Objective: To observe the effect of electroacupuncture (EA) of "Zusanli"(ST36) and "Sanyinjiao"(SP6) on serum TNF-α, IL-1β, and IL-6 and expression of synovial matrimetalloproteinases (MMPs) and articular morphology in collagen-induced arthritis (CIA) rats, so as to explore its mechanisms underlying relief of arthritis.
Methods: Thirty male SD rats were randomly divided into normal control, CIA model and EA groups (n=10 rats per group). The arthritis model was induced by multi-point intradermal injection of bovine type Ⅱ collagen emulsion. EA (2 Hz/100 Hz, 1 mA) was applied to bilateral ST36 and SP6 for 30 min, once a day for 28 days. The hind-limb paw volume was measured and the arthritis index (AI) score given according to the swelling degree, rigidity and deformity of the ankle joint (0-4 points). After EA intervention, the morphological damage of the affected ankle joints was revealed by H.E. staining, safranin O-fast green staining, and tartrate-resistant acid phosphatase (TRAP) staining, separately. The levels of serum TNF-α, IL-1β, and IL-6 were measured by ELISA, and the expression levels of MMP-1, MMP-3, MMP-13, and receptor activator of nuclear factor Kappa B ligand (RANKL) in the synovial tissue were detected by Western blot.
Results: Compared with the normal control group, the paw volume, AI score, TRAP-revealed number of osteoclasts, contents of serum TNF-α, IL-1β and IL-6, and expression levels of MMP-1, MMP-3, MMP-13 and RANKL proteins were significantly increased in the model group (P<0.01, P<0.05). Following the intervention, the paw volume, AI score, number of osteoclasts, contents of serum TNF- α, IL-1β and IL-6, and expression levels of MMP-1, MMP-3, MMP-13 and RANKL proteins were significantly decreased in the EA group (P<0.05, P<0.01) in contrast to the model group. H.E. and safranin O-fast green staining showed rough articular cartilage surface with thinned cartilage layer, obvious hyperplasia of the synovial tissue with many inflammatory cells, and serious damage and degradation of the cartilage matrix in the model group, these situations were relatively milder in the EA group.
Conclusion: EA of ST36 and SP6 can reduce the articular damage in collagen-induced arthritis rats, which is associated with its function in reducing inflammatory response and down-regulating the expression of synovial MMP-1, MMP-3, MMP-13 and RANKL proteins.
目的：观察电针对胶原诱导型关节炎(CIA)大鼠关节炎性反应及骨质破坏的缓解效应，探讨针刺防治类风湿性关节炎的可能机制。方法： SD大鼠随机分为正常组、模型组和电针组，每组10只。采用大鼠尾根部多点皮内注射牛Ⅱ型胶原乳剂法诱导建立CIA模型。电针组取双侧“足三里”“三阴交”穴进行电针干预，疏密波，2 Hz/100 Hz，强度1 mA，30 min/次，1次/d，连续28 d。每周监测各组大鼠关节炎指数和足容积；干预结束后通过HE染色、番红O-固绿染色和酒石酸酸性磷酸酶染色观察大鼠踝关节病理学改变；酶联免疫吸附法检测大鼠血清中肿瘤坏死因子-α(TNF-α)、白介素-1β(IL-1β)和白介素-6(IL-6)含量；Western blot法检测大鼠滑膜组织中基质金属蛋白酶(MMP)-1、MMP-3、MMP-13和核因子κB受体激活因子配体(RANKL)蛋白的表达水平。结果：与正常组比较，模型组大鼠足容积增大、关节炎指数升高(P<0.01)；踝关节滑膜增生，伴有大量炎性细胞浸润，关节软骨与骨部分损毁，破骨细胞数量增加(P<0.01)；血清中TNF-α、IL-1β和IL-6含量升高(P<0.05)；膝关节滑膜组织中MMP-1、MMP-3、MMP-13及RANKL蛋白表达上调(P<0.01, P<0.05)。与模型组比较，电针组大鼠足容积减小、关节炎指数降低(P<0.05)；踝关节面较完整，滑膜组织增生不明显，炎性细胞浸润减少，软骨层较厚，破骨细胞数量减少(P<0.01)；血清中TNF-α、IL-1β和IL-6含量降低(P<0.05)；膝关节滑膜组织中MMP-1、MMP-3、MMP-13及RANKL蛋白表达下调(P<0.01, P<0.05)。结论：电针干预“足三里”“三阴交”穴对CIA大鼠关节炎性反应与骨质破坏具有较好的缓解效应，该作用可能是通过抑制滑膜细胞分泌炎性因子和骨破坏相关蛋白来实现的。.
Keywords: Bone and cartilage; Collagen-induced arthritis; Electroacupuncture; Inflammatory factor; Synovium.