Oxidative Stress And Genetoxicity Induced By Nitenpyram And Acetamiprid Exposure In Earthworm

The Neonicotinoid insecticides are one of the most important pesticides to protect the plant from sucking mouthparts pests. Nowadays, the Neonicotinoid insecticides have been widely used all over the world. More than ten varieties of such insecticides have already been made to market. Nitenpyram and Acetamiprid are porpular in the worldwide, followed the footstep of Imidacloprid which is the representative of the first generation of neonicotinoid insecticides. From recent years, a large amount of such insecticides have entered into our ecological environment through the way of surface runoff and soil residue, and made negative effects on the untarget organisms. So, it is necessary to study the toxicity of Nitenpyram and Acetamiprid to untarget organisms, which is significant to evaluate their ecological safety.To investigate the soil ecological environment effect of Nitenpyram and Acetamiprid,this article selects the international recognized biological model animal- Eisenia foetida as a biological indicator, and the soil selects the artificial soil ruled by OECD(2004). The concerntration of Nitenpyram was set by 0mg?kg-1, 0.5mg?kg-1, 1mg?kg-1, 2.5mg?kg-1, while the concerntration of Acetamiprid was set by 0mg?kg-1, 0.05mg?kg-1, 0.1mg?kg-1, 0.25mg?kg-1, 0.5mg ? kg-1. Earthworms were studied after 7, 14, 21, 28 days. The present study was conducted to investigate the effect of Nitenpyram and Acetamiprid on ROS generation,antioxidant enzymes(SOD and CAT) activity, GST activity, MDA content and the DNA damage of the earthworm. The results will be useful to evaluate the oxidative stress and gene toxicity of the two pesticides, which is also important to recognize the potential hazards of these insecticides to the soil ecological system.The main results are showed as follows:(1)Under the exposure of Nitenpyram and Acetamiprid, the ROS levels changed significantly. The high concerntration of Nitenpyram(2.5mg?kg-1) increased the ROS level at first and then decreased gradually to a low level, while the low concerntrations(0.5mg?kg-1and 1mg ? kg-1) remained the ROS content in nomal. About Acetamiprid, nearly all concentrations raised the ROS level in varying degrees.(2)Both the two varieties of Neonicotinoid insecticides changed the activity of antioxidant enzyme. The SOD activity was significantly activated after exposure to the2.5mg?kg-1 and 1mg?kg-1 concerntration of Nitenpyram, while the 0.5mg?kg-1 concerntration of Nitenpyram is nearly unchanged; however, to the the Acetamiprid, the effection to SODactivity was not obviously. On the other side, under the exposure of two insecticides, CAT activity was activiated in the beginning and then suppressed gradually. At the end, the CAT activity was similar with the Control.(3)The GST activity was influenced after the exposure to Nitenpyram and Acetamiprid.Under the exposure of Nitenpyram, the GST activity was suppressed at 7d and then increased gradually. At 28 d the GST activity becomed suppressed. While it is suppressed from 14 d to28d with the stimulation of Acetamiprid.(4)Under the exposure of both two Neonicotinoid insecticides, the MDA contents in earthworm had a tendency that increasing at the first and decreasing in the end.(5)The result of Single Cell gel electrophoreses test showed that Nitenpyram and Acetamiprid had caused DNA damage in Eisenia foetida. The Olive tail Moment and tail DNA content showed that both two insecticides can cause the dose-response relationship. But from the time range, we can see that the degree of DNA damage was declined in the end.The results above indicate that the two Neonicotinoid insecticides, Nitenpyram and Acetamiprid, can cause the oxidative stress and DNA damage of earthworms and change the activity of anti-oxidative enzyme. The research illustrates that Nitenpyram and Acetamiprid show the ecotoxity to the soil ecosystem.