Melatonin combined with compound betamethasone for articular cartilage lesions in rats with knee osteoarthritis / 中国组织工程研究

ABSTRACT

BACKGROUND: Due to lack of the distribution of vessels and nerve, self-repairing capability of articular cartilage tissue is poor after inflammatory erosion.OBJECTIVE: To evaluate the effects of melatonin combined with compound betamethasone on the articular cartilage of osteoarthritis (OA) in rats.METHODS: Thirty Sprague-Dawley rats received intra-articular injection of papain solution for establishing knee OA models.Meanwhile, 20 of them underwent constant intensive light condition for establishing pinealectomy models. Ten rats that under pinealectomy were administered melatonin combined with compound betamethasone. Another 10 normal control rats receiving no treatment served as controls. After 4 weeks of treatment, serum melatonin concentrations at 2 a.m. (highest melatonin concentration within circadian rhythms) and 2 p.m. (lowest melatonin concentration within circadian rhythms) were detected by ELISA. At the same time, all rats were sacrificed to collect femoral condyle cartilage for gross observation.After decalcification and toluidine blue staining, articular cartilage lesions were evaluated based on Mankin scores.RESULTS AND CONCLUSION: After OA model was created, cartilage surface was uneven, lost their luster, the chondrocytes were poorly arranged, severe loss of staining was observed, serum level of melatonin was decreased, and circadian change was unobvious. Constant intensive light condition further aggravated cartilage damage. After treatment by melatonin combined with compound betamethasone, softened cartilage disappeared, there were more regular chondrocytes arrangement, and dispersed chondrocytes and loss of staining were gradually decreased. In addition, there was significant difference in Mankin scores of toludine blue staining among groups (P ＜ 0.05). These findings indicate that melatonin combined with compound betamethasone can restrain the progression of cartilage damage.