A unique biomaterial, DNA/atelocollagen membrane, was newly developed. The effect of DNA/atelocollagen combined with bovine derived-bone morphogenetic proteins (BMP) on osteogenesis was evaluated histologically in subcutaneous tissue and supra-alveolar and periodontal defects. DNA/atelocollagen was prepared as a composite of DNA from salmon milt and pepsin-digested type I collagen (atelocollagen) from bovine dermis. The composite fiber showed structural characteristics of DNA-coated atelocollagen on phase-contrast and fluorescence microscopy. The time-course of bone induction was investigated, using a rat ectopic bone formation assay. DNA/collagen (10×5×1mm) was subcutaneously implanted with 100μg of BMP induced osteoblast differentiation 1 week after operation. Histological examination of the BMP/DNA/collagen showed direct bone formation, and carrier DNA/collagen fibers were found in woven bone. Wounds through the supra-alveolar bone and periodontal ligament (10×5×5mm) were surgically created on the mesial root of the mandibular second and third premolars in 6 beagle dogs. The defects were immediately filled with either DNA/collagen (10×5×5mm) combined with 500μg of BMP or DNA/collagen alone, or were left unfilled (controls). Animals treated with BMP/DNA/collagen showed regeneration of alveolar bone, periodontal ligament, and cementum on the exposed dentin at 4 and 6 weeks, while the other groups showed virtually no regeneration. In addition, the newly formed bone and cementum were separated by a periodontal ligament-like tissue, and no ankylosis was seen. These results indicate that DNA/collagen is an effective absorbable material that can be used as a carrier matrix for BMP. DNA/collagen sponge combined with BMP may promote tissue regeneration without disturbing periodontal homeostasis in supra-alveolar and periodontal defects.
