Bone formation in ectopic and osteogenic tissue induced by a novel BMP-2-related peptide combined with rat tail collagen

Bone morphogenetic proteins (BMPs) play an important role in regulating osteoblast differentiation and subsequent bone formation, mainly evidenced by the induced osteogenic ability of BMP-2 from BMPs. However, BMP-2 alone does not induce the expected efficacy due to its short retention in vivo. In this study, a novel BMP-2-related peptide (designated P24) derived from the “knuckle epitope” of BMP-2 was coupled covalently to type I collagen derived from rat tail and observed under scanning electron microscopy (SEM) in low vacuum mode. The BMP-2-related peptide/collagen composite was implanted in vivo into the pocket of the quadriceps musculature of Sprague-Dawley (SD) rats and then harvested 3 or 6 weeks after surgery. It was found that lyophilized collagen retained a porous network structure with an average inner-diameter of 90 ∼ 160 μm. Based on radiographic evaluation and histological examination, BMP-2-related peptide/collagen induced significant ectopic bone formation compared to that of rat tail collagen alone as a control. Our results indicate collagen served as a good carrier for newly synthesized BMP-2-related peptide and that the BMP-2-related peptide/collagen composite was an effective substitute in bone tissue engineering.