Probiotics alleviate cognitive dysfunction associated with neuroinflammation in cardiac surgery

Neuroinflammation plays a key role in the progression and pathogenesis of postoperative cognitive dysfunction, but it does not always occur in the local response to primary injury. In this study, we revealed that probiotics alleviate cognitive dysfunction associated with neuroinflammation in cardiac surgery. Rats were administered a probiotic or placebo once a day by gavage for 2 weeks until the day of surgery. Cardiac surgery was induced by ischemia/reperfusion of the left coronary artery. Key factors, such as the gut microbiome, the gut barrier and the blood-brain barrier (BBB), were systematically investigated to determine whether changes in the gut microbiome lead to neuroinflammation. We used 16S rDNA sequencing to confirm that cardiac surgery induced intestinal flora dysbiosis by altering the number of organisms rather than the structure in the cecum microbiome, which occurs at the same time as damage to the gut barrier. Cardiac surgery also increased BBB permeability, suggesting that disruption of the microbiome may increase the likelihood of neuroinflammation. Probiotics-induced alterations in the intestinal flora significantly reduced the level of inflammatory cytokines (IL-6 and IL-1β). Importantly, we found that the administration of probiotics significantly improved spatial memory impairment in rats after cardiac surgery, as measured by the Morris water maze. Overall, dysbiosis of the gut flora may aggravate cognitive impairment associated with neuroinflammation after cardiac surgery, and probiotics may attenuate this effect.