Study On Molecular Mechanism Of Metabolic Damage Induced By Tebuconazole Exposure

Approximately 2 million tons of pesticides are used in the world each year,and global pesticide use is expected to increase to 3.5 million tons in2021.Pesticides have insecticidal and antibacterial effects on crops,vegetables and fruits,but due to their biomagnification and persistence,the widespread use of pesticides will cause potential health hazards to the ecological environment and humans.Tebuconazole,a typical triazole fungicide,has been listed by the US Environmental Protection Agency as one of the potential human carcinogens.Presvious evidence have shown that tebuconazole is widely present in a variety of environmental media and poses an inevitable health risk to humans,and considerable adverse outcomes have been recorded,including liver toxicity,endocrine disrupting effects,developmental toxicity,and reproductive toxicity.The related research on the health risks of tebuconazole exposure is urgent.Metabolism is very important to the organism,and which is the integration of all chemical reactions in our body.Metabolism is a crucial process that controls how we use or store energy and nutrients in food.Tebuconazole may have an impact on the functions of the body by affecting the level of metabolism.However,research on the effects of tebuconazole exposure on the body’s metabolism and related mechanisms of action is still lacking.In view of this,this study is proposed to investigate the metabolic disorder of mice induced by tebuconazole exposure and its potential molecular mechanism.Firstly,C57BL/6 mice were exposed to different concentrations of tebuconazole to explore its effect on liver damage and the potential mechanism of ROS-mediated abnormal liver metabolism.In this study,high performance liquid chromatography（LC-MS/MS）was used to detect the level of tissue distribution after tebuconazole exposure,and to explore its main accumulation organs;The activity of serum aspartate aminotransferase（AST）and alanine aminotransferase（ALT）were selected as a biochemical indicator to evaluate liver function damage;The histopathological changes of the liver were observed by HE staining of liver slices;The m RNA expression level of tebuconazole genes related to bile metabolism and fatty acid metabolism were detected by RT-q PCR technology;The reactive oxygen species（ROS）,malondialdehyde（MDA）,glutathione peroxidase（GSH-PX）and superoxide dismutase（SOD）were analyzed to clarify the effects of tebuconazole on oxidative stress.In addition,with the help of molecular docking technology,the mode of action of tebuconazole and PPAR-α/LXR-αnuclear receptors were explored.The results showed that tebuconazole mainly accumulates in the liver,and significantly up-regulates the enzyme activities of AST and ALT,which leading to liver dysfunction.Additionaly,tebuconazole induced the appearance of fatty vacuoles in the liver,and increased the transcriptional expression of phase I and phase II metabolic enzymes.The expression of genes involved in bile metabolism and fatty acid metabolism were increased,which disturbs the internal environment balance of lipids and steroids,and induced the occurrence of oxidative stress in the liver.Importantly,PPAR-αand LXR-αplayed a crucial role in metabolic homeostasis.The results of previous studies suggest that tebuconazole exposure will couple with ROS to induce liver dysfunction,metabolic abnormalities and oxidative stress in the liver of mice.Both heart disease and liver disease are considered a serious burden on the health system.Studies have suggested that triazole fungicides are related to heart damage.However,it is not clear whether tebuconazole exposure can induce cardiac damage by affecting cardiometabolism.In this study,firstly,the ATP content was detected to characterize whether the energy state of the myocardium has changed;Then,the contents of fatty acids and glucose and the m RNA levels of energy substrate-related transport genes were analyzed to explore the utilization of energy substrates;Additionally,the expression of genes related to mitochondrial function of cardiomyocytes and the contents of calcium homeostasis markers Na⁺K⁺-ATPase（sodium pump）and Ca²⁺-ATPase（calcium pump）were dectected to study the damage of cardiomyocyte mitochondrial function;Lastly,the role of insulin signaling pathways and nuclear receptors were explored in process of cardiometabolic disorders.The results showed that tebuconazole could accumulate in the heart after exposure,and further induced the ATP energy supply obstacle in the mouse heart.During this process,the decomposition of the energy substrate fatty acid were inhibited,and the level of glucose were increased,which inducing abnormal cardiometabolic and cardiomyocytes.Morever,mitochondrial function was impaired and the internal balance of ion homeostasis was broken.Importantly,the insulin resistance signaling pathway and RXRαreceptors were involved in the regulation of this metabolic disorder.This study revealed the adverse effects of tebuconazole exposure on the cardiovascular system of mice and suggested its health risks to mammalian cardiovascular diseases.The typical triazole fungicide tebuconazole was chosen as the research object to investigate the molecular mechanism of liver and heart metabolic disorders and the mode of action of related nuclear receptors following exposure.It is meaningful to evaluate the health risk of typical triazole fungicides,and which provides new ideas for the prevention and diagnosis of related diseases in real life,and provides a theoretical basis for formulating pesticide risk management measures.