The Study Of Intestinal Bacterial Translocation And Immune Barrier Of Intestinal Mucosa In The Rat Of Cirrhosis

ObjectiveThe spontaneous bacterial peritonitis and enteric origin endotoxemia are frequentin cirrhosis. The cause of the infection is bacterial translocation from bowel. Thebacterial translocation is promoted by three mechanisms: intestinal bacterialovergrowth, damage of the mucosal barrier and suppression of the host immunedefenses. The gut-associated lymphoid tissue is an independent immune organ,which plays an important role in protecting bowel from invasion of the microbialpopulation and pathogen. In our study, a rat model for cirrhosis was made byadministering carbon tetrachloride and ethyl alcohol. The morpholog of intestinalmucosa, the bacterial translocation and endotoxin were studied with the model.The phenotypes of T lymphocyte in the venous blood, intestinal intraepithelial,lamina propria, Peyer's patches and mesenteric lymph node in cirrhotic rat weredetected by flow cytometry.Methods一, morphologic changes of intestinal mucosaBoth villus height, surface area and crypt depth of jejunal were measured. Theultrastructure of small intestine were studied with electron microscope.二, bacterial translocation and endotoxemiaThe homogenates of the liver, spleen and mesenteric lymph node from twoexperimental groups were cultured separately on blood agar plates. The endotoxinwas measured by limulus endotoxin analysis kit.三, T lymphocyte and subpopulation in venous bloodThe lymphocytes of venous blood were isolated and labeled with mouse anti-ratCD3, CD4 and CD8 monoclonal antibody. Flow cytometry was performed.四, T lymphocyte and subpopulation in the gut-associated lymphoid tissueThe T lymphocyte in the intestinal intraepithelial, lamina propria, Peyer's patchesand mesenteric lymph node were isolated and labeled with mouse anti-rat CD3,CD4 and CD8 monoclonal antibody. Flow cytometry was performed.Results一, The villus height and surface area in the cirrhotic group was significantlydecreased. The tight junction in the epithelial cell was vague , and the architectureof mitochondria and rough endoplasmic reticulum were changed in cirrhosis.二,. In the cirrhotic group, the incidence of bacterial translocation to liver, spleenand mesenteric lymph node was 16.67, 16.67 and 41.6% respectively. The level ofendotoxin in the cirrhotic group was higher than the control.三, There was a preferential decrease in the CD3+ population of venous blood inthe cirrhotic group, but the subpopulations did not change compared with thecontrol.四, The number of intestinal intraepithelial lymphocyte was significantlyincreased in the cirrhosis group. The CD3+ population in the cirrhotic group didnot change, CD4+CD8- subpopulation was decreased and CD4+CD8+subpopulation was increased significantly compared with the control. The CD3+population of lamina propria, Peyer's patches and mesenteric lymph node in thecirrhosis group were decreased significantly compared with the control.ConclusionThe bacterial translocation and endotoxemia were significantly noted in thecirrhotic rat. The morphologic changes of intestinal mucosa, the abnormal ofsystemic immune and the immune function alterations of the gut-associatedlymphoid tissue are correlated to the bacterial translocation in cirrhotic rat.