Shiyan dongwu yu bijiao yixue (Oct 2022)
Effect of Dexamethasone on Cartilage Degeneration in Rats with Collagen-induced Arthritis
Abstract
ObjectiveTo establish a rat model of collagen-induced arthritis (CIA), a rat model of rheumatoid arthritis, and to study the protective effect of dexamethasone (DEX) on cartilage in CIA rats.MethodsThirty Wistar rats were randomly divided into three groups: normal, model, and DEX groups. The CIA model was established by intradermal injection of a white emulsion mixed with 0.1 mL bovine type II collagen and Freund's incomplete adjuvant in equal proportions into the distal part of the rat tail. The dates of the two injections were recorded as days 0 and 7, respectively. After the establishment of the CIA model, DEX (1 mg/kg) was intraperitoneally injected in the treatment group 3 times a week for 4 weeks. After the administration, the rats were euthanized, and the knee cartilages of 10 rats in each group were divided into three parts. The first part was fixed, decalcified, and stained with Alcian blue to observe the pathological changes in the cartilage layer. The second part was used for detection of mRNA expression of matrix metalloproteinase (MMP)-9 and MMP-13, and a disintegrin-like and metalloproteinase with thrombo-spondin motifs (ADAMTS)-4 and ADAMTS-5 by using real-time quantitative PCR analysis in the femoral head cartilage. The third part was used for detection of the expression levels of MMP-9, MMP-13, and ADAMTS-5 using immunohistochemistry in the cartilage layer of knee joint.ResultsCompared with the model group, the decrease of cartilage area, cartilage thickness, and cartilage cell numbers were significantly inhibited after DEX treatment (P<0.05). The cartilage surface was smooth and the invasion degree significantly improved, which indicated that cartilage destruction was inhibited. After DEX treatment, the mRNA levels of MMP-9, MMP-13, ADAMTS-4, and ADAMTS-5 in the cartilage of CIA rats were decreased (P<0.001), and the protein expression levels of MMP-9, MMP-13, and ADAMTS-5 were also significantly decreased (P<0.05).ConclusionDEX can inhibit the expression of various MMP in CIA rats and has a therapeutic effect on cartilage destruction.
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