Study on the changes of FABP4 and PPARγ levels in knee tissues of patients with osteoarthritis

Objective: To investigate the expression and significance of fatty acid-binding protein4（FABP4）and peroxisome proliferator-activated receptor γ（PPARγ）in the tissues around the knee joint of patients with osteoarthritis (OA). Method: A total of 32 obese patients with OA（BMI>25 Kg/m ² ）and 20 non-obese patients with OA were collected from Hospital affiliated to Shandong First Medical University who underwent surgical treatment. In addition, 25 patients with joint surgical injuries who underwent knee surgery at the same time were selected as the control group. The clinical data of the three groups (including age, height, blood routine indexes and biochemical routine indexes) were collected, and the statistics were collated. At the same time, specimens of periarticular tissues (including articular cartilage, synovium, suprapatellar fat pads, and infrapatellar fat pads) that had been discarded during the surgical procedure were collected from all three groups of patients. Western blot, qRT-PCR and immunofluorescence double staining were used to detect the expression and distribution of FABP4 and PPARγ in the tissues around the knee joint in obese patients with OA and non-obese patients with OA. Confirmation that informed consent was obtained from all subjects or their legal guardians. Result: In synovial tissue, the expression of FABP4 in OA obese patients was significantly higher than that in OA non-obese patients and control group ( P <0.01), and the expression of PPARγ in OA obese patients was significantly lower than that in non-obese OA patients and control group ( P <0.01). In the synovial tissues of OA patients, the green fluorescence intensity of FABP4 was significantly enhanced ( P <0.01), and the red fluorescence intensity of PPARγ was significantly decreased ( P <0.01). Conclusion: Aberrant expression of FABP4 and PPARγ may be a potential therapeutic target affecting the development of OA.