The effect of Sennoside A on the improvement of lipopolysaccharide -associated encephalopathy through gut microbiota

Abstract Background Accumulating evidence suggests that the intestinal flora is involved in many neurodegenerative diseases. Sepsis can lead to severe intestinal flora imbalance and brain dysfunction. In this study, we investigated Sennoside A may relieve lipopolysaccharide(LPS)-associated encephalopathy via its effect on the gut microbiota in rats. Methods Adult male Sprague-Dawley (SD) rats and germ free (GF) rats were used. The ordinary and germ free SD rats were adopted as a LPS-associated encephalopathy model with or without Sennoside A administration. We investigated gut microbiota diversity and structure, conducted electroencephalograms (EEG) and measured the levels of TNF-α, IL-1β and IL-6 in the cortexes of Sprague Dawley (SD) rats with or without Sennoside A administration. Horizontal fecal microbiota transplantation (FMT) and germ-free rats were used to confirm the important roles of gut microbiota in the mitigation of LPS-associated encephalopathy in rats after Sennoside A supplementation. Results We found that Sennoside A treatment markedly improved brain function in septic rats including decreased ratios of abnormal EEG and lowered levels of TNF-α, IL-1β, and IL-6 in the rat cortexes. While the gut microbiota changed in septic SD rats, Sennoside A improved gut microbial composition, which might mediate its brain protective effects in sepsis. Sennoside A also reduced inflammation in the cortexes of septic rats via gut microbiota improvement. In germ-free rats that received lipopolysaccharide(LPS),Sennoside A could not lower the ratios of abnormal EEG, and could not alleviate TNF-α, IL-1β, and IL-6 levels in the rats’ cortexes. FMT lowered the ratios of abnormal EEG and alleviate TNF-α, IL-1β, and IL-6 levels in rats’ cortexes, which confirmed our hypothesis that the effect of Sennoside A on the improvement of LPS-associated encephalopathy through gut microbiota. Conclusion Our data confirm our hypothesis that Sennoside A likely exerts its brain protective effects through gut microbiota alteration.