全身照射后肠黏膜通透性与肠三叶因子mRNA表达的关系

Relationship between intestinal permeability and expression of intestinal trefoil factor mRNA in mice after total body irradiation

目的探讨全身照射（TBI）对肠道黏膜通透性和肠三叶因子（ITF）mRNA表达的影响以及二者之间的关系。方法32只BALB／c小鼠随机均分为4组：空白对照组和总剂量8．0Gy全身照射后4、8和12d组。TBI剂量8．0Gy，剂量率1．0Gy／min。高效液相色谱一蒸发光散射检测器分析（HPLC-ELSD）检测尿液标本中乳果糖与甘露醇的排出率比值（L／M），评价各组小鼠的肠道通透性；收集空肠组织标本，实时荧光定量PCR检测肠道ITFmRNA表达水平。结果TBI后4、8和12d组L／M比值分别为0．5092±0．0353，0．7174±0．0116和0．7295±0．0063，均明显高于空白对照组（0．2908±0．0533，F=321．47，P〈0．05）。TBI后4、8和12d组ITFmRNA表达水平分别为0．78612±0．1428，0．2521±0．1223，和0．2306±0．0221，均显著低于空白对照组（1．3498±0．0476，F=235．71，P〈0．05）。各TBI组中L／M与肠道ITFmRNA水平呈显著负相关（r=-0．985，P〈0．01）。结论TBI后随着时间延长ITFmRNA表达逐渐下降而肠黏膜通透性逐渐增加，即TBI后ITFmRNA表达与肠道通透性呈显著负相关。ITF在TBI所致肠道黏膜通透性增加中起着保护作用。

Objective To investigate the change of the intestinal permeability, the expression level of intestinal trefoil factor （ITF） mRNA and the relationship between them after total body irradiation （TBI） , and explore the effect of TBI on the development of intestinal permeability and the expression level of ITF mRNA. Methods Twenty two BALB/e mice were randomly divided into 4 equal groups： 3 groups at 4, 8 and 12 d after TBI with the total dose of 8.0 Gy and the dose rate of 1.0 Gy/min respectively, and a control group. Lactulose （L） and mannitol （M） were perfused into the esophagus before the experiment and urine samples were collected. Liquid chromatography was used to measure the L/M excretion ratio in the urine samples collected 4, 8, and 12 days after the TBI. And then the mice were killed with their intestine were taken out. The expression of ITF mRNA in the jejunum tissue was detected by real-time fluorescence quantitative PCR. Results The urine L/M ratio levels of the groups 4, 8 and 12 days after TBI were （0.5092 ＋ 0.0352）, （0.7174 _＋ 0.0116）, and （0.7295 ＋ 0.0533） respectively, all significantly higher than that of the control group [ （0. 2908 ±0. 0533）, F = 321.47,P 〈 0. 05 ]. The ITF mRNA expression levels of groups 4, 8 and 12 days after TBI were （0. 78612 ± 0. 1428） , （0. 2521 ±0. 1223）, and （0. 2306 ± 0.0221 ） respectively, all significantly lower than that of the control group [ （ 1. 3498 ± 0. 0476）, F = 235.71 ,P 〈 0. 05 ]. The urine L/M ratio was significantly negatively correlated with the expression of ITF mRNA in all TBI groups （ r = - 0. 985, P 〈 0. 01 ）. Conclusions The intestinal permeability increases and the expression level of ITF mRNA decreases after TBI. The urine L/M ratio is negatively correlated with the expression level of ITF mRNA after TBI. ITF is involved in protection against intestinal permeability induced by TBI.