Abstract
A DNA/protamine complex powder, prepared from the reaction between DNA and protamine sulfate solutions, was mixed with water to make a paste. The ALP activity of MC 3T3 E1 cultured on a thin film of the complex paste was higher than that cultured on a plastic well. It was found that DNA/protamine complex induced new bone formation from the results of micro-computed tomography (μ-CT) images and conventional histological sections with hematoxylin and eosin staining in rat cranial defect tests. μ-CT image analyses showed that newly formed bone areas in defects for DNA/protamine complex were significantly higher than those for sham operation (controls) two and three months after surgery. Although the area of red-appearing osteoids reduced with increasing times after surgery, stimulated new bone formation areas were observed around newly formed bone in histological sections stained with Villanuva osteochrome bone stain. Therefore, DNA/protamine complex paste with a biodegradable property will be a useful injectable biomaterial for the repair of bone defects.
