| Objective:1.To construct a mouse model of alcohol-induced depression-like behavior;2.To explore whether Akkermansia muciniphila(A.muciniphila,AKK)can alleviate alcohol-induced depression-like behavior in mice;3.To understand the potential mechanism by which A.muciniphila improves alcohol-induced depression-like behavior in mice.Methods:1.After modeling by chronic alcohol gavage(alcohol gavage 12,control gavage 12)and NIAAA chronic and binge ethanol feeding(ethanol liquid diet 12,control liquid diet 12)by using 48 of 8 weeks old male C57BL/6 mice,the behavioral comprehensive assessment of multiple dimensions such as gross activity,depression and anxiety-like behavior,learning and memory function was performed to ensure the successful construction of alcohol-induced depression-like behavior model in mice;2.A.muciniphila gavage intervention was performed in the modeled mice(chronic alcohol gavage:alcohol gavage+A.muciniphila gavage 12,alcohol gavage+glycerine gavage 12;and NIAAA chronic and binge ethanol feeding:ethanol liquid diet+A.muciniphila gavage 12,ethanol liquid diet+glycerine gavage 12)by using 48 of 8 weeks old male C57BL/6 mice)to comprehensively assess the changes of behavioral parameters and evaluate the improvement effect of A.muciniphila gavage on alcohol-induced depression-like behavior in mice;3.By detecting neurotransmitters such as 5-HT,alcohol concentration in vivo after alcohol gavage and alcohol metabolism enzyme activities,liver function and other indicators,the potential mechanism of A.muciniphila gavage in improving alcoholinduced depression-like behavior in mice was understood.Results:1.Mice in NIAAA chronic alcohol spontaneous diet model had significantly increased motionlessness time in forced swimming test(P<0.05);in tail-suspension-test,mice in chronic alcohol gavage model group had significantly increased motionlessness time(P<0.0001);in sugar water preference test,mice in chronic gavage alcohol group had decreased sugar water preference,but there was no statistically significant difference(P>0.05).There were no significant differences in other behavioral assessments such as total movement distance in the open field experiment,movement time and movement distance in the central area of the open field experiment,short-term memory and long-term memory in the conditioned fear experiment between the model group(chronic alcohol gavage model and NIAAA chronic alcohol spontaneous diet model)and control group(P>0.05).At the same time,mice developed significant liver function damage in the chronic alcohol gavage model,as shown by increased AST and ALT(P<0.05),while alcohol-induced liver function damage was not observed in the NIAAA chronic alcohol spontaneous diet model.2.The NIAAA model mice in the A.muciniphila gavage intervention group showed reduced motionlessness time in the Tforced swimming test,although there was no statistically significant difference(P=0.0522);the A.muciniphila gavage intervention group in the chronic alcohol gavage model mice had significantly reduced motionlessness time in forced swimming test(P<0.01)and muctailension-test(P<0.05);the sugar water preference in the A.muciniphila gavage group was significantly increased in the chronic alcohol gavage model in the sugar water preference test(P<0.05).In terms of between the A.muciniphila gavage group and the saline control group,in open field test,there was no significant difference in the total movement distance and total movement time between the two groups(P>0.05),and there was no significant difference in the central region movement time and central region movement distance between the two groups(P>0.05);in the conditioned fear experiment,there were no significant differences in short-term memory and long-term memory between the two groups(P>0.05).At the same time,A.muciniphila gavage intervention could reduce the spontaneous alcohol consumption of mice treated with chronic alcohol spontaneous diet,but there was no significant statistical difference(P=0.0668);A.muciniphila gavage also significantly alleviated the liver function injury of mice caused by chronic alcohol equal gavage exposure,mainly manifested as decreased ALT and AST(P<0.05).3.Further mechanistic studies revealed that colonization with A.muciniphila significantly reduced alcohol concentrations in serum(P<0.0001),intestinal tissue(P<0.001),and liver(P<0.001)after chronic gavage with the same amount of alcohol,but did not significantly affect the activities of alcohol-metabolizing enzymes such as ADH/ALDH in serum,intestinal tissue,and liver of host mice.Also,colonization of muca-iniphila significantly increased the production of 5-HT neurotransmitters(P<0.05)in the gut and increased the trend of 5-HT neurotransmitters in the prefrontal cortex,but there was no statistically significant difference(P=0.09).On the other hand,to further explore whether A.muciniphila improves depression-like behavior in mice by protecting liver function,significant liver function injury was induced and significant liver tumors were formed in orthotopic transplanted hepatoma cell model mice,while behavioral assessment revealed that mice in the model group showed significant depression-like behavior.Combined with imaging assessment,it was found that prophylactic and continuous administration of A.muciniphila gavage effectively slowed down the growth of orthotopic transplanted liver cancer in mice,as shown by significantly lower tumor volume growth than glycerol gavage mice at 10 d(P<0.05)and 15 d(P<0.05);ADC values were significantly higher in A.muciniphila gavage mice at 10 d(P<0.05)and 15 d(P<0.001).Meanwhile,A.muciniphila gavage effectively improved the depressionlike behavior of mice with liver cancer,as shown by the decrease in the duration of motionlessness state of mice resulting from liver cancer by A.muciniphila gavage intervention in tail-suspension-test(P<0.05).Conclusion:1.Both chronic alcohol gavage model and NIAAA chronic alcohol spontaneous diet model mice showed typical depressionlike behavior in behavioral assessment without affecting their overall activity,anxiety-like behavior and negative emotional memory;mice showed significant liver function damage in chronic alcohol gavage model,while alcohol-induced liver function damage was not observed in NIAAA model.2.A.muciniphila gavage intervention can improve the depression-like behavior of mice modeled by chronic alcohol gavage model and NIAAA chronic alcohol spontaneous diet without affecting their overall activity,anxiety-like behavior and negative emotional memory;meanwhile,A.muciniphila gavage intervention can significantly reduce the spontaneous alcohol consumption of NIAAAmodeled mice;A.muciniphila gavage can also significantly alleviate the liver function damage of mice induced by chronic alcohol equal gavage exposure.3.Colonization of A.muciniphila degrades alcohol in the digestive tract and reduces the action of alcohol and its toxic metabolites on the human body,which may be one of the mechanisms by which it improves liver function and alleviates alcohol-induced depression-like behavior.At the same time,colonization of A.muciniphila increases the production of the neurotransmitter 5-HT in the intestine and prefrontal cortex,which may be another mechanism of its action in relieving alcohol-induced depression and depression due to impaired liver function.It is also suggested that the mechanism of A.muciniphila in alleviating alcohol-induced depression-like behavior is also multi-targeted and requires further systematic in-depth exploration. |
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