Biological evaluation of chitosan nanofiber membrane for guided bone regeneration.

BACKGROUND: Chitosan is known as a biodegradable and non-toxic natural polymer that enhances wound healing and bone formation. The aims of this study are to evaluate the biocompatibility of chitosan nanofiber membranes and to examine the effect of the chitosan nanofiber membranes on bone regeneration in rabbit calvarial defects.
METHODS: In vitro cell proliferation tests using human osteosarcoma cell line MG63 and reverse transcription-polymerase chain reaction (RT-PCR) to evaluate the expression of alkaline phosphatase (ALP), collagen, osteocalcin (OCN), and GAPDH were done on chitosan nanofiber membranes. Chitosan nanofiber membranes were implanted in subcutaneous connective tissue and observed for 2, 4, and 6 weeks in rats. Ten-millimeter diameter round cranial defects were made in rabbits and covered by chitosan nanofiber membranes for 4 weeks. Specimens were decalcified and observed by a light microscope.
RESULTS: MG63 cells proliferated for 28 days on the chitosan nanofiber membranes and expressed ALP, collagen, OCN, and GAPDH at 2 weeks. Chitosan nanofiber membranes that were grafted into rat subcutaneous tissue maintained their shape and space for bone regeneration for as long as 6 weeks. No inflammation could be seen on the membrane surface or in the surrounding tissues. In the rabbit calvarial defects, new bone filled the defects and fused to the original old bone in 4 weeks.
CONCLUSIONS: The biocompatibility of the chitosan nanofiber membrane was confirmed, with enhanced bone regeneration and no evidence of an inflammatory reaction. This experiment shows that the novel biodegradable chitosan nanofiber membrane may be useful as a tool for guided bone regeneration.