To assess the activity of cathepsin D (CAT-D) and alpha-1 antitrypsin (AAT) in blood in patients with hip or knee osteoarthritis, and to explore whether these two enzymes could be served as serum biomarkers for cartilage degeneration.
Th e activity of CAT-D and AAT in blood serum of 44 women and 26 men with hip or knee osteoarthritis was determined by the method of ELISA before total joint replacement and on the 10th day aft er the surgery. One hundred healthy volunteers were chosen as the control. All data were analyzed by using SPSS19.0 software.
Compared with the controls, the activity of CAT-D in patients with osteoarthritis was decreased by 25% (P<0.05) and 50% (P<0.05) before and after the surgery, respectively. The activity of AAT in the osteoarthritis patients before the surgery was not significantly changed compared with the control group (P>0.05), but it was increased by 80% after the surgery than that in the control group (P<0.05). There was no significant difference in the activities of 2 enzymes between hip and knee osteoarthritis (P>0.05). The gender, hypertension, diabetes and age did not affect the activities of the 2 enzymes (P>0.05).
AAT might be a possible inflammatory indicator in the osteoarthritis. CAT-D and AAT enzymes are not affected by gender, age, hypertension and diabetes, etc, and they might be served as potential biomarkers for cartilage degradation.