| Objective:Depression is a clinical manifestation of mood disorders,which mainly shows significant and lasting low mood due to a variety of inducements,with the characteristics of high incidence and recurrence rate,high morbidity and high mortality.At present,the causes of depression and process is still not fully elucidated,drugs and treatment also needs to be further optimized,and the effecti've and stable animal models can provide strong guarantee for the research of depression.In the previous experiment,a model of depression rats based on the imbalance of neurotransmitter in the brain was established by injecting dopamine D1 receptor blocker SCH23390 into the CA1 of the left hippocampus.The depressive symptoms shown in this model can be reversed by positive drugs.Though this method had been proved to be an efficient,stable,easy way to operate and can be quantified depression animal models,but it needed to be installed by micro-injection casing in the process of building trace injection casing,casing installation not only extended the building time,and the subsequent unable to use this model to carry out the water maze,such as forced swimming experiment.Therefore,this experiment intended to eliminate the casing installation process and further optimized the molding process.Methods:1.Evaluation of the effectiveness of the improved model:The healthy rats were randomly divided into 3 groups(the normal control group,the original model group and the improved model group)according to the sucrose consumption test.The improved model injected the SCH23390 into CA1 directly without tube.The dose of SCH23390 was 8?g/?L,1?L/d,1 injection every other day and 4 times totally;In the original model group,SCH23390 was injected through the casing to the CA1 area of the hippocampal area.The concentration was 2?g/?L,the volume was 1?L/d,each injection lasted for 2 days and rested for1 day,with a total of 6 times.The normal control group did not do any injection.The weight-changing rate and behavior test(sucrose consumption test and open-field test)was recorded in the first and second week after modeling.The depression degree between improved and original model was evaluated based on the weight-changing and behavioral performance.The security was evaluated by the content of the serous IL-1? and TNF-a measured by the ELISA.2.Analysis of the pathological features of the modified model:The healthy rats were randomly into 2 groups:the normal control group and the improved model group,according to the sucrose consumption test.The following indicators in the bilateral hippocampus and cerebral cortex were measured after 2 weeks:the content of 5-HT,DA,NE,5-HIAA with HPLC-MS;the content of AchE with ELISA;the content of 5-HT1A,5-HT2A with western-blot.3.Validity evaluation of the modified model:The healthy rats were randomly into 3 groups:the blank control group,the improved model group and Xiaoyao Pills group according to the sucrose consumption test.After modeling,Xiaoyao Pills group were treated with Xiaoyao Pills(1.5g/kg/d)(ig.)for2 weeks.The blank groups were given the same amount of distilled water by intragastric perfusion for 2 weeks.Then,the weight-changing rate,sucrose consumption test and open-field test were tested.After the last behavior test,the indicator of bilateral hippocampus and cerebral cortex were tested:the content of 5-HT,NE,5-HIAA with HPLC-MS and the content of 5-HT2A with Western-bloting.All the indicators were used for evaluating the the effects of Xiaoyao Pills of the improved model.Results:1.The results of evaluation of the effectiveness of the improved model7 days after modeling,compared with the normal control group,the weight changing rate was significantly decreased(p<0.01).So were the results of the sucrose consumption test and rearing open-field test(p<0.05,p<0.01).It showed that both the original and improved model could make the rats depressive.But there was no significant difference of the behaviour test between the original model group and the improved model group(p>0.05),showing the same depressive degree of both of the two modeling methods.14 days after modeling,compared with the normal control group,the weight changing rate was significantly decreased(p<0.01).So were the results of the sucrose consumption test and rearing open-field test(p<0.05,p<0.01).It showed that both the original and improved model could keep the depressive state in 2 weeks.But there was no significant difference of above indicators between the original model group and the improved model group(p>0.05).It showed that the improved model could keep the depressive in 2 weeks and the effects of depression were the same with the original model.ELIS A results showed that,compared with normal control group,model group improved rat IL-1? and TNF-a contents had no statistical difference(p>0.05),which showed that improved method did not cause the inflammatory response in rats.2.The results of analysis of the pathological features of the modified model:2 weeks after modeling,it showed that the content of 5-HT,NE in the left hippocampus of the improved model group increased significantly campared with the normal control group(p<0.01),the content of 5-HIAA decreased significantly(p<0.01),but the decrease of DA content and the increase of AchE content were not significant(p>0.05).The content of 5-HT1A didn't change obviously(p>0.05)and the content of 5-HT2A decreased significantly(p<0.01).The content of 5-HT,NE in the right hippocampus increased significantly(p<0.01),the content of 5-HIAA decreased significantly(p<0.01),the decrease of DA content and the increase of AchE content was not significant(p>0.05).The change of 5-HT1A content was not obvious(p>0.05)and the decrease of 5-HT2A content was significant(p<0.01).The increase of 5-HT,NE,AchE was not significant,neither of the content of 5-HIAA,DA and 5-HT2A(p>0.05).The 5-HT1A content didn't change obviously.It was indicated that the improved model conformed to the pathological features of the depression model.3.The results of validity evaluation of the modified model:After 2 weeks of treatment with the Xiaoyao pills,compared with the normal control group,the weight-changing rate increased significantly(p<0.01).The sucrose consumption test and open-field test also increased,but it was not significant(p>0.05).The content of 5-HIAA of bilateral hippocampus increased significantly(p<0.05).But the decrease of the 5-HT,NE in the bilateral hippocampus did not change significantly(p>0.05)The content of 5-HT2A did not increase significantly(p>0.05).It indicated the effectiveness of Xiaoyao pills to the improved model.Conclusion:Through the improvement of new type of depression rat model set up early characterized by a neurotransmitter imbalance by the research team,canceled the casing installation program,and changed the dose and frequency to 8?g/?L/d,1 injection every other day and 4 times totally.By the analysis of validity,inflammation,pathological features and validity,it was proved that the improved model method was effective,less time of modeling,could be used more widely for using in the water maze and forced swimming test and can not cause the inflammatory.It was a ideal model. |
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