肠粘膜TLR4信号参与心肺复苏过程细菌移位

【目的】探讨心肺复苏（CPR）过程中肠粘膜TLR4信号表达是否参与肠内细菌移位，介导复苏后脓毒症产生的可能机制。【方法】 通过建立大鼠心脏骤停及复苏模型，设定CPR自主循环建立后6h（CPR-6h）及48h （CPR-48h）为早期和后期阶段，western blot方法测定两阶段肠粘膜TLR4表达及其细胞内信号MAPKs的磷酸化蛋白表达（包括pERK、pJNK、pp38MARK）、肠系膜淋巴结及肝脏组织细菌培养检测肠外器官的细菌移位以及扫描电镜观测肠粘膜细胞间连接增宽或开放比例。【结果】 CPR-6h组，TLR4、pERK、pJNK和pp38MAPK蛋白均表达增加（P<0.05，与sham比较），2.01%肠粘膜细胞间连接增宽，肠系膜淋巴结和肝组织细菌培养分别为（3700±109 ）cfu/g和（800±85） cfu/g；然而CPR-48h组，除pERK外，肠粘膜TLR4、pJNK和pp38MAPK蛋白表达下降（P<0.05，与CPR-6h 比较），8.4%细胞间连接增宽, 肠系膜淋巴结和肝组织细菌培养分别为（14300±2750）cfu/g和（4400±623）cfu/g, 细菌移位程度及细胞间连接增宽或开放比例明显增高（P<0.001，与CPR-6h比较）。【结论】 CPR后期阶段TLR4表达降低提示其识别细菌能力下降，可能与后期细菌移位有关。

Intestinal Mucosal TLR4 Signal Involves in Bacterial Translocation in a Rat Model of Cardiopulmonary Resuscitation

【Objective】 To investigate whether intestinal expression of Toll-like receptor 4(TLR4) signaling was involved in bacterial translocation and mediated sepsis generation in a rat model of cardiopulmonary resuscitation(CPR).【Methods】 Through the establishment of rat model of CPR,the experimental animals were set CPR-6 hour group(CPR-6h) and CPR-48 hour group(CPR-48h) as the early and late stages after the establishment of spontaneous circulation,then observed two-stage intestinal TLR4 expression and MAPKs(pERK,pJNK,and pp38MAPK) expression of intracellular signaling proteins by using Western blot,detected bacterial translocation by bacterial culture of mesenteric lymph nodes(MLNs) and liver tissue,determinated intestinal epithelial damage by observing cell junction widening or opening ratio.【Results】 In the CPR-6h group,TLR4,pERK,pJNK,and pp38MAPK protein expression were significantly increased(P < 0.05,compared with sham control),and a low percentage of cell junction widening or opening ratio(2.01%) and a small quantity of colonies of colony-forming unit per gram(cfu/g) were observed in the mesenteric lymph nodes(MLNs) and liver tissue.However,in the CPR-48h group,except for pERK,TLR4,pJNK,and pp38MAPK protein were decreased,which were compared with those in the CPR-6h group(P < 0.05).However,the percentage of cell junction widening or opening ratio was much higher than that in the CPR-6h and sham groups(8.4%,P < 0.001).Moreover,the bacterial colonies of mesenteric lymph nodes and liver tissue were(14 300 ± 2 750)cfu/g and(4 400 ± 623)cfu/g,which were remarkably increased when compared to CPR-6h groups (3 700 ± 1 090)cfu/g and(9 800 ± 850)cfu/g,P < 0.001].【Conclusion】 The lower expression of intestinal mucosal TLR4 signal was observed during the late stage of CPR,which suggested that intestinal mucosal cells may reduce its ability to sense and identify bacteria,which resulted in bacterial translocation.