淫羊藿苷对Ⅱ型胶原诱导型关节炎大鼠骨破坏及血清RANKL/OPG的干预作用

Effect of Icariin on Bone Destruction and Serum RANKL/OPG Levels in Type Ⅱ Collagen-induced Arthritis Rats

目的观察淫羊藿苷对Ⅱ型胶原诱导型关节炎(collagen-induced arthritis,CIA)大鼠血清破骨细胞分化因子(receptor activator of NFκB-ligand,RANKL)和护骨素(osteoprotegerin,OPG)的影响及对骨破坏的保护作用。方法除正常组(8只)外,其余大鼠用牛Ⅱ型胶原和完全弗氏佐剂注射诱导建立CIA大鼠模型。选取关节炎指数(arthritis index,AI)≥6分的CIA大鼠24只,根据其AI评分分为模型组、甲氨喋呤组和淫羊藿苷组,每组8只。正常组和模型组给予生理盐水灌胃,甲氨喋呤组给予甲氨喋呤每周5mg/kg灌胃,淫羊藿苷组给予淫羊藿苷20mg/(kg·d)灌胃,均连续给药4周。每周记录大鼠AI评分。给药结束后,HE染色观察踝关节组织形态学变化;X射线检查足趾骨质破坏与骨质疏松情况;ELISA法测定血清RANKL、OPG水平。结果给药4周后,与模型组比较,淫羊藿苷组AI评分、Larsen评分、血清RANKL水平及RANKL/OPG比值明显降低,OPG水平明显升高,差异均有统计学意义(P<0.05,P<0.01);甲氨喋呤组上述指标均降低,差异无统计学意义(P>0.05)。HE染色示淫羊藿苷组关节滑膜增生、炎症细胞浸润与软骨面破坏程度明显减轻。结论淫羊藿苷能缓解或减轻CIA大鼠骨破坏程度,其作用机制可能与降低CIA大鼠血清RANKL水平,提高OPG浓度进而降低RANKL/OPG比例有关。

Objective To observe the effect of Icariin （ICA） on serum receptor activator of NFKB-ligand （RANKL）/osteoprotegerin （OPG） production and bone destruction in type 11 collagen-in- duced arthritis （CIA） rats. Methods The CIA rat model was established in all rats, except those in the normal group （n =8） using bovine type ]] collagen and complete Freund＇s adjuvant. Totally 24 CIA rats with arthritis index （AI） ≥ 6 were selected and divided into the model group, the methotrexate （MTX） group, and the ICA group according to the AI score, 8 in each group. Normal saline was given to rats in the normal group and the model group by gastrogavage. MTX at the weekly dose of 5 mg/kg was given to rats in the MTX group. ICA at the daily dose of 20 mg/kg was given to rats in the ICA group. All medication lasted for 4 weeks. The AI scores were recorded once a week. Histomorphologic changes of the ankle joint were observed by HE staining. The bone destruction and the osteoporosis of the foot phalanx were detected by X-ray. Serum levels of RANKL and OPG were determined by enzyme-linked immunosorbent assay （ELISA）. Results After 4-week intervention, when compared with the model group, AI score and Larsen score were significantly lower, the serum RANKL concentration and the RANKL/OPG ratio obvi- ously decreased, while the serum OPG concentration obviously increased in the CIA group （P 〈0.05 ,P 〈 0.01 ）. In the MTX group, the aforesaid indices decreased, but without statistical difference （P 〉0.05）. Results of HE staining indicated that hyperplasia of joint synovium, infiltration of inflammatory cells, and the degree of articular cartilage destruction were obviously alleviated in the ICA group. Conclusion ICA could alleviate or lessen the degree of articular cartilage destruction in CIA rats ,and its mechanism might be associated with reducing serum levels of RANKL and elevating levels of OPG, thus further decreasing the ratio of RANKL/OPG.