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目的研究尾吊模拟失重大鼠小肠黏膜紧密连接(TJ)蛋白的表达。方法 24只Wistar大鼠随机分为3组:对照组(Con),悬吊14 d组(TS-14d)和悬吊21 d组(TS-21d)。测定空肠TJ蛋白Occludin,Zonula Occludens-1(ZO-1)的免疫组化、实时荧光定量表达;透射电镜下观察TJ和微绒毛的结构;紫外分光光度法测定血浆二胺氧化酶(DAO)、d-乳酸浓度。结果组化观察表明悬吊组Occludin和ZO-1的表达较对照组均下降,而TS-21d较TS-14d组下降更为明显;透射电镜观察发现悬吊组小肠上皮微绒毛间距增宽,TJ和桥粒数量减少,微绒毛结构破坏;悬吊组的血浆DAO和d-乳酸浓度均高于对照组,而TS-21d较TS-14d组升高更为明显;直线回归分析发现Occludin,ZO-1的表达与DAO,d-乳酸的浓度呈显著负相关。结论模拟失重可以使大鼠小肠黏膜紧密连接蛋白表达减少,从而导致小肠黏膜通透性增加。
Objective To study the expression of tight junction (TJ) protein in small intestine of tail-suspended rats. Methods Twenty-four Wistar rats were randomly divided into three groups: Con group, TS-14d suspension group and TS-21d suspension group. The expression of TJ protein Occludin and Zonula Occludens-1 (ZO-1) in jejunum were determined by real-time fluorescence quantitative analysis. The structures of TJ and microvilli were observed under transmission electron microscope. The levels of plasma diamine oxidase (DAO) d-lactate concentration. Results The histochemical observation showed that the expression of Occludin and ZO-1 in the suspension group decreased compared with the control group, while TS-21d decreased more significantly than the TS-14d group. Transmission electron microscopy showed that the microvilli in the suspension group broadened, TJ and the number of desmosomes decreased, and the structure of microvilli was destroyed. The concentrations of DAO and d-lactate in the suspension group were higher than those in the control group, while the TS-21d group was more obvious than the TS-14d group. The linear regression analysis showed that Occludin, ZO-1 expression and DAO, d-lactic acid concentration was significantly negatively correlated. Conclusion Simulated weightlessness can decrease the expression of tight junction protein in rat intestinal mucosa, leading to increased intestinal mucosal permeability.