黄芪补肾活血汤对芳香化酶抑制剂诱导骨质疏松模型小鼠破骨细胞活性的影响

Effects of Huangqi Bushen Huoxue Decoction on osteoclast activity in a mouse osteoporosis model induced by aromatase inhibitors

背景:芳香化酶抑制剂尽管显著提高了激素受体阳性乳腺癌患者的临床获益,但其相关的不良事件——骨质疏松严重影响了患者的生活质量,黄芪补肾活血汤能有效预防芳香化酶抑制剂所致骨质疏松的发生,但是其作用机制尚不清楚。目的:探究黄芪补肾活血汤对芳香化酶抑制剂所致骨质疏松模型小鼠破骨细胞活性的影响及机制。方法:选取60只8周龄C57BL/6J雌性小鼠随机分为假手术组、模型组、黄芪补肾活血汤高、中、低剂量组、阳性对照组各10只,除假手术组外,其余组小鼠均切除双侧卵巢联合皮下注射来曲唑构建绝经后芳香化酶抑制剂所致骨质疏松模型,黄芪补肾活血汤高、中、低剂量组分别给予19.24,9.62,4.81 g/(kg·d)黄芪补肾活血汤进行灌胃(1次/d),阳性对照组给予阿仑膦酸钠5 mg/kg灌胃(1次/周)。给药3个月后,Micro-CT检测胫骨骨密度和骨微结构,对股骨进行苏木精-伊红染色、抗酒石酸酸性磷酸酶染色及免疫组化检测核因子κB受体活化因子配体、骨保护素蛋白表达,ELISA检测血清中Ⅰ型胶原交联羧基端肽、抗酒石酸酸性磷酸酶5b水平。结果与结论:①与假手术组相比,模型组小鼠骨密度显著下降、骨小梁形态疏松断裂、血清中Ⅰ型胶原交联羧基端肽、抗酒石酸酸性磷酸酶5b水平显著上升,表明芳香化酶抑制剂所致骨质疏松模型构建成功;②与模型组相比,黄芪补肾活血汤高、中、低剂量组和阳性对照组小鼠骨密度、骨微结构显著改善,骨小梁形态增粗致密,血清中Ⅰ型胶原交联羧基端肽、抗酒石酸酸性磷酸酶5b水平显著下降,破骨细胞数量减少,核因子κB受体活化因子配体蛋白表达下降,骨保护素蛋白表达升高。结果表明,黄芪补肾活血汤可能调控核因子κB受体活化因子配体/核因子κB受体活化因子/骨保护素信号通路抑制破骨细胞活性,改善骨小梁形态和骨微结构,提高骨密度,进而预防芳香化酶抑制剂所致骨质疏松模型的发生发展。

BACKGROUND:Although aromatase inhibitors significantly improve the clinical benefit of patients with hormone receptor-positive breast cancer,its associated adverse event-osteoporosis seriously affects the quality of life of patients.Huangqi Bushen Huoxue Decoction can effectively prevent the occurrence of aromatase inhibitor-induced osteoporosis,but its mechanism of action is unclear.OBJECTIVE:To investigate the effects of Huangqi Bushen Huoxue Decoction on osteoclast activity in a mouse model of osteoporosis induced by aromatase inhibitors and relevant mechanisms.METHODS:Sixty 8-week-old female C57BL/6J mice were randomly divided into sham operation group,model group,high-,medium-and low-dose Huangqi Bushen Huoxue Decoction,and positive control group,with 10 mice in each group.Bilateral ovaries were removed to establish postmenopausal animal models in all the groups except for the sham operation group.After 1 week of recovery,letrozole was injected subcutaneously to establish postmenopausal osteoporosis models via subcutaneous injection of letrozole(an aromatase inhibitor).The high-,medium-and low-dose Huangqi Bushen Huoxue Decoction groups were intragastrically given 19.24,9.62 and 4.81 g/kg/d Huangqi Bushen Huoxue Decoction(once a day),respectively.The positive control group was given alendronate 5mg/kg once a week.After 3 months of administration,Micro-CT was used to detect tibial bone mineral density and bone microstructure.Hematoxylin-eosin staining and tartrate-resistant acid phosphatase staining of the femur were performed.Immunohistochemistry was used to detect the protein expression of receptor activator of nuclear factor-κB ligand and osteoprotectin in the femur.ELISA was used to detect the serum levels of carboxyterminal cross-linked telopeptides of type I collagen and tartrate-resistant acid phosphatase 5b.RESULTS AND CONCLUSION:(1)Compared with the sham operation group,the model group showed a significant decrease in bone mineral density,sparse and fractured trabecular morphology,and a significant increase in serum levels of carboxyterminal cross-linked telopeptides of type I collagen and tartrateresistant acid phosphatase 5b,indicating that the model of aromatase inhibitor-induced osteoporosis was successfully constructed.(2)Compared with the model group,the high-,medium-,and low-dose Huangqi Bushen Huoxue Decoction groups showed significant improvement in bone mineral density and bone microstructure,thickening and densification of trabecular morphology,significantly decreased serum levels of carboxyterminal cross-linked telopeptides of type I collagen and tartrate-resistant acid phosphatase 5b,a decrease in the number of osteoclasts and the expression of receptor activator of nuclear factor-κB ligand proteins,and an increase in the expression of osteoprotegerin.To conclude,Huangqi Bushen Huoxue Decoction may regulate the receptor activator of nuclear factor-κB ligand/receptor activator of nuclear factor-κB/osteoprotegerin signaling pathway,inhibit osteoclast activity,improve trabecular morphology and bone microstructure,and increase bone mineral density,thus preventing the occurrence and development of aromatase inhibitor-induced osteoporosis.