Metabolic Toxicity And Mechanism Of Acrylamide Exposure On Diabetic Mice

Acrylamide(ACR)is a small molecular weight organic compound whose polymers are widely used in industry.In addition,ACR is also an endogenous food contaminant,mainly generated by the Maillard reaction of starch-rich food during high-temperature cooking,and currently,high concentrations of ACR have been detected in a large number of foods,which has a high risk of human exposure and has caused widespread concern.Currently,studies on the toxic effects of ACR show that ACR exposure has various toxic effects such as neurotoxicity,reproductive toxicity,genotoxicity and potential carcinogenicity,and can interfere with the normal lipid metabolism and glucose metabolism homeostasis of the body,with endocrine disrupting effects.Diabetes mellitus is a common endocrine metabolic disease with a rapidly increasing global incidence.Numerous studies have confirmed that diabetic patients,as a susceptible population,are more sensitive to environmental pollutantinduced toxicity,but whether ACR exacerbates glucolipid metabolism disorders in diabetic patients and whether diabetic patients are more sensitive to ACR-induced toxicity has not been elucidated.The study of pollutant toxicity found that the toxic effects were sexually dimorphic,and female organisms were more susceptible to pollutant toxicity than male organisms.The experimental study of ACR body uptake showed that the body uptake rate of ACR in female organisms was significantly higher than that in male rats.Accordingly,we hypothesize that the toxic effects of ACR on female organisms may be different from those of males.Therefore,in this thesis,we propose to investigate the endocrine metabolic toxic effects of ACR exposure in female diabetic mice by establishing a female diabetic mouse model;the susceptibility of female diabetic mice to ACR-induced endocrine metabolic toxicity was analyzed by using various statistical analysis tools;and an insulin-resistant BRL cell model was established to investigate the susceptibility mechanism of endocrine metabolic toxicity due to ACR exposure.This study has important implications for the health of the female diabetic population.The main contents of this study are as follows:(1)An ACR exposure model in female diabetic mice was established to systematically study the endocrine metabolic toxicity of ACR exposure and to investigate its pathways of endocrine metabolic toxicity.The results showed that ACR exposure increased FBG levels and lipid levels(TC,LDL-C,HDL-C),inhibited hepatic glycogen synthesis,upregulated fatty acid synthesis and transport and gluconeogenesis gene expression in female diabetic mice,and inhibited the expression of fatty acid metabolism genes,which leading to the further exacerbation of gluconeogenesis and lipid metabolism disorders in female diabetic mice.It indicated that ACR exposure could cause endocrine metabolic toxicity effects.Compared with healthy organisms,the toxic effects of ACR exposure on diabetic organisms were greater,and the metabolic toxicity was stronger in female diabetic mice than in male diabetic mice;ACR exposure further reduced body weight,induced hepatic lipid deposition,upregulated the expression of inflammatory and oxidative stress genes,downregulated the expression of ACR metabolic genes,which could exacerbate hepatic impairment in female diabetic mice(AST and ALT levels were elevated),oxidative stress damage(elevated MDA levels and i NOS enzyme activity,decreased GSH levels and SOD and GSH-PX enzyme activity)and inflammatory damage(elevated IL-1β,IL-6 and TNF-α levels),and in turn interfered with glycolipid metabolic processes in liver cells;In addition,ACR exposure upregulated PERK,ATF-4,CHOP TRAF-2 protein expression and e IF-2α and JNK phosphorylation levels and p-e IF-2α/e IF-2α and p-JNK/JNK ratios,and down-regulated Bcl-2 protein expression,which indicated that ACR interfered with glucose and lipid metabolism and caused endocrine and metabolic toxicity by activating hepatic ERS and apoptotic pathways.(2)To analyze the susceptibility of female diabetic mice to metabolic toxicity caused by ACR exposure.Based on the data obtained in Chapter 2,PCA was used to downscale the data,and the analysis determined that oxidative stress,inflammatory response,endoplasmic reticulum stress,glucose metabolism and lipid metabolism were the principal component indicators that were significantly altered in ACR exposure,these indicators were associated with ACR-induced metabolic toxicity;Five key biomarkers(MDA levels in liver,TNF-α levels in serum,p-e IF-2 α protein expression in liver,G6 PD enzyme activity in liver and TC level in serum)were obtained,which were analyzed by IBR integration analysis.It is clear that ACR exposure can interfere with the normal metabolic homeostasis,exacerbate the metabolic abnormalities and stress levels in diabetic organisms,and further worsen their metabolic disorders.The diabetic organisms are more sensitive to the metabolic toxicity caused by ACR exposure than normal organisms.Finally,the interaction effect between diabetes mellitus and ACR exposure was determined by factorial analysis,the results showed that the diabetes mellitus and ACR exposure had the significant interaction effect in terms of oxidative stress,inflammatory response,endoplasmic reticulum stress and glucolipid metabolism,which further clarified the susceptibility of diabetic mice to metabolic toxicity caused by ACR exposure.(3)An ACR exposure model in insulin-resistant BRL cells was established to investigate the mechanism of metabolic toxicity susceptibility caused by ACR exposure.The results showed that ACR exposure could reduce glucose uptake and increased intracellular lipid levels,further exacerbating the disorders of glucose and lipid metabolism in insulin-resistant BRL cells,which indicated that ACR had metabolic toxicity effects,and insulin-resistant BRL cells were more sensitive to ACR-induced metabolic toxicity than normal BRL cells.The possible mechanism is:(1)ACR affects fatty acid synthesis and transport,gluconeogenesis,inflammation and oxidative stress-related gene expression in insulin-resistant BRL cells,and exacerbated oxidative stress damage and inflammation damage,which further interfered with the metabolic homeostasis of insulin-resistant cells,and thus causing metabolic toxicity;(2)ACR further induces ROS accumulation in insulin-resistant BRL cells,which could exacerbate the activation of ERS signaling pathway(promoting phosphorylation of PERK,e IF-2α and IRE-1α)and apoptotic signaling pathway(activating Caspase-3 and increasing Bax/Bcl-2 ratio),promoted apoptosis of BRL cells,aggravated their metabolic dysfunction,and then caused metabolic toxicity.The activation of both ERS and apoptotic pathways was attenuated after ROS clearance or ERS signaling pathway blockade,suggesting that ACR-induced ROS accumulation and ERS pathway transduction components are the key pathways of metabolic toxicity caused by ACR exposure.