Abstract
Background: Varieties of animals were used to study osteoarthritis pathogenesis. The Diannan small-ear pig, which is native to Yunnan, China, is thought to have an articular anatomy similar to that of humans and is more likely to be a source of pathological tissues than other animals. The aim of this study was determine whether this animal can serve as a more effective osteoarthritis model.[A1] Methods: Twenty-seven adult pigs were randomly divided into three groups and underwent the Hulth procedure, papain articular injection [A2] , and conventional breeding. After 4, 8, and 12 weeks, cartilage tissues from knee joint were extracted for general and histological observation, immunofluorescence, and biochemical analysis. [A3] Synovium was taken out for stromal cell-derived factor-1 analysis. Results: Histopathological observation showed obvious cartilage loss in two experimental groups, this cartilage loss was more severe in the chemical groups. Synovial stromal cell-derived factor1 levels increased over time in all groups. mRNA and protein levels of matrix metalloproteinase-3 were much higher in the chemical groups than in the other groups, whereas levels of collagen type II[A4] and aggrecan were significantly lower in the chemical groups than in the other groups. Immunofluorescence assays of collagen type II[A5] revealed an apparent reduction in this marker in the chemical groups compared with the other groups. Conclusions: These results indicated that the Diannan small-ear pig can be used as an effective osteoarthritis model. In addition, it is much more convenient and much faster to induce osteoarthritis by intra-articular injection of papain, which is a method worthy of being promoted.