亚硝酸盐对凡纳滨对虾血细胞毒性及p53基因表达的影响

随着水产动物集约化养殖的迅猛发展，水质污染问题日益加剧，环境中亚硝酸盐的含量不断上升，成为水产养殖中诱发爆发性疾病的重要环境因子。为探讨亚硝酸盐对凡纳滨对虾（Litopenaeus vannamei）血细胞的毒性以及 p53 mRNA 的影响，通过预试验以及前期资料获取亚硝酸盐对凡纳滨对虾的毒性效应，选取0 mg／L 对照组和20 mg／L 浓度组，用流式细胞术检测血细胞活性氧（ROS）、一氧化氮（NO）含量和非特异性酯酶活性，运用荧光定量 PCR 技术检测 p53基因表达量变化。结果显示，在亚硝酸盐应激12 h 后，对虾血细胞的 NO 含量与对照组相比有显著升高（P ＜0．05），在应激24、48、72 h 后有极显著的升高（P ＜0．01）；ROS 含量在应激12、48、72 h 时有极显著升高（P ＜0．01），在应激24 h 时与对照组相比有显著的升高（P ＜0．05）。非特异性酯酶活性在应激24、48、72 h 显著下降（P ＜0．05），p53的表达水平在应激48 h 和72 h 后显著升高（P ＜0．05）。研究表明，亚硝酸盐应激诱导对虾血细胞产生了过量的 NO 和 ROS，造成氧化胁迫作用，诱导凋亡相关基因的表达，最终导致细胞凋亡。

Effects of Nitrite Stress on Haemocyte Toxicity and p53 Gene Expression of Litopenaeus vannamei

The present study analyzed the toxic effects of nitrite on haemocyte parameters and p53 gene expression of the white shrimp Litopenaeus vannamei. At the beginning and after 4, 8, 12, 24, 48 and 72 h of nitrite exposure, reactive oxygen species (ROS) production, nitric oxide (NO) production, esterase activity and p53 gene expression in shrimp haemocytes were determined. The results showed that NO and ROS production were significantly increased after 12, 24, 48 and 72h exposure. Esterase activity decreased significantly after 24, 48 and 72h. Gene expression level of p53 significantly increased after 48 and 72h. These results indicated that nitrite stress induced overfull production of ROS and NO, caused oxidative stress, and then induced the expression of apoptosis-related genes which finally resulted in apoptosis.