Effect of platelet-rich plasma (PRP) binding CTRP9 mediated PUM1-TLR4 on chondrocyte proliferation, apoptosis and oxidative stress in osteoarthritis

Abstract Purpose : Platelet-rich plasma (PRP) is now widely used in the treatment of osteoarthritis. C1q/tumor necrosis factor-related protein-9 (CTRP9) is a newly discovered protein with remarkable anti-inflammatory, anti-oxidant and anti-apoptotic properties. We investigated whether PRP and CTRP9 could act synergistically to regulate the proliferation and apoptotic process of chondrocytes from osteoarthritis patients, as well as the response to oxidative stress by interfering with the PUM1-TLR4 signaling pathway. Methods : CTRP9 was transfected into HC-OA cells using lentiviral vectors and grouped by adding PRP; cell viability and proliferation were detected by CCK-8 and plate cloning assay; chondrocyte apoptosis was detected by flow cytometry; an OA mouse model was established by anterior cruciate ligament transection (ACLT); bone damage was visualized by toluidine blue staining; the expression of CTRP9, PUM1 and TLR4 in cells and tissues were detected by WB and qRT-PCR; WB detected the expression of apoptotic proteins (Bcl-2, Bax and Caspase-3) in arthritic cells and tissues; ELISA detected the expression of IL-1β, TNF-α and IL-6 as well as GSH, MDA and SOD in cells and tissues. Results: In cellular experiments, HC-OA group exhibited a reduction in cell viability, an increase in apoptosis rate, and elevated levels of inflammatory response and oxidative stress, while overexpression of CTRP9 and addition of PRP enhanced cell viability and diminished apoptosis rate., and alleviated inflammatory response and oxidative stress, and both of them acted simultaneously with better effect. In animal experiments, in comparison to the model group, overexpression of CTRP9 and addition of PRP resulted in increased expression of CTRP9 and PUM1, decreased TLR4, decreased Bax and Caspase-3, increased Bcl-2, and reduced inflammatory response and oxidative stress, and the effect of both simultaneous actions was more obvious. These results suggest that PRP synergized with CTRP9 can reduce the pathological response of osteoarthritis and is expected to be used as a therapeutic approach for osteoarthritis. Conclusion: Platelet-rich plasma (PRP) combined with CTRP9 stimulates the proliferation of arthritic chondrocytes and reduces apoptosis by up-regulating PUM1 and decreasing TLR4, thereby reducing the body's oxidative stress and inflammatory response.