| Background:Depression is a common chronic mental disorder which can cause functional injury of many systems including central lesion.It seriously affects people’s health.The most common TCM Syndrome of depression is syndrome of stagnation of liver qi and spleen deficiency.At present,the pathogenesis of depression and the syndrome of stagnation of liver qi and spleen deficiency are not fully revealed,and the relationship between the change of 5-HT system and the pathogenesis of depression and syndrome of stagnation of liver qi and spleen deficiency have been widely studied.Therefore,as the key material affecting the synthesis of 5-HT,the expression of TPH2 and IDO1 can be used as an effective site for the study of the pathogenesis of depression and syndrome of stagnation of liver qi and spleen deficiency.Objective:The study established the depression with syndrome of stagnation of liver qi and spleen deficiency rat model by chronic immobilization stress method,and evaluated the model from rats’ general status,behavior change and objective indicators.The expressions of TPH2 and IDO1 and the contents of tryptophan and 5-HT in rat’s hippocampus were detected by molecular biological technique to study the relationship between the change of 5-HT system and the central mechanism of depression and syndrome of stagnation of liver qi and spleen deficiency.Meanwhile,study the regulatory role of xiaoyaosan to provide experimental evidence for the clinical use of xiaoyaosan to depression and syndrome of stagnation of liver qi and spleen deficiency.Method:48 SD rats were randomly divided into 4 groups(n=12 in each group):normal group,model group,xiaoyaosan group and fluoxetine group.The rats were adaptive fed for 7 days,and then the model was established by chronic immobilization stress.The modeling process lasted for 21 days.The behavior of rats were evaluate through the observation of the general condition,food intake,change of body weight,sucrose preference test,novelty suppressed feeding test and open-field experiment.The same weight of hippocampus in each sample were used for ELISA to determin the contents of tryptophan and 5-HT in hippocampus,then the real-time fluorescence quantitative PCR and Western blot were used to observe the gene and protein expression of TPH2 and IDOI1.Results:General state:From the macro point of view,the rats in the model group had obvious depression like behaviors,the food intake and body weight in model group were significantly lower than normal group(P<0.01),and food intake and body weight of xiaoyaosan group,fluoxetine group and normal group had no significant difference.Behavioral experimental results:In the sucrose preference test,the sucrose preference of rats in model group was lower than that in normal group,xiaoyaosan group and fluoxetine group(P<0.01);in the novelty suppressed feeding test,feeding time of rats in model group was significantly longer than that in normal group(P<0.01),xiaoyaosan group and fluoxetine group had no significant difference with model group;the number of central enterance and total cross number of rats in the model group was significantly lower than that in normal group(P<0.01),and the central residence of rats in model group were significantly higher than that in normal group(P<0.01),the central enterance,total cross number and residence time of rats in xiaoyaosan group were significant difference with model group(P<0.05,P<0.01).ELISA results:The content of 5-HT in hippocampus of rats in model group was significantly lower than that of normal group(P<0.05),the content of 5-HT in xiaoyaosan group and fluoxetine group was significantly higher than that in model group(P<0.01);the content of tryptophan in model group was significantly higher than normal group,xiaoyaosan group and fluoxetine group(P<0.01),and there is no significant difference between normal group,xiaoyaosan group and fluoxetine group.QPCR results:The gene expression of TPH2 in hippocampal of model group,xiaoyaosan group and fluoxetine group were significantly lower than that in normal group(P<0.05),and there was no significant difference between the model group,xiaoyaosan group and fluoxetine group;the gene expression of IDO1 gene in hippocampal of model group was significantly higher than that in other three groups(P<0.01),normal group,xiaoyaosan group and fluoxetine group had no significant difference.Western blot results:Compared with normal group,the expression of TPH2 in model group,xiaoyaosan group and fluoxetine group were significantly decreased(P<0.01),and the expression of TPH2 in xiaoyaosan group was higher than that of normal group and fluoxetine group(P<0.05);compared with the normal group,xiaoyaosan group and fluoxetine group,the expression of IDO1 in model group was significantly increased(P<0.01),normal group,xiaoyaosan group and fluoxetine group showed no significant difference.Conclusion:This study successfully eastablished the combination of disease and syndrome rat model of depression and syndrome of stagnation of liver qi and spleen deficiency by chronic immobilization stress and found that the expressions of TPH2 and IDO1 had changed in hippocampal of model rats which affected the tryptophan metabolism and 5-HT production.It indicated that the pathogenesis of depression and syndrome of stagnation of liver qi and spleen deficiency might be associated with the expression changes of TPH2 and IDO1,and xiaoyaosan had a certain regulating effect for TPH2 and IDO1.The relationship between the changes of TPH2 and IDO1 and the pathogenesis of depression,the regulation mechanism of xiaoyaosan still needed to be further studied. |
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