低氧和高氧对大菱鲆幼鱼红细胞核异常及氧化抗氧化平衡的影响

The effects of hypoxia and hyperoxia on nucleus anomaly,SOD,CAT activities and MDA content in juvenile turbot Scophthalmus maximus

研究了极低氧(0.2、1.0、2.0 mg/L)、低氧(3.0、5.0 mg/L)和高氧(11.0、14.0 mg/L)处理28 d期间,大菱鲆幼鱼外周血红细胞核异常以及血清超氧化物岐化酶(SOD)、过氧化氢酶(CAT)活力和肝脏丙二醛(MDA)含量等氧化抗氧化平衡中参数的变化。结果显示,极低氧条件下,0.2、1.0和2.0 mg/L组的实验鱼分别在处理2 h、1 d和2 d内全部死亡,其余各组则没有出现死亡现象。溶解氧(DO)对大菱鲆核异常包括微核及总核异常率的影响表现出明显的时间和剂量累积效应,到28 d时才在5.0、14.0 mg/L组和对照组中(正常充气,约7.0 mg/L)观察到微核现象。恢复正常充氧14 d后,高氧组和对照组中仍有微核现象出现。2 h时极低氧组SOD活力较高。其他各处理时间时,SOD活力在各组之间差异显著。各组CAT活力在2 h时未发生明显变化,在7、28和42 d时差异显著(P<0.05)。极低氧组大菱鲆肝脏MDA含量较低,低氧组和高氧组MDA含量均随着处理时间的延长逐渐降低。恢复后低氧组MDA含量显著升高(P<0.05)。研究还发现,对照组大菱鲆也会受到过氧化的胁迫作用,而5.0 mg/L组的总核异常率和所测氧化还原指标在整个实验期间均未发生明显变化。

The effects of different dissolved oxygen（DO） concentrations,including severe hypoxia（0.2,1.0,2.0 mg/L）,hypoxia（3.0,5.0 mg/L）,normoxia（normal aeration as control,about 7.0 mg/L） and hyperoxia（11.0,14.0 mg/L）,on nucleus anomaly in erythrocytes,superoxide dismutase（SOD）,catalase（CAT） activities in serum and malondialdehyde（MDA） concentration in liver were studied in juvenile turbot Scophthalmus maximus.Fish mortality was only observed in the 0.2,1.0 and 2.0 mg/L groups,in which all fish died in 2 h,24 h and 48 h,respectively.The effects of DO on nucleus anomalies were shown with obvious time-cumulative effects and dose-cumulative effects in the 28-day experiment.The micronuclei were first observed in the 5.0,14.0 mg/L and control groups on day 28.They were still found in hyperoxia and control groups after recovery for 14 days.The SOD activities in different groups showed significant difference at each sampling time（P0.05）.The difference in CAT activities among experiment groups was significant only after 7-day exposure（P0.05）.The MDA concentration increased with the increasing concentration at 2 h.The MDA concentration in hypoxia and hyperoxia groups decreased with time duration.After 14-day recovery,the MDA concentration in hypoxia groups was significantly higher compared with those in control groups（P0.05）.Additionally,the oxidative stresses were also found in control groups.No obvious changes on the total nucleus anomalies and other anti-oxidative index were found in 5.0 mg/L groups.