| Objective: To explore the significance of nanobacteria (NB) translocation and the disturbance of gut barrier function in rats suffering critical abdominal cavity infection.Methods: The models of critical abdominal cavity infection were made by cecal ligation plus puncture (CLP). It was studied to observe the psyche status, diet, activity and color of hair, and to detect the rectal temperature, number of the leucocyte in blood, the positive rate of NB in blood and stool before or after critical abdominal cavity infection respectively. The blood and stool samples were cultured with NB culture medium and identified by transmission electron microscopy (TEM) and polymerase chain reaction (PCR) for NB 16S rRNA gene. PCR products were analyzed by agarose gel electrophoresis and sequenced. At the same time, it was experimented to detect the positive rate of common bacteria and to assay the level of endotoxin in the blood samples at different time in the abdominal infection group and control group. Immunohistochemical technique was applied for assaying proliferating cell nuclear antigen (PCNA) index of the jejunum and ileum samples at different time. The experimental data was test with Paired-Samples T test, McNemar test and One-way-ANOVA by SPSS 10.0.Results: (1) The positive rates of NB were 17.5% and 42.5% (p<0.05) in the blood samples before and after CLP respectively by TEM, and which were 20.0% and 47.5% (p<0.05) by PCR. The positive rates of NB were 90.0% and 92.5% (p>.05) in the stool samples before and after CLP respectively by TEM, and which were 95.0% and 95.0% by PCR (p>0.05). (2) Compared with the control group, the rats of experimental group were more mindless, less diet, dull and less activities. (3) Compared with the control group, the average rectal temperature of the experimental group rats was higher significantly (39.98+0.43C vs 38.37+0.34C , p<0.01), and the average numer of leukocyte was higher significantly too(21.13+3.27xl09/L vs 10.43+2.23x109/L, p<0.01) on postoperative 2d. (4) The endotoxin level of the blood at 1d, 2d and 4d in the experimental group were higher than that in the control group and the control group (0.76+0.03 EU/ml vs 0.12+0.02 EU/ml, 1.42+0.10 EU/ml vs 0.15+0.01 EU/ml, 1.94+0.07 EU/ml vs 0.13+0.01 EU/ml, all were p<0.01). (5) The positive rates of common bacteria culture of the blood at Id, 2d and 4d in the experimental group were 20%>. 30% and 10%, while all those were zero in the control group. (6) The inflammatory reaction of small intestine mucous membrane was more severe in the infection group than the control group. Observed with microscope in the experimental group, it showed interstitial edema, vascular engorgement and infiltration of neutrophilic granulocyte in the small intestine mucous membrane and submucosa. And the changes of rarefaction and disorder of arrangement in microvillus of the intestinal epithelium were observed byelectron microscope too. (7) Compared with the control group, the PCNA indexes at 1d and 2d in the experimental group were higher (in jejunum: 24.10+4.27 vs 16.84+1.49 , 22.30+3.68 vs 15.23+2.54, in ileum: 23.86+2.02vs 14.26+1.51, 20.55+3.04 vs 15.20+2.76, all were P<0.01). The PCNA index at postoperative 1d was the highest in the experimental group, afterward, it was descent significantly(24.10+4.27, 22.30+3.68 and 17.63+2.29 in jejunum at 1d, 2d and 4d, 23.86+2.02, 20.55+3.04 and 15.18+2.12 at 1d, 2d and 4d in ileum, all were P<0.01)Conclusions: There exists NB in the stool of rats commonly. The difference of the positive rates of NB in the blood sample was significant before CLP than after CLP significantly. That may be associated with NB translocation during critical abdominal cavity infection. It deserves to further insight into the relationship between NB and the infection of abdominal cavity. The disturbance of gut barrier function in rats was induced by critical abdominal cavity infection. Then bacteria and endotoxin translocation occurred, therefore SIRS. The PCNA index was increasing during critical abdominal cavity infection i... |
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