淫羊藿苷调节酸性微环境减轻绝经后老年骨质疏松性疼痛

Icariin regulates acidic microenvironment to alleviate pain caused by postmenopausal osteoporosis in the elderly

背景:前期研究已证明,淫羊藿苷在促进骨形成和抑制骨吸收方面具有重要作用,但其对骨质疏松介导的骨痛产生的影响尚未见报道。目的:探讨淫羊藿苷减轻绝经后老年性骨质疏松性骨痛的可能机制。方法:①动物实验:将200只C57BL/6小鼠随机分为4组:假手术组、模型组、模型+淫羊藿苷组,模型+碳酸酐酶Ⅱ抑制剂组。除假手术组外,其余各组摘除小鼠卵巢建立绝经后骨质疏松模型。模型+淫羊藿苷组在造模后第2天灌胃淫羊藿苷,每2周进行1次疼痛行为学实验并取材,持续20周。microCT检测股骨骨量、苏木精-伊红染色及TRAP染色检测破骨细胞活性、免疫荧光染色检测神经元形态及相关离子通道表达。②细胞实验:提取小鼠骨髓来源的破骨细胞前体细胞,在体外使用RANKL/M-CSF体系诱导分化为破骨细胞并添加不同浓度淫羊藿苷(1,10μmol/L)干预。采用抗酒石酸酸性磷酸酶染色检测破骨细胞分化,采用鬼笔环肽染色检测破骨细胞肌动蛋白环,采用骨板吸收实验检测破骨细胞噬骨功能,采用pH计检测体系pH值,采用Western Blot检测破骨细胞分化相关蛋白表达。此外,提取小鼠背根神经节来源神经细胞并用淫羊藿苷处理,采用CCK8检测神经元活性,采用降钙素基因相关肽染色检测神经元形态。结果与结论:①与模型组相比,模型+淫羊藿苷组小鼠骨密度更高,骨组织中抗酒石酸酸性磷酸酶阳性破骨细胞较少,神经元活性降低,神经元瞬时受体电位香草酸亚型1通道及碳酸酐酶Ⅱ表达减少;模型+淫羊藿苷组小鼠相对于模型组对疼痛的敏感性降低。②淫羊藿苷在体外有抑制破骨细胞分化及噬骨能力,且在相对无毒的pH范围内增强背根神经节神经元的活性,抑制背根神经节中降钙素基因相关肽的表达,并可抑制背根神经节中瞬时受体电位香草酸亚型1离子通道的表达。③结果表明淫羊藿苷通过对破骨细胞的作用调节酸性微环境可减轻绝经后骨质疏松症介导的骨痛。

BACKGROUND:Previous studies have demonstrated that icariin has important roles in promoting bone formation and inhibiting bone resorption,but its effects on osteoporosis-mediated bone pain have not been reported.OBJECTIVE:To investigate the possible mechanism of icariin alleviating bone pain in postmenopausal senile osteoporosis.METHODS:(1)Animal experiment:200 C57BL/6 mice were randomly divided into 4 groups:sham group(n=50),model group(n=50),icariin treatment group(n=50),and carbonic anhydrase II inhibitor(Brinzolamide)treatment group(n=50).Ovariectomy was performed on C57BL/6 mice to establish a postmenopausal osteoporosis model in all groups except the sham group.The icariin group was given icariin on the second day after modeling,and pain behavior tests(Von Frey,Hot Plate,and Tail Flick tests)were performed every 2 weeks for 20 weeks.After sampling,bone mass was detected by microCT,osteoclast activity was detected by hematoxylin-eosin and tartrate-resistant acid phosphatase staining,and neuronal morphology and related ion channel expression were detected by tissue immunofluorescence staining.(2)Cell experiment:Osteoclast precursor cells derived from mouse bone marrow were extracted and induced to differentiate into osteoclasts using the RANKL/M-CSF system in vitro and supplemented with icariin of different concentrations(1 and 10μmol/L).Tartrate-resistant acid phosphatase staining was used to detect osteoclast differentiation,ghost pen cyclic peptide staining was used to detect osteoclast actin ring,bone plate absorption assay was used to detect osteoclast osteophagy function,pH value of the system was detected by pH meter,and expression of osteoclast differentiation-related proteins was detected by western blot.In addition,mouse dorsal root ganglion-derived nerve cells were extracted and treated with icariin.Cell counting kit-8 was used to detect neuronal activity and CGRP staining was used to detect neuronal morphology.RESULTS AND CONCLUSION:Compared with the model group,the icariin treatment group had higher bone mineral density,fewer tartrate-resistant acid phosphatase-positive osteoclasts in bone tissue,decreased neuronal activity,and decreased neuronal transient receptor potential vanilloid subtype 1 channel and carbonic anhydrase II expression.Behavioral results showed that the icariin treatment group was less sensitive to pain than the model group.Icariin inhibited osteoclast differentiation and bone phagocytosis in vitro.Icariin enhanced the activity of dorsal root ganglion neurons and inhibited the expression of calcitonin gene-related peptide and transient receptor potential vanilloid subtype 1 channels in dorsal root ganglia in a relatively non-toxic pH range.To conclude,icariin alleviates bone pain caused by postmenopausal osteoporosis by regulating the acidic microenvironment through its effect on osteoclasts.