Fig. 2. Differences in intestinal mucosal inflammatory factors and permeability biomakers between MDD (n = 6) and HCs (n = 6).

A ELISA was used to measure related markers and found TLR-4 (P = 0.0033), NF-κB (P = 0.0014), NLRP3 (P = 0.0017) were increased in MDD group. Two-sample T test was used. Data are presented as mean values with SD. ns indicates non-significant. Scatter plot indicate median and error range. The upper and lower whiskers indicate median±SD. B The permeability biomakers such as Claudin-1 (P = 0.0070), ZO-1 (P = 0.0030), Occludin (P = 0.0210) were decreased that was confirmed by immunohistochemistry (×200 and ×400 magnificent). Two-sample T test was used. Data are presented as mean values with SD. Scatter plot indicate median and error range. The upper and lower whiskers indicate median ± SD. C The correlation analysis were performed and found the relative abundance of Clostridium were negatively correlated with the level of MCSF and hs-CRP; The inflammatory factor were negatively correlated with the permeability biomarkers (Claudin-1, ZO-1, Occludin) and SCFAs (Acetic acid, Propionic acid, Butyric acid); and positively correlated with the total score of HAMD-17. The Butyric acid was positively correlated with Occludin and negatively correlated with TLR-4, NF-κB, NLRP3, TNFR2 and HAMD-17. The Claudin-1 was positively correlated with intestinal mucosal repair markers such as GH and EG-VEGF. Pearson correlation analyses were implemented with FDR correction. The red and blue of the table represent positive and negative correlations respectively. P-value is marked as follows: ***P ≤ 0.001; **P ≤ 0.01; *P ≤ 0.05. All statistical tests are two-sided. Source data are provided as a Source Data File.