The effect of vitamin E on neuronal apoptosis in hippocampal dentate gyrus in rabbits fed with high-cholesterol diets

BACKGROUND: Hypercholesterolemia that can increase stress oxidative has destructive effects on brain functions. Vitamin E is a powerful antioxidant and its effects on decrement of oxidative stress in the diseases such as Alzheimer's and hypercholesterolemia are demonstrated. The aim of this study was evaluation of the effects of vitamin E on the level of neuronal apoptosis in granular layer of dentate gyrus in the rabbits that fed with high-cholesterol diet. MATERIALS AND METHODS: Male New Zealand white rabbits were divided into the control, the Vitamin E (50 mg/kg; gavage), the high-cholesterol diet (containing 2% cholesterol), and the high-cholesterol diet-vitamin E groups. Serum levels of cholesterol, LDL, and HDL, before and after the regimen for 6 weeks, were measured. Then, the rabbits for immunohistochemical staining (TUNEL Test) and evaluation of neuronal apoptosis in dentate gyrus of hippocampal formation were anesthetized and brains were dissected. RESULTS: Results showed that after the regimens, serum levels of cholesterol, LDL, and HDL in the cholesterol receiving groups were increased significantly (P < 0.05). Histological results demonstrated that neuronal apoptosis in the dentate gyrus of the high-cholesterol diet group was increased significantly (P < 0.05) comparing to the control group; however, vitamin E decreased apoptosis as there wasn’t any significant differences between the high-cholesterol diet-vitamin E and control groups. CONCLUSIONS: Present results showed that consumption of high-cholesterol diets through hypercholesterolemia and its complication can induce neuronal death in hippocampus and probable resulting cognition disorders; however, vitamin E has neuroprotective effects and prevents neuronal apoptosis significantly.