中文摘要：

为探究亚硝态氮对于草鱼离体肝细胞抗氧化系统的影响，将分离得到的离体草鱼肝细胞在含0（空白），1，10和100 mg/L （浓度以氮计）的亚硝酸钠的M199生长培养基中，分别培养6、12、24、48和96 h后，检测肝细胞中超氧化物歧化酶（ SOD ）、过氧化氢酶（ CAT ）、γ-谷氨酰半胱氨酸合成酶（γ-GCS ）和谷胱甘肽转移酶（GST）的活性，谷胱甘肽（GSH）水平以及总抗氧化能力（TAC）。结果显示：高浓度的亚硝酸钠会引起肝细胞内的SOD、 CAT、 GST、γ-GCS活性显著升高；除100 mg/L实验组外，各实验组的 GSH水平均显著高于对照组，而TAC则随着亚硝酸钠浓度的升高，表现为先升高后下降的规律，且当亚硝酸钠浓度为10 mg/L时， TAC达最高水平。结果表明，较低剂量的亚硝态氮急性暴露可激活肝细胞抗氧化系统并促进其提高抗氧化能力，而高剂量亚硝态氮（100 mg/L）则显著降低了肝细胞的抗氧化能力。

英文摘要：

To investigate the effects of nitrite on the anti-oxidative system of grass carp （ Ctenopharyngodon idle lus） isola-ted hepatocyte, the hepatocytes were exposed to four experimental groups （0, 1, 10 and 100 mg nitrite per liter）.The activities of superoxide dismutase （SOD）, catalase （CAT）, γ-gutamylcysteine synthetase （γ-GCS） and glutathione S-transferase （GST）, glutathione （GSH） content,and the total antioxidant capacity （TAC） were assayed at 6, 12, 24, 48 and 96 h, respectively after exposure .The results showed that the activities of SOD、 CAT、 GST andγ-GCS increased significantly after exposure in higher dose groups .The contents of GSH in hepatocytes exposed to nitrite were significantly higher than that in control group except for the 100 mg/L group.Nitrite exposure exerted deleterious effect on the TAC of hepatocytes and its activity increased initial and then declined .The TAC exposed to 10 mg/L nitrite was significantly high-er than that of other groups .In short , acute exposure of low dose nitrite could activate the antioxidant system of hepato-cytes and promote the antioxidant capacity , but high dose nitrite might depress the antioxidant capacity significantly .