Figure 6.

A diagram showing possible mechanisms underlying Nfat1 deficiency-induced OA. Arrows with solid lines indicate mechanistic observations from this study. Arrows with dotted lines indicate proposed mechanisms described in previous publications [3, 4, 6, 36, 37]. Nfat1 deficiency initiates OA-like changes due to dysfunction of adult articular chondrocytes, leading to articular cartilage degradation and repair activities in and around articular cartilage. Periarticular osteophytes and thickened subchondral bone may cause abnormal mechanical loads on the joints and exacerbate the progression of OA, which supports the concept that OA is not exclusively a disorder of articular cartilage [4, 6, 36–38].