コラーゲンを担体とした遺伝子組み換えヒト骨形成因子による骨誘導に関する研究

Abstract

We studied osteoinduction by recombinant human bone morphogenetic protein-2 (rhBMP-2) with the use of porcine skin-derived atelopeptide type I collagen (CL) as a carrier. Ten μg of rhBMP-2 with 3 mg CL was implanted into the calf muscle of 10-week-old Wistar rats. In the control groups, 3 mg CL only was implanted. Ten days (BMP group I, CL group I; n=5) or four weeks (BMP group II, CL group II; n=5) after implantation, soft X-ray and light microscopic exminations were performed.Soft X-ray findings showed a radiopaque shadow in the implanted muscles in the BMP groups. In BMP group I, a radiopaque shadow was observed partially at the outermost edge of the implanted materials. In BMP group II, a radiopaque shadow was observed at all areas of the implant. In contrast, no such shadows were observed in the CL groups.Histological examination revealed new bone formation in the BMP groups. Woven bone appeared at the outermost edge of the implant material in BMP group I. Trabecular bone and osteoblast-like cells were observed around almost the entire circumference of the implant material in BMP group II. There was no evidence of bone or cartilage in the CL groups. From 10 days to 4 weeks after implantation, osteoinduction was continuously promoted by rhBMP-2 with CL, and the amount of CL decreased in the implant. These results suggest that rhBMP-2 may play an important role in reconstructive surgery for extensive bony defects and augmentation.