环氧合酶-2在应激胃黏膜适应性细胞保护中的作用

目的：研究环氧合酶-2(COX-2)、乳癌相关肽(PS2)、诱导型一氧化氮合酶(iNOS)在水浸束缚应激(WRS)大鼠胃黏膜基因中表达的变化，探讨其在应激胃黏膜适应性细胞保护中的相互关系及作用。方法采用重复WRS制作模型，动态监测胃黏膜血流量(GMBF)，大体及光镜下观察黏膜损伤程度(UI)及组织学变化，逆转录-多聚酶链反应(RT-PCR)和Western blot检测COX-2、PS2，及iNOS表达变化。结果：单次应激造成胃黏膜广泛损伤，重复应激后胃黏膜产生适应性，胃黏膜血流量上升，损伤逐渐减轻，4次应激后，损伤指数降低为单次应激的21．99％，并且胃腺区细胞增殖。单次应激后，PS2表达减弱，而COX2及iNOS增强；重复应激后，PS2基因表达逐渐增强，而COX-2及iNOS基因表达逐渐减弱；正常时，COX-2及iNOS几乎无无达，PS2主要在胃腺颈部表达；应激后，PS2不但在胃腺颈部黏膜增殖带表达增强，在胃腺基底部亦有表达，COX-2及iNOS在溃疡及其边缘存在。结论：胃黏膜适应性细胞保护伴有细胞增殖，PS2表达逐渐增强，COX2及iNOS表达逐渐减弱，表明三者在这一现象中重要的调节作用。

Role of the mucosal gene expression for COX-2 during gastric adaptation to stress

Objective To determine the role of the mucosal gene expression for COX-2 and PS 2 as well as for iNOS during gastric adaptation to WRS in rats. Methods Wistar rats were exposed to single or repeated WRS for 4h every other day for up to 6 days,gastric mucosal blood flow was measured by LDF-3 Flowmeter,the extent of gastric mucosal lesions were evaluated grossly and histologically and expression of COX-2,PS 2 and iNOS were determined by RT-PCR and Western blot.Results WRS applied once produced numerous gastric mucosal erosions,but with repeated WRS ,the adaptation to this WRS developed,the area of gastric mucosal lesions being reduced by 21.99% after four consecutive WRS. Expression of PS 2 was markedly decreased and expression of COX-2 and iNOS were markedly increased after single stress;But this adaptation to WRS was accompanied by the increased GMBF and active cell proliferation in the neck region of gastric glands and by the increased expression of PS 2,and while by the reduced expression of COX-2 and iNOS.Conclusion Gastric adaptation to WRS injury involved in cell proliferation,increased expression of PS 2 and reduced expression of COX-2 and iNOS, it suggested that they play an important role in this phenomenen.