| With the continuous improvement of living standard,people concern nutrition,health and food safety more and more.The proportion of fruits on food production and consumption is gradually increasing because of its rich nutrition.And pesticide residues in fruits become the focus in food safety work.Pesticides can induce neurotoxicity,genotoxicity,immunotoxicity,reproductive and developmental toxicity,and other potential toxicity.Using high dose of pesticides can produce residues in the environment and food products.It will enter the body through diet and cause great threat to human health.In order to reduce the resistance of pests and achieve better control effect,people usually used compound pesticides or used different pesticides simultaneously in the process of agricultural production such as the mixture of organophosphorus and pyrethroid.This leads to the phenomenon that food products may contain residues of several different pesticides.As a result,the human body exposed to the complex mixtures of pesticides unavoidably through diet and environment.So the combined toxicity and action mechanisms among different pesticides should also pay attention to.In addition,traditional studies on pesticide toxicity are mostly using living animals as experimental model in vivo.However,animal experiments are time-consuming,high-energy and high cost.Cell experiment in vitro is a rapid,simple and low cost method.This method is gradually used for evaluation of pesticide mixtures safety in recent years.Organophosphorus pesticide isocarbophos and pyrethroid pesticide fenpropathrin both have high detection rate in fruits.They are both typical nerve poison.Studying the combined effect between them is helpful to formulating pesticide residue limit standards and safety evaluation.Human neuroblastoma cell line SH-SY5 Y was used in this paper as test object.The first part is to study the cytotoxicity induced by isocarbophos and fenpropathrin when used individually or in mixture,through determining the cell vitality,and use Combination Index(CI)to evaluate their combined effect of cytotoxicity.The second part is to study the neurotoxicity induced by isocarbophos and fenpropathrin when used as individuals or in mixture,through observing cellular morphology and determining the AChE activity,and to evaluate their combined effect of neurotoxicity.The third part is to study the oxidative stress induced by isocarbophos and fenpropathrin when used individually or in mixture,through determining the intracellular reactive oxygen species(ROS)level,the SOD activity,the CAT activity,the cellular content of malondialdehyde(MDA),the relative expression level of Nrf2 gene,and evaluate to their combined effect of oxidative stress.The main results are as follows:(1)Under the exposure concentrations and exposure time of this test,isocarbophos and fenpropathrin both can induce cytotoxicity to SH-SY5 Y when used as individuals or in mixture,leading to a decline in cell vitality.And the cytotoxicity has positive correlation with exposure concentrations and exposure time.The median lethal concentration of isocarbophos to SH SY5 Y cells are 201.06 ?mol/L(12h),116.78 ?mol/L(24h),53.12 ?mol/L(48h)and 19.72 ?mol/L(72h).The median lethal concentration of fenpropathrin to SH SY5 Y cells are 227.70 ?mol/L(12h),150.94 ?mol/L(24h),56.79 ?mol/L(48h)and 21.30 ?mol/L(72h).Cytotoxicity of Isocarbophos was slightly stronger than fenpropathrin.(2)Under the exposure concentrations of this test,isocarbophos and fenpropathrin both can induce neurotoxicity to SH-SY5 Y cells when used as individuals or in mixture,leading to a decline in AChE activity and some morphological changes such as cell density decreased,cell body shrank and neural axon growth suppressed.The neurotoxicity of Isocarbophos was stronger than fenpropathrin.(3)Under the exposure concentrations of this test,isocarbophos and fenpropathrin both can induce oxidative stress to SH-SY5 Y cells when used as individuals or in mixture.They can stimulate the intracellular reactive oxygen species(ROS),leading to the increase of ROS level and a decline in antioxidase activity(SOD,CAT).These changes increased oxidative damage degree of cell,inducing lipid peroxidation and activating cells Nrf2 signaling pathways,ultimately causing the increase of cellular MDA content and Nrf2 gene relative expression level.Fenpropathrin induces stronger oxidative stress than isocarbophos.(4)Under the exposure concentrations of this test,isocarbophos and fenpropathrin present synergism to cytotoxicity and oxidative stress of SH-SY5 Y cells.The inhibitions of pesticide mixture on cell vitality,SOD activity and CAT activity are stronger than two pesticides used as individuals.With the increase of exposure concentration,isocarbophos and fenpropathrin present synergism,additive and antagonism successively to neurotoxicity.The results of this paper provided data support for the toxicology research of organophosphorus pesticide isocarbophos and pyrethroid pesticide fenpropathrin.They also provide a certain reference for combined pesticide residues pollution risk assessment of organophosphorus and pyrethroid.Pesticides have neurotoxicity,genotoxicity,immunotoxicity,reproductive and developmental toxicity,and other potential toxicity.Using high dose of pesticides can produce residue in the environment and food products.It will enter the body through diet and cause great threat to human health.In order to reduce the resistance of pests and achieve better control effect,people usually used compound pesticides or used different pesticides simultaneously in the process of agricultural production such as organophosphorus and pyrethroid.This leads to that food products may simultaneously contain residues of several different pesticides.As a result,the human body exposure to the complex mixtures of pesticides unavoidably through diet and environment.So the combined toxicity and action mechanisms between different pesticides are also gradually attention.In addition,traditional studies on pesticide toxicity mostly use living animals as experimental model in vivo.But animal experiments are time-consuming,high-energy and high cost.Cell culture in vitro is rapid,simple and low cost.This method is gradually used for evaluation of pesticide mixtures safety in recent years.This paper chose human neuroblastoma cell line SH-SY5 Y as test object.The first part is to study the cytotoxicity induced by organophosphorus pesticide isocarbophos and pyrethroid pesticide fenpropathrin in fruits when used individually or in mixture,through determining the cell vitality,and use Combination Index(CI)to evaluate their combined effect of cytotoxicity.The second part is to study the neurotoxicity induced by isocarbophos and fenpropathrin when used individually or in mixture,through observing cellular morphology and determining the AChE activity,and evaluate their combined effect of neurotoxicity.The third part is to study the oxidative stress induced by isocarbophos and fenpropathrin when used individually or in mixture,through determining the intracellular reactive oxygen species(ROS)level,the SOD activity,the CAT activity,the cellular content of malondialdehyde(MDA),the relative expression level of Nrf2 gene,and evaluate their combined effect of oxidative stress.The main results are as follows:(1)Under the exposure concentrations and exposure time of this test,isocarbophos and fenpropathrin both can induce SH-SY5 Y cells to produce cytotoxicity when used individually or in mixture,leading to a decline in cell vitality.And the cytotoxicity has positive correlation with exposure concentrations and exposure time.Test obtained the median lethal concentration of isocarbophos and fenpropathrin to SH SY5 Y cells for the first time.Isocarbophos has slightly stronger cytotoxicity than fenpropathrin.(2)Under the exposure concentrations and exposure time of this test,isocarbophos and fenpropathrin both can induce SH-SY5 Y cells to produce neurotoxicity when used individually or in mixture,leading to a decline in AChE activity and some morphological changes such as cell density decreased,cell body shrank and neural axon growth suppressed.Isocarbophos has stronger neurotoxicity than fenpropathrin.(3)Under the exposure concentrations and exposure time of this test,isocarbophos and fenpropathrin both can induce SH-SY5 Y cells to produce oxidative stress when used individually or in mixture.They can stimulate the intracellular reactive oxygen species(ROS),leading to the increase of ROS level and a decline in antioxidase activity(SOD,CAT).These changes increased oxidative damage degree of cell,inducing lipid peroxidation and activating cells Nrf2 signaling pathways,ultimately causing the increase of cellular MDA content and Nrf2 gene relative expression level.Fenpropathrin induces stronger oxidative stress than isocarbophos.(4)Under the exposure concentrations and exposure time of this test,isocarbophos and fenpropathrin present synergism to cytotoxicity and oxidative stress of SH-SY5 Y cells.The inhibitions of pesticide mixture on cell vitality,SOD activity and CAT activity are stronger than two pesticides used individually.With the increase of exposure concentration,isocarbophos and fenpropathrin present synergism,additive and antagonism successively to neurotoxicity.The results of this paper can provide data support for the toxicology research of organophosphorus pesticide isocarbophos and pyrethroid pesticide fenpropathrin.They also provide a certain reference for combined pesticide residues pollution risk assessment of organophosphorus and pyrethroid. |
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