Macrophage polarization in IL-10 treatment of particle-induced inflammation and osteolysis

Abstract

This study investigated the therapeutic influence and potential mechanism of IL-10 in ameliorating orthopedic debris particle-induced inflammation and osteolysis. A murine air pouch with bone implantation and polyethylene particles was also used to evaluate the therapeutic effects of IL-10. The data suggested that the particle challenges significantly promoted macrophage activation and osteoclastogenesis, with dramatically increased macrophage infiltration into the pouch membranes and elevated tartrate-resistant acid phosphatase positive cell deposition. Immunohistochemical stains revealed a significantly higher ratio of induced nitric oxide synthase expressing cells in the particle-challenged group; treatment with IL-10 resulted in marked switching to CD163(+) cells. Also, IL-10 effectively reduced tartrate-resistant acid phosphatase positive stained cells in the pouch membranes, and minimized the bone mineral density Loss compared with untreated samples. Real-time PCR and Western blot examination Indicated that IL-10 treatment significantly diminished the particle-induced IL-1 beta expression but promoted expression of CD163, transforming growth factor-beta 1, and CCR2. Furthermore, IL-10 significantly inhibited the ultra-high-molecular-weight polyethylene particle-elevated phospho-STAT1 and phospho NF-kappa B p65 productions, and promoted phospho-STAT3 expression. Overall, the data indicate the pivotal effects of IL-10 on macrophage polarization. The effects of IL-10 in ameliorating local inflammation and osteolysis may be associated with macrophage polarization through the up-regulation of the Janus activating kinase/STAT3 signaling pathway, and the down-regulation of NE-kappa B and Janus activating kinase/STAT1 expression.