A Study On Extracted Of The Banna Small-ear Pigs Bone Morphogenetic Protein And Its Bone-induced Activity

Objective To evalute the osteoinductivity of Banna small-ear inbred-line pigs bone morphogenetic protein. Methods Bone morphogenetic protein were extracted from Banna small-ear inbred-line pigs and common pigs fresh cortical bone according to the method reported by Urist , the relative molecular weight of the bone morphogenetic protein was measured by SDS-PAGE. 72 BALB/C mice, weighted about 20g, male, were divided into 4 groups randomly, then 2mg or 5mg of sepBMP and cpBMP was implanted separately into the thigh muscle of pouches of the different four groups. The animals were sacrificed at the end of 7 days, 14 days, 28 days postoperative respectively, the samples were collected to observe the inducing ectopic bone formation and the dose-effect relationship with administration of sepBMP and cpBMP by using X-ray , histological analysis, alkaline phosphatease(ALP) measurement . Results sepBMP contained polypeptide fragments with MW at ladder 14, 22, 27, 31, 48, 66kD as shown in SDS-PAGE. Radiologically showed no new bone formation in all groups . Histologically, after the 7th day implantation, a large quantity of mesenchymal cells differentiated with active chondrogenesis. The 14th day later, a large amount of cartilage and woven bone formed, and laminar bone and bone marrow were showed on day 28 after implantation. ALP assay analysis showed that at the 7th ,14th and 28th days of BMPs implantation, the ALP activities of 5mg BMP implanted groups were significantly higher than that of 2mg BMP implanted and control groups, while there were no significant differences among the same dose cpBMP implanted groups. Conclusion BMP extracted from Banna small-ear pigs possesses a obviously osteoinductive activity, and the osteoinductive has a dose-dependent relationship, satisfactory osteogenesis required 5mg ofsepBMP implantation. Compare the osteoinductive activity, no significant differences was found between sepBMP and cpBMB currently studies. This may be helpful for clinical application of Banna small-ear inbred-line pigs xenograft.