小分子药物BNTA通过上调Insig1缓解高胆固醇引起的骨关节炎

骨关节炎(osteoarthritis,OA)是运动系统常见的退行性疾病,具有高发病率和高致残率。骨关节炎的发病机制目前尚不明确,既往研究认为骨关节炎发病主要与创伤因素相关,而近期研究表明,以胆固醇代谢异常为主的代谢性因素同样与骨关节炎密切相关,骨关节炎的治疗以早期对症治疗和晚期手术治疗为主,尚无针对病因的特效药物。既往研究中发现,有一种具有软骨保护作用的小分子药物BNTA,其在创伤引起的骨关节炎中具有较好的疗效,但其对高胆固醇引起的骨关节炎的作用尚不明确。本研究为探究BNTA对高胆固醇引起的骨关节炎的治疗作用及其机制,采用高胆固醇饮食构建了大鼠骨关节炎模型,取膝关节石蜡切片进行组织学评估,使用油红O染色评估大鼠软骨细胞内的脂质积聚情况,使用RT-qPCR、免疫荧光和免疫组化评估软骨细胞合成代谢、分解代谢及胆固醇代谢相关基因和蛋白质的表达。结果显示,BNTA可缓解高胆固醇大鼠骨关节炎模型中的病理表现,改善OARSI评分。在大鼠软骨细胞中,BNTA可促进合成代谢相关基因col2、sox9、acan的表达,抑制分解代谢相关基因mmp13、adamts5的表达,可改善高胆固醇引起的大鼠软骨细胞脂质积聚。在大鼠软骨细胞和高胆固醇大鼠骨关节炎模型中BNTA均可上调Insig1表达。本研究证实,高胆固醇可在体内和体外实验中加重骨关节炎,可引起大鼠软骨细胞脂质积聚增加。在体内和体外实验中BNTA均能缓解高胆固醇引起的骨关节炎表型,改善软骨细胞内的异常脂质积聚,其作用可能为通过上调Insig1抑制细胞内的胆固醇生物合成,从而缓解脂质异常积聚。

The Small Molecule Drug BNTA Alleviates Osteoarthritis Caused by High Cholesterol by Upregulating Insig1

Osteoarthritis (OA) is a common degenerative disease of the motor system with a high morbidity and disability rate. The pathogenesis of OA is not clear at present. Previous studies believe that the pathogenesis of OA is mainly related to trauma factors, while recent studies have shown that metabolic factors, including abnormal cholesterol metabolism, are also closely related to OA. The treatment of OA is mainly symptomatic treatment at the early stage and surgical treatment at the late stage, and there is no specific drug. Previously, BNTA, a small molecule drug with cartilage protective effects, has been shown to have a good effect on OA caused by trauma, but its effect on OA caused by high cholesterol remains unclear. In order to explore the therapeutic effect of BNTA on OA caused by high cholesterol and its mechanism, the OA model of rats was constructed by adopting high cholesterol diets, and paraffin sections of knee joints were taken for histological evaluation. Lipid accumulation in chondrocytes of rats was assessed by oil red O staining. The expression of genes and proteins related to anabolism, catabolism and cholesterol metabolism in chondrocytes was assessed by RT-qPCR, immunofluorescence and immunohistochemistry. The results showed that BNTA could alleviate OA pathological manifestations and improve the OARSI (Osteoarthritis Research Society International) score in the OA model of high cholesterol rats. In rat chondrocytes, BNTA can promote the expression of anabolism-related genes col2, sox9 and acan, inhibit the expression of catabolism-related genes mmp13 and adamts5, and improve the lipid accumulation caused by high cholesterol in rat chondrocytes. BNTA can up-regulate Insig1 expression in rat chondrocytes and the OA model of high cholesterol rats. This study confirmed that high cholesterol can aggravate OA in vivo and in vitro, and can increase lipid accumulation in rat chondrocytes. Taken together, BNTA can alleviate OA phenotypes induced by high cholesterol and improve abnormal lipid accumulation in chondrocytes, possibly by inhibiting cholesterol biosynthesis in cells by upregulating Insig1, thereby alleviating abnormal lipid accumulation.