正加速度暴露对大鼠肠黏膜通透性的影响

目的  分析正加速度（+Gz）暴露下大鼠外周血D-乳酸及二胺氧化酶（DAO）含量的变化，探讨+Gz暴露对大鼠肠黏膜通透性的影响及机制。方法  32只雄性SD大鼠随机分成4组，每组8只，分别标记为A组（正常对照组）、B组（+5 Gz组）、C组（+10 Gz组）、D组（重复暴露组）。采用动物离心机模拟+Gz暴露，B、C组大鼠分别以+5和+10 Gz暴露5 min，D组大鼠重复暴露于+5 Gz 1.5 min，+10 Gz 2 min，+5 Gz 1.5 min，除A组外，其他各组大鼠每日暴露1次，持续5 d。实验结束后次日麻醉大鼠，取大鼠肠黏膜标本及外周血清，镜下观察大鼠肠道组织病理学特点，并检测各组大鼠血清D-乳酸及DAO水平。结果  除A组外，其他各组大鼠小肠组织肉眼及光镜下观察均有损伤，损伤程度D组>C组>B组；与A组比较，其他各组大鼠血清D-乳酸及DAO水平均明显升高（P <0.05），血清D-乳酸水平C组低于D组（P <0.01）；血清DAO水平B组低于C组和D组（P <0.05）。结论  +Gz暴露可增加大鼠肠道黏膜通透性，破坏大鼠肠道机械屏障，损伤程度与+Gz暴露值有关。

Effects of positive acceleration exposure on intestinal permeability in rats

Objective To explore the effect of positive acceleration (+Gz) on mechanical barrier of intestinal mucosa in rats and its mechanism. Methods Thirty two male SD rats were randomly divided into 4 groups, i.e. group A (control group), group B (+5 Gz value group), group C (+10 Gz value group) and group D (repeated exposure group) with 8 in each group. The animal centrifuge was used to simulate the exposure of acceleration. +5 Gz value group and +10 Gz value group were continuously exposed to the respective value for 5 min; repeated exposure group was continuously exposed to +5 Gz value for 1.5 min, +10 Gz value for 2 min and +5 Gz value for 1.5 min. The three groups were exposed to the respective acceleration for 5 d. Intestinal mucosa tissue and blood samples were taken on the next day after experiment. Intestinal mucosal injury was observed under light microscope. Blood samples were used to examine the level of D-lactate and diamine oxidase (DAO). Results Except for the group A, intestinal mucosal injury was observed in the other three groups, it was the most serious in the group D, followed by the groups C and B. Compared with the group A, the blood content of D-lactate and DAO significantly increased in the other three groups (P < 0.05). The level of D-lactate in the group C was significantly lower than that in the group D (P < 0.01). The level of DAO in the group B was significantly lower than that in the groups C and D (P < 0.05). Conclusions Positive acceleration exposure can cause intestinal injury in rats. The changes of the content of D-lactate and DAO in blood suggest that positive acceleration exposure can weaken the function of mechanical barrier of intestinalmucosa in rats.