Vitamin D3 Improves Spatial Memory and Modulates Cytokine Levels in Aged Rats

Abstract Background: Vitamin D deficiency is associated with an increased risk of dementia. An association between vitamin D deficiency and subjective cognitive complaints in geriatric patients has been reported. Objective: This study aimed to evaluate the neurochemical and behavioral effects of vitamin D3 (1α-25 Dihydroxyvitamin D3) on 2-, 6-, 13-, 22-, and 31-month-old male Wistar rats. Research Methods & Procedures: The animals were supplemented with vitamin D at doses of 42 IU/kg and 420 IU/kg for 21 days. The radial maze test was performed to evaluate spatial memory. After the behavioral test, the frontal cortex and hippocampus were dissected for the enzyme immunoassay analyses to measure cytokine levels (TNFα, IL-1β, IL-6, and IL-10). Results: Our results showed that vitamin D supplementation was able to reverse the spatial memory impairment at the supplemented doses (42 and 420 IU/kg) in 6-, 13-, and 22-month-old animals and at a dose of 420 IU/kg in 31-month-old animals. Conclusion: Our results suggest vitamin D has a modulatory action on pro- and anti-inflammatory cytokines, since older animals showed increased cytokine levels than the 2-month-old animals. The lower dose (42 IU/kg) was able to regulate both pro- and anti-inflammatory cytokines in the hippocampus. Our results suggest that vitamin D may exert an immunomodulating effect on aging