Effects of Vitamin E on the Osteoblast Differentiation

Vitamin E is thought to affect bone formation and bone remodeling. In this study, we investigated the effects of vitamin E (alpha-tocopherol and delta-tocopherol) on the osteoblasts isolated from rat calvariae. At 4 and 7 days (Day 4 and 7) alter induction of osteoblastic differentiation, treatment of alpha-tocopherol (100 and 200 mu M) and delta-tocopherol (2 and 20 mu M) for 3 days significantly decreased alkaline phophatase activity of the cultured osteoblasts. At Day 14, however, no significant change was detected in ALP activity and expression of bone sialoprotein mRNA in the osteoblasts treated with alpha-tocopherol or delta-tocopherol for 3 days. Expression of osteocalcin mRNA was decreased by treatment of alpha-tocopherol (100 and 200 mu M) and delta-tocopherol (2 and 20 mu M) at Day 4 and 7. At Day 14, expression of osteocalcin mRNA was decreased only with treatment of 200 mu M alpha-tocopherol. In addition, the noncalcified nodules were decreased by treatment of alpha-tocopherol (200 mu M) and delta-tocopherol (20 mu M) at Day 7. However, treatment of alpha-tocopherol and delta-tocopherol showed no significant change of formation of calcified nodules at Day 14. These results indicate that vitamin E inhibits differentiation of osteoblasts especially from early stage to osteoid-producing stage.