Neuroprotective Role of Vitamin D3 Against Insulin Resistance and Diabetic Induced Memory Dysfunction in Rats

Background and Objective: Diabetes is a risk factor for cognitive dysfunction. Diabetes associated with impairment of insulin signaling and oxidative stress pathway in the brain. This study aimed to evaluate the neuroprotective role of vitamin D3 against diabetic induced memory dysfunction in rats of Alzheimer's disease. Materials and Methods: Type 3 diabetes were induced by a high-fat diet plus streptozotocin in Wistar rats. Diabetic rats were divided into six subgroups, positive control (non-treated), vitamin D3 groups (100,500 and 1000 IU/kg/day), vitamin D3 plus rivastigmine and rivastigmine monotherapy. Treatment started after the onset of hyperglycemia for 4 months. Novel object recognition test was used to assess cognitive after treatment followed by estimation of insulin, beta-amyloid-42, malondialdehyde, glutathione and superoxide dismutase level in the hippocampus by ELIZA kits. Results: Vitamin D3 significantly alleviated cognitive deficits (p<0.001) in novel object recognition test and further resulted in marked elevation (p<0.001) in hippocampal insulin level, which in turn reduced the accumulation of beta-amyloid-42 (p<0.01) as well as attenuated of oxidative stress via significantly elevated of glutathione level and marked reduction of malondialdehyde and superoxide dismutase level compared to positive control. Conclusion: These findings suggested that vitamin D3 treatment could alleviate cognitive deficit associated with type 3 diabetes due to its anti-oxidative and anti-diabetic potential.