Objective To study the expression of inducible nitric oxide synthase（iNOS） in cartilage of temporomandibular joint osteoarthriti（TMJOA）, and to evaluate the role of iNOS in the progression of TMJOA. Methods The goats were used and TMJOA was induced by injection of collagenase in upper joint space. The joints were obtained and were investigated by using immunohistochemistry at 2, 4, 12, 24 weeks after injection. Results Almost no expression of iNOS in normal cartilage of TMJ. In the diseased joints, strong or definite iNOS reactivity was expressed. Conclusion iNOS plays an important role in the progression of TMJOA.
