title: Osteogenic potential for replacing cells in rat cranial defects implanted with a DNA/protamine complex paste.
abstract: Osteoinductive scaffolds are required for bone tissue engineering. The aim of the present study was to assess the osteoinductive capacity of deoxyribonucleic acid (DNA)/protamine complexes in a rat model of critical-size calvarial defects. In addition, we investigated whether cultured mesenchymal-like cells (DP-cells) outgrown from DNA/protamine complex engrafted defects could differentiate to become osteogenic cells in vitro. DNA/protamine complexes were prepared by reactions between DNA and protamine sulfate solutions with stirring. Critical-sized (8mm) calvarial defects were created in the central parietal bones of adult rats. Defects were either left empty or treated with DNA/protamine complex scaffolds. Subsequently, micro-computed tomography (micro-CT), histological, and immunohistochemical analyses were performed. Micro-CT and histological assays showed that DNA/protamine complex engrafted defects had enhanced bone regeneration. DP-cells were expanded from explants of DNA/protamine complex engrafted defects using an explant outgrowth culture system. Osteogenesis-related factors were assessed in DP-cells after treatment with an osteoblast-inducing reagent (OIR). After 3months, nearly complete healing was observed for DNA/protamine complex engrafted calvarial defects. Increased alkaline phosphatase (ALP) activity and Alizarin red staining were found for cultured DP-cells. These cells had high expression levels of osteogenic genes, including those for RUNX-2, ALP, osteopontin, and osteocalcin. These results indicated that DNA/protamine complexes could facilitate bone regeneration in calvarial defects. Moreover, in vitro osteogenic induction experiments showed that DP-cells outgrown from DNA/protamine engrafted defects had an osteogenic potential. Based on these results, we suggest that DNA/protamine complexes may recruit osteocompetent cells in these defects, where they differentiate to osteogenic cells.
authors: Department of Oral Growth and Development, Division of Pediatric Dentistry, Fukuoka Dental College, Fukuoka, Japan.
authors: Masako
authors: M
authors: Toda
authors: Department of Morphological Biology, Division of Pathology, Fukuoka Dental College, Fukuoka, Japan. Electronic address: johno@college.fdcnet.ac.jp.
authors: Jun
authors: J
authors: Ohno
authors: Department of Oral Rehabilitation, Section of Fixed Prosthodontics, Fukuoka Dental College, Fukuoka, Japan.
authors: Yosuke
authors: Y
authors: Shinozaki
authors: Department of Oral Growth and Development, Division of Pediatric Dentistry, Fukuoka Dental College, Fukuoka, Japan.
authors: Masao
authors: M
authors: Ozaki
authors: Research Center for Regenerative Medicine, Fukuoka Dental College, Fukuoka, Japan.
authors: Tadao
authors: T
authors: Fukushima
mesh_terms: D000818:Animals; D001861:Bone Regeneration / Q000187:drug effects; D004247:DNA / Q000737:chemistry* / Q000627:therapeutic use; D008297:Male; D010012:Osteogenesis / Q000187:drug effects; D011479:Protamines / Q000737:chemistry* / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley; D012886:Skull
chemical_list: D011479:Protamines; D004247:DNA
keywords: Bone regeneration; Critical-size bone defect; DNA/protamine complex; Explant outgrowth culture; Scaffold