It was previously proved an association of TGF-β1 and PDGF-BB with the pathogenesis of osteoarthritis (OA) by experiments of OA animal models. In this study, we aimed to determine whether serum concentrations of TGF-β1, PDGF-BB and CTX-1 were related to the knee OA. knee OA cases were collected from the first affiliated hospital of Shihezi university and healthy controls were recruited from the community. The severity of knee OA was defined as kellgren-lawrence (K-L) classification criteria.Serum levels of chemical biomarkers were compared between knee OA cases and controls or among K-L grade 2 to grade 4 groups. The serum concentrations of the TGF-β1, PDGF-BB and CTX-1 were determined by ELISA .

Inclusion Criteria:

• OA diagnosis was on the basis of the diagnosis and treatment guideline of the American Academy of Orthopedic Surgeons

Exclusion Criteria:

Participants who met the following criteria were excluded：

• the knee OA concomitant with hip OA,
• suppurative and rheumatoid arthritis,
• gout patients,
• patients who underwent knee arthroscopy surgery within 6 months,
• bilateral or unilateral knee replacements,
• the knee joint trauma patients,
• histories of glucocorticoid and/or sterol hormones.

210 patients diagnosed with knee OA in clinics were found in hospital patients .

Healthy controls were recruited from community questionnaires in Shihezi city, Xinjiang province, China.