Bone formation process using Type I collagen gel as scaffold

Objectives:Type I collagen accounts for 90% of the total protein in organic matrix of bone. It not only provides the structural framework with viscoelastic properties but also defines compartments for ordered mineral deposition. It has been reported that the apatite crystals are firstly nucleated in the gap region, and the growing mineral platelets are highly organized in a staggered manner within the collagen fibrils. Therefore the use of type I collagen as scaffold may promote efficient bone regeneration. In this study, we made a histological analysis of process of bone formation using type I collagen gel as bone regeneration material.

Methods:A 3-mm-diameter defect was prepared in the calvarial bone of each rat. The defects were filled with 3% type I atelocollagen gel and were covered with atelocollagen membrane. Specimens were explanted at 1, 2 and 4 months after treatment and were subjected to histological evaluation. Additionally our samples were analyzed immunohistochemically by the immunostaining of osteopontin (OPN), osteocalcin (OC), dentin matrix protein 1(DMP1) and Runx2.

Results:Type I collagen gel had a place in the bone defect without absorption and inflammation. At 1 month after treatment, vascular cells were observed in the gel. After 2 month, increase of vascular cell and mineralization of type I collagen gel around the cell were found. Some of cells showed positive reaction for Runx2. Additionally new bone formed in the bone defect showed positive reaction for OPN, OC and DMP1, meaning normal bone formation.

Conclusion:Type I collagen gel supplied to bone defect was expended to new bone formation without absorption. Type I collagen gel as scaffold was considered to be efficient and safe for bone regeneration.