Study Of Ischemia Injury And Correlative Mechanism In Miniature Swine Pancreas Transplantation

Objectiv 1.To establish a stable model of miniature swine pancreas transplantation; 2.To observe the effects of the function of pancreas graft with the different period of cold ischemia; 3.To investigate the relationship and correlative mechanism of the pancreas graft cell apoptosis and the cold ischemia injury.Mathod1. A total of 30 miniature swines were divided into donors and recipients randomly and animal model was established with pancreas transplantation. The total pancreas with a short segment of duodenum was transplanted to a recipient by anastomosis of vessels to the recipient abdominal aorta and vena cava and small bowel segment to the jejunum with enteric drainage. During recipient operation, mean arterial pressure(MAP) and central venous pressure(CVP) were monitored. Liquid supplement, anti-coagulation and anti-infection were conducted postoperatively. Meanwhile, the recipients were observed closely and the survival rate of recipients was calculated in postoperative period.2. A total of 40 miniature swines were divided into donors and recipients randomly and animal model was established. Recipients were divided into four groups: cold ischemia time 0h, cold ischemia time 3h, cold ischemia time 6h, cold ischemia time 9h. Type 1 diabetes mellitus model was established by resecting pancreas of the recipient. The pancreas graft tissue was taked at 30 minites after pancreas transplantation. The tissue was divided 3 parts which was used for electron microscope observation, detecting cell apoptosis(TUNEL) and the expression of HSP-70,TNF-αrespectively. In addition, the blood was taked consecutively for measuring the level of blood glucose, serum amylase and insulin in serum.Results 1. Of the 15 miniature swine recipients studied, there were 14 cases survived exceeding 1 day. The successful rate of operation was 93%. The average operation time of donor and recipient was 69.3 and 75.5 minutes. One recipient died at 2 hours after operation because of circulatory failure due to too much blood loss during operation, another died at 3 day after operation because of anastomotic stoma fistula due to infection. The level of blood glucose of the rest 13 recipients was normal at 2 day after operation.2. The blood glucose started to lower at 2 hour after reperfusion and stabilized at 24 hour after reperfusion. The level of the blood glucose and serum amylase at 2h and 8h after operation in the group of CIT 9h was higher than the rest three groups (P<0.05). The level of the blood glucose and serum amylase at 2h and 8h after operation in the group of CIT 3h,6h was higher than the group of CIT 0h(P<0.05). But it hasn't significant difference between the group of CIT 3h and 6h(P>0.05).3. At 0.5h after reperfusion apoptosis cells were found in the pancreas graft tissue in each group and the number of apoptosis cells was more along with prolonging of cold storage time. Apoptosis index has significant difference among each group(P<0.01). The expression of TNF-αwas the lowest in the group of CIT 0h, increased along with prolonging of cold ischemia time, and was the highest in the group of CIT 9h. The expression of TNF-αhas significant difference among each group(P<0.05 or P<0.01). The expression of HSP-70 was the highest in the group of CIT 0h, decreased along with prolonging of cold ischemia time, and was the lowest in the group of CIT 9h. The expression of HSP-70 has significant difference among each group(P<0.05 or P<0.01).Conclusions1. The animal model of pancreas transplantation is easy, stable and reliable by anastomosis of vessels to the recipient abdominal aorta and vena cava and small bowel segment to the jejunum with enteric drainage in miniature swine, so it can be a ideal model for studying ischemia reperfusion injury of pancreas graft.2. Cold ischemia injury is one of the important reasons of pancreas graft functional defect after transplantation.3. Apoptosis as a kind of cell death form participates the process of pancreas cold ischemia injury and the degree of cell apoptosis aggravates along with prolonging of cold ischemia time.4. TNF-αparticipates the process of pancreas ischemia injury and the mechanism might be that TNF-αinduces apoptosis. HSP-70 might inhibit apoptosis, so it has protective effects on hypothermia perfusion and preservation of pancreas.