Investigation Of The Mechanism Of The Reproductive Toxicity Of Zearalenone On Cells From Target Organ

Zearalenone(ZEA),a mycotoxin produced by several species of Fusarium,is a frequent contaminant of cereal crops worldwide.Reproductive toxicity is most prominent among the diverse toxicological effects induced by ZEA,and it harms the reproductive system.Thus far,the mechanism of ZEA reproductive toxicity has not been clearly demonstrated,and little is known about the toxicity of this mycotoxin on the molecular level.In the present work,we examined the oxidative stress,hormone production and regulation of gene expression combined with the proteomic technology to identify the possible mechanism of ZEA toxicity on mouse leydig tumor cell(MLTC-1)and mouse granulosa tumor cell(KK-1).The main results obtained were summarized as follows:(1)ZEA inhibited the MLTC-1 cell viability in a dose-independent manner.ZEA triggered the production of reactive oxygen species(ROS),activated lipid oxidation,decreased mitochondrial membrane potential,induced DNA strand break,and caused cell apoptosis and necrosis.(2)The effect of ZEA on KK-1 cell viability showed hormetic dose-response curves,which is characterized by a low-dose stimulation and a high-dose inhibition.The mitochondrial membrane potential increased at low level of ZEA treatment,and then decreased at high concentrations.ZEA triggered the production of ROS,activated lipid oxidation,induced DNA strand break,and caused cell apoptosis and necrosis.(3)ZEA treatment broke the balance of hormone excretion homeostasis.ZEA regulated the transcription and translation process of the key enzyme and protein in hormone synthesis.(4)2-DE proteomic was performed in MLTC-1 and KK-1 cells exposed to ZEA,and 22 and 25 differentially expressed proteins were identified at least 1.2 fold,respectively.The majority of the proteins were involved in ATP synthesis,redox regulation,DNA damage,and stress response.(5)An iTRAQ-based mitoproteomics approach was employed to identify the molecular mechanism of zearalenone toxicity using mitochondria of mouse leydig tumor cells.The results suggest that lipid metabolism changed significantly after low-dose ZEA exposure,resulting in two alterations.One is the increase in energy production through promoted fatty acid uptake and β-oxidation,along with excessive oxidative stress;the other is an inhibition of steroidogenesis and esterification,possibly resulting in reduced hormone secretion.