| Acute pancreatitis(AP),a sudden inflammation of the pancreas caused by various etiologies including gallstone,hypertriglyceridemia,alcohol,etc.,is one of the most common causes for acute abdomen conditions in both medical and surgical patients.It is reported that AP occurs in 13-45 per 100 thousand individuals every year.Among all the AP events,mild acute pancreatitis(MAP),also called acute interstitial edema pancreatitis,accounts for most of the cases.While,about 10-20%of the AP patients would suffer severe acute pancreatitis(SAP),also called acute necrotizing pancreatitis.The mortality of SAP patients ranges from 10%to 40%and could up to 70%in those patients with IPN.Generally,SAP patients have two death peaks.The early death peak is usually caused by systemic inflammatory response syndrome(SIRS)and related multiple organ dysfunction syndrome(MODS).While the late death peak is mostly caused by sepsis and MODS.The intestine actively promotes the development of sepsis and mortality of the SAP patients.SAP would cause intestinal injury.The injuried intestine would in turn accentuate the disease course of SAP through a variety of pathophysiological changes.Currently,the mechanisms for intestinal injury in SAP include ischemia reperfusion injury,intestinal flora disturbance,etc.Whereas,latest studies indicated that,immune cells play a key role in the progress of SAP and might mediate the inflammatory injury.Treg cell is a class of immune cells that can regulate the immune response and alleviate immunological injury.A series of researches have showed that,in the conditions of intestinal inflammatory diseases such as inflammatory bowel disease(IBD),the depletion of Treg cells would significantly promote the development of intestinal inflammation,suggesting that intestinal immune response might mediate the process of the inflammatory response.Therefore,We hypothesized that the immune-mediated inflammatory injury played a key role in the intestinal mucosal injury in SAP.In this thesis,the dynamic changes of the intestinal immune responses,especially the changes in Treg cells and CD4+T lymphocytes were observed in the rats with 4%sodium taurocholate-induced SAP.In addition,the relationships between intestinal immune response and the local and systemic inflammatory reactions were analyzed.Then,sodium butyrate was used as an intervention for SAP rats and the protective effects of sodium butyrate on intestinal and systemic immunoinflammatory injuries were also observed.This thesis could be divided into two parts:PART ?:The immune-mediated inflammatory injury of the intestinal mucosa in severe acute pancreatitis ratsObjective:The intestinal immune disorder might play a certain role in the development of intestinal inflammation in severe acute pancreatitis(SAP)and might mediate the process of intestinal injury.The purpose of this study was to observe the dynamic change of the intestinal immune responses,especially the changes of intestinal Treg cells and CD4+T lymphocytes,in SAP rats.Furthermore,the correlations between intestinal immune responses and the intestinal and systemic inflammatory responses were analyzed.Methods:Twenty-four 7-10 week-old rats used in this study were randomly divided into four groups:Negative control group,SAP 24 h group,SAP 48 h group and SAP 72 h group.SAP was induced by the injection of 4%sodium taurocholate into the biliopancreatic duct.The samples were collected after the rats were euthanized by exsanguination.Blood samples were collected to detect the serum level of TNF-?.Ileum and colon samples were collected for evaluation of histopathological lesions,myeloperoxidase(MPO)activities as well as the expressions of tight junction proteins and Foxp3.And the samples of pancreas,lung and kidney were also collected for histopathological assessment.Furthermore,fresh intestinal samples were also collected and the proportion of Treg cells and CD4+T lymphocytes were assessed using flow cytometry.Results:The SAP rats developed obvious inflammatory pathological injuries in the intestines when compared to the control rats:the inflammatory pathological scores of the ileum and colon were increased markedly,the number of the intestinal goblet cells was decreased significantly,the number of the inflammatory cells were significantly increased,intestinal MPO activities were markedly increased and the expressions of ZO-1 and Occludin were reduced markedly.At the same time,rats developed significant intestinal immune disorders after SAP modeling:the expressions of Foxp3 in ileum and colon were significantly decreased,the proportion of the Treg cells located in lamina propria was markedly reduced(P<0.001)and the proportion of CD4+T lymphocytes was markedly increased(P<0.001).Moreover,the serum level of TNF-? was dramatically increased after SAP modeling,peaking at 72 h(P0O.001).Correlation analysis revealed close relations between ileac and colonic Foxp3 expressions and their MPO activities(P both<0.001),with r2 of 0.59 and 0.70,separately.In addition,the ileac and colonic Foxp3 expressions were also closely correlated to serum levels of TNF-?(P both<0.001),with r2 of 0.56 and 0.85,separately.Conclusions:Rats developed significant immune disorder of the intestinal mucosa after SAP modeling and the extent of the intestinal immune disorder was closely related to the intestinal inflammatory responses,suggesting that the intestinal mucosal immune disorder might mediate the process of intestinal inflammatory reaction and its related injury.Immune-mediated inflammatory injury might be a potential mechanism for intestinal mucosal injury in SAP.PART ?:Protective effect of butyrate on the immunoinflammatory injury of the intestinal mucosa in severe acute pancreatitis ratsObjective:Butyrate,an immune nutrient,could modulate the immune and inflammatory responses of the intestine.The purpose of this study was to assess the protective effect of sodium butyrate on the immunoinflammatory injury of the intestinal mucosa in SAP rats as well as its effect on systemic inflammatory response.Methods:Eighteen 7-10 week-old rats used in this study were randomly divided into three groups:Sham operation group(Control group),SAP 72 h group(SAP group),SAP 72 h+Butyrate group(Intervention group).SAP was induced by the injection of 4%sodium taurocholate into the biliopancreatic duct.Samples were collected after the rats were euthanized by exsanguination.Blood samples were collected for detection of serum TNF-?.Ileum and colon samples were collected for assessment of the histopathological lesions,MPO activities as well as the expressions of tight junction proteins and Foxp3.Moreover,lung and kidney samples were also collected for histopathological evaluation.Additionally,fresh samples of whole blood and intestine were collected and the proportion of Treg cells and CD4+T lymphocytes were assessed using flow cytometry.Results:Sodium butyrate was able to modulate the intestinal immune responses of the SAP rats:the expressions of Foxp3 and GPR109a were up-regulated significantly in the intestine,the proportion of Treg cells located in the lamina propria was dramatically increased(P<0.01)and the proportion of CD4+T lymphocytes was decreased after sodium butyrate intervention.At the same time,Sodium butyrate could attenuate the intestinal inflammatory injuries of the SAP rats:the inflammatory pathological scores of the ileum and colon were markedly reduced(P both<0.05),the number of the intestinal goblet cells were significantly increased,the number of the inflammatory cells were significantly reduced,MPO activities were dramatically decreased and the expressions of ZO-1 and Occludin were up-regulated markedly after sodium butyrate intervention.In addition,sodium butyrate could also decrease the systemic inflammatory cytokines significantly and ameliorate organ injuries(lung and kidney)of the SAP rats.Conclusions:Sodium butyrate could stimulate the differentiation of Treg cells in the lamina propria,probably via the activation of GPR109a in macrophages and dendritic cells(DCs).In this way,sodium butyrate could modulate the immune responses of the intestinal mucosa and attenuate immune-mediated inflammatory injuries in SAP rats.In addition,sodium butyrate could also improve the systemic inflammatory responses and protect the organ injuries of the SAP rats. |
PDF Full Text Request