中文摘要：

目的研究热打击对肠黏膜屏障上皮细胞间紧密连接及凋亡的影响。方法采用肠上皮细胞株Caco-2建立肠屏障模型,检测经37~43℃热打击后细胞的单层跨膜电阻抗（TEER）值及对大分子物质辣根过氧化物酶（HRP）的通透性,采用Western blotting检测occludin蛋白的表达水平,Annexin V-FITC/PI流式细胞术检测细胞凋亡情况。结果随着热打击温度的升高,TEER值降低,HRP通透性增加,37℃热打击细胞的TEER值和HRP通透性与39、41、43℃热打击细胞差异均有统计学意义（P〈0.01）。热打击温度从37℃到41℃,occludin蛋白的表达逐渐增加,于41℃达峰值,此后逐渐下降。43℃时随热打击时间延长,occludin蛋白表达逐渐降低。随热打击温度（37~43℃）升高,细胞凋亡逐渐增加（P〈0.05或P〈0.01）。结论热打击可造成肠上皮紧密连接的明显破坏,细胞凋亡增加,从而破坏肠屏障功能。

英文摘要：

Objective To investigate the heat stress-induced dysfunction of intestinal barrier including intestinal tight junction and apoptosis of epithelial cells. Methods Human intestinal epithelial Caco-2 cell monolayers, serving as the intestinal barrier model, were exposed to different temperature （37-43℃） for designated time. Transepithelial electrical resistance （TEER） and horseradish peroxidase （HRP） flux permeability were measured to evaluate barrier integrity. Level of tight junction （TJ） protein occludin was analyzed by Western blotting. Cell apoptosis rate was determined using Annexin V-FITC/PI kit by flow cytometry. Results Compared with the 37℃ group, TEER lowered and the permeability for HRP increased significantly after heat exposure （P〈0.01） in 39 ℃, 41 ℃ and 43 ℃ groups. The expression of occludin increased when the temperature was elevated from 37 ℃ to 41℃, and it reached the maximal level at 41 ℃. However, its expression gradually decreased with passage of time at 43℃. Cell apoptosis was enhanced with elevation of the temperature （P〈0.05 or P〈0.0 1）. Conclusion Heat stress can induce damage to tight junction and enhance apoptosis of epithelial cells, thus causing dysfunction of intestinal epithelial barrier.