Enhanced healing of rat calvarial defects with sulfated chitosan-coated calcium-deficient hydroxyapatite/bone morphogenetic protein 2 scaffolds

Tissue Eng Part A. 2012 Jan;18(1-2):185-97. doi: 10.1089/ten.TEA.2011.0297. Epub 2011 Dec 2.

Abstract

Calcium phosphate cements (CPCs), which are widely used in bone regeneration, possess good biocompatibility and osteoconductivity and have been demonstrated to be candidate carriers for bone growth factors. However, limited release of growth factors from CPCs and slow degradation of the materials are not desirable for certain clinical applications. Previous studies have shown that calcium-deficient hydroxyapatite (CDHA) from CPCs presents more rapid degradation rate than CPCs. In this study, a hybrid growth factor delivery system was prepared by using bone morphogenetic protein 2 (BMP-2) loaded CDHA porous scaffold with sulfated chitosan (SCS) coating for improved release profile. We tested the BMP-2 release characteristic of CDHA/BMP-2/SCS composite in vitro and its ability to repair rat calvarial bone defects. A higher percentage of BMP-2 was released when sulfated chitosan coating was present compared with CDHA/BMP-2 group. Eight weeks postoperation, the repaired crania were evaluated by microcomputed tomography, sequential fluorescent labeling, histological analysis, and immunohistochemistry. CDHA/BMP-2/SCS group promoted the most extensive new bone formation than CDHA/BMP-2 and CDHA groups. Our observations suggest that sulfated chitosan coating could enhance the release profile of CDHA/BMP-2 composite in vitro and promote new bone formation in vivo. The hybrid CDHA/BMP-2/SCS system is a promising growth factor delivery strategy for bone regeneration.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biomechanical Phenomena / drug effects
  • Bone Morphogenetic Protein 2 / pharmacology*
  • Bone Regeneration / drug effects
  • Calcification, Physiologic / drug effects
  • Chitosan / pharmacology*
  • Coated Materials, Biocompatible / pharmacology*
  • Delayed-Action Preparations
  • Disease Models, Animal
  • Durapatite / pharmacology*
  • Fluorescent Dyes / metabolism
  • Kinetics
  • Male
  • Microscopy, Electron, Scanning
  • Osteogenesis / drug effects
  • Rats
  • Rats, Inbred F344
  • Skull / diagnostic imaging
  • Skull / drug effects*
  • Skull / pathology*
  • Tissue Scaffolds / chemistry
  • Wound Healing / drug effects*
  • X-Ray Microtomography

Substances

  • Bone Morphogenetic Protein 2
  • Coated Materials, Biocompatible
  • Delayed-Action Preparations
  • Fluorescent Dyes
  • chitosan sulfate
  • Chitosan
  • Durapatite