Effects of DNA/protamine and DNA/gelatin Paste on Bone Formation at Tooth Extraction Wound Sites

抄録

DNA/protamine complex has been reported to enhance bone formation in animal experiments. Another notable property of the complex is that it becomes a paste after being knead with water. Conventionally, DNA/protamine paste is prepared by kneading the DNA/protamine complex with water; however, conventional DNA paste has problems with regards to the preparation method, handling, moldability, etc. In the present study, we developed a new method for preparing DNA pastes, called the on-the-spot preparation method. DNA/protamine paste was prepared by mixing DNA into viscous liquid protamine or mixing gelatin into viscous liquid DNA. The viscosity of the DNA/protamine and DNA/gelatin paste was better than that of the conventional DNA/protamine-complex paste. The DNA/protamine and DNA/gelatin pastes were injected into the extracted sockets of rat maxillary molars. Microfocus X-ray computed tomography (micro-CT) and histological observation of nondecalcified sections after 2 weeks of injection revealed that the DNA/protamine and DNA/gelatin paste enhanced the formation of new bone in the extracted sockets. Quantitative analysis for calcification degree and newly formed bone mass showed there was a significant difference between DNA/protamine paste- and DNA/gelatin paste-injected specimens. The bone formation ability of DNA/gelatin paste is better than that of the DNA/protamine paste in the extracted sockets of rat maxillary molars. It is suggested that DNA paste prepared by on-the-spot preparation method will be useful candidate materials for bone regeneration.