The Empirical Study Of Pancreatic Microcirculation Of Rats With Acute Pancreatitis By Confocal Lase Endoscope

Background and purpose: Acute pancreatitis (AP) is a common clinic disease, about 10% of which will develop into severe acute pancreatitis (SAP). Its developing process and mechanism of are very complex and roughly divided into the several theories as follows: 1.trypsinization; 2.cell factors and inflamatory mediators; 3.microciculation failure; 4.second attact; 5.excessive activation of leucocyte. In recent years, the effect of pancreatic microcirculation dysfunction (PMD) on AP development catches more and more attention because pancreatic microcirculation is closely related to physiological and pathological changes of pancreas, involving the pathological process of pancreatic injuries caused by AP and shock, self-adjustment of pancreatic endocrine function, and the relations between endocrine functions and exocrine functions. The development of laboratory technologies and the knowledge of AP pathological and physiological mechanism showed that not all pancreatic hemorrhagic necrosis is caused by pancreatin histolysis. Of all the factors, PMD with the ischemic characterization is outstanding. Is pancreatic hemorrhagic necrosis the direct result of pancreatin or PMD? What is the initial factor of PMD. All the above problems are hot topics in this field worth further exploration. Confocal Lase Endoscope (CLE) is the upgrading version of traditional electronic endoscope by combining confocal lase microscope, which is capable of×1000 amplification and mainly applicable to diagnosis of early digestive tract tumors, yielding high sensitivity and positive rate. Based on its performance, CIE was used in the present study to review the changes of pancreatic microcirculation and AP in different phases, understand the function of CLE, estimate the prospect of this equipment in clinic and empirical study of AP, and shed some light on exploration of novel methods for APM study. .Methods Thirty-two adult Sprague-Dawley rats (SD rats) were divided randomly into two groups: the control group (n=8) and the test group (n=24). The rats in the control group were given a belly operation to turn out abdominal organs followed by exposing stomach, duodenum and pancreas. After venous blood collection, those rats were injected 0.5% Fluorescein sodium(Fs) at 4 ml/kg through inferior vena and put under CLE to observe and record normal pancreatic microcirculation with images. The test group was sub-divided into three parts, twelve hours group(n=8), twenty-four hours group(n=8), forty-eight hours group(n=8). The rats in the test group were also given an belly operation turn out pancreas. Then the end of common bile ducts of those rats were ligated with"0"silk rope to establish the experimental AP model. After establishment of AP model, those rats were given a belly operation again to observe abdominal status and pathological changes of pancreas with naked eyes. Then those rats were phlebotomized and injected 0.5% Fs through inferior vena at 12h, 24h, 48h respectively, followd by putting under CLE to detect and record the changes of AP microcirculation (the same as for the control group). Pancreatic tissues from both groups were made into sections and analyzed by comparison of the image from CIE with general pathological images..Results①The experimental AP models were established by ligating the end of common bile tube and a part of models proved to be SAP models after serological detection and histological observation.②The normal group were observed under CIE: normal structure of pancreatic acini, complete microcirculatory texture of pancreas, detectable capillaries of microcirculation and red blood cells, of which the number was countable when they cross a section of a capillary. The development effect of pancreatic acini was not so vivid as that of microcirculation.③In the test group, conspicuous alteration of AP microcirculation in different phases were detected under CIE. In twelve hours group, the structure of pancreatic microcirculation and acini was almost normal and red blood cells was still visible, but the flow rate of red blood cells slowed down. The development effect of microcirculation was not so vivid as that in the normal group, but the structure of the test group showed little differences from that of the control group. In twenty-four hours group, the structure of most pancreatic acini was vague, but still normal pancreatic acini was detected after careful observation. The detected microcirculation with complete structure decreased significantly compared to twelve hours group. Both the number and the flow rate of red blood cells detected in capillaries decreased compared to twelve hours group. In forty-eight hours group, the development effect of pancreatic acini was vague, and a complete and normal pancreatic acini and microcirculation was almost invisible. Quite a few capillaries and much fewer red blood cells were detected, and there was almost no flow of red blood cells.④No clear islet tissues and leukocytes were detected and identified under CIE to help to make the judgment whether micro thrombus was formed.Conclusions①This experiment verified the value of CIE in study of pancreatic microcirculation and disclose the advantages and advancement of CIE in judging the blood state of AP microcirculation in vivo.②However, CLE is incompetent in identifying some tissues and blood cells, which will challenge diagnosis of some diseases.③In addition, the current stain used fro CLE is not adaptive to staining requirements of different tissues and organs.