The Cytotoxicity And Mode Of Action On Cells Of Two Practical Pesticides

Pesticides screening plays an important role in the development of new insecticides. Compared with traditional screening in vivo, the method of screening in vitro is more economic and convenient with good repeatability. As the development of molecular biology and biotechnology, screening in vitro method will be more widely used in the research of pesticides. This study evaluatesd the compounds’ biological activity and mechanism of action based on screening in vivo and in vitro methods. Firstly, we choosed insect cells Sf9, S2 and mammal HeLa cells to measure the cytotoxicity of different compounds and select highly active pesticides by MTT. Our results indicated that fipronil administrated the concentration-and time-dependent S2 cell proliferation. Intracellular biochemical assays, including apoptotic analysis, western blotting, mitochondrial membrane potential assasy, showed that fipronil effectively induced apoptosis in Drosophila S2 cells through caspase-dependent mitochondrial pathways. Fipronil-induced S2 cell apoptosis coincided with a decrease in the mitochondrial membrane potential, a significant decrease of Bcl-2 and DIAP1 and an increase reactive oxygen species, which induced the release of Cyt c from mitochondrial and then actived caspase-9 and caspase-3. In addition, we found Imidacloprid, Cycloxaprid, Seven-Membered Azabridge Neonicotinoid Analogue IPP167225 had high toxicity to Periplaneta americana nymph using injection methods. By acute dissection of DUM neurons loaded DiBAC4(3) fluorescent dye, we found all three compounds induced cell membrane depolarization, and also influenced the enzyme activity of Na+-K+-ATPå'ŒCa2+-Mg2+-ATP in cockroach’s head. In conclusion, this research explored the cytotoxicity of different pesticides and studied the mode of action of Fipronil, Imidacloprid, Cycloxaprid and IPP167225 through the cell toxicology, molecular biology and fluorescent analysis, in order to provide the evidence for efficiently compounds’screening and structure modification.