Experimental Study Of Exogenous Lysolecithin On The Role Of Pancreatitis In Rat Brain Damage

Pancreatic encephalopathy (PE) is one of the severe complications of acute pancreatitis. This experiment was designed and conducted to explore its unknown pathogenesis from whether lysophosphatidyl choline (LPC) can cause permeability change in pancreatitis rats' blood-brain barrier(BBB) and cause demyelination occurring in pancreatitis rats' brain in order to provide clues for the diagnosis and treatment of PE.Objective To verified LPC, one of products made by pancreatin during pancreatitis, whether affected the permeability of pancreatitis rats' BBB and demyelinated the brain tissues of pancreatitis rats.Methods Young male or female Sprague-Dawley rats, which were provided by the experimental animal center of Nanjing Mednical University, weighing from 230 to 270gm, were divided into test group, control group one and control group two randomly. Every group was consist of 10 rats.Part 1: Acute edematous pancreatitis rats models induced and ectogenetic LPC venously applied.Acute edematous pancreatitis were induced following Aho HJ method~[1], then test group rats were venously applied with LPC from caudal vein. Control group one were injected saline through tail vein after being induced edematous pancreatitis model successfully. Control group two was treated with venous injection LPC from the rats tails after pseudo-operation (opening abdominal cavity finding the pancreatic duct then close abdominal wall ).LPC or saline were applied 5 days successively for every group.Part 2: A research about ectogenetic LPC opening the BBB of pancreatitis rats.The rats were involved in magnetic resonance imaging ( MRI ) examination while Magnevest ( contains Gd-DTPA ) was employed as a contrast medium 7 ~10days after the rats last uptaken LPC or saline to determine whether the rats' BBB was opening or not. Kept the rats in well condition by offering warm environment and oxygen supply to make sure the rats alive.Horseradish peroxidase ( HRP ) was inserted through the rats' internal carotid artery the day after MRI examination. The rats brain specimens were taken off 25 minutes after the HRP was applied. Left half of the brain was put into liguid nitrogon vessel and make sure that horseradish peroxidase— diaminobenzidine examination ( HRP—DAB ) was making in 2days to decide whether the BBB of the rats was open or not; Right half of the brain was delivered to the pathology department with wet compress by semi-wet saline dipped carbasus, then the specimens were kept in 4% formaldehyde-calcium fluid for detecting whether demyelination had taken place .Part 3: A Research about demyelination effects of ectogenetic LPC on pancreatitis rats' brain tissue.1. Ponceau G staining to detect whether demyelination was occurring in the brain of the rats.The specimens were embedded with wax mass in 5 days after they were taken from rats, then cut the sections at thick around 6~8um and stainned the sections about 3~5minutes with ponceau G fluid soon after the sections were routinely dewaxed into distilled water. The sections were washed by distilled water then were dealed with 1% phosphorus—tungstic acid fluid 1 minutes and then stained by brilliant green 1 minutes and at last differentiating the sections by 1% phosphorus—tungstic acid fluid for several seconds. After that the sections were washed by tap-water, dehydrating, clearing, and blocking.2. The luxol fast blue (LFB) staining method was also employed to detect the demyelination of the rats' brain, but with its steps is complicated so the writer give the details in the following text.results 1. results about BBB permeability changing: The BBB permeability of the test group increased greatly while both control groups had basically intact BBB in HRP—DAB examination. A statistical difference exists between the test group and both control groups with/P<0.01. Regional extent of HRP extravasation was observed in the test group which was considered the characteristic change of HRP extravasation in BBB. 2. As for MRI examined, no BBB open was observed in experimental group rats and contrast gro...