Long-term Abuse Of Ketamine Combined With Ethanol Induced Neurodegeneration Analogous To Alzheimer’s Disease In Middle-aged And Elderly Mice

Objective:In order to study the mechanism of Long-term abuse of ketamine combined with ethanol promote neurodegeneration analogous to Alzheimer’s disease in middle-aged and elderly mice.Methods:According to the random number table,mice were randomly allotted into 4 study groups(n=18):control group(group C),intragastric injection with ethanol(group E),ketamine injection group(group K),ketamine combined with ethanol intragastric injection group(group KE),each study group was further divided into two subgroups:3 months group and 6 months group.The mice were fed until they were 12 weeks old and given the drug.Ketamine(30mg/kg)and 20%ethanol(2ml/kg)were given by intraperitoneal injection and gavage every day during the study period respectively,according to the weight of the mice.Immunohistochemical staining was used to detect the changes in the total amount of Tau protein and the expression of beta-amyloid in the prefrontal cortex,striatum and hippocampus of mice.Western Blot method was used to detect the expression changes of proteins Tau(phosphor Thr231),Tau(phospho S396),Tau(phospho Ser404),GSK-3,GSK3beta(phospho Ser9)and PP2A in the prefrontal cortex,striatum and hippocampus of mice.Results:Immunohistochemical staining results:in the 3 months group,the expression levels of Tau and Aβ in the group K are the highest in the prefrontal cortex,striatum and hippocampus of mice,and the expression levels of Tau and Aβ in the group K decrease gradually with the extension of the administration time.Western Blot results:the ratio of each tau hyperphosphorylation to Tau protein can better reflect the phosphorylation of Tau protein in related brain regions.Tau(phosphoThr231)and Tau(phosphoS396)proteins are significant inceresed in the striatum and hippocampus of KE group,which is administration time-dependent.Tau(phosphoSer404)protein is significant increase in the prefrontal cortex,striatum and hippocampal brain regions of KE group.And in the group KE,the expression of three phosphorylation sites of Tau protein in striatum is higher than it in hippocampus.Tau protein phosphorylation is mainly regulated by protein kinase(GSK-3β)and protein phosphatase(PP2A),while GSK-3β activity is affected by its Ser9 site phosphorylation.There is no significant difference in GSK-3β protein between the prefrontal cortex,striatum,and hippocampal brain regions of mice.In the 3 months administration group,the highest expression of GSK3beta(phosphor Ser9)protein in the prefrontal cortex of mice is found in the KE group and shows a time-dependent relationship;After administration of drugs for 3 months,GSK3beta(phosphoSer9)protein is highest expressed in striatum of K group,while is highest expressed in the striatum of KE group when administration of drugs for 6 months.Treatment with drugs for 3 and 6 months,GSK3beta(phosphoSer9)protein is highest expressed in the hippocampus of K group.And the expression of PP2A protein gradually decreased with the prolongation of ketamine and combined ethanol abuse time.Conclusion:1.Long-term abuse of ketamine leads to an increase in the expression of Aβ proteins and Tau proteins in the prefrontal cortex,striatum and hippocampus of adult mice.2.Long-term abuse of ketamine combined with ethanol can lead to overphosphorylation of Tau protein at Thr231,S396 and Ser404 sites in prefrontal cortex,striatum and hippocampus of aged mice.3.Ketamine may promote Tau hyperphosphorylation by activating GSK-3 activity and inhibiting the activity of PP2A.4.Ethanol may synergistically promote tau hyperphosphorylation,which be induced by ketamine,by increasing gsk-3 beta activity,and the striatum of mice model after co-administration with ketamine and ethanol is the most susceptible brain area.