Communication Between Traumatized Cartilage And Infrapatellar Fat Pad In Knee Joint

To understand the pathogenesis of post-traumatic osteoarthritis, it is important to consider the potential interactions among different tissues in the joint. The infrapatellar fat pad (IPFP) lies underneath the patella, and is located closely to the cartilage surfaces and thought to play a role in distributing the mechanical load. Recent studies have focused on the IPFP for its potential role in releasing paracrine inflammatory mediators that reach the cartilage.Pro-inflammatory cytokines, such as interleukin (IL)-1β, IL-6and tumor necrosis factor(TNF)-a are considered critical mediators in osteoarthritis pathophysiology.However, the involvement of IPFP in the degeneration of traumatized cartilage and the action of the pro-inflammatory cytokines is incompletely understood. In this study, we have assessed the influence of IPFP-conditioned media (FCM) on the degeneration of traumatized cartilage produced using a custom-designed impact device, and the involvement of pro-inflammatory cytokine crosstalk in this process.We found the most effective impact is36MPa and48hours after impact. We found IL-6would be the most important communication pro-inflammatory cytokines between the cross-talk between IPFP and traumatized cartilage.IL-6would promote the degeneration of traumatized cartilage but have little effects on healthy cartilage. Meanwhile, FCM might increase the expression of iNOS and decrease the gene expression of TIMP1/2/3.We also isolated Adipose-derived stem cell and adipocytes in IPFP to be cultured with medium from traumatized cartilage. We found the gene expression of IL-6changes in those cells.