Skeletal muscular transformation in osteogenetic process of bone defect repaired with compound vascularized muscle flap with bone morphogenetic protein

Abstract：BACKGROUND: Intractable repair of bone defect with bad local soft tissues is the essential question in clinic and is expected to deal with.OBJECTIVE: To probe into skeletal muscular changes during osteogenetic process in bone defect repair with vascularized muscle flap that was taken as the carrier of bone morphogenetic protein (BMP).DESIGN: Observation and comparison were designed in the experiment.SETTING: Experimental Animal Center of Nanfang Hospital affiliated to Southern Medical University.MATERIALS: rhBMP-2, 20 New Zealand healthy white rabbits of clean grade, weighted varied from 1.5 to 2.5 kg, of either gender.METHODS: The experiment was performed in Experimental Animal Center of Nanfang Hospital affiliated to Southern Medical University from January 2000 to August 2002. Ten rabbits were employed and bone defect was modeled 15 mm long on the lower section of radium. After nerve removed,the muscular flap of deep flexor muscle of fingers was implanted into the defect. In addition, the compound of fibrin and rhBMP-2 was grafted into the muscular flap. Four rabbits were sacrificed in 1, 2, 4, 6 and 8 weeks successively under anesthetization for gross observation, histological, TUNEL and ultrastructure examinations of muscular flap on bone defect.MAIN OUTCOME MEASURES: Gross observation, histological, TUNEL and ultrastrncture examinations of muscular flap on bone defect in rabbits tion of muscular flap on radial defect in rabbits: Skeletal muscle was atrophic gradually and muscle fiber almost disappeared in 8 weeks and reamination of muscular flap on radial defect in rabbits: It was displayed in histology that while skeletal muscle was atrophic, a part of cell karyon apmuscular flap of radial defect in rabbits: It was indicated with TUNEL staining that there were large amounts of colored positive karyons or karyon flap in radial defect of rabbits: Skeletal muscular filaments disappeared gradually by time lasting, karyon presented chromatin bordering, pyknosis and fragmentation, indicating typical apoptotic alternations.CONCLUSION: During osteogenetic process of bone defect repaired with compound BMP vascularized muscular flap, muscle fibers were atrophic gradually and apoptotic, terminally, substituted by bone tissues.