Fig. 4

Changes in the preoperative gut microbiota aggravate POCD and systemic inflammation in rats. A Experimental design. After 2 weeks of acclimatization and 2 weeks of antibiotic treatment, fecal material from either control patients or POCD patients was transferred to Sham-C group (n = 10)/Surgery-C group (n = 10) or Surgery-P group (n = 10) rats for 3 weeks. Then, the rats underwent sham surgery or abdominal surgery. The MWM test was conducted on postoperative days 7–12. Serum and hippocampal samples were subsequently analyzed. Escape latency (B) and swimming speed (C) of the three groups of rats from days 1 to 5 during the acquisition session of MWM test. The swimming time in the target quadrant (D) and number of platform crossings (E) of the three groups of rats on day 6 during the probe trial session of the MWM test. F Typical motion traces of the three groups of rats in the MWM test. Levels of TNF-α (G), IL-1β (H) and IL-6 (I) in the serum of rats. Levels of TNF-α (J), IL-1β (K) and IL-6 (L) in the hippocampus of rats. M Representative immunofluorescence images of Iba-1⁺ (red) staining in the hippocampus of rats (scale bar = 500 μm). N Representative immunofluorescence images of nuclei (blue) and Iba-1⁺ (red) staining in the hippocampus of rats (scale bar = 100 μm). O Quantitative analysis of Iba-1⁺ (microglial marker) cells. Data are expressed as mean ± SEM. compared with Sham-C group, *P < 0.05, **P < 0.01; compared with Surgery-C group, ^#P < 0.05, ^## P < 0.01