| ObjectiveThrough researching literature treating depression based on the theory of the relationship between liver,spleen and emotion,we have further discussed and explored the pathogenesis of traditional Chinese medicine of depression of liver stagnation and spleen deficiency syndrome.Animal experiments were performed using the chronic unpredictable mild stress(CUMS)method,and the depression rats model of liver stagnation and spleen deficiency syndrome were successfully replicated.We studied how BDNF and its receptor TRKB and intestinal floras affect the central nervous system and intestinal nervous system of the mechanism of depression of liver stagnation and spleen deficiency syndrome from the depression state and gastrointestinal reactions in the rats model of liver stagnation and spleen deficiency syndrome.We have explored and discussed the mechanism of Xiaoyao Powder in interventing depression model rats of liver stagnation and spleen deficiency syndrome based on the expression changes of BDNF and its receptor TRKB in hippocampi and intestines and the changes of intestinal floras and the changes in colonic epithelial ultrastructure.Methods1.Theoretical research: Through investigating and organizing ancient and modern related literature,we have combed the relationship between thephysiological functions of the liver and spleen and the emotions.We have summarized and generalized the close links between the liver,spleen and depression.We have also compared and summarized the depression-related diseases in the traditional Chinese medicine literature.We have analyzed the formula composition of Xiaoyao Powder,organized and discussed the mechanism of its intervention on depression of liver stagnation and spleen deficiency syndrome.2.Experimental research: Fifty SPF male SD rats were randomly divided into 5 groups: normal group,modeling group,fluoxetine group,Xiaoyao Powder group and Bifidobacterium group.Modeling was performed using a mature chronic unpredictable mild stress method with a modeling time of 6weeks.Changes in macroscopic characterization of the rats were observed during modeling,and body weight and food intake were recorded weekly,and each group was administered intragastrically for 6 weeks.The behavioral changes were observed through the sucrose preference experiment and the open field experiment.The ultrastructure of colonic epithelium was observed by transmission electron microscopy.The changes of intestinal barrier were mainly observed.The expression of BDNF and its receptor TRKB gene in hippocampi and intestines were detected through PCR.The 16 Sr DNA method was operated to detect changes in the intestinal floras in the colons.Results1.Changes in macroscopic representation: Before the models were established,the rats in each group had a good mental state,they were active,the fur were smooth and were less shedding,the stool was in normal state.From the third week after modeling,the rats in the modeling group showed poor mentality,looked burnout and some of them lied on their backs.Their reaction was slower than before,and they liked to huddle in the corner.Their fur were dry and dull yellow,with more fur shedding,less food intake,worsestool sate,and slower weight gaining.2.Behavioral testing: The results of sugar water preference test showed that the preference of rats in the model group was significantly lower than that in the normal group and the treatment group(P<0.01),which reflected the changes of mental depression in the modeling group.The results of open field experiments showed that the total moving distance of the rats in the modeling group was significantly shorter than that of the other four groups(P<0.01),the resting time was significantly longer than that of the other four groups(P<0.01),and the moving distance in the central area was also significantly shorter(P<0.01);the rats in the modeling group looked uneasy when they were moving in the central area and were looked like to huddled up in the surrounding corners.3.Ultramicroscopic observation: Compared with the normal group,the model rats colonic epithelial cells were unevenly distributed,the density was low,the microvilli were swollen and the length was different,some of the microvilli were even lost and lodging.It is also seen that the mitochondria are swollen,the mitochondria are ambiguous,the structure are difficult to recognize,and the endoplasmic reticulum are obviously expanded.Part of the cell tight junction gaps are widened,and some complex structure of the tight junctions are destroyed.Compared with the modeling group,the Xiaoyao Powder group had obvious structural changes under the electron microscope.The colonic epithelial cells were arranged regularly,and the mitochondria and tight junctions were repaired.4.PCR detection of BDNF and TRKB gene expression in the hippocampi and intestines: Compared with the normal group,the expressions of BDNF and its receptor TRKB in the hippocampi of the modeling group was significantly decreased(P<0.01),while the expressions of BDNF and its receptor TRKB in the intestines was significantly increased(P<0.01).Compared with the modeling group,the results showed that fluoxetine,Xiaoyao Powder and Bifidobacterium significantly increased the expressions of BDNF and TRKB in hippocampi(P<0.01),and decreased the expressions of BDNF and TRKB in the intestines.(P<0.05).5.Results of 16 Sr DNA detection of Bifidobacteria: Compared with the normal group,the expression of bifidobacteria in the modeling group was significantly decreased(P<0.01).Compared with the modeling group,the expression of bifidobacteria was significantly increased in the bifidobacteria group(P<0.01).Xiaoyao Powder group and modeling group in comparison,the results were also statistically significant(P<0.05).Conclusion1.In the pathogenesis of depression,liver stagnation and spleen deficiency occupies an important position.2.The pathogenesis of depression of liver stagnation and spleen deficiency syndrome may be related to the decrease of BDNF and TRKB in hippocampi,the increase of BDNF and TRKB in intestines,the change of intestinal barrier function and intestinal floras,and the changes of intestinal motility and visceral hypersensitivity.3.Xiaoyao Powder can effectively improve the depression and gastrointestinal function of depression rats of liver stagnation and spleen deficiency syndrome.The mechanism may be related to the regulation of BDNF and its receptor TRKB expression and intestinal floras changes in hippocampi and intestines.And thus it is speculated that BDNF and its receptor TRKB and intestinal floras play an important role in the network of brain-gut axis. |
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