| Acute pancreatitis ( AP) is a common and potentially fatal disease, and high mortality is characteristic of severe pancreatitis (SAP) , therefore, how to promote treatment effect and decrease mortality is always a difficulty for clinical surgeons. The key problem which we find in clinical practice is nonoperative treatment or operative drainage and necrotizing tissues clearance could not stop the development of pancreatitis.Multiple complications and high mortality in SAP mainly because of the pathogeneses have been incompletely recognized. Nowadays, there are four hypotheses about pathogenesis of SAP which were pancreatic enzyme itself digesting , pancreatic microcirculation disorder, leukocyte activating overly and intestinal bacterial translocation. The research on SAP more further, the hypothesis of pancreatic microcirculation was more important, and it was considered the initiated , continued and aggravated factor of SAP. Severe pancreatic microvascular contraction and microthrombosis resulted in or aggravated pancreatic necrosis more severely. Therefore, it will improve pancreas blood flow, inhibit the development of pancreatic inflammation and necrosis, shorten the course and increase survival rate of SAP.This study attempted to explore the relations between SAP and pancreatic microcirculation, the effect of urokinase on the pancreatic microcirculation of SAP by observing pancreas blood flow, the levels of TXA2 and PGI2, and the pathologic changes of pancreas on the basis of SAP model in Wistar rats.Materials and Methods1. experimental materialsA total of 192 male Wistar rats (provided by experimental center of the animal , The Second Affiliated Hospital of China Medical University) , weights ranged from 220g to 250g, were randomized into control group(C) pancreatitis group(P) and treatment group(T). each group was divided into subgroup A and B, rats in subgroup A were used to measure pancreas blood flow, and rats in subgroup B, blood samples and pancreas tissues were collected to observe the changes of TXA2/PGI2 levels and pancreas tissues pathologic changes. Each subgroup was divided into four small groups as the phases of 2h, 6h, 12h, 24h after SAP model was finished successfully.2. Experiment methods: Establish SAP model:Rats were forbidden to give foods, but permitted to drink water freely 12 hours before experiment Following the Abo methods to establish SAP model, by using retrograde injection of 5% sodium taurocholate(5%NaTc, 0. 1ml/100g) into the cholangiopancreatic duct, the injection rate Was 0.1ml per minute, and keep the injection pressure five minutes. And resumed the experiment after pancreas tissues showed edema and hyperemia. Duodenum was only flipped gently in the rats of group C, Urokinase( 1000u/100g) was injected thought the punctured pipe of neck vein 30 minutes after finishing the SAP model. Rats in subgroup B were drawn 4 ml blood from inferior cava vein under anesthesia at the phase of 2h 6h 12h 24h accordingly after SAP model was finished triumphantly, plasma was collected and stored at - 70C, pancreas were harvested from each rat and fixed in 10% buffered formalin.2. 1 pancreas tissue blood flow : Radioactive biomicrosphere technique was used to measure the pancreas blood flow at the phase of 2h 6h12h and 24h.2.2 TXA2/PGI2 levels measurement: To measure the levels of TXA2/PGI2 with the methods of radioimmunoassay (RIA) , TXA2/ PGI2 RIA Kit purchased from East-Asia Immunization Technique Institute of the 301 hospital.2. 3 Pancreas pathologic histology: pancreas tissues were embedded in paraffin and sliced into sections, stained by hematoxylin and eosin. Observed the pancreatic pathologic changes by pathologist with light microscope, on the principle of blindness according to the reported grade standard.3. Statistics: The mean values of pancreas blood flow and the TXA2/PGI2 levels and pancreas pathologic changes were expressed with the standard error of the mean. The chi-square test was appropriately used, and T-test was used to test the me... |
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