中文摘要：

目的研究NO对肠上皮Caco-2细胞表达分泌片（SC）的影响。方法采用MTT方法观察一氧化氮（NO）对Caco-2细胞的杀伤作用;采用免疫组化、Western blot、real-time PCR方法检测NO对肠上皮细胞表达SC的变化影响。结果高浓度NO对Caco-2细胞有直接杀伤作用。与无NO刺激组比较,用不同浓度NO刺激后SC阳性细胞、Caco-2细胞SC蛋白和SC基因的表达明显减少（P＆lt;0.01）。结论NO可直接引起Caco-2细胞损伤,抑制肠上皮细胞分泌SC,因此NO可能削弱肠道免疫防御。

英文摘要：

Objective To study the influence of nitric oxide （NO） on the expression of secretory component（SC ） in the intestinal Caco-2 cells.by nitrous oxide （NO）. Methods MTT was used to examine the killing effect of NO on Caco-2 intestinal epithelial cell line. lm- munocytochemistry,Western blot,quantitative real-time PCR were employed to detect SC-positive cells,polymericlg receptor （pLgR）mRNA and protein expression of SC. Results High-dose NO could kill the intestinal epithelial cells directly. SC-positive cell number, SC protein and mRNA expression of NO treated group were less than those of the untreated group （P 〈 0.01 ）. Conclusion NO may impair the intestinal immunity defense through killing the intestinal epithelial cells and inhibiting the expression of secretory component in the intestinal epithelial cells.