Abstract: Objective To investigate whether gut microbiota disturbance after cardiopulmonary bypass (CPB) contributes to the development of perioperative neurocognitive disorders (PND). Methods Fecal samples were collected from healthy individuals and patients with PND after CPB to prepare suspensions of fecal bacteria, which were transplanted into the colorectum of two groups of pseudo-germ-free adult male SD rats (group NP and group P, respectively), with the rats without transplantation as the control group (n=10). The feces of the rats were collected for macrogenomic sequencing analysis, and serum levels of IL-1β, IL-6 and TNF-α were measured with ELISA. The expression levels of GFAP and p-Tau protein in the hippocampus of the rats were detected using Western blotting, and the cognitive function changes of the rats were assessed with Morris water maze test. Results In all the 3 groups, macrogenomic sequencing analysis showed clustering and clear partitions of the gut microbiota after the transplantation. The relative abundances of Klebsiella in the control group (P<0.005), Akkermansia in group P (P<0.005) and Bacteroides in group NP (P<0.005) were significantly increased after the transplantation. Compared with those in the control group, the rats in group NP and group P showed significantly decreased serum levels of IL-1β, IL-6 and TNF-α and lowered expression levels of GFAP and p-Tau proteins (all P<0.05). Escape platform crossings and swimming duration in the interest quadrant increased significantly in group NP (P<0.05), but the increase was not statistically significant in group N. Compared with those in group P, the rats in group NP had significantly lower serum levels of IL-1β, IL-6 and TNF-α and protein expressions of GFAP and p-Tau (all P<0.05) with better performance in water maze test (P<0.05). Conclusion In patients receiving CPB, disturbances in gut mirobiota contributes to the development of PND possibly in relation with inflammatory response.

Key words: gut-brain axis; macrogenomics; cardiopulmonary bypass; perioperative neurocognitive disorders