ObjectiveTo study the effect of intraarticular injection of crosslinked-chitosan in the treatment of knee osteoarthritis in rabbits.MethodsThirty-two New Zealand white rabbits were randomly divided into 4 groups (groups A, B, C, and D; 8 rabbits in each group). The knee osteoarthritis models were prepared by anterior cruciate ligament transection in the left hind in groups A, B, and C. At 4 weeks after operation, the rabbits were received intraarticular injection of 0.6 mL crosslinked-chitosan in group A, 0.3 mL chitosan (once per 2 weeks, for twice) in group B, and 0.3 mL saline (once per 2 weeks, for twice) in group C. The rabbits in group D were treated with sham operation in the left hind, and received intraarticular injection of 0.3 mL saline (once per 2 weeks, for twice). At 8 weeks, the macroscopic observation, histological examination (HE staining, Safranin-fast green double staining, and Mankin score), scanning electron microscopy (SEM) observation, and immunohistochemical staining of collagen type Ⅱ were performed.ResultsMacroscopic and SEM observations showed that the cartilage in group D was basically the same as normal and better than that in groups A and B, and the abrasion of cartilage in group C was the most serious. The histological observation results in groups A and B were slightly similar and better than those in group C, but not up to the structure of group D. The macroscopic score and Mankin score of groups B and C were significantly higher than those of group D (P<0.05), and there was no significant difference between group A and group B (P>0.05). Immunohistochemical staining results showed that the collagen type Ⅱ positive percentage of chondrocytes was significantly higher in group D than that in groups B and C, and no significant difference was found between group A and group B (P>0.05). ConclusionThe crosslinked-chitosan can significantly improve the osteoarthritis of the rabbit knee, delay the pathological changes of osteoarthritis, and decrease the frequency of injection.