흰쥐에서 난소절제술 시행후 대퇴 골밀도와 말초혈액 및 골수 TNF-α 의 변화에 관한 연구

Abstract

Although the mechanism of the increase in bone resorption induced by estrogen deficiency is still controversial, recent studies have suggested that estrogen may modulate the secretion of bone resorption cytokines that are produced in the bone microenvironment and influence bone remodeling. Among them, TNF-α promotes bone resorption by stimulating the activity of mature osteoclasts and osteoclastogenesis, and the production of this cytokine is mediated by estrogen. We performed thsi study to evaluate the effect of oveariectomy on femur bone mineral density and levels of TNF-α in the culture media of bone marrow monocytes. The experimental animals were 15 female Sprague-Dawley rats that were 6 weeks of age and weighed an average of 172.8 gm at the beginning of the study. Bilateral ovariectomy were performed in all rats from a vental approach. Bone mineral density(BMD) of femur and levels of TNF-α of culture media of peripheral blood and bone marrow monocytes were measured before and 8 weeks after operation with using DPX-L and ELISA assay, respectively. Serum levels of LH. FSH, E2 were measured by RIA assay. BMD of femur was lower after ovariectomy(0.20±0.03 g/cm2) than before ovariectomy(0.25±0.06) g/cm2)(p<0.05). Serum levels of LH, FSH were higher after ovariectiomy(0.71±0.29mu/ml. 10.27±1.21 mu/ml) than before ovariectomy(0.17±0.04 mU/ml. 2.79±0.61 mlU/ml)(p<0.01) and serum level of E2 was lower after ovariectomy(6.37±4.75 Pg/ml) than before ovariectomy(7159.16±385.82 pg/ml)(p<0.01), respectively. Levels of TNF-α in culture media of bone marrow monocytes were higher after ovariectoy(59.26±5.65 pg/ml) than before ovariectomy(23.37±4.13 pg/ml)(p<0.01), but there were no statistically significant differences in culture media of the peripheral blood monocytes(before ovariectomuy: 22.96±3.62 pg/ml; after ovariectomy: 23.55±2.98pg/ml)(p>0.05). It is possible that increased production of TNF-α in estrogen deficieny induced by ovariectomy occures in the bone microenvironment and cytokine may play a critical causal role in inducing bone loss.