Abstract:Subheading: Role of Matrix Metalloproteinase in the Patients with Stable Phase COPD. Objective: The research aims to quantitatively evaluate the serum MMP-9, inhibitors of TIMP-1, TNF-α, and OPG/RANK/RANKL in the patients with COPD accompanied by osteoporosis. Method: We selected 90 male patients with stable phase COPD who received treatment in our hospital from September 2012 to May 2014. They were divided into three groups by bone mineral density (BMD), COPD normal bone mass group, low bone mass group, and osteoporosis group of 30 patients each. MMP-9, TIMP-1, TNF-α, and OPG/RANK/RANKL were detected with the ELISA method. The ELISA method was used to detect the levels of serum bone alkaline phosphatase (sBAP), serum osteocalcin (sOC), serum type I collagen cross-linked C telopeptide (sCTX). Result: There were significant differences in BMI and CAT scores between the osteoporosis group, the normal bone mass group, and the low bone mass group (P<0.01). The bone density of lumbar vertebra in the low bone mass group and the osteoporosis group decreased when compared with that in the normal bone mass group. The differences were statistically significant (P<0.05, P<0.01). The density of femoral neck in the low bone mass group and the osteoporosis group was significantly lower than that in the normal bone mass group. And there were significant differences (P<0.01). There were significant differences in level of serum MMP-9 among the three groups (P<0.01). Conclusion: MMP-9, TNF-α, and OPG/RANK/RANKL may play a collaborative role in occurrence and progression of pulmonary parenchyma damage and osteoporosis.