微囊藻毒素MC-LR对罗非鱼(Oreochromis niloticus)肝脏谷胱甘肽含量及其相关酶活性的影响

The Effect of MC-LR on Glutathione Concentration and Its Related Enzymes Activity in Liver of Tilapia(Oreochromis niloticus)

采用腹腔注射的方式研究了微囊藻毒素MC-LR(注射剂量为500μg.kg-1 BW)胁迫下罗非鱼(Oreochromis niloticus)肝脏谷胱甘肽(GSH)含量及其相关酶γ-谷氨酰半胱氨酸合成酶(γ-GCS)、谷胱甘肽硫转移酶(GST)、谷胱甘肽还原酶(GR)和谷胱甘肽过氧化物酶(GPx)活性的动态变化。结果表明,MC-LR能够对罗非鱼肝脏GSH含量及其相关酶活性产生明显影响。在MC-LR胁迫下,与对照组相比,GSH含量呈现先下降后上升趋势,总体上被诱导;罗非鱼肝脏γ-GCS和GST在试验过程中出现两次显著升高现象,在GST作用下,GSH与MC-LR结合会造成GSH的消耗,γ-GCS和GR的活性增强能够使GSH含量升高,从而使罗非鱼肝脏GSH能够维持一定水平;GR和GPx的活性均表现为先上升后下降,它们能有效调节罗非鱼肝脏GSH-GSSG缓冲系统,从而在减轻或消除由MC-LR侵入而造成的肝细胞氧化胁迫中发挥重要作用。

The effects of microcystin-LR（MC-LR）on the dynamic changes of the concentration of glutathione（GSH）and the activity of GSH related enzymes,such as γ-Glutamylcysteine synthetase（γ-GCS）,Glutathione S-transferase（GST）,Glutathione peroxidase（GPx）,Glutathione reductase（GR）in the liver of tilapia were studied by intraperitoneal injection.The results showed that GSH concentration and its related enzymes activities could be significantly influenced by MC-LR.GSH concentration in tilapia liver decreased firstly and then in-creased and GSH concentration increased as a whole during the test.Both γ-GCS and GST activity had two peak values that were all signifi-cant higher than that of the control during the test.The combination of GSH and MC-LR could contributed to GSH consumption and the in-crease of γ-GCS and GR activity could increase GSH concentration,therefore,the GSH concentration in the liver of tilapia could maintain initial value.The activities of both GR and GPx increased firstly and then decreased.GR and GPx could effectively adjust the GSH-GSSG buffer system,which plays an important role in lightening or eliminating the liver cells oxidation intimidation caused by MC-LR invading.