| BackgroundSyndrome of stagnation of liver qi and spleen deficiency,one of the most commonly seen syndrome,involves liver and spleen,the pathogenesis of which is stagnation of liver qi and spleen deficiency interaction.Liver controlling conveyance and dispersion causes liver qi invading spleen and dysfunction of spleen in transportation causes stagnation of liver qi.Due to the pathological relation between liver and spleen,brain-gut axis,a bi-directional pathway closely relate to emotion and appetite has become a hot stop in the research of syndrome of stagnation of liver qi and spleen deficiency.Brain-gut peptide is a endocrine signaling molecule regulating food intake and energy balance through brain-gut axis in the central and peripheral nerve system.Vasoactive intestinal peptide(VIP)is a widely distributed brain-gut peptide,producing its biological effect as a neurotransmitter or by its receptors.VIP could play a role in regulating gastrointestinal tract,stress and learning and memory.A stable rats model of syndrome of stagnation of liver qi and spleen deficiency has been extablished by chronic unpredictable midl stress method,which can be used for further study.It is found in the previous researches that there is abnormal expression of brain-gut peptide in the rats model of syndrome of stagnation of liver qi and spleen deficiency,which may be one of the reasons of brain-gut reaction disorder.However,it is not crystal clear how VIP and its receptors play a role in the syndrome of stagnation of liver qi and spleen deficiency.Xiaoyao Powder is a famous prescription focusing on treating syndrome of stagnation of liver qi and spleen deficiency,first documented in Taiping Huimin Heji Ju Fang.It is found that Xiaoyao Powder possesses great regulating effect on rats model of syndrome of stagnation of liver qi and spleen deficiency by adjusting abnormal brain-gut peptide expression.But if VIP and its receptors be the target of Xiaoyao Powder requires further study.ObjectiveIn this study,the central(hippocampus)and peripheral(colon)expression of VIP and VPAC2 in model rats with syndrome of stagnation of liver qi and spleen deficiency were detected,in order to discuss the essence of syndrome of stagnation of liver qi and spleen deficiency as well as the possible mechanism of abnormal brain-gut interaction.At the same time,regulating effects of Xiaoyao Powder on VIP and VPAC2 were observed to exploring the mechanism and target of Xiaoyao Powder in treating syndrome of stagnation of liver qi and spleen deficiency.MethodsSyndrome of stagnation of liver qi and spleen deficiency rats model were established by chronic unpredictable mild stress.Moderlization methods included stress,hot bathing,ice water swimming,strange objects stimulation,white noise,cage tilt,fasting and water prohibition,all methods were conducted based on table of random number.The general condition,body weight and food intake were monitored,the open field test and sugar preference test were conducted,Xiaoyao Powder,Guipi Pill and fluoxetine were used to observe their effects on this syndrom,all toghter to evaluate this model comprehensively.Expression of VIP and VPAC2 in both hippocampus and colon were detected by reverse transcription-quantitative polymerase chain reaction(RT-qPCR).Then the regulating effects of Xiaoyao Powder on VIP and VPAC2 were determined.(1)Enzyme linked immunosorbent assay(ELIS A)was used to measure the content of VIP in colon of rats to observe the effects of Xiaoyao Powder.Results(1)After 6 weeks of chronic unpredictable mild stress,rats in the model group showed gradually decreases in food intake and body weight with the yellow hair,lazy less moving,depression,dry stool dry and wet appearance.Behavioral results showed that total number of lattices and times of modification decreased in the open field experiment,and the immobility time of forced swim test was increased.Related indexes in Xiaoyao Powder group,Guipi Pill group and fluoxetine group improved in different degrees.(2)RT-qPCR results showed mRNA expression of VIP and VPAC2 in hippocampus and VPAC2 in colon increased significantly while mRNA expression of VIP in colon decreased,and mRNA expression of VIP in hippocampus of the Xiaoyao Powder group decreased comparing with the model group.(3)ELISA results showed that expression of VIP in the colon of model rats decreased while Xiaoyao Powder group increased compared with model group,which is consistent with RT-qPCR.Conclusions(1)Rats model of syndrome of stagnation of liver qi and spleen deficiency have been established.Rats exposed to chronic unpredictable mild stress showed gradually decreases in food intake and body weight with the yellow hair,lazy less moving,depression,dry stool dry and wet appearance.While treated with Xiaoyao Powder,Guipi Pill and fluoxetine showed improved sign also according with results before.RT-qPCR results showed that the mRNA expression of VIP and VPAC2 in hippocampus and VPAC2 in colon of rats model of syndrome of stagnation of liver qi and spleen deficiency increased significantly,while mRNA expression of VIP in colon decreased,(2)The central and peripheral abnormal expression of VIP and its receptor maybe one of the reasons why exception occurred within brain-gut interaction in syndrome of stagnation of liver qi and spleen deficiency,decreased VIP in colon maybe one of the reasons that symptoms as less foodintake,loose stool,abdominal distention coocred in the rats model of syndrome of stagnation of liver qi and spleen deficiency.(3)Xiaoyao Powder could improve the central and peripheral abnormal expression of VIP and its receptor,and regulating symptoms such as depression,abdominal distension,loose stool,pointing out that one of the possible mechanism of Xiaoyao Powder in treating syndrome of stagnation of liver qi and spleen deficiency is by regulating the abnormal expression of brain-gut peptide through brain-gut axis.Given all the results gained in this experiment,it is concluded that abnormity of brain-gut axis and brain-gut peptide is one of the biological basis of syndrome of stagnation of liver qi and spleen deficiency,abnormal brain-gut interaction caused parasecretion of brain-gut peptide such as VIP,so food intake and body weight of rats increased and showed certain degree of depression.Xiaoyao Powder could improve related symptoms by regulating these abnormal expression brain-gut peptide.All together indicated the mechanism of exception occurred within brain-gut interaction in syndrome of stagnation of liver qi and spleen deficiency and the targets of Xiaoyao Powder. |
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