Studies Of Skeletal Repair By Calcium Sulfate With A Novel Peptide Derived From Bone Morphogenetic Protein-2

Part I Studies of the synthesis and osteoinductive activity ofa peptide derived from Bone Morphogenetic Protein-2Objective: To study the synthetic method and osteoinductive activity of the BMP-2related peptide.Methods: The BMP-2related peptide(P24) was made through FMOC/tBu solid-phasesynthetic method. Cultivate SD rat mesenchymal stem cells(MSC) in MSC completemedium, MSC osteogenic complete medium and MSC complete mediums with10μg/ml and30μg/ml P24. After2weeks and3weeks, detect the expression ofalkaline phosphatase(ALP).Results: The ALP contents of the mediums with30μg/ml P24were higher than that ofthe osteogenic complete mediums at2and3weeks.Conclusion: The P24derived from BMP-2, which was prepared by solid-phasepeptide synthetic method, has osteoinductive activity in vitro. The osteoinductiveactivity of the medium with30μg/ml P24is better than that of the osteogenic completemedium. Part II Experimental studies of skeletal repair by calcium sulfate withBMP-2related peptide P24Objective: To study the ability of skeletal repair of calcium sulfate(CS) with BMP-2related peptide P24. Methods:60New Zealand white rabbits were randomly divided into five groups, thecontrol group (group A), CS group (group B),50μgP24/2gCS group (group C),100μgP24/2gCS group (group D),200μgP24/2gCS group (group e). Femoral condylebone defects with the diameter of7mm and the depth of10mm were made in allrabbits. The materials were implanted into these defects respectively. The gross, X-ray,Micro-CT and histological observations were made to compare the ability of skeletalrepair between the five groups at4,8and12weeks after the operation.Results: The gross observation: At12weeks after the operation, bone defects of groupA were obvious, group B were repaired most and group C, D and E were repaired all.X-ray: The X-ray grades about skeletal repair of group C, D and E were better than thatof group B at12weeks after the operation, which showed significant difference(P<0.05). Micro-CT: At12weeks after the operation, Micro-CT observations showedthe best skeletal repair in group D and E, better in group C, worse in group B, and theworst in blank control group, group A. Comparison between groups had significantdifferences (P<0.05) in bone mineral density(BMD), bone volume fraction(BVF),trabecular number(Tb.N), and structure model index(SMI)．Histological observation:At12weeks after the operation, group A were filled with fibrous connective tissue,while group B, C, D and E were filled with primitive trabecula bone. The trabeculabone density were highest in group D and E, higher in group C, lower in group B, andthe lowest in group A.Conclusion: The BMP-2related peptide P24has osteoinductive activity in vivo. Therepair effect of P24/CS is better than CS. The material with the ratio of100μgP24/2gCS can effectively promote the bone defect repair.