Injectable natural polymer hybrid hydrogel targeting aseptic loosening due to wear particle induced osteolysis

Aseptic loosening represents a significant factor contributing to joint replacement failure, primarily associated with diminished bone formation and heightened osteoclast-induced osteolysis. Here, a natural polymer-based injectable hydrogel that encapsulates irisin protein (referred to as I-OG hydrogel) is reported. The hierarchical cross-linked structure of the I-OG hydrogel confers favorable mechanical properties, desirable self-healing ability, and acceptable injectability and, more importantly, sustains continuous release of the protein at the interface between the bone and implant prosthesis. The I-OG hydrogel effectively fills the gap between the titanium pin and bone tissue, successfully inhibiting aseptic loosening induced by titanium particles, which outcome confirms the occurrence of irisin protein's slow-release process and its inhibitory effect on osteolysis. Mechanistically, our in vitro experiments demonstrated that irisin released from the I-OG hydrogel upregulates the Wnt/β-catenin signaling pathway in bone marrow stromal cells (BMSCs) through integrin αV, while concurrently downregulating the NF-κB (P65) signaling pathway in osteoblasts. These molecular events ultimately promote osteogenic differentiation and inhibit osteoclast activation. Collectively, our findings establish that the I-OG hydrogel effectively counteracts aseptic loosening by resisting osteolysis caused by titanium particles and enhancing periprosthetic bone formation, and offers promising prospects for the treatment of aseptic loosening in prosthetic implants. Irisin is thought to be produced by muscles as an actin. This project was undertaken by synthesising a natural polymer based injectable hydrogel encapsulating Irisin, called I OG hydrogel, and injecting it into the tibiae of aseptic loose mice. After 5 weeks of treatment, we analysed differential mRNA expression in tibiae between each group. It was demonstrated that I OG hydrogel inhibited the development of aseptic loosening by modulating integrin pathway, Wnt pathway and inflammatory pathway.