OXIDATIVE STRESS-INDUCED COGNITIVE IMPAIRMENTS IN OBESITY CAN BE REVERSED BY VITAMIN D ADMINISTRATION IN RATS

Background and Aim: In the current study we aimed to investigate the effects of vitamin D on cognitive function, NF-κB, TNF-α concentration and markers of oxidative stress (SOD,GPX, CAT and MDA) in the hippocampus of high-fat diet-induced obese rats.Methods: forty male Wistar rats were divided into two groups: either control diet or high-fat diet for 16 weeks; then each group was randomized into two groups including: CD + Migliol, CD + vitamin D, HFD + Migliol and HFD + vitamin D. Vitamin D was administered at 500 IU kg-1 dosage for 5 weeks. Also, weight changes measured weekly. Five weeks after supplementation, Morris water maze test was performed to examine cognitive function. NF-κB and TNF-α concentration in the hippocampus were determined using ELISA kits. Moreover, oxidative stress markers in the hippocampus were measured by spectrophotometry methods. Serum vitamin D concentration was also measured.Results: HFD significantly increased TNF- (P = 0.04) and NF- B (P = 0.01) concentrations in the hippocampus compared with CD. Vitamin D treatment led to a significant reduction in hippocampus NF- B concentrations in HFD + vitamin D group (P = 0.001); however, vitamin D had no effect on TNF- concentrations. Moreover, HFD significantly induced oxidative stress by reducing GPx, SOD and increasing MDA concentrations in the hippocampus. Vitamin D led to a significant weight reduction (P=0.02) in HFD + D in comparison to HFD group. Also, vitamin D supplementation in HFD group significantly increased GPx, SOD and reduced MDA concentrations.Conclusion: Vitamin D improved hippocampus oxidative stress and inflammatory markers in obese rats and improved cognitive performance.

Keywords:

Obesity , Cognitive impairment , Oxidative stress in brain , Vitamin D