Vitamin E does not Support Bone Quality in Orchidectomized Rats

Vitamin E is known to improve antioxidant status, but the effect of vitamin E on bone quality in orchidectomized rats is unknown. In the present study, thirty-two 1-y-old male rats were randomized to two groups: a sham-control group (n=8) and an orchidectomized group (n=24). The orchidectomized group was divided into three groups of eight and assigned to one of the following treatments: orchidectomy (ORX), low-dose vitamin E of 65.6 mg/Kg diet or high-dose vitamin E of 656 mg/Kg diet. Four months after the study began, all rats were killed, blood was collected, and plasma was harvested for antioxidant status, tartrate resistant acid phosphatase (TRAP), and IGF-I. Orchidectomy decreased (P<0.05) plasma antioxidant and IGF-I, reduced bone (P<0.05) quality and bone strength, increased (P<0.05) plasma TRAP and urinary excretion of calcium and magnesium compared to the sham-control group. In contrast to ORX, vitamin E increased (P<0.05) plasma antioxidant and had no beneficial effect on indices of bone quality, bone resorption and bone formation marker, or urinary calcium and magnesium excretion. In conclusion, vitamin E appears to decrease oxidative stress without improving bone quality in orchidectomized rats.