Acceleration of bone formation using insitu-formed hyaluronan-hydrogel containing bone morphogenetic protein-2 in a mouse critical size bone defect model.

Abstract

An enzymatic crosslinking strategy using hydrogen peroxide and horseradish peroxidase is receiving increasing attention for application with in situ-formed hydrogels (IFHGs). IFHGs may also be ideal carrier materials for bone repair, although their ability to carry bone morphogenetic protein-2 (BMP2) has yet to be examined. We examined the effectiveness of an IFHG made of hyaluronan (IFHG-HA) containing BMP2 for promoting bone formation in a mouse critical size bone defect model. C57/BL6J mice received a 2-mm femoral critical-sized bone defect before being randomly assigned to one of the following treatment groups (n =6): control (no treatment), IFHG-HA only, PBS with BMP2, and IFHG-HA with BMP2. X-ray radiographs were utilized to track new bone formation, and micro-computed tomography and histological examination were performed on new bone formed at the bone defect site two weeks after surgery. Mice treated with PBS with BMP2 and IFHG-HA with BMP2 had greater bone volume (BV) and bone mineral content (BMC) than those receiving control, and successfully achieved consolidation. Mice treated with IFHG-HA with BMP2 had significantly higher BV and BMC than those treated with PBS with BMP2. IFHG-HA may be an effective carrier for BMP2 to enable delivery for bone defect repair.