| BackgroundThe clinical feature of leukoencephalopathy are myelin reduce,myelinoclasis and necrosis,which can cause the morphologic and functional changes of nerve fiber,abnormal white matter structure and function may be one pathogenesis of mental disorders.Electroconvulsive therapy(ECT)is an effective therapy in dealing with some kinds of mental illness,but its mechanism is still not very clear.Those research of the ECT treatment mechanism may be a key to the study of the mechanism of mental diseases.ObjectiveWe do this experiment to find how electroconvulsive shock(ECS)influence the white matter demyelination model caused by cuprizone,to obtain data about the influence of ECS that may change MBP and CNPase in corpus callosum,prefrontal lobe and hippocampus.And we can also observe the change of behavior during the process of feeding by CPZ and stimulate by ECS.It may provide some information about the mechanism of ECT,and it would promote the study of pathomechanism of mental disorders.Methods1.Group the mice: We selected 120 healthy adult male C57BL/6 mouse that were 6-8 weeks old and 20-25 g,and then they were separated into four groups as CNT+Sham,CNT+ECS,CPZ+Sham and CPZ+ECS randomly,each group including 30 mice;2.Model of demyelination by CPZ: CPZ+Sham and CPZ+ECS collectively were called CPZ group,and they were fed by 0.2% CPZ for six weeks.CNT+Sham and CNT+ECS were fed with normal fodder as CNT group in the same condition.And we selected 6 mouse randomly from the four group to kill at the end of 6th week.3.Stimulated by ECS: After 6 weeks,CNT+ECS and CPZ+ECS were stimulated by ECS for two weeks continuously,while CNT+Sham and CPZ+Sham receive sham stimulation,and we selected 12 mouse from each group to kill at the end of 8th week,the rest of mouse would continue to receive corresponding simulation,and they would be killed at the end of 10 th week.4.Protein detection: Through immunofluorescence histochemical method,we detect the expression of MBP in corpus callosum.We use western blot to test MBP and CNPase protein expression in mouse prefrontal lobe and hippocampus.We test integral optical density(IOD)values by Image Pro plus software and then they were compared among those groups.5.Statistical methods: We use SPSS 21.0 to analysis those mass of data.According to the characteristics of data,we selected corresponds statistical methods.Those data that obeys the normal distribution will be presented by meanąSD.Using independent samples t test to compared mean values in two different groups.And we use One-way ANOVA to analysis the measurement data in multiple groups.And the repeated measurement data were analyzed by repetitive measurement deviation analysis.When P<0.05,the results have significant difference.Results1.The change of behavior during this experiment: During the process of feeding by CPZ,food intake and body weight were difference between two groups significantly(P<0.05).At the end of 8th and 10 th week,body weight were significantly difference among four group,P value are 0.000 and 0.017,and at the end of 8th and 10 th week,food intake were also significantly difference among four group.Before feeding with CPZ,there was no significant difference between CNT group and CPZ group in open-field test.After the end of 6th week,CPZ group's total distance and the number of rearing in open field test was significantly difference among four groups,P value were 0.022 and 0.000.But the total distance and the percentage of the distance in center region did not differ between the two groups.At the end of 8th week,there was significantly difference in total distance and the number of rearing among four groups,both P value were 0.000.But the percentage of the distance in center region did not differ among the four groups while the total distance of center region was significantly difference(F =4.593,P=0.029).At the end of 10 th week,there was significantly difference in total distance and the number of rearing among four groups,both P value were 0.000.But the total distance of center region did not differ among the four groups while the percentage of the distance in center region was significantly difference(F =8.361,P=0.000).The difference in percentage of sucrose intake between CNT group and CPZ group was not significantly before and after feeding with CPZ.The percentage of sucrose intake was significantly difference among the four groups(F =5.505,P=0.004),while the water consumption had no remarkable difference among the four groups.The percentage of sucrose intake was significantly difference among the four groups(F=12.252,P=0.001),and the water consumption also had remarkable difference among the four groups(F=17.725,P=0.000).In Rota-rod test,at the end of 6th,8th and 10 th week,the time of standing on the rod were significantly difference among four goups,P value were 0.004,0.002 and 0.001 successively.And the rotate speed when mice fall down from the rotating rod were significantly difference among four goups,P value were 0.009,0.000 and 0.001 successively.2.The repaire effect of ECS in corpus callosum tested by immunofluorescence: At the end of 6th weeks,as shown by immunofluorescence studies,MBP in corpus callosum was significantly difference among four groups(F =8.483,P=0.007).At the end of 8th week,MBP in corpus callosum was significantly difference among four groups(F =8.483,P=0.007).At the end of 10 th weeks MBP in corpus callosum was significantly difference among four groups(F =6.110,P=0.018).3.The repaire effect of ECS in prefrontal lobe and hippocampus tested by western blot: at the end of 6th week,we found that the protein content of CNPase and MBP in CPZ group's prefrontal cortex was less significantly than CNT group's,and P value were 0.003 and 0.004,and we also found the same trend in CPZ group's hipoocampus by western blot,P value were 0.005 and 0.007.At the end of 8th week,the protein content of CNPase and MBP were significantly difference amon four group in prefrontal cortex,both P value both were 0.000.And we also found the same trend among the four groups in hipoocampus,P value were 0.049 and 0.008 by western blot.At the end of 10 th week,the protein content of CNPase was significantly difference among four group in prefrontal cortex(F =6.706,P=0.014),while the protein content of MBP had no remarkable difference among four groups in prefrontal cortex(F=2.704,P=0.092).And we also found the same trend among the four groups in hipoocampus by western blot,P value were 0.013 and 0.004.Conclusions1.The time of ECS improved the behavior of demyelination mouse earlier than repair effect of white matter demyelination,long time of ECS may induce some abnormal behavior of mouse.2.The repair effect of ECS on white matter demyelination caused by CPZ may affected by how long ECS last,short time ECS didn't induce demyelination repair while long time ECS promote it. |
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