促甲状腺激素对破骨细胞分化的影响

Effects of thyroid stimulating hormone on osteoclast differentiation

目的探讨促甲状腺激素(TSH)对小鼠单核/巨噬细胞系RAW264.7细胞诱导分化为破骨样细胞过程的影响。方法体外培养小鼠单核/巨噬细胞系RAW264.7细胞,以破骨细胞分化因子(RANKL)诱导分化,同时加用不同浓度TSH处理7 d,抗酒石酸酸性磷酸酶(TRAP)染色鉴定并计数阳性细胞数量,采用Real-time PCR方法检测分化标志蛋白TRAP、基质金属蛋白酶-9(MMP-9)及组织蛋白酶K(Cathepsin K)的基因表达。结果RAW264.7细胞可在RANKL诱导下分化为破骨样细胞,高表达TRAP、M M P-9和Cathepsin K基因,TSH可剂量依赖性抑制细胞分化并下调上述基因的表达。结论 TSH可抑制破骨细胞的分化,对于维持骨量可能具有重要作用。

Objective To study the effects of thyroid stimulating hormone （TSH） on the differentiation of RAW264.7 cells into osteoclast like cells. Methods RAW264.7 cells were induced to differentiate into osteoclasts by addition of ligand of receptor activator of NF-KB （RANKL）, and treated with different doses of TSH for 7 days. Tartrate resistant acid phosphatase （TRAP） staining was used to identify and count osteoclasts. The mRNA expression of osteoclastic phenotypes and functioning genes including TRAP, matrix metalloproteinase-9 （MMP-9） and Cathepsin K in different groups were detected by Real-time PCR. Results RAW264.7 cells could be induced to differentiate into mature osteo- clasts and express high levels of TRAP, MMP-9 and Cathepsin K by RANKL. TSH dose-dependently inhibited the cell differentiation and down-regulated the expression of the genes above including TRAP, MMP-9 and Cathepsin K. Con- dusion TSH negatively regulates osteoclast differentiation, which may contribute to the maintenance of bone mass.