中文摘要：

目的：研究梯度热打击对体外培养肠黏膜上皮细胞活性和增殖的影响。方法：肠黏膜上皮细胞株IEC-6经培养后分为正常对照组（37℃、5％CO2培养箱培养）及39℃、41℃、43℃热打击组（分别在相应温度培养箱中培养），相差显微镜观察各组细胞培养1h的形态学改变，CCK8法比较各组细胞培养0、1、3、5、7h的细胞活性和24h增殖率，流式细胞术研究细胞周期的改变。结果：与正常对照组比较，各热打击组各个时相细胞形态变圆，伪足变短，细胞间隙增大，活力下降（P〈0．01）。24h细胞增殖实验显示，与正常对照组比较，39℃组7h及41℃和43℃组各时相增殖率显著下降（P〈0．01），呈时间及温度依赖关系。流式细胞术检查显示，热打击组细胞呈现细胞周期G0／G1和G2／M期阻滞。结论：热打击对IEC-6细胞具有细胞毒效应，可抑制IEC-6细胞的增殖，造成细胞周期G0／G1和G2／M期阻滞。

英文摘要：

Objective： To investigate the effect of gradient heat stress on the viability and proliferation of intestinal epithelial cells in vitro. Methods： The cultured intestinal epithelial cells IEC-6 were divided into normal control group（37 ℃ ）and 39 ℃ , 41 ℃ , 43 ℃ heat stress groups. The IEC-6 cells in different groups were cultured in a 5 % carbon dioxide incubator, and they were exposed to the different temperature in vitro. Phase contrast microscope was used to observe the morphology of IEC-6 1 hour after thermal stimulation, and CCK 8 assay was used to determine cellular viability after 0, 1, 3, 5, 7 hours of thermal stimulation, as well as 24-hour proliferation rate of each group. Flow cytometry was used to investigate the influence of heat stress on the change of IEC-6 cell cycle. Results： Compared to the normal control group, cells of each heat stress group became rounded, with shorter pseudopod, increase in cellular interspace, and declination of vitality（P〈0.01）. The assay of 24-hour proliferation indicated that the proliferation rate of the cells undergone 7 hours of exposure to 39 ℃ group and that of each phase of cells underg one 41 ℃ and 43℃ were significantly decreased compared to the normal control group（P〈0.01）, and the decrease was time-and thermal-dependent. With flow cytometry, arrest of cell cycle at G0/G1 and G2/M phases was observed in heat stress groups. Conclusions： Heat stress has eytotoxic effect on intestinal epithelial cells IEC-6. It inhibits cellular proliferative capacity, and arrests cell cycle at G0/G1 and G2/M phases.