Abstract: Objective　To establish a rheumatoid arthritis (RA) model in Wistar rats using an adjuvant combined collagen tail injection method, and to evaluate the model through pharmacological intervention. Methods　Thirty male Wistar rats aged 6-8 weeks with an average body weight of (170±10) g were included in this study. Six rats were assigned to the normal control group, and the remaining 24 rats were used to establish RA models via immunization with bovine type II collagen (CII) combined with Freund’s adjuvant. Primary and booster immunizations were performed by multi-site intradermal injection of collagen-adjuvant emulsion at the base of the tail. Twenty days after the primary immunization, paw volume, paw thickness, arthritis index and body weight were measured to verify model establishment. A total of 18 rats with successful modeling were selected and randomly divided into three groups: model group, methotrexate (MTX) group and etanercept group (n=6). All animals were treated once every three days for 9 consecutive weeks. MTX was administered via intraperitoneal injection, while etanercept was given by subcutaneous injection. Rats in the normal control and model groups received an equal volume of 0.9% sodium chloride solution. During the intervention, the arthritis index and joint swelling were assessed every three weeks, and serum levels of tumor necrosis factor-α (TNF-α) and anti-CII antibodies were detected. Upon completion of intervention, the pathological conditions of ankle and knee joints in the hind limbs of rats were observed through imaging and histopathological testing, as well as the expression changes of interleukin-6 (IL-6), interleukin-17A(IL-17A), and vascular endothelial growth factor (VEGF) in synovial tissue. The therapeutic effects of the two drugs were comprehensively evaluated.Results　Compared with the normal group, the model group showed significantly increased paw thickness, paw volume and arthritis index in RA rats, as well as elevated expression of IL-6, IL-17A and VEGF in synovial tissues of the hind-limb ankle and knee joints (P<0.05, P<0.01). Severe destruction of articular cartilage and massive fibrous tissue hyperplasia were observed in the joint cavity. After intervention with MTX or etanercept, paw thickness, paw volume and arthritis index of RA rats were significantly reduced. Serum anti-CII antibody titers, TNF-α levels, and the expression of IL-6, IL 17A and VEGF in synovial tissues of the hind-limb ankle and knee joints were all significantly decreased (P<0.05, P<0.01). The severity of articular cartilage destruction was alleviated, fibrous tissue hyperplasia was reduced, and symptoms including joint space narrowing, joint ankylosis, inflammatory cell infiltration, erosion and destruction were improved.Conclusion　The RA model in Wistar rats induced by the modified adjuvant-combined collagen method recapitulates the pathological features of human RA and is suitable for efficacy studies of therapeutic drugs for RA.

Key words: rheumatoid arthritis, bovine type II collagen, Wistar rats, model, evaluation

摘要： 目的　采用佐剂联合胶原尾注法建立Wistar大鼠类风湿关节炎(RA)模型,并通过药物干预对模型进行评 价。方法　选取30只6~8周龄、体质量(170±10)g的雄性Wistar大鼠造模,其中6只为正常对照组,另外24只采 用牛Ⅱ型胶原(CⅡ)联合弗氏佐剂法构建RA大鼠模型。通过尾根部多点皮内注射胶原-佐剂混合乳液进行初次 免疫与加强免疫,首次免疫20 d后,依据大鼠足容积、足厚度、关节炎指数及体质量判定造模效果,筛选18只造模 成功大鼠,随机分为模型组、甲氨蝶呤组(MTX)和依那西普组,每组6只。各组大鼠均每3日给药一次,持续干预9 周,其中MTX组予以腹腔注射MTX,依那西普组予以皮下注射依那西普,正常组与模型组给予等量0.9%氯化钠溶 液。实验期间每3周评估大鼠关节炎指数、关节肿胀程度,检测血清肿瘤坏死因子-α(TNF-α)和抗CⅡ抗体水平。 干预结束后,通过影像学及病理组织学检测观察大鼠后肢踝、膝关节病变状况,观察滑膜组织中白细胞介素-6 (IL-6)、白细胞介素-17A(IL-17A)及血管内皮生长因子(VEGF)的表达变化,综合评价两种药物的干预效果。 结果　与正常对照组相比,模型组RA大鼠足掌厚度、足容积和关节炎指数均显著升高,后肢踝关节和膝关节滑膜 组织中IL-6、IL-17A、VEGF的表达量增加,差异有统计学意义(P<0.05,P<0.01);关节腔内软骨组织破坏严重,大 量纤维组织增生。MTX或依那西普药物干预后,RA大鼠的足掌厚度、足容积和关节炎指数均显著降低;血清抗C Ⅱ抗体效价、TNF-α及后肢踝关节和膝关节滑膜组织中IL-6、IL-17A、VEGF的表达量均显著下降,差异有统计学意 义(P<0.05,P<0.01);关节腔内软骨组织破坏的严重程度减轻,纤维组织增生减少,关节腔狭窄和关节强直以及炎 性细胞浸润、侵蚀、破坏等症状均得到改善。结论　改良佐剂联合胶原诱导法致Wistar大鼠RA模型病症特点符合 人类RA特点,且适用于RA治疗药物的疗效研究。

关键词: 类风湿关节炎, 牛Ⅱ型胶原, Wistar大鼠, 模型, 评价