| Object: The purpose of this study was to explore the role of intestinal microflora and cytokines in the pathogenesis of depression,and the correlation between them.It also researched the relationship between intestinal microflora and clinical features,and provide theoretical basis for the etiology,clinical diagnosis and treatment of depression.Methods: 1.According to the diagnostic criteria of depression in the Fifth edition of the American mental disorders diagnostic and Statistical Manual(DSM-V),78 patients with first-episode depression and 86 healthy volunteers matched for age,sex,education level and BMI were selected.The general information,HAMA and HAMD scores were collected after entering the group.Samples of blood and feces were collected second days after entering the group.Samples of blood and feces were collected again in the case group after 6 weeks of treatment(40 cases),and the HAMD scores were also evaluated.DNA of intestinal microflora were extracted by using fecal DNA extraction kit,and detect the contents of Bifidobacterium,Lactobacillus,Escherichia coli,Bacteroides,Clostridium,Bacteroides fragilis by QPCR.The levels of IL-1?,IL-2,IL-6,IL-10 and TNF-?in serum were measured by enzyme-linked immunosorbent assay.2.Two independent samples t-test was used to compare the difference of intestinal microflora's contents and cytokines level,and two paired sample t-test was used to analyze the differences before and after treatment in the depression group.The correlation between cytokines level,clinical datas and intestinal microflora's contents were analyzed by Pearson correlation.After 6 weeks of antidepressant treatment,the correlation between the change of intestinal microflora and the HAMD reduction rate was analyzed by Pearson correlation analysis.All the tests were tested by bilateral tests,and the test level was set to P<0.05.Results: 1.Comparison of general social demography datas and clinical datas Comparison of first-episode depression patients and healthy control group: gender(x 2=1.008,P=0.315),age(t=1.062,P=0.29),culture level(t=1.72,P=0.087)and BMI(t=1.733,P=0.085)were no significant difference between the two group;HAMD scores(30.73 ± 6.049)and HAMA scores(14.58 ± 6.57)of the case group were significantly higher than the control group(5.57.1.52),(4.24 ± 1.22),the difference was statistically significant(P<0.01).2.Comparison of intestinal microflora's contents(lg copies/g)in case group and control group The contents of Bifidobacterium(7.46 ± 0.48),Escherichia coli(7.84 ± 0.31),Lactobacillus(7.97 ± 0.60),Bacteroides(7.32 ± 0.76)in case group were lower than the healthy control group(7.67 ± 0.45),(8 ± 0.48),(8.28 ± 0.68),(7.60 ± 0.73),the difference was statistically significant(P=0.005,P=0.017,P=0.002,P=0.015).3.Comparison of cytokines(ng/L)between case group and control group The levels of IL-1?(50.11 ± 3.08),IL-2(41.31 ± 6.67),IL-6(30.64 ± 5.59),TNF-?(27.32 ± 1.92)in case group were significantly higher than the control group(45.95 ± 3.74),(36.49 ± 3.98),(27.57 ± 5.97),(23.55 ± 2.28),the difference was statistically significant(P=0.000,P= 0,P=0.001,P=0.000). 4.Pearson correlation between intestinal microflora and cytokines in case group There was a negative correlation between the content of Bifidobacterium and the level of TNF-?(r=0.225,P=0.048;r=0.273,P=0.016).The content of Escherichia coli was negatively correlated with IL-6 level(r=-0.317,P=0.005).The content of Lactobacillus was negatively correlated with the level of IL-2(r=-0.569,P=0.000).5.Correlation of Intestinal microflora's contents with clinical datas in case group The content of Lactobacilli was negatively correlated with HAMD scores(r=-0.289,P=0.01).The content of Bifidobacterium was negatively correlated with the age of onset(r=-0.25,P=0.027).6.Comparison of intestinal microflora's content(lg copies/g)and HAMD scores of patients between after and before treatment We collected 40 cases of effective treatment in patients with depression(HAMD scores reduction rate was over 50%),compared with before treatment,the contents of Bifidobacterium(8.07 ± 0.88)and Lactobacillus(8.34 ± 0.58)were higher than before treatment(7.36 ± 0.47),(7.97 ± 0.63),and the difference was statistical significance(P=0.000,P=0.001).After treatment,the scores of HAMD(9.6 ± 4.47)were significantly lower than that before treatment(30.9 ± 6.27),and the difference was statistically significant(P=0.000).7.Comparison of cytokines(ng/L)of patients after treatment and before treatment The levels of IL-1?,IL-2,IL-6 and TNF-?in patients with antidepressant treatment decreased significantly compared with those before treatment,and the difference was statistically significant(P =0.005,P =0.000,P =0.014,P =0.001).8.Correlation of Intestinal microflora's content with clinical datas in case group after treament There was a negative correlation between the content of Lactobacilli and the levels of IL-2,TNF-?(r=-0.534,p=0.000,r=-0.349,p=0.027).9.Correlation between the increased content of Bifidobacterium,Lactobacilli and the HAMD scores reduction rate in patients after treatment There was no correlation between the increased content of Bifidobacterium and the reduction rate of HAMD after antidepressant treatment.The increased content of Lactobacilli was positively correlated with the reduction rate of HAMD scores(r=0.415,P=0.008).Conclusion: 1.A variety of intestinal microflora decreased in the first episode of depression,and the levels of various inflammatory cytokines increased.The contents of intestinal microflora and the levels of inflammatory cytokines were related.The contents of bifidobacterium were decreased and correlated with increased levels of TNF-?.The contents of escherichia coli were decreased and correlated with increased levels of IL-6.The contents of lactobacilli were decreased and correlated with increased levels of IL-2.The contents of lactobacilli in the depression were lower,the more severity of depressive symptoms.2.After effective antidepressant treatment,the contents of lactobacilli and bifidobacterium were increased,and the levels of IL-2,IL-6,TNF-?,IL-1?were decreased.The contents of intestinal microflora were also associated with inflammatory cytokines after treatment.The contents of lactobacilli were more,the lower levels of IL-2 and TNF-?.The content of lactobacilli were increased more,the HAMD scores decreased more significant in the patients. |
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