HIIT reversed the OA-induced inflammatory response
Compared with control rats, the contents of SP and IL-6 in the serum of OA rats were significantly increased. However, HIIT can reduce the contents of SP and IL-6 in the serum of OA rats (P  < 0.05, Figure 3A ). IHC analyzed the inflammatory factors of the cartilage extracellular matrix. Compared with control rats, the expression of MMP-13 and IL-6 displayed significantly increased in OA rats. However, HIIT decreased MMP-13 and IL-6 expression of OA rats (P  < 0.05, Figure 3 B-C).