Expression and correlation of matrix metalloproteinase-7 and interleukin-15 in human osteoarthritis

Objectives: To investigate the expression and correlation of matrix metalloproteinase (MMP)-7 and interleukin (IL)-15 in human osteoarthritis (OA). Methods: From October 2013 to December 2014, 30 patients with OA were enrolled. In addition, anther 30 patients with simple meniscus injury were collected as a control group. There were no significant differences in age and gender between the two groups. Articular cartilage tissue was obtained from both OA patients and control group patients. Protein, mRNA, and serum expression levels of MMP-7 and IL-15 in the both two groups were determined by immunohistochemical (IHC), in situ hybridization, and enzyme- linked immunosorbent assay (ELISA) assay, respectively. Additionally, correlation between MMP-7 and IL-15 expression level in cartilage tissue and serum was assessed using Pearson correlation analysis. Results: Protein, mRNA, and serum expression levels of MMP-7 and IL-15 in patients with OA were all significantly increased in OA patients compared with the control group. Besides, there were strong positive relationships between articular MMP-7 level and serum MMP-7 level (R-2 = 0.573, P = 0.018), between articular IL-15 level and serum IL-15 level (R-2 = 0.861, P = 0.023), and between serum IL-15 level and serum MMP-7 level (R-2 = 0.602, P = 0.012). Conclusion: These results suggest that MMP-7 and IL-15 might play important roles in the pathogenesis of OA, and IL-15 and MMP-7 has positive correlation in OA.