Objective: Synovitis associated with osteonecrosis of the femoral head (ONFH) is responsible for several clinical symptoms. However, the mechanisms underlying synovitis and the inflammatory environment remain unclear. This study analyzed the proinflammatory mediation expression of IL-17 and Th17, which perform key functions in regulating inflammatory processes in the inflamed synovium and peripheral blood in ONFH.
Methods: Synovial fluid from the hips of 23 patients and 5 controls was collected during surgery, and peripheral blood samples were obtained from 34 patients and 9 controls. The expression of IL-17 in the synovium was detected by immunohistochemistry, and the levels of Th17 and IL-17 in the blood were measured by flow cytometry and ELISA. Pain assessment was performed for all the patients and controls.
Results: An inflamed synovium was characterized by increased leukocyte infiltration and IL-17 expression in comparison with the control. Preoperative levels of Th17 and IL-17 were significantly higher in the peripheral blood of the ONFH group than those in the controls. The symptoms were also positively correlated with the Th17 levels of the ONFH patients.
Conclusion: Th17 cells were recruited to an inflamed synovium, and inflammatory cytokine IL-17 was expressed at an increased level in the hip synovium of ONFH patients, which possibly contributed to clinical syndrome development. Overall, this study will help in identifying new therapeutic strategies for ONFH, especially the targeting of IL-17 to decrease inflammation and pain. < p > < /p >.
Keywords: IL-17; T helper 17 lymphocyte; inflammation; osteonecrosis of femoral head; pain; visual analogue scale.