Ectopic Revascularization Of Allograft Segment In Rabbits

1 Background With the mechanical, industrial, transportation development increasingly today, more and more various high-energy and complex injuries occur. The highest incidence is the lower leg of open comminuted fracture, easily lead to infection after operation,and formate chronic osteomyelitis at the end.[1]. Radical debridement of the removed bone segment is an important method of treatment of infection, but cause the bone defect especially long bone defect and control of local wound infection often need a long treatment process. Infectious of long bone defect after trauma is orthopedic problems, allograft bone for infectious long bone defect repair has not yet been reported, whether it can be used for infective treatment of long bone defect? We envision that putting allogeneic bone segments in the body parts of rich blood supply, make its vascularization again, after wound infection being thoroughly controlled, to repair the bone defect with vascular pedicle vascularized allograft bone transplantation.2 ObjectiveThe experimental object is Chinese white rabbit,putting the preparated allogeneic bone segments in the rabbit saphenous artery of abundant blood supply, explore its time for completing revascularization.3 Methods3.1 Select 10 Chinese white rabbit, execu air embolism by ear venous, take out the rabbit tibia strictly abiding the principle of aseptic. Put off the osurrounding muscles and periosteum, cut into 1.5 cm length of bone, shave the bone marrow tissue with a curet thoroughly, wash clean with sterile saline, soaked in 10% of gentamicin 30 minutes, with well sterilization double plasma bag packing after irradiated sterilization. Refrigerate 4°12h,--30° 12h after freezing, place-80° deep cryogenic refrigerator 3 weeks, to further remove antigen.3.2 The research object is healthy adult Chinese white rabbits. According to random number table the 60 white rabbit were randomly divided into two groups, the experimental group and control group. In experimental group,put the 1.5 cm length of allogeneic bone segments in rabbit thigh saphenous artery around the rectus muscle and shares the medial muscular clearance, with the 1.0 mm needle fixed on the femur. In the control group, put the same length with autogenous tibial paragraphs in rabbit thigh. In postoperative 4 weeks,8 weeks,12 weeks, respectively by gross observation and immunohistochemical method to detect bone of vascular endothelial growth factor (vascular endothelial growth factor, VEGF) and CD34 protein expression in endothelial cells and carry on the statistics processing.4 ResultsExperimental and the control group,part of surgical site the white rabbit thigh infect, not included in the statistical standards,supply the gaps in time. VEGF is mainly distributed around the new blood vessels, osteoblasts, chondrocytes and undifferentiated ectomesenchymal cells. Postoperatively 4,12 weeks, the expression of VEGF in the experimental group compared with controls, there was no statistically significant difference. Postoperatively 8 weeks, the expression of VEGF in the experimental group compared with controls, the difference was statistically significant, and two groups of VEGF expression quantity of 4 weeks less than 8 weeks (P> 0.05), 12 weeks more than 8 weeks(P>0.05). CD34 protein mainly distribute in the haversian canal centered vascular endothelial cells. Postoperatively 4 weeks, experimental group quantity of CD34 positive blood vessels compared with control group, the difference is statistically significant. Postoperatively 8,12 weeks, the experimental group quantity of CD34 positive blood vessels compared with control group, there is no statistically significant difference. Two groups of CD34 positive blood vessels of four weeks less than 8 weeks (P> 0.05),8 weeks more than 12 weeks, (P> 0.05). Postoperatively 4 weeks,in the experimental group and control group, the graft surface and medullary cavity on both ends have a small amount of fibrous tissue membrane, combined with bone segments loosely, easily separated. The surface of bone feel smoothly,look the luster. Postoperatively 8 weeks, two groups of allograft surface fibrous tissue membrane thicken, and stick with bone tightly, not easily separated. The surface of bone is uneven, like a cone, a part of the bone resorpted, look the luster. Postoperatively 12 weeks, fibrous tissue on the surface of membrane in two groups of allograft further thicken, and stick with bone further tightly, not easily separated, The surface of bone is uneven than 8 weeks, look further luster.5 ConclusionsLong allogeneic segment tibia of Rabbit in rich blood supply of ectopic for 2 months can achieve revascularization.There is no obvious difference with autologous bone segments.