vitamin d regulatory effect on restraint stress-induced changes in serum corticosterone and hippocampus bdnf levels in the male rats

Background: chronic stress exerts negative effects on cognitive functions through inducing changes in the hippocampus. brain-derived neurotrophic factor (bdnf) is an essential factor in cognitive functions, which is considerably reduced under chronic stress. 1,25(oh)2 vitamin d plays neuroprotective roles partially by regulating the expression of various neurotrophic factors. objectives: since few studies have studied the impact of vitamin d on bdnf levels, we conducted this brief experiment to understand the role of vitamin d in maintaining hippocampal bdnf protein levels by using restraining as a model of chronic stress in rats. methods: rats underwent restraint stress 3 h/day for 28 days, during which they received vitamin d (5, 10 μg/kg) or its vehicle (ip, twice weekly). after the stress period, serum corticosterone (cort) and hippocampus bdnf protein levels were measured. results: restraint stress increased serum cort (p < 0.001) and reduced bdnf protein levels (p < 0.001) as compared to the non-stress group. vitamin d markedly maintained bdnf levels close to normal (p < 0.001), but did not change cort levels significantly. conclusions: this study demonstrated that 3h/day of chronic restraint stress for 28 days boosted serum cort and declined hippocampal bdnf levels, similar to stronger restraint stress models. vitamin d maintained bdnf level close to normal in the hippocampus, but it did not affect cort level significantly.