二甲双胍改善佐剂性关节炎大鼠骨破坏的作用和机制研究

目的探讨二甲双胍治疗类风湿性关节炎（rheumatoidrthritis arthritis，RA）骨破坏的作用及机制。方法采用Freund完全佐剂诱导佐剂性关节炎（adjuvant arthritis，AA）大鼠模型。全身评分评价不同剂量二甲双胍对AA大鼠炎症的作用；对各组大鼠踝关节和足部通过X射线成像进行检查；ELISA法对大鼠外周血中钙离子、磷离子、骨保护素（OPG）、核因子κB受体活化因子配体（RANKL）等指标进行测定；免疫组织化学法测定大鼠膝关节腺苷酸活化蛋白激酶（AMP-activated protein kinase，AMPK）、白细胞介素-6（IL-6）、肿瘤坏死因子α（TNF-α）蛋白表达。探讨二甲双胍对AA大鼠骨破坏的影响及机制。结果二甲双胍可以改善AA大鼠的全身炎症反应，减轻足爪部肿胀，尤其是高剂量效果更明显。二甲双胍各剂量组均可明显改善AA大鼠的局部骨密度降低和骨缺损；二甲双胍高剂量组血清钙、磷离子水平升高；不同剂量的二甲双胍均可以提高血清OPG，降低RANKL的水平；与模型组相比，二甲双胍可增加AMPK蛋白表达，降低IL-6、TNF-α蛋白表达，以上差异均有统计学意义（P<0.05~P<0.01）。结论二甲双胍可对RA骨破坏起到保护作用；作用机制可能与其抗炎、调节血清骨代谢指标及激活AMPK信号通路影响OPG-RANKL-RANK系统相关。

Study on the effects and mechanism of metformin on bone destruction induced by adjuvant arthritis in rats

ObjectiveTo investigate the effects and mechanism of metformin on bone destruction in rheumatoid arthritis(RA).MethodsThe adjuvant arthritis(AA) models with complete Freund's adjuvant(CFA) were established in rats.The systemic inflammation score was used to evaluate the effects of different doses of metformin on inflammation in AA rats; the ankle and foot of each group were examined using X-ray imaging; ELISA was used to measure the serum calcium, phosphorus, osteoprotectin(OPG), nuclear factor κB receptor activator ligand(RANKL) in peripheral blood of rats; the expression levels of AMP-activated protein kinase(AMPK), interleukin-6(IL-6) and tumor necrosis factor α(TNF-α) were measured by immunohistochemistry.The effects of metformin on bone destruction in rats was evaluated.ResultsMetformin could improve the systemic inflammatory response, and reduce paw swelling in AA rats, especially at high dose.All dose metformin groups could significantly improve the local bone mineral density and bone destruction in AA rats.The serum levels of calcium and phosphorus ion increased in high-dose metformin group.Different doses of metformin could increase the serum OPG level, and decrease the serum RANKL level.Compared with the model group, metformin could increase the protein expression of AMPK, decrease the protein expression of IL-6 and TNF-α, and the differences of which were statistically significant(P<0.05 to P<0.01).ConclusionsMetformin plays a protective role on the bone destruction of RA.The mechanism of action may be related to the effects of anti-inflammation, regulation of serum bone metabolism index and activation of AMPK signaling pathway to affect the OPG-RANKL-RANK system.