| The Role of Apoptosis in the Injury of Gut BarrierFunction after Salmonellosis in Rats(Abstract)Apoptosis controlled by serious genes is a programmed cell death (PCD) with distinct morphological and biochemical features, which have differently physiological forms from necrosis. Although apoptosis play a central role in maintaining the normal homeostatic conditions, it can result in pathological injury of tissues and organs when apoptosis is induced by abnormal factors. Recent studies indicate that overexpression of genes related apoptosis in certain cells can be induced by a variety of stress mediators during trauma and sepsis (i.e. endotoxin, inflammatory cytokines such as TNF, IL-i, IL-6, nitric oxide, etc.), which has abnormal apoptosis of the cells occurred and their function injured. The epithelial cells and lymphocytes in intestinal tract are cells that often take actively rapid differentiation, therefor, they have a feature of more actively apoptosis.Objective In order to understand the effect of apoptosis on intestinal barrier function, Salmonella infection in rat were used to explore that ~D the relationship between the injury of intestinal barrier function and apoptosis of epithelial cells and related lymphocytes in intestine at different time after salmonella infection; @~ the relationship between apoptosis and endotoxicemia in portal vein as well as bacterial translocation of mesenteric lymph node (MLN); The impact of oxide stress on apoptosis of epithelial cells in intestineIn present study, 110 male Wister rats were divided randomly into two groups:group A (control group n60) and group B (infection group n~50). The rats in group B were given salmonella enteritidis gastrically while the rats in group A underwent the same manipulation with saline without salmonella. The regulation of developing apoptosis occurred in gut epithelial cells after infection wasobserved by apoptosis percentage (ap%), DNA electrophoresis, Tunel method andelectronic microscope. Meanwhile, the blood samples in two groups were takenfrom portal vein after infection 6 to 96 hours, respectively, lipopolysaccharide(LPS), diamine oxidase (DAO) and D-lactic dehydrogenase (D-LDH) weremeasured and tissue guantitative bacterial culture of MLN as well as bacterialidentification were perfOrmed to observe the pathological changes of intestinalmucous and bacterial translocation.Our data indicated that: l.The ap% of enterocytes in group B raPidlyincreased 6 hours post-infection, peaking at 24 hours post-infection, and alwayshigher than in group A (p<0.0l). 2. Gel electrophoresis showed that the DNAladder was clearly observed at l2h post-infection in group B other than in groupA. 3. Apoptotic cells were discerned at the villi of the mucosa at 6h post-infectionin group B by TUNEL method, more than in group A, and the apoptotic cellsshedding into the intestinal lumen could also be observed in group B. 4. Apoptoticenterocytes showed their special features of condensed nuclei and margination ofchromosome under electronic microscopy. 5. The changes of gut barrier functions:The levels of LPS in portal vein increased more significantly at 6h post-infection,peaking at 24h post-infection in group B than in group A(pwt0.0l). The changesof intestinal D-LDH corroborated with portal endotoxin. The contents of intestinalDAO decreased at l2h in group A. Bacterial culture of MLN samples showed thatthe bacteria positive were 40% at 6h post-infection and l00% at 24h post-infectionin group B, and that no bacteria at 3h were cultured in group A. The changes ofD-LDH and LPS in portal vein after infection were basically paralled. The DAOvalue in group B decreased at l2h post-infection and began to increase at 96hpost-infection. 6. The MDO and XO from intestinal mucous in group Bdemonstrated an increasing tendency, which showed the positive correlation withap% of enterocytes, while TSH and NPSH showed down tendency after infection,which showed the negative correla... |
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