Study Of Survival On VEGF To Promote The Imitation Limb Replantation Of Unanastomosis In Rabbit

Objective: To explore the effects of VEGF on micro-angiogenesis and venous blood return in the imitation model of rabbit limb replantation of unanastomosis, so as to provide a basis for clinical treatment research. Methods: 30 New Zealand adult white rabbits were selected without sexual restriction and were randomly divided into 2 groups: the VEGF experimental group and the saline control group, with 15 in each; then according to postoperative bleeding time, the experimental group and the saline control group were randomly assigned into 3 groups of 5 each, postoperative bleeding time was divided into 3 observing time-points: at the 6th, 9th and 12th day after operation. Models of the imitation anastomose only artery of the rabbit limb replantation, which were established by amputating all along the hind limbs of ankle plane and retaining only the posterior tibial artery and dorsalis pedis artery, at the same time, resuture amputated organize except veins, the left hind limb for the side of biopsy and the right hind limb for the side of observation of limb survival were marked respectively. Modeling after the experimental group was injected immediately with 0.5ml of containing 3μg VEGF of 0.9 % sodium chloride solution in amputated ring plane, while the control group was injected with 0.5ml of 0.9 % sodium chloride solution. The cross-section of left hindlimb tissue were detected at the time points of the 6th, 9th and 12th day after operation, which observed the changes of the microvascular morphology with HE deying, measured the micrangium of number and diameter with CD34 immunohistochemical staining, and estimated difference of micrangium number and diameter in each group; meanwhile, the right hindlimb bloodletting after operation were stopped successively, to continue feeding animals 5 days, to observe and photograph for the limb survival, to calculate the survival rate of the skin by the digital photography combined with the Medical Image J image analysis software. Results: (1) Observation of the gross specimens: the experimental group and control group of the replantation of limbs showed various degrees of necrosis at the 6th day after operation to stop bloodletting after operation, the experimental group was large than the control group of the range of surface serious,while the skin survival rate lower than the experimental group (P<0.01), the difference was significant; there was no limb necrosis at the 9th and 12th day after operation, the replantation of limbs swelling was more obviously than the experimental group, but also the would-healing time effect of retarding. (2) HE staining showed that the experimental group at the 6th day after operation in medium-sized and small blood vessels mainly, in the control group mainly to the small blood vessels; the 9th day after operation to the large blood vessels mainly in the experimental group, in the control group mainly to the medium-sized blood vessels; the 12th day after operation the beginning of the experimental group of vascular integration, the beginning of thickening of the wall, you can see scars, vascular control group has integrated trends, suggesting that wound healing in experimental group than the control group was significantly ahead of schedule. (3) Immunohistochmistry staining display: at various observing time-points, the experimental group were obviously higher than the control group of vascular density (P<0.05), microvessel diameter obviously larger than the control group (P<0.05), there was a significant difference, both of which had statistical significance; at the 9th day after operation, the microvessel of density was the highest (P<0.05) and the microvessel of diameter was the largest (P<0.05), there was a significant difference which had statistical significance. Conclusion: (1) VEGF can promote micro-angiogenesis, improve venous blood return in the imitation limb replantation of unanastomosis in rabbit, and promote the role of survival of replanted limbs. (2) The microvessel of density was the highest and the microvessel of diameter was the largest in angiogenesis and about the 9th day after operation.