氧自由基在创伤性大鼠脑损伤后肠道细菌移位中的作用

目的 探讨氧自由基在创伤性脑损伤大鼠肠黏膜屏障应激性变化机制中的作用.方法 雄性Wistar大鼠64只,随机分为2组:创伤性脑损伤(TBI)组(32只)和对照组(32只),再分别按术后6、12、24、48 h时相点分为4个亚组(n=8).测定肠黏膜组织丙二醛(MDA)、超氧化物歧化酶(SOD)和谷胱甘肽(GSH)水平,检测肠系膜淋巴结等多器官的组织匀浆中标记大肠杆菌的检出率.结果 TBI组多脏器荧光标记大肠杆菌检出率明显高于对照组(6、12、24、48 h组分别为:8.3%比2.1%、25.0%比2.1%.27.1%比2.1%、12.5%比0.0%,均P＜0.05);同时,该组各时相点肠黏膜组织匀浆中MDA含量明显高于对照组(nmol/mg pro,6、12、24、48 h组分别为:4.9±0.7比2.6±0.3、6.1±0.8比2.8±0.5、5.9±0.4 比 2.6±0.3、5.3±0.5比2.7±0.4,均P＜0.05);而GSH(mg/gpro,6、12、24、48 h组分别为:287±36比408±53、192±25比421±46、160±48比432±35、241±31比394±51,均P＜0.05)、SOD(U/mg pro,6、12、24、48 h组分别为:19.5±3.3比21.1±1.9、11.8±2.6比20.7±5.3、13.3±3.3比20.0±3.3、15.1±1.5比21.2±3.2,均P＜0.05)则明显低于对照组.结论 创伤性脑损伤模型大鼠伤后早期肠黏膜通透性升高,导致细菌移位增加,氧自由基在这一病生理过程中起重要作用.

Effect of oxygen free radicals on bacterial translocation in rats with traumatic brain injury

Objective To investigate the effect of oxygen free radicals on intestinal mucosal barrier in traumatic brain injury rats.Methods A total of 64 health male Wistar rats were divided randomly into two groups:traumatic brain injury(TBI)(n=32);Control group with sham operation(n=32).Each group was divided into four subgroups at 6,12,24 and 48 h post-operation(n=8).The levels of malondialdehyde(MDA),superoxide dismutase(SOD) and glutathione(GSH) were measured in intestinal mucosa,mesenteric lymph nodes,liver,spleen,pancreas,lung and kidney tissue.The marked bacilli were counted under a fluorescent microscope.Results The positive rates of bacterial translocation in TBI group were obviously hisher than those of control group(6 h:8.3% vs 2.1%,12 h:25.0% vs 2.1%,24 h:27.1% vs 2.1%.48 h:12.5% vs 0.0%,P＜0.05).The levels of MDA in TBI group were obviously higher than those of control group(6 h:4.9±0.7 vs 2.6±0.3,12 h:6.1±0.8 vs 2.8±0.5,24 h:5.9±0.4 vs 2.6±0.3,48 h:5.3±0.5 vs 2.7±0.4(nmol/mg pro),P＜0.05),and GSH (6 h:287±36 vs 408±53:12 h:192±25 vs 421±46;24 h:160±48 vs 432±35;48 h:241±31 vs 394±51(mg/g pro)P＜0.05).SOD(6 h:19.5±3.3 vs 21.1±1.9;12 h:11.8±2.6 vs 20.7±5.3;24 h:13.3±3.3 vs 20±3.3:48 h:15.1±1.5 vs 21.2±3.2(U/mg pro).P＜0.05)were lower than the control group at the same time point.Conclusions Bacterial translocation occurs obviously in TBI rats.It indicates that oxygen free radicals play important roles in stress-related changes of intestinal mucosal barrier in early stage of traumatic brain injury.