The promoting effect of chitosan thermosensitive hydrogel complex with chitosan nanoparticles carrying BMP-2 plasmid DNA on alveolar bone regeneration in beagle dogs

Abstract

Objective To construct the chitosan/BMP-2 plasmid thermosensitive hydrogel complex CS/CSn（pDNA-BMP2）-GP，and evaluate the effect of this composite system on alveolar bone regeneration in beagle dogs. Methods Periodontitis models were established in the second and third premolars from 4 beagle dogs. All teeth were randomly divided into three groups： CS/CSn-GP group，CS/CSn（pDNA-BMP2）-GP group and blank control group. In the CS/CSn-GP group，CS/CSn-GP was injected. In the CS/CSn（pDNA-BMP2）-GP group，CS/CSn（pDNA-BMP2）-GP was injected. In the blank control group，no material was injected. All animals were sacrificed 8 weeks later. The alveolar bone regeneration in periodontitis was observed by Masson staining. The expression of alkaline phosphatase （ALP） in bone defects was observed by calcium and cobalt staining. Results Masson staining showed that different degrees of alveolar bone regeneration was noted in the CS/CSN-GP and CS/CSn（pDNA-BMP2）-GP groups，and significant regeneration was noted in the CS/CSn（pDNA-BMP2）-GP group. Calcium and cobalt staining revealed strongly-positive ALP in the CS/CSn（pDNA-BMP2）-GP group，weakly-positive ALP in the CS/ CSN-GP group，and negative result in the blank control group. The average optical density value in the ALP-positive staining area in the CS/CSn（pDNA-BMP2）-GP group was higher than that in the CS/CSn-GP group，followed by that in the blank control group（all P < 0.05）. Conclusions CS/CSn-GP composite repair system exerts positive effect on alveolar bone regeneration. Inclusion of pDNA-BMP2 can significantly promote the effect on alveolar bone regeneration.

Keywords

• periodontitis|chitosan nanoparticle|tissue engineering scaffold|bmp-2|thermosensitive hydrogel