Effects of Short-Term Administration of Hydrocortisone, Prednisolone and Dexamethasone on Bone Metabolism in Rats

摘要

Prolonged administration of glucocorticoid (GC) causes a serious osteoporosis. GCs with different anti-inflammatory potency, so hydrocortisone (20 mg/kg), prednisolone (5 mg/kg), and dexamethasone (0.8 mg/kg) were administered daily to rats for two weeks, and we compared and examined effects of each GC on bone metabolism in this study. As the results, significant decreases in serum osteocalcin levels (bone formation marker) and serum tartrate-resistant acid phosphatase-5b levels (bone resorption marker) and a significant decrease in the bone mineral density (BMD) of the femoral metaphysis were observed in the dexamethasone administered group. However, there is no significant change on the serum biochemical markers and BMD levels after administration of hydrocortisone or prednisolone. As the results of bone histomorphometric analysis, both osteoid volume per bone volume (OV/BV) and osteoblast number per bone surface (N.Ob/BS) which represents bone formation parameters, and eroded surface per bone surface (ES/BS) and osteoclast number per bone surface (N.Oc/BS) which represents bone resorption parameters were significantly decreased by administration of dexamethasone. These results suggest that GCs with a high anti-inflammatory potency, such as dexamethasone, have a great influence on the bone metabolism and cause a change in BMD even in a short-term administration.