The preventive effect of photocrosslinked Hep/GelMA hydrogel loaded with PRF on MRONJ.

Background: Medication-related osteonecrosis of the Jaw (MRONJ) is a rare but severe side effect in patients treated with medications such as Bisphosphonates (BPs). Its pathophysiological mechanism needs to be more precise. Establishing preventive measures and treatment standards is necessary. This study aimed to develop a composite hydrogel scaffold constituted by methacrylated gelatin (GelMA), methacrylated heparin (HepMA) and PRF, and investigate its potential application value in the prevention of MRONJ. Methods: GelMA, HepMA, and PRF were prepared using specific ratios for hydrogel scaffolds. Through mechanical properties and biocompatibility analysis, the release rate of growth factors and the ability to promote bone differentiation in vitro were evaluated. To explore the healing-enhancing effects of hydrogels in vivo, the composite hydrogel scaffold was implanted to the MRONJ rat model. Micro-computed tomography (Micro-CT) and histological examination were conducted to evaluate the bone morphology and tissue regeneration. Results: The Hep/GelMA-PRF hydrogel improved the degradation rate and swelling rate. It was also used to control the release rate of growth factors effectively. In vitro, the Hep/GelMA-PRF hydrogel was biocompatible and capable of reversing the inhibitory effect of zoledronic acid (ZOL) on the osteogenic differentiation of MC3T3-E1s. In vivo, the micro-CT analysis and histological evaluation demonstrated that the Hep/GelMA-PRF group exhibited the best tissue reconstruction. Moreover, compared to the ZOL group, the expression of osteogenesis proteins, including osteocalcin (OCN), type collagen I (Col I), and bone morphogenetic protein-2 (BMP-2) in the Hep/GelMA-PRF group were all significantly upregulated (P < 0.05). Conclusions: The Hep/GelMA-PRF hydrogel scaffold could effectively control the release rate of growth factors, induce osteogenic differentiation, reduce inflammation, and keep a stable microenvironment for tissue repair. It has potential application value in the prevention of MRONJ. [ABSTRACT FROM AUTHOR]