qPCR results in each group.

Effect of different frequencies treadmill exercise on the expression MMP-13 and TIMP-1 mRNA in knee joint cartilage from rats with MIA-induced OA. The gene expression of MMP-13 and TIMP-1 was determined by qPCR as described in Materials and Methods. The data were representative of three separate experiments and β-actin was used as an internal standard. Differences between CG and OAG were significant (*P<0.001) and differences between OAG and the different treadmill frequency groups were significant (+P<0.001). One-way ANOVA, n = 9 rats in each group, means with 95% confidence interval.