Fig. 5

Remodeling of gut microbiota by FMT reverses surgery-associated breakdown of gut barrier integrity and alleviates PND. A Flow chart of the experiment indicates the handling of the donor and recipient mice in the FMT experiment and the detection time of each cognitive behavior. B Swimming path diagrams of the two groups of mice in the MWM test on postoperative day 12 and day 13. C Latency to find the platform in the MWM test from 8 to 12 days after surgery of the two groups of mice. D The retention time of the two groups of mice in the platform quadrant in the MWM test in the 13th day after surgery. E The number of times that the two groups of mice crossed the platform in the MWM test in the 13th day after surgery. F Freezing time in the fear conditioning test in the 16th day after surgery of the two groups of mice. G Novel object exploration index in novel object recognition in the 19th day after surgery in both groups of mice. H Analysis of the α-diversity of the gut microbiota in the feces of the two groups of mice. I PCoA was used to calculate the Bray–Curtis distance matrix to analyze the beta diversity of gut microbiota in the feces of the two groups of mice. J Cluster analysis heatmap of genus-level species composition of the feces indicates the relative abundance changes of the top 10 genus-level flora species (average of each group) among the two groups of mice. K LEfSe was used to find species with significant differences at all taxonomic levels of the gut microbiota in the feces of the two groups of mice. The comparison strategy was one-against-all, and the LDA threshold was 2. L Venn diagram indicates the OTUs detected in the feces by 16S rRNA gene sequencing, as well as shows OTUs unique to each group and OTUs share among the two groups. M In vivo imaging system was used to image the mice with FITC-dextran gavage treatment in the two groups, no FITC-dextran gavage mice were used as control. The red area displays the fluorescence-positive area of FITC-dextran after enhancement. N Correlation with M, positive area of FITC-dextran in mice of the two groups was calculated using ImageJ to indicate the permeability of the intestine. O Immunofluorescence staining was used to detect the expression level of the tight junction protein ZO-1, Cluadin-1, and Occludin in the mouse colon tissues in the two groups. P Correlation with O, the fluorescence intensity of ZO-1, Cluadin-1, and Occludin in the mouse colon tissues in the two groups was calculated. Q Immunofluorescence staining was used to detect the expression level of the tight junction protein ZO-1, Cluadin-1, and Occludin in the mouse ileum tissues in the two groups. R Correlation with Q, the fluorescence intensity of ZO-1, Cluadin-1, and Occludin in the mouse ileum tissues in the two groups was calculated. S Immunohistochemical staining was used to detect the expression level of IL-17a and IL-22 in the mouse ileum tissues in the two groups. T Correlation with R, the mean IOD/area of IL-17a and IL-22 in ileum was calculated. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001