treatment.