中文摘要：

目的：研究桂皮醛对激素诱导的体外破骨细胞增殖分化及骨吸收功能增强的保护作用及分子机制。方法RANKL联合M-CSF体外诱导RAW264．7细胞分化为破骨细胞,分为对照组、地塞米松处理组和不同浓度（11．6、23．2、46．4μg · L^-1）桂皮醛（ cinnamic alde byde, CA ）干预组；TRAP染色试剂盒鉴定成熟破骨细胞；MTT法观察地塞米松和桂皮醛在不同时间点对破骨细胞增殖的抑制作用；ELISA法检测细胞培养液上清中TRACP5b的表达水平；RT-PCR分析破骨细胞相关转录因子（RANK、NFATc1）mRNA的表达状态。结果地塞米松处理后,破骨细胞的增殖分化及骨吸收功能明显增强（ P〈0．05）；而经不同浓度桂皮醛干预后,与地塞米松组相比,细胞增殖活性、上清液中TRACP-5b的含量以及RANK、NFATc1mRNA的表达水平随药物浓度的增加呈剂量依赖性降低（ P〈0．05）。结论桂皮醛可有效抑制激素诱导的破骨细胞的增殖及骨吸收功能,其作用机制可能是通过下调RANK以及下游 NFATc1基因的表达。

英文摘要：

Aim To investigate the protective effect of cinnamic aldehyde （ CA ） on hormone-induced osteo-clasts proliferation and bone resorption in vitro and its molecular mechanisms. Methods RAW264. 7 cells induced into osteoclast were treated with RANKL and M-CSF and then were divided into control group, dexa-methasone （ DEX ） group and different doses of CA （11. 6, 23. 2, 46. 4 μg·L-1 ） groups. OCs were ob-served after tartrate resistant acid phosphatase（ TRAP） staining. The cell proliferation was determined by MTT assay at different time points. The expression levels of TRACP5 b in cell cultured supernatants were measured by ELISA. RT-PCR technique was applied to examine the transcriptional levels of RANK and NFATc1 . Re-sults In MTT assay, the proliferation of osteoclasts stimulated by dexamethasone was promoted seriously compared with negative control group （ P 〈 0. 05 ） . Meanwhile, DEX could strengthen the content of TRACP5 b and up-regulate the expressions of RANK and NFATc1 mRNA. After administration of CA, the proliferation was inhibited, while the enhanced expres-sion of TRAP5b was reversed,and the over-expressions of RANK and NFATc1 mRNA were obviously down-regulated in a time-and-dose-dependent manner （ P 〈0. 05 ） . Conclusion The results suggest that CA in-hibits proliferation and bone resorption of osteoclast in-duced by DEX, which may be mediated by down-regu-lation of RANK and NFATc1 mRNA.