| Objective:Ethanol,also known as alcohol,is one of the most frequently abused drugs in the world.Alcoholism,as a serious medical and social problem,has become a major cause of death and disability worldwide.Chronic ethanol exposure is also involved in a negative reinforcement process that increases the prevalence of a variety of psychosocial disorders,including anxiety and depression.In recent years,the incidence of mental disorders and disability-adjusted life years related to ethanol abuse in China have been increasing gradually.However,the mechanism of depression induced by ethanol and the changing rules of time and dose are still not clear.Therefore,in-depth study on the mechanism of mental disorders caused by ethanol could help to improve the toxicological mechanism of ethanol-caused neuropsychiatric damage,and provide further theoretical basis for the prevention and treatment of ethanol-induced nerve damage.Ethanol not only acts directly on the central nervous system,but also has a strong negative effect on the gastrointestinal system.More and more evidence has shown that ethanol intake interferes with the composition of gut microbiota by affecting the gastrointestinal microenvironment,activating the intestinal immune system and disrupting intestinal homeostasis.With the development of high-throughput sequencing and omics technology,it has been found that the alteration of gut microbiota can affect the central nervous system through multiple pathways,and participate in the pathogenesis of many mental or neurodegenerative diseases such as depression,autism,Parkinson’s disease and so on.Up to now,the relationship between gut microbiota,ethanol and depression disorder has been unclear.The purpose of this study is to further clarify the effects and rules of chronic ethanol exposure on depression disorder,to determine the role of gut microbiota in ethanolinduced mental disorders,and to further explore the underline mechanism.Methods:1.Chronic ethanol exposure mouse model for 60,90 and 180 days were established using10% or 20%(m/V)ethanol concentration,and the blood ethanol concentration of mice was detected.Forced swimming test was used to detect depressive-like behavior of mice.WB and q PCR were used to detect the expression of AMPAR receptor and its phosphorylation,inflammatory factors and apoptosis-related proteins in the hippocampus of mice.2.90 days chronic ethonal exposure mouse model was establishe using 20%(m/V)ethanol concentration,and the probiotics as added as a comparison.Behavioral and emotional changes of mice were reflected by multiple behavior tests,including OFT,EPM,FST,and serum cortisol levels.16 S r RNA gene sequencing was used to detect the changes in gut microbiota of mice.HE staining,q RT-PCR and FD4 gavage were used to detect the structure and function of intestinal barrier.ELISA and Luminex were used to detect serum LPS and various inflammatory factors.WB,q RT-PCR and immunofluorescence were used to detect hippocampal neuroinflammation,apoptosis,expression of neurotrophic proteins and synaptic proteins.3.The gut microbiota of the control and ethanol groups were transplanted into healthy recipient mice by fecal microbiota transplantation.Behavioral tests and serum cortisol levels were used to detect behavioral changes of mice,16 S r RNA gene sequencing was used to detect the changes in gut microbiota of mice.HE staining,ELISA,immunofluorescence and other methods were used to detect the function of intestinal barrier and blood-brain barrier,expression of hippocampal neurotrophic proteins and synaptic proteins.Activation of NLRP3 inflammasome and microglia,inflammatory factors and chemokines in hippocampus were detected by WB,immunofluorescence and protein microarray.4.Hippocampal NLRP3 silenced mice were obtained by injection of adeno-associated virus into the lateral ventricle,and the chronic ethanol exposure model at 20%(m/V)concentration for 90 days was established.The anxiety-like and depressive-like behavior,changes of gut microbiota,changes of intestinal barrier and blood-brain barrier,and the expressions of neurophic proteins and synaptic proteins in hippocampus were detected.Luminex was used to comprehensively detect the changes of inflammatory factors in serum.5.The gut microbiota of hippocampal NLRP3 silenced mice were transplanted into healthy recipient mice.Five behavioral tests were used to reflect the anxiety-like and depressivelike behavior,and the changes in gut microbiota,the structure of the intestinal barrier and blood-brain barrier,serum LPS and inflammatory factors,hippocampal neuronal damage,and activation of glial and NLRP3 inflammatory were detected.The association between gut microbiota,inflammatory factors and depressive-like behavior in mice were investigated by causal mediation analysis.Results:1.Chronic ehtnaol exposure for 90 days significantly increased the immobile time in forced swimming test,decreased the expression of hippocampal AMPARs Glu A1 subunit and its phosphorylation at Ser831 and Ser845,nad increased inflammatory factors and apoptosis,especially in 20%9m/V)ethanol groups.2.Chronic ethanol exposure induced anxiety-like and depressive-like behavior,high stress condition,changes in gut microbiota,intestinal barrier damage,increased serum LPS and IL-1β,blood-brain barrier damage,hippocampal neuroinflammation and neuron damage in mice.These changes could be alleviated by probiotics.3.The gut microbiota of mice exposed to chronic ethanol exposure induced anxiety-like and depressive-like behavior,high stress condition,intestinal barrier damage,increased serum LPS and IL-1β,blood-brain barrier damage,hippocampal neuroinflammation and neuron damage in recipient mice.4.After silenced NLRP3 expression in the hippocampus of mice,chronic ethanol exposure could still induce changes in gut microbiota,intestinal barrier injury,increase of serum LPS and IL-1β,and blood-brain barrier injury,but no depressive-like behavior,hippocampal neuroinflammation or neuron injury was observed.5.After chronic alcohol exposure,the gut microbiota of NLRP3 silenced mice induced depressive-like behavior,intestinal barrier injury,increase of serum LPS and inflammatory factors,blood-brain barrier injury,NLRP3 inflammasome activation,hippocampal neuroinflammation and neuron injury.Conclusion:1.Chronic ethanol exposure induced anxiety-like and depressive-like behavior were associated with the alteration of gut microbiota in mice.Chronic ethanol exposure could increase serum LPS,IL-1β,TNF-α,IFN-γ and other inflammatory factors by changing the gut microbiota,and then activate NLRP3 inflammasome in hippocampus,leading to neuroinflammation and anxiety-like,depressive-like behaviors.2.Regulation of gut micobiome or inhibitionof NLRP3-related neuroinflammation may be a prospective therapeutic target for ethanol-induced psychiatric disorders. |
PDF Full Text Request