TNF and osteoarthritis: Briefly, the surgically induced osteoarthritis (OA) model was established using ADAMTS-7 transgenic mice and ADAMTS-7 small interfering (si)RNA knockdown mice; the results demonstrated that TNF-α activates the expression of ADAMTS-7 through NF-κB mediator and ADAMTS-7 upregulates TNF-α and forms a positive loop between ADAMTS-7 and TNF-α in the pathogenesis of OA [24, 25].