| Objective To observe structural characteristic of small-ear porcine cancellous bone deproteinized and its compounds with small-ear porcine bone morphogenetic protein (sepBMP) and discuss the bone induction activity and immunologic characteristic of combined bone of small-ear swine.Methods (Part one) After small-ear porcine cancellous granules deproteinized were combined with sepBMP and scanned by SEM, deproteinized cancellous bone, sepBMP and combined bone were separately implanted into thigh muscle pouches of BALB/c rats. Regular roentgenographical, histological observation and alkaline phosphatase (ALP) activity assay were performed at different time intervals after implantation. (Part two) Three kinds of cancellous particles with different antigenicity combined with sepBMP were implanted in the right thigh muscle pouches of BALB/c mice respectively. The examinations of interleukin 2(IL-2) level of the supernatant of splenic cell culturing, histological features and ALP activity of the specimens were taken at 2,7, 14 and 28 day postoperatively. .Results (Part one) Regular pores and smooth surface of deproteinized bone and phenomenon that the sepBMP was distributed sufficiently in the pores were found by SEM. Roentgenographs showed high density images at the region of implantation of combined bone group beginning from 14 day postoperatively. Histological observation showed good effect ofosteogenesis in the combined bone group which was higher than that in the other groups in terms of the ALP level.(Part two) The results revealed that there was a transient increase in IL-2 level in all groups at the second day after implantation which was then seen declining considerably. Fresh carrier (FC) group manifested the most powerful activity in IL-2 while partially deproteinized carrier (PDC) and deproteinized carrier (DC) groups showed the lowest level in that. Satisfactory osteogenetic ability and histocompatibility were detected in groups of DC and PDC at 7 ,14 and 28 day after implantation according to histological observation and ALP activity which appeared the highest in DC and PDC groups and the lowest in FC group (P<0.01) .At 28 day, osteogenetic image analysis showed the value of FC group was significantly lower than that of other two groups (P<0.01) and there was no significant difference between DC and PDC groups. A conspicuous negative correlation could be identified between the production of IL-2 and the activity of ALP and the amount of bone formation. Conclusion Findings indicate that small-ear porcine deproteinized cancellous possesses fine structure which is suitable to combine sepBMP sufficiently and improves bone induction. The relationship between degree of immunologic rejection which causes bone formation reducing and ability of osteogenesis is negative correlation. At the same time, PDC and DC groups occupy high osteogenetic ability without evoking immune rejection. |
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