[Effect of intra-articular injection of platelet-rich plasma on interleukin-17 expression in synovial fluid and venous plasma of knee osteoarthritis patients].

Objective: To investigate the interleukin-17 (IL-17) levels changes in both synovial fluid and venous plasma of patients with primary knee osteoarthritis (OA) after intra-articular injection of platelet-rich plasma (PRP).

Methods: Between January 2015 and January 2016, 30 patients with primary knee OA were treated by intra-articular injection of PRP once a week for 3 weeks (trial group). Thirty healthy individuals were recruited into the study as control. There was no significant difference in gender, age, and body mass index between 2 groups ( >0.05). Visual analogue scale (VAS) score and Knee Society Score (KSS) were used to evaluate pain level and function of the knee for patients with OA. The IL-17 levels in both venous plasma and synovial fluid were measured before injection and at 1, 3, 6, and 12 months after injection in trial group and the IL-17 levels in venous plasma were measured in control group. The levels were determined using ELISA method.

Results: There was no knee joint swelling, fever, local infection, or other uncomfortable symptoms for all patients in process of PRP injection. All patients were followed up 13.5 months on average (range, 12-15 months). In trial group, the VAS scores at different time points after injection were significantly lower than that before injection ( <0.05). And the KSS scores at different time points after injection were significantly higher than that before injection ( <0.05). There was no significant difference in VAS and KSS scores between different time points after injection ( >0.05). The IL-17 levels in venous plasma before and after injection in trial group were significantly higher than that in control group ( <0.05). The IL-17 levels in venous plasma at each time point after injection were significantly lower than that before injection ( <0.05). There was no significant difference in IL-17 levels in both venous plasma and synovial fluid between different time points after injection ( >0.05).

Conclusion: Intra-articular injection of PRP can significantly release the pain symptoms, improve joint function, and reduce IL-17 levels in both synovial fluid and venous plasma of the patients with knee OA, but IL-17 levels can not reduce to normal level.