阴离子表面活性剂十二烷基硫酸钠对草鱼(Ctenopharyngodon idellus)抗氧化功能的影响

EFFECTS OF SODIUM DODECYL SULFATE ON ANTIOXIDANT ENZYMES IN CTENOPHARYNGODON IDELLUS

以草鱼为实验对象,采用不同浓度的十二烷基硫酸钠(SDS)进行10天暴露实验,研究阴离子表面活性剂对鱼类抗氧化酶的影响。急性毒性实验表明,SDS对草鱼的96hLC50为5·2mg/L。亚致死浓度SDS暴露可导致草鱼超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活性发生变化。在所有受检组织中,SOD和GSH-Px活性在暴露初期均受到不同程度的诱导,但随着SDS浓度升高和暴露时间延长,酶活性均呈明显的下降趋势,提示SDS暴露所引起的酶活性变化与暴露浓度和暴露时间有一定的相关性。此外,实验还显示两种抗氧化酶在草鱼各组织中的分布均存在明显差异。其中,肝脏SOD和红细胞GSH-Px活性较高,易于检测,且对SDS胁迫敏感。这些结果表明,SDS暴露对草鱼具有一定毒性,对抗氧化酶活性亦有明显的负面影响。

The environmental risk of anionic surfactants has become a topic of concern, which have been realized and assessed in biological toxicity in recent years. A large number of studies have investigated the toxic effects of various environmental contaminants on fish. Most of previous investigations focused on demonstrating the toxicity and toxicological mechanism of heavy metals, inorganic nitric compounds and organic contaminants. Unlike the constant control of some other contaminants, surfactant contaminants are still be released to water environment in millions of tons every year. Recently, increasing studies have been carried out to reveal the effects of anionic surfactants on fish viability, reproductivity, avoidance response and other functions. However, few reports were involved in the impacts of anionic surfactants on fish antioxidant enzymes. In this study, sodium dodecyl sulfate （SDS） was used as a reference anionic surfactant to evaluate the effects of anionic surfactants. Fish samples were juvenile grass carps in almost identical size. An acute toxicity test showed that the 96h LC50 of SDS to grass carp was 5.2mg/L. The activities of superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px） were determined in grass carp after exposures in three concentrations （0.01, 0.20 and 4.0 mg/L） of SDS for 10 days. The exposure effectiveness was judged by the change of enzyme activity. Determination of SOD in muscle, plasma and liver and GSH-Px in gills, plasma and red ceils indicated that SDS exposure resulted in changes in enzyme activity. Compared to the controis, the activities of both enzymes in all tested tissues were induced in early stages of the exposure, and then the enzyme activities decreased with increase of SDS concentration as the exposure time extended, suggesting that the enzyme activities correlated to the SDS concentration and the exposure time. Our data also revealed that the distribution of both antioxidant enzymes were different in various tissues. The highest activities of SOD and GSH-Px were found in red ceils and liver, respectively, which were easy to detect and sensitive to SDS exposure. As a conclusion, we believed that exposure to SDS could cause a significant toxic effect on grass carp, and the SDS pollutant menace in water environment showed negative effect on SOD in liver and GSH-Px in red ceils.