伽马辐照对斑马鱼胚胎谷胱甘肽还原酶活性及基因表达的影响

谷胱甘肽还原酶(GR)是一种重要的抗氧化酶,其在生物体的抗氧化系统中起着关键作用.为了研究伽马辐照对斑马鱼胚胎GR活性及基因表达的影响,本实验用不同的辐照剂量(0.01、0.05、0.1、0.5和1 Gy)分别对三个发育时期(原肠胚期、体节期和咽囊期)的斑马鱼胚胎进行了辐照处理.分析了各组GR的活性,并采用荧光实时定量PCR技术(qRT-PCR)检测了GR基因的表达水平.结果显示,伽马辐照以剂量依赖的方式调整了斑马鱼胚胎GR的活性及GR基因的表达.随着辐照剂量的增加,GR活性及其mRNA的相对表达量呈现先升高后回落的趋势.这表明,GR是一种可以对伽马辐照作出早期预警的生物标志物.斑马鱼胚胎可以通过上调GR基因的表达,来增加GR的合成,从而提高对伽马射线的防御能力.但是,这种反应和调整是有限度的.咽囊期胚胎比其它两个时期的胚胎对伽马射线的防御能力更强.

The Effects of Gamma Irradiation on Activities and Gene Expression of Glutathione Reductase in ZebrafishEmbryos

Glutathione reductase (GR),one of the most important antioxidant enzyme,plays a crucial role in the antioxidant system of an organism.This study was aimed to investigate the effects of gamma irradiation on activities and gene expression of glutathione reductase (GR) in zebrafish embryos.Different doses of gamma rays (0.01,0.05,0.1,0.5 and 1 Gy) were used to irradiate zebrafish embryos at three developmental stages (gastrula period,segmentation period and pharyngula period),respectively.The activities of GR were assayed and quantitative real-time polymerase chain reaction (qRT-PCR) was performed to measure GRgene expression.The results showed that gamma irradiation modulated the activities and gene expression of GR in a dose-dependent manner.The activities and relative mRNA levelsof GR rose at first and went down later with the increase of the irradiation doses.It was indicated that GR was a suitable biomarker for forecasting the gamma irradiation.By upregulating the gene expression of GR,and therefore increasing the synthesis of GR,the zebrafish embryos can enhance the resistance to gamma rays.But such reaction and adjustment are limited.And,the zebrafish embryos at pharyngula period had a greater ability to defend the gamma rays than those at other stages.