| With the rapid development of agriculture, industry and transportation, the rate of vascular injury is also increasing, about 3% of the total number of trauma. In addition, vascular puncture or intubation angiography iatrogenic factors also increase the chance of vascular injury, vascular injury may result in hemorrhage and necrosis limb ischemia, or loss of function. In the First and the Second World War, ligation is the main treatment to the vascular injury, the amputation rate was very high. DeBakey reported in the Second World War, among the 2471 cases of arterial injury in American forces, only 81 cases of arterial repair were done, about half of patients limb gangrene need amputation after artery ligation. Until the Korean War artery repair was widespread and successfully conducted. In 1988 Hughes reported that amputation rate declined from 49 per cent to 13 percent. In the Vietnam War, although the use of high-speed bullet caused a more serious soft tissue injury, after timely debridement and repair, American surgeons treated more than 7,500 cases of vascular injury, amputation rate remained at around 13%. Early diagnosis and prompt treatment can decrease mortality and amputation rate and reduce dysfunction of limb ischemia .In recent years, with the development of the related disciplines such as traumatic surgery for extremity vascular injury research, anatomy, pathology, pathophysiology, molecular biology and molecular immunology, vascular damage and repair research has been made great progress. After its clinical application of theory and technology, the harm of vascular injury greatly reduced.Vein graft is a common method to repair peripheral vascular defect. However, physical stimulation lead to vein graft injury. At the same time with hemodynamic changes, the vein graft will go through a process of arterialization. The walls of vein graft thicken excessively and vessel walls become rigid. Eventually vein graft is restenosis. How to inhibit intimal hyperplasia of vein graft is the key to prevent restenosis.Part 1 The experimental study of artery defect repaired by double-layer autologous vein graftHow to inhibit intimal hyperplasia of vein graft is one of the focus of recent research. Now some experiments are confirmed that vein grafts external support can inhibit intimal hyperplasia of vein graft and increases long-term patency rate. At present the application of vein graft external support can be divided into two categories, the absorbent one and the permanent one, all of them are synthetic materials. These materials will result in some complication such as chronic inflammation, local infection and tunica adventitia fibrosis ,if they are long-term in human body. We will take the autogenous vein as the external support of vein graft, and show if the intimal hyperplasia have been inhibited through animal experiments.Objective To report the experimental observation of artery defect repaired by double-layer autologous vein graft.Methods The left and right femoral arteries of 12 goats was randomly divided into 2 groups and recorded as a control group and an experimental group. The artery defect was repaired by double-layer autologous vein graft in the experimental group, and repaired by simple-layer vein graft in the control group. The diameter of each vein graft was measured 1 hour ,1 week,2 weeks and 4 weeks after operation. The vein grafts in two groups were harvested 1 week,2 weeks and 4 weeks after operation and the thickness of the neointima was calculated by using computerized image analysis system. Immunohisto -chemical staining for proliferative cell nuclear antigen(PCNA) and terminal deoxynucleotidyltransferase-mediated dUTPbiotinnick end labeling assay was performed for each harvested vein graft in two groups.Result The diameter for vein grafts have increased in the control group and the experimental group 1 week, 2 weeks and 4 weeks after operation. The diameter of vein grafts in the experimental group were smaller than that in the control group. The intimal thickness of vein grafts were respectively 72.68± 12.87um, 172.62±48.01um, 284.39±37.72um in the control group and 50.35±8.92um, 105.38±26.39um, 201.84±30.21um in the experimental group 1 week ,2 weeks and 4 weeks after operation. The PCNA index were respectively 26.93±2.08,45.78±4.32,29.60±2.59 1 week ,2 weeks and 4 weeks after operation in control group. TUNEL index were respectively 18.93±2.06,27.68±3.34,21.15±1.43 1 week ,2 weeks and 4 weeks after operation in control group. The PCNA index were respectively 19.75±1.71,33.26±3.30,21.54±3.52 1 week, 2 weeks and 4 weeks after operation in experimental group. TUNEL index were respectively 15.11±1.18,22.56±2.55,17.98±2.04 1 week, 2 weeks and 4 weeks after operation in experimental group. The PCNA index and TUNEL index in the experimental group were less than that in the control group.Conclusion Double vein graft can effectively inhibit intimal hyperplasia of vein graft.Part 2 The inhibition of atorvastatin on intimal hyperplasia of vein graftVein graft is a common method to repair peripheral vascular defcet. However, physical stimulation lead to vein graft injury. At the same time with hemodynamic changes, the vein graft will be going through a process of arterialization. The wall of vein graft become excessive thickening and vessel wall become rigid. Eventually vein graft is restenosis. How to inhibit intimal hyperplasia of vein graft is the key to prevent restenosis. Statins are the new hypolipidemic drugs. In addition to lowering blood lipids, there is still a wide range of pharmacological effects. Atorvastatin is the next generation of statin drugs. A study shows that statin drugs can effectively inhibit the intimal hyperpasia after arterioplasty. To clear whether atorvastatin can reduce the vein graft intimal hyperplasia after the vei graft transplantation, we have conducted animal experiments.Objective To research the inhibition of atorvastatin on intimal hyperpas -ia of vein graft of experimental goats.Methods Twenty goats were divided into 2 groups randomly and recorded as a controlled group and a atorvastatin group. Four cm vein grafts were harvested and then were transplanted to the femoral arteries. The goats in the controlled group was fed goat chow regularly and the others in the atorvastatin group was fed regularly goat chow supplemented with 60 mg/day atorvastatin. The vein grafts were harvested 2 weeks and 4 weeks after operation and the thickness of the neointima was calculated by using computerized image analysis system. Immunohistochemical staining for proliferative cell nuclear antigen and terminal deoxynucleotidyl transferase -mediated dUTPbiotinnick end labeling assay was performed in two groups.Result The intimal thickness of grafts was 205.74±20.17 um and 331.70±25.18 um in the controlled groups and 168.84±19.34 um and 194.51±17.02 um in the atorvastatin group on 2 weeks and 4 weeks after operation . The intimal thickness of grafts in a atorvastatin group were significantly thinner than that in a control group. The numbers of PCNA positive cells in the atorvastatin group were less than that in the controlled group. The numbers of TUNEL positive cells in the atorvastatin group were more than that in the controlled group.Conclusion Atorvastatin can inhibit intimal hyperpasia of vein graft.Part 3 Effect of vein transplantation with vein graft of different diameter on intimal hyperplasiaUp to now, Autogenous vein is still a perfect substitute for repair of small-caliber artery (<6 mm) defect. But because of histological changes of vein graft under the arterial environment, intimal hyperplasia of vein graft contributed to the lower long-term patency rate of vessel. It is not clearly reported whether the intimal hyperplasia is different in vein graft of different caliber or not. We chose vein graft of different diameter to repair artery defects, and observed the changes of histomorphology, to clarify whether vein graft of different diameter had different intimal thickeness or not.Objective To explore whether the intimal hyperplasia is different in vein graft of different calibre or not.Method Selecting 24 healthy goats with the same age and same weight and all animal were randomly divided into 3 groups labeled as group A, B and C. Choosing vein graft of different diameter, all vein grafts were reversed and anastomosed to repair a femoral artery defect of goats. The diameter of vein grafts were significantly smaller than that of local artery in group A, and significantly bigger than that of local artery in group C, and similar to that of local artery in group B. The hemodynamic indexes were detected on 1day, 2 weeks and 4 weeks after operation. The vein grafts were harvested 2 weeks and 4 weeks after operation and the thickness of neointima was calculated by using computerized image analysis system. Immunohistochemical staining for proliferative cell nuclear antigen was performed in three groups.Results The thickness of neointima was 255.67±23.93um in group A, 200.14±36.33 um in group B and 276.39±39.05 um in group C 2 weeks after operation . The thickness of neointima was 379.42±26.39 um in group A, 315.12±18.69 um in group B and 394.99±20.19 um in group C 4 weeks after operation. The thickness of neointima in group B was significantly thinner than that in group A and C. The wall shear stress was 32.52±0.93 dynes/cm2 1 day after operation, 30.97±1.20 dynes/cm2 2 weeks after operation and 28.36±1.01 dynes/cm2 4 weeks after operation in group A. It was 26.97±0.97 dynes/cm2 1 day after operation, 25.06±1.44 dynes/cm2 2 weeks after operation and 22.99±1.11dynes/cm2 4 weeks after operation in group B. It was 18.52±1.17 dynes/cm2 1 day after operation, 17.46±0.70 dynes/cm2 2 weeks after operation and 16.28±0.99 dynes/cm2 4 weeks after operation in group E.Conclusion The thickness of neointima is thinner if the diameter of vein graft is similar to that of local artery.Part 4 Experimental evaluation on combined general anesthesia to goatsAnimal experiments is an important and effective research method in the scientific research work. The choices of experimental animals and the establishment of experimental model are particularly important. The laboratory animals of vascular surgery commonly used in scientific research are rabbits, dogs, pigs and goats. The blood vessels of rabbit are small and vein walls are thin, greatly different from those of human beings. So the surgical operation is difficult, and patency rate is low. Some envisaged of experiments can not be achieved easily. Therefore dogs, pigs and goats and other large animals become suitable choice of vascular surgery experiment . Goats are docile and have slender limbs. The distribution of blood vessels is superficial, so it is easy to operate. Arteriovenous diameter and wall thickness is similar to human small vessels. So goats are the ideal experimental animals in vascular surgery of scientific research. In order to facilitate the process of the experimental operation, guarantee the quality of vascular anastomosis, alleviate the suffering of animals, the anesthesia is very important. The anesthesia of experimental animal request efficience, convenience and low mortality. Goats are ruminants. Inappropriate anesthesia may cause noticeable shortness of breath or breathing difficulties. Barbiturates are the anesthetics in common use. It will lead to more obvious respiratory inhibition, if a larger amount of them are administrated. Therefore choosing efficient, safe, and convenient method of anesthesia for the goats in the animal experiments is particularly important.Objective To find an appropriate anesthesia for the goat in experiment -tal vascular surgery.Methods Thirty goats were divided into 3 groups randomly and recorded as group A, group B, and group C. The goats in group A were anesthetized by intramuscular injection of 3% pentobarbital sodium. The animals in group B were anesthetized by intramuscular injection of ketamine. Diazepam, ketamine and pentobarbital sodium were used in group C. The onset time of anesthesia, the maintenance of anesthesia time , the anesthetic dosage and the anesthetic death rate were recorded.Result The onset time of anesthesia was 18.1±2.6 min first anesthesia in group A and anesthesia kept93±9.6 min. 1236.6±69.2 mg pentobarbital sodium were administrated to each goat if anesthesia would be kept 192.1±10.3 min , and death rate was 33.3% in group A. The onset time of anesthesia was 10.4±1.5 min first anesthesia in group B and anesthesia kept 29.5±3.9 min. 458.6±21.3mg ketamine were administrated to each goat if anesthesia would be kept 80.9±6.9 min in group B. The onset time of anesthesia was 5.6±1.4 min first anesthesia in group C and anesthesia kept 110±15.9 min. 736.2±55 mg pentobarbital sodium and 257.3±9.5mg ketamine were administrated to each goat if anesthesia would be kept 239±13.3 min , and death rate was 10% in group C. Combined anesthesia showed the longer anesthetic time, excellent anesthetic effect and lower anesthetic death rate.Conclusion It is an excellent anesthesia to the goat for experimental vascular surgery by using combined anesthesia of diazepam, pentobarbital sodium and ketamine .
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