桔梗总皂苷治疗大鼠佐剂性关节炎的作用及其对GRP78/XBP1/CHOP信号通路的影响

摘要

目的 探讨桔梗总皂苷(CKS)对佐剂性关节炎(AA)大鼠的作用及部分机制研究.方法 60只SD大鼠随机分为6组,每组10只,分别为正常组、模型组、CKS低、中、高剂量组(50、100、200 mg/kg)及阳性药来氟米特组(2 mg/kg).采用弗氏完全佐剂注射左后足趾皮内建立AA大鼠模型,观察各组大鼠足肿胀度、多发性关节炎指数并进行组织病理学检查;ELISA试剂盒检测血清中肿瘤坏死因子-α(TNF-α)和白介素 1β(IL-1β)的水平;Real-time PCR 和 Western blot 法检测各组大鼠滑膜组织中葡萄糖调节蛋白78(GRP78)、X盒结合蛋白1 (XBP1)、CCAAT增强子结合蛋白同源蛋白(CHOP)、TNF-α mRNA和蛋白表达的情况.结果 CKS(100,200 mg/kg)可显著抑制大鼠继发性足肿胀并减轻其膝关节的病理变化;可将大鼠血清中TNF-α和IL-1β的水平明显降低(P< 0. 05);同时可以下调GRP78、XBP1、CHOP、 TNF-α mRNA和蛋白的表达(P<0.05).结论 CKS对AA大鼠具有一定的治疗作用,其机制可能是与抑制内质网应激 GRP78/XBP1/CHOP信号通路,从而抑制滑膜细胞分泌和表达的TNF-a有关.%Objective To explore the effect of Platcodon grandiflorum total saponins (CKS) in adjuvant-induced arthritis (AA) rats and its possible mechanisms. Methods Sixty SD rats were randomly divided into six groups: normal group, model group, CKS(50 mg/kg), CKS(100 mg/kg), CKS(200 mg/kg) group and leflunomide (2 mg/kg) group. AA animal model was induced by complete Freund's adjuvant mothed, then the paw swelling, polyarthritis index and histopathological changes were observed. Tumor necrosis factor-a (TNF-α) and interleukin 1β(IL-1β) from blood serum were detected by ELISA. The mRNA and protein expressions of 78-KD glucose regulated protein (GRP78), X-box binding protein 1 (XBP1), CCAAT/enhancer binding protein homologous (CHOP) and TNF-a were evaluated by real-time PCR and Western blot assay. Results In vivo, our data showed that CKS(100, 200 mg/kg) could obviously suppress the secondary paw swelling, improve the morphologic changes of articular cartilages and synovium, and decrease TNF-a and IL-1β serum levels (P＜ 0. 05). The real-time PCR and Western blot results displayed that CKS could significantly inhibit GRP78, XBP1, CHOP and TNF-a expressions in AA group (P＜ 0. 05). Conclusion This study indicates that CKS could improve the adjuvant-induced arthritis in a dose-dependent manner. The inhibition of GRP78/XBP1/CHOP/TNF-a signaling pathways is involved in CKS-mediated modulation of inflammation.