| BackgroundSubthreshold depression is a relatively mild depressive state that is different from clinical depression.Although the severity is lower,the incidence of subthreshold depression are significantly higher than that of major depressive disorder.Subthreshold depression has a serious impact on individual body and mind,which leading to the decline of individual occupational function,and the damage to social function,causing serious social medical burden and other problems.There are many causes of depression disorder.The latest research showed that depression disorder was closely related to the structure of intestinal flora.Research had confirmed that depression patients had intestinal microbial disorder.As an intermediate state between depression and health,it is not known whether subthreshold depression has pathological changes in intestinal flora structure or is consistent with normal population.In the investigation of constitution of depressed people,qi deficiency constitution and qi stagnation constitution were the two most common constitutions of depressed patients.TCM believes that constitution play an important role in the occurrence of diseases,and different constitution are more susceptible to specific diseases.whether individual will get sick after being stimulated by inside and outside,which the specific symptom type will be,whether the patients will self-heal,are all depending on constitution type to a great extent.There is a close relationship between the constitution of traditional Chinese medicine and the intestinal flora.ObjectiveWe compared the differences and similarities of intestinal flora structure between subliminal depressed individuals and healthy individuals in order to explore whether subthreshold depression has caused pathological changes and analyzed the specific characteristics of intestinal flora structure changes,so as to provide physiological evidence for the study of subliminal depression.We detected the intestinal microflora structure of subthreshold depressed people with qi-deficient and qi-stagnation,and the differences were compared with the healthy control group respectively,to compare the similarities and differences of intestinal microflora structure of the two constitutions subthreshold depressed individuals,and to explore the role of constitution in the intestinal microflora structure disorder of the subthreshold depressed people.Methods1.Subthreshold depression group and healthy control group were screened according to CES-D and the HAMD-17.Fresh stool samples were collected from two groups of participants.High-throughput sequencing of the amplified fragment of 16S rDNA gene V4 was performed,and the obtained data were analyzed for biological information.2.Subthreshold depressed population was screened according to CES-D and HAMD-17,and the subthreshold depressed population with qi-deficiency and qi-stagnation were screened according to the TCM constitution scale further.The healthy control population was matched.Fecal samples were collected,high-throughput sequencing of the amplified fragment of 16S rDNA gene V4 was performed,and the obtained data were analyzed for biological information.Results1.The comparison results between SD and HC showed that the total number of sequences was 3912992,with an average of 41628±6851 sequences in each fecal sample.The average of the SD group fecal samples contained 40439±7809 valid sequences,and the average of the HC group fecal samples contained 43 825±3794 valid sequences.In this study,the sequences with more than 97%similarity were clustered into one OTU,and a total of 20,478 OTU were obtained.At the phylum level,bacteroidetes and firmicutes were the two bacteria with the highest abundance in both the SD group and the HC group.At the class level,SD group and HC group were both dominated by bacteroidetes and clostridium.Order level,SD group and HC group were both dominated by bacteroidetes,clostridium.At the level of family,the dominant bacteriaceae in the two groups were both bacteroidetes,prevovaceae,verruciaceae,and heliconidaceae.At the genus level,the dominant bacterial genera in the two groups were both bacteroidetes,prevotella and faecobacteria.At the species level,Prevotella copri and Faecalibacterium prausnitzii dominated both the two groups.The diversity analysis results showed that the samples in the SD group were significantly lower than those in the HC group in sobs(P=0.029)and ace index(P=0.029),and there was no significant difference in the other diversity index.The results of PCA analysis showed that the distribution of the SD group and the HC group basically overlapped,but the distribution of the SD group was more dispersed and the distribution of the HC group was more concentrated.The results of PLS-DA analysis showed that there were significant differences between the distribution of the SD group and the distribution of the HC group.The analysis of betweeen-group differences showed that the relative abundance of 45 OTUs in the SD group was significantly lower than these in the HC group,while the relative abundance of 20 OTUs in the HC group was significantly lower than these in the SD group.According to the species classification,the microbial in the SD group with significantly higher relative abundance than those in the HC group were mostly belonging to proteobacteria and actinobacteria,while those significantly lower in the HC group were mostly belonging to firmicutes,lactobacillus and bifidobacteria.2.Comparison results among the qi-deficient subthreshold depression group and qi-stagnation subthreshold depression group and HC group respectively showed that the total number of OTU sequences with annotation results was 1884184,with an average of 41871±6134 sequences in each stool sample.The sequences with more than 97%similarity were clustered into one OTU,and a total of 9956 OTUs were obtained.The average OTU obtained in each sample was 221±44.At the phylum level,bacteroidetes and firmicutes were the two with the highest abundance in all the three groups.At the class level,bacteroidetes and clostridium dominated all the three groups.At the order level,bacteroidetes and clostridium dominated all the three groups.At the level of family,the dominant bacteriaceae in all the three groups were bacteroidetes,prevovaceae,verruciaceae,and heliconidaceae.At the genus level,the dominant bacterial genera in all the three groups were bacteroidetes,prevotella and faecobacteria.At the species level,Prevotella copri and Faecalibacterium prausnitzii dominated all the three groups.The diversity analysis results showed that there was no significant difference between the three groups in each activity diversity index.The results of PCR analysis showed that there was a basic coincidence between the SD qi-deficiency group,the SD qi-stagnation group and the HC group,but no significant difference among the three groups.The results of PLS-DA analysis showed that there were significant differences between the distribution of the three groups.The difference analysis between the groups showed that there were significant differences between the SD qi-deficiency group and the SD qi-stagnation group and the HC group,but the degree of difference was significantly different.There were 62 OTUs in the difference between the HC group and the SD qi-deficiency group,among which there were 6 orders,11 families,16 genera and 10 species.However,a total of 24 OTUs in qi-stagnation group were different from HC,and there were 3 bacteriaceae,5 bacteriaceae,5 bacteriaceae and 6 bacteria species.The number of differences between the total OTU,order,family,genus and species in the SD qi-deficiency group and the HC group were significantly higher than the differences between the SD qi-stagnation group and the HC group.Conclusion1.Although the SD people did not reach the clinical diagnostic criteria of depression,the structure of the intestinal flora in them has been disrupted.The intestinal flora richness in SD population was significantly decreased.The composition of intestinal flora was significantly different from that of healthy people.The relative abundance of harmful bacteria or potential pathogenic bacteria such as proteobacteria increased,and the relative abundance of beneficial bacteria such as lactobacillus and bifidobacteria decreased.2.Both the SD qi-deficiency and the SD qi-stagnation populations have the phenomenon of the imbalance of intestinal flora structure,which is manifested as the increase of the relative abundance of harmful bacteria or potential pathogenic bacteria such as proteobacteria and the decrease of the relative abundance of beneficial bacteria such as lactobacillus and bifidobacteria.However,this phenomenon was more serious in the SD group of qi-deficient quality,and there were more differences between qi-deficient quality and healthy people,indicating that the constitution would affect the intestinal flora structure of individuals with subthreshold depression.The reason for the more serious qi-deficient quality may be related to the low immunity and weak spleen and stomach in qi-deficient quality people. |
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