宫内窘迫胎鼠肾组织环氧化酶-2表达的实验研究(英文)

Expression of cyclooxygenase-2 in the kidney of fetal rats following intrauterine distress

目的 缺血缺氧性肾损伤是一个复杂的病理生理过程,炎症反应在其中占有重要的作用。该文 旨在观察宫内窘迫后胎鼠肾组织炎症介质环氧化酶 2(COX 2)蛋白和基因表达及其代谢产物前列环素I2(PGI2), 前列腺素E2(PGE2)和血栓素(TXA2)的动态变化,初步探讨COX 2在宫内窘迫胎鼠肾损伤发病机制中的作用。方 法 制备胎鼠宫内缺血缺氧再灌注模型(缺血缺氧组:缺血缺氧30min;再灌注组:缺血缺氧30min后,分别再灌注 0.5h,2h,6h,12h,24hand30h)。各时间点分别取胎鼠20只,假手术组胎鼠22只,将肾组织匀浆后采用 RT PCR,Western印迹杂交和放免法进行检测。同时苏木精 伊红染色观察肾组织病理学改变。结果 宫内窘迫 后胎肾组织COX 2蛋白和基因表达上调,PGI2的稳定代谢产物6 keto PGF1α及PGE2均于再灌注2h开始增高(P <0.05)。其中6 keto PGF1α增加迅速,于再灌注12h达高峰(P<0.01),PGE2于再灌注24h达最高水平(P< 0.01),而TXB2增加幅度不大。结论 宫内缺血再灌注从转录水平诱导胎肾COX 2蛋白表达增强,COX 2的主要 代谢产物是PGI2和PGE2。COX 2可能通过PGI2和PGE2对缺血性胎肾损伤具有保护作用,因此,在围产期肾损 伤不宜应用COX 2抑制剂。

Objective To examine the mRNA and protein expressions of cyclooxygenase-2 (COX-2) and the kinetic changes of three metabolites (PGI 2, PGE 2 and TXA 2) of COX-2 in kidney tissues of fetal rats after intrauterine distress (ID), and to explore the possible roles of COX-2 in the pathogenesis of kidney impairment of fetal rats after ID. Methods A model of intrauterine ischemia and hypoxia of fetal rats was made by occluding one side of vessels supplying two horn uteri. The fetal rats in the other side were used as Sham-operation group (n=22). After 30 minutes of blood occlusion, reperfusion started. Pups were removed 0, 0.5, 2, 6, 12, 24 and 30 hrs post-reperfusion respectively (n=20 for each time point). After the renal tissues of fetal rats were homogenized, RT-PCR, Western blotting and radioimmunoassay methods were used to detect the mRNA and protein expressions of COX-2 and the kinetic changes of PGI 2, PGE 2 and TXA 2 concentrations. At the same time, hematoxylin-eosin staining was used to observe the histopathological changes of the kidney.Results After intrauterine ischemia, hypoxia and reperfusion, the expressions of COX-2 protein and gene in fetal rat kidney were significantly up-regulated. Compared with the Sham-operation group, the concentrations of 6-keto-PGF 1α and PGE 2 began to increase following 2 hrs of reperfusion, and reached a peak 12 hrs and 24 hrs after reperfusion respectively. The TXB 2 concentration in the Ischemia-reperfusion group was not different from the Sham-operation group at any reperfusion time point.Conclusions Intrauterine ischemia, hypoxia and reperfusion can induce the up-regulation of COX-2 expression in fetal kidney at the transcriptional level. COX-2 may play a protective role in ischemic impairment of fetal kidney through PGI 2 and PGE 2. It is suggested that COX-2 inhibitors should not be used for kidney impairment patients during the perinatal period.