心理应激对小肠细菌和小肠黏膜的影响

Effects of psychological stress on small intestinal bacteria and mucosa in mice

目的通过观察心理应激对小肠细菌和小肠黏膜的影响，探讨心理应激后小肠功能的变化及其发生机制。方法用猫恐吓小鼠的方法制备心理应激模型。取近端小肠组织进行细菌培养观察小肠细菌。通过测定血浆中的D-木糖含量来观察小肠黏膜的损伤情况。结果（1）应激组近端小肠大肠杆菌（1．79±0．27）log10（CFU／g）与对照组（1．32±0．22）log10（CFU／g）相比明显增加（P〈0．01），应激组乳酸杆菌与大肠杆菌的比例（0．52±0．56）较对照组（1．14±1．07）明显降低（P〈0．05），应激组乳酸杆菌（2．31±O．63）log10（CFU／g）较对照组（2．41±0．34）log10（CFU／g）减少，但差异无显著性（P〉0．05）。（2）心理应激后血浆中的D-木糖含量[（3．02±0．85）mmoL／L]较对照组[（0．94±0．33）mmoL／L]明显升高（P〈0．01）。（3）血浆中的D-木糖含量与近端小肠大肠杆菌数量呈正相关（r=0．6713，P〈0．05）。结论心理应激后小肠功能紊乱可能与小肠微生态失衡和小肠黏膜的损伤有密切联系。

Objective To investigate the effects of psychological stress on small intestinal bacteria and mucosa in mice, and to explore the relationship between small intestinal disfunction and small intestinal bacteria and mucosa under psychological stress. Methods 48 mice were randomly divided into psychological stress group and control group. An animal model with psychological stress was established lodging the mice and a hungry cat in separate layers of a two-layer cage. D-xylose levels in plasma were measured for estimating the damage degree of small intestinal mucosa. A section of the proximal small intestine was harvested under sterile condition and processed for quantitation for aerobes （ Escherichia coli） and anaerobes （ Lactobacilli ）. The quantitation of bacteria was expressed as logl0 [ colony forming units/g]. Results D-xylose concentrations in plasma in psychological stress mice were significantly higher than those in the control group （ 3.02 ± 0. 85 mmol/L vs 0. 94 ± 0. 33 mmol/L, P〈0.01 ）. Psychological stress resulted in quantitative alterations in the aerobes （E. coli）. There was an increase in the number of E. coli in the proximal small intestinal flora （ 1.79±0.27 logl0（CFU/g） vs 1.32 ± 0.22 logl0（CFU/g） , P 〈 0.01 ）, and there was decrease in relative proportion of Lactobacilli and E. coli of stressed mice （0.52 ± 0.56 vs 1.14 ± 1.07, P〈0.05 ）, while there was no significant difference in the anaerobes （Lactobacilli） between the two groups （2.31 ± 0.63 logl0 （CFU/g） vs 2.41 ± 0.34 logl0 （CFU/g） P 〉 0.05 ）. D-xylose concentrations in plasma was significantly and positively correlated with the number of E. coli in the proximal small intestinal flora （ r = 0. 6713, P 〈 0.05 ）. Conclusion Small intestinal disfunction under psychological stress may be related to dysbacteriosis and the damage of mucosa.