Osteoinduction Of A Bone Morphogenetic Protein-2 Related Peptide In Vitro And In Vivo

Objective: To investigate the activity of osteoinduction of a synthetic peptide developed according to the bone morphogenetic protein 2 (BMP-2) in vitro and in vivo.Methods: BMP-2 related peptide and hydrogel vector were prepared. The recombinant human bone morphogenetic protein-2 (rhBMP-2) and BMP-2 related peptide combined with hydrogels respectively were the experimental groups and the blank hydrogel was the blank control group. 60 SD rats were divided into 6 groups randomly with 10 in each group. The blank hydrogel were implanted in group A as blank control group. 5 mg,10 mg,20 mg,40 mg active peptide combined with hydrogel were implanted in group B,C,D,E respectively. Complex of 5μg rhBMP-2 and hydrogel were implanted in group F as control group. The quadriceps muscle pouch model was prepared of 1cm incision on the left thigh in each rat and implanted with experimental materials respectively. Radiological examinations (X-ray, CT) and HE staining were performed 6 weeks after modeling to compare the osteogenic effect in each group. Culture the rhBMP-2 and different concentrations of active peptides with the rat osteoblast precursor cells (MC3T3-E1), rhBMP-2 as the control group and normal culture medium as blank control. Detection the activity of alkaline phosphatase(ALP) in 3,5,7 days respectively to compare the differences between each group.Results:①G roup A, B, D showed no significant high density, group E had irregular high density; group C, F showed a significantly higher density of block shadow in X ray and CT scan.②Hydrogel vector in each group were fully degraded histologically. No osteoblasts,trabecula and new trabecular bone could be observed in group A, B and D; group E showed some of osteoblasts and cartilage lacuna; in group C and F the bulky massive new bone and new trabecula wrapping around by a large number of osteoblasts and peripheral neovascularization could be observed.③The activity of cellular ALP in the compound of rhBMP-2 peptides and different doses of BMP-2 related peptide were significantly higher than the blank control group, especially in rhBMP-2 group. ALP activity in peptide group increased with the dose gradually went up and showed time dependence that ALP activity gradually increased with increasing time and reached a peak in the 5th day and then decreased gradually.Conclusion: Bone morphogenetic protein peptides can induce ectopic bone formation in rats and can induce rat osteoblast precursor cells differentiating into bone cells significantly as bone morphogenetic protein -2 and has a good prospect in bone regeneration.