Abnormal expression of key genes and proteins in the canonical Wnt/ß-catenin pathway of articular cartilage in a rat model of exercise-induced osteoarthritis.

ABSTRACT

To investigate the molecular pathogenesis of the canonical Wnt/ß-catenin pathway in exercise-induced osteoarthritis (OA), 30 male healthy Sprague Dawley rats were divided into three groups (control, normal exercise­induced OA and injured exercise­induced OA groups) in order to establish the exercise­induced OA rat model. The mRNA and protein expression levels of Runx­2, BMP­2, Ctnnb1, Sox­9, collagen Ⅱ, Mmp­13, Wnt­3a and ß­catenin in chondrocytes were detected by reverse transcription­quantitative polymerase chain reaction, western blotting and immunohistochemical staining. The mRNA levels of Runx­2, BMP­2 and Ctnnb1 were upregulated in the normal exercise­induced OA and injured exercise­induced OA groups; while Runx­2 and BMP­2 were upregulated in the injured exercise­induced OA group when compared with the normal exercise­induced OA group. The protein levels of Mmp­13, Wnt­3a and ß­catenin were increased and collagen Ⅱ was reduced in the normal exercise­induced OA and injured exercise­induced OA groups. Ctnnb1, Wnt­3a and ß­catenin, which are key genes and proteins in the canonical Wnt/ß­catenin pathway, were abnormally expressed in chondrocytes of the exercise­induced OA rat model. Ctnnb1, ß­catenin and Wnt­3a were suggested to participate in the pathogenesis of exercise­induced OA by abnormally activating the Wnt/ß­catenin pathway during physical exercise due to excessive pressure. The results of the present study may provide an improved understanding of the pathogenesis of exercise-induced OA.