The Research Of Acute Toxic Effect And Molecular Mechanism Of Beta Cypermethrin In Zebrafish

Beta cypermethrin is widely used in agricultural production and daily life of pest controlling, however it is highly toxic to aquatic organisms. In this study, the activity of total superoxide dismutase (total SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione S-transferase (GST), acetylcholin esterase (AchE), and related gene expression of Sod1, Cat, Gpx1a, Ache, as well as the cytochrome P450 related gene cyp1a, cyp3a65, cyp3cl expression and apoptosis in different tissues of adult zebrafish were measured after the acute exposure of beta cypermethrin, in order to explore the effective biomarkers used in early warning of aquatic toxicity of pesticides, hope to provide parameters for the foundation of aquatic environment safety evaluation method of pesticide. Results are as follows:(1)The acute tocixity test showed that the 24 h,48 h,72 h, and 96 h medial lethal concentration (LC50) of beta cypermethrin to zebrafish were 10.304 μg·L-1,9.333 μg·L-1, 8.26 μg·L-1 and 7.816 μg·L-1, respectively, which indicated that beta cypermethrin belongs to highly toxic substances. The symptoms of poisoning, including curling, tic, faster flapping of operculum, weaker swimming ability, intermittent appearance of irregular fast moving and striking behavior were observed during the test.(2)The enzymatic activities of total SOD, CAT, GPX, GST, and AchE in zebrafish to beta cypermethrin were increase in low dose and decrease in high dose. According to the time alignment, after the exposure of low concentration of beta cypermethrin, the activities of total SOD, CAT and AchE in zebrafish were all increase, and the increasing amplitude showed a trend of increase as the exposure time extension, however, the increasing amplitude of GPX and GST activity was decrease, even at 72 h and 96 h the activities of GPX and GST were significantly decrease when compared with control group.(3)The results of antioxidant related gene expression showed that, beta cypermethrin would up-regulate the mRNA expression of Sod1, Cat, Gpx1a, and Ache in zebrafish liver, gut, and brain, the up-regulation ratio increased firstly and then decreased as the exposure time extension.(4)The detection of gene expression of cytochrome P450 showed that beta cypermethrin up-regulated the expression of cyp1a and cyp3a65 in zebrafish, but cyp3c1 was less affected, especially in the gut of zebrafish, there was no significant change of cyp3cl expression after beta cypermethrin exposure.(5)The research of apoptosis showed that 8 μg·L-1 beta cypermethrin could induce different levels of apoptosis in zebrafish liver, brain, and gill.All the results indicated that the cooperation of neurotoxicity and oxidative damage lead to the toxication even death to zebrafish. The activity of antioxidant enzyme and related gene expression can all act as biomarker to evaluate the pollution of beta cypermethrin to aquatic environment, but they can show different dose-effect relationship and time-effect relationship. The use of cytochrome P450 as biomarker is also an effective measure in monitoring the beta cypermethrin pollution, but suitable CYP450 is needed. And under a certain concentration, beta cypermethrin can induce apoptosis, thus lead to tissue damage in zebrafish, so apoptosis can also act as biomarker to evaluate the aquatic toxicity of beta cypermethrin.