Abstract: Objective To evaluate the clinical significance of biomarkers of cartilage synthesis and degradation for early diagnosis and prognosis of knee osteoarthritis (OA). Methods Two hundred and twenty-seven knee OA outpatients and inpatients in Shenmu Hospital were collected as the knee OA group, while 178 healthy physical examiners as the control group during the same period. Serum pro-collagen ⅡA N-teminal peptide (PⅡANP),cartilage oligomeric matrix protein (COMP), matrix metalloproteinase (MMP-3), and urinary cross-linked C-telopeptide (CTX-Ⅱ)were measured by enzyme-linked immunosorbent assay. The degree of knee OA involvement and quality of life were assessed by antero-posterior and lateral radiographs of both knees and the SF-36 brief health questionnaire, respectively. Results 1)Compared with the control group, the serum PⅡANP level decreased and serum COMP, MMP-3 as well as urinary CTX-Ⅱ increased in the knee OA group (P＜0.05). 2)Serum PⅡANP was lower (P＜0.05), serum COMP, MMP-3(P＜0.05) and urinary CTX-Ⅱ levels were higher in mid-late stage knee OA group than early knee OA group and control group. 3)Serum PⅡANP levels were inversely correlated with K-L grade (P＜0.05), serum COMP and MMP-3 levels were positively correlated with K-L grade (P＜0.05), and serum COMP level was positively correlated with age (P＜0.05). Serum PⅡANP level was negatively correlated with mental health dimension in the SF-36 scale (P＜0.05); serum COMP level was negatively correlated with physical function dimension (P＜0.05) but positively correlated with mental health dimension (P＜0.05). Conclusions The expression of PⅡANP, COMP, MMP-3 and CTX-Ⅱ is abnormal in knee OA and related to the progress of the severity of the disease, so is a potential reference index for the diagnosis and prognosis of knee OA.

Key words: knee osteoarthritis, procollagen ⅡA N-teminal peptide, cartilage oligomeric matrix protein, matrix metalloproteinase, crosslinked C-telopeptide