悬浮物对褐牙鲆抗氧化酶活性及相关基因表达的影响

为探究褐牙鲆(Paralichthys olivaceus)幼鱼抗氧化系统酶活力及相关基因表达在悬浮物胁迫下的变化情况,设计了浓度为5 000、10 000 mg·L-1悬浮物水体对褐牙鲆(14.53 cm±1.58 cm)肌肉、肝脏、鳃及血液总超氧化物歧化酶(T-SOD)、谷胱甘肽转移酶(GST)、过氧化氢酶(CAT)酶活力及SOD2、GST、CAT的mRNA转录水平表达变化情况。结果显示:在悬浮物胁迫24 h或者48 h时,4种组织3种酶活力具有升高的趋势(P0.05);4种组织的T-SOD酶活力在96 h均高于对照组(P0.05),肌肉、鳃丝及血液中SOD2基因相对表达量96 h实验组低于对照组(P0.05);肌肉中CAT酶活力呈现先升高再降低趋势,鳃中CAT基因相对表达量呈现先降低、再升高、再降低的趋势;肝脏、鳃、血液中GST酶活力在悬浮物胁迫下呈现升高趋势,4种组织GST基因相对表达量在12~24 h时呈现升高趋势。研究表明:悬浮物对褐牙鲆抗氧化酶活力及相关基因的表达具有一定的影响,血液中3种酶活力变化幅度最大,鳃中3种基因相对表达水平变化幅度最大,这与血液及鳃参与呼吸作用过程有关;抗氧化酶活性及基因相对表达变化趋势并不完全一致。本研究可为揭示褐牙鲆应对悬浮物胁迫的耐受机制及褐牙鲆耐悬浮物品种选育提供基础数据。

Effects of Suspended Substances Stress on Antioxidant System Enzyme Activities and Gene Expression of Paralichthys olivaceus

Japanese flounder, Paralichthys olivaceus is an important enhancement species in Bohai Bay of China. The high suspended substances (SS) concentration of the seawater caused a serious impact on the survival and proliferation of P. olivaceus organisms. It is well known that environmental stress can induce oxidative stress. However, there is little information about the effects of SS changes on antioxidant system of Japanese flounder. In this study, Japanese flounder (14.53 cm±1.58 cm) were exposed to SS with the concentration of 5 000 mg?L^-1 and 10 000 mg?L^-1. The activities of total superoxide dismutase (T-SOD), catalase (CAT), glutathions S-transferase and the relative expressions of SOD₂, CAT and GST gene in muscle, liver, gill and blood were analyzed in Japanese flounder after 0 h, 24 h, 48 h, 72 h and 96 h exposure. The results showed that all enzyme activity in four tissues have a rising trend (P<0.05) after 24 h or 48 h exposure to SS. The T-SOD activity in four tissues after 96 h exposure were higher than control group (P<0.05), while the SOD₂ gene relative expression of muscle, gill and blood in exposure group are lower than the control group (P<0.05) after exposure to SS for 96 h. The CAT activity in muscle showed a trend of increasing first, then decreasing, while the CAT gene relative expression showed a trend of decreasing first, then increasing, and decreasing again. The GST activity of liver, gill and blood showed a trend of increasing after exposure to SS, and the GST gene expression of four tissues showed a trend of increasing after exposure to SS from 12 to 24 h. It is suggested that the SS has a certain effect on antioxidant enzyme activities and gene expressions of P. olivaceus. The variations of enzyme activities of blood and the variations of gene relative expressions of gill are larger than other tissues, which is associated with the fact that the blood and gills is involved in the respiration process. The variations of antioxidant enzyme activities are not entirely consistent with the variations of the relative gene expressions.