Mechanisms Of Chronic Sleep Deprivation Induced Gut Microbiota Dysbiosis In Cognitive Impairment In Mice

Background and Purpose Sleep is essential for human health and plays an important role in maintaining homeostasis of the immune system,metabolic system,gastrointestinal system,cardiovascular system.Numerous clinical and animal studies have shown that sleep disturbance contributes to cognitive decline and is a risk factor for AD.Interestingly,accumulating evidence indicates that gut microbiota dysbiosis exists in both AD and sleep disorders,therefore,whether gut microbiota plays a key role in the cognitive decline caused by sleep disorders deserves further investigation.In this paper we used sleep deprivation(SD)mouse model to explore whether the gut microbiota is involved in the change of cognitive behavior and what’s molecular mechanisms in the processMethods Morris water Maze and novel object recognition test were used to discover the behavioral phenotypic differences between sleep-deprived mice and wild-type mice.Fecal microbiota transplantation(FMT)was used to confirm that gut microbiota of sleep-deprived mice can cause cognitive decline in wild-type mice.The composition of gut microbiota was detected by 16 S r RNA sequencing.The expression of tight junction protein ZO-1,Occludin,Claudin 5,NLRP3,IL-1β and IBA-1 were detected by western blot.Immunofluorescence was used to detect the activation of microglia in mouse hippocampal and prefrontal cortex.The integrity of colonic epithelial barrier was detected by HE staining,alcian blue and immunofluorescence.Lipopolysaccharide(LPS),inflammatory factors of IL-1β and IL-6 in peripheral blood were detected by ELISA.ResultsChronic sleep deprivation led to a significant decline in cognitive function.Water maze test and new object recognition test suggested that the learning and memory functions of mice were impaired.Compared with normal mice,sleep deprived mice had disorder of intestinal flora,significant changes in alpha diversity and beta diversity,and changes in a variety of bacteria.At the same time,chronic sleep deprivation can lead to the thinning of mucus layer on the surface of colon,the increase of epithelial permeability,the translocation of LPS and the increase of peripheral inflammatory cytokines.The mechanism may be related to the activation of NLRP3 inflammatory body in mouse colon and the damage of intestinal barrier.We also found that chronic sleep deprivation can lead to the increase of cerebral vascular permeability and the activation of NLRP3 inflammatory bodies and microglia in mouse hippocampus and prefrontal cortex.Their interaction can cause immune inflammatory response in the brain and decline of cognitive function.In order to further confirm the role of intestinal flora in the decline of cognitive function caused by sleep deprivation,we transplanted the intestinal flora of chronic sleep deprivation mice into recipient mice.It was found that the recipient mice had decreased learning and memory function,thinner colonic mucosal thickness,increased epithelial permeability,activation of colonic NLRP3 inflammatory bodies,translocation of LPS and increase of peripheral inflammatory cytokines.In mice with chronic sleep deprivation,we found that the increase of intestinal microflora activation in the frontal cortex and microglia in rats with chronic sleep deprivation were also the driving factors of sleep deprivation.We explored the molecular mechanism of NLRP3 inflammatory corpuscles in cognitive impairment induced by chronic sleep deprivation in mice.Sleep deprivation in NLRP3 knockout mice can significantly improve the decline of cognitive function after chronic sleep deprivation,restore the integrity of intestinal barrier,and reduce peripheral inflammatory factors and LPS.We also found that the permeability of blood-brain barrier decreased and the activation of brain microglia decreased in NLRP3 knockout mice.Therefore,we propose that mouse knockout of NLRP3 gene can restore the intestinal barrier and blood-brain barrier,reduce the concentration of LPS and inflammatory factors in peripheral blood,inhibit the immune inflammatory response in the brain,and reverse the cognitive impairment caused by chronic sleep deprivation.Conclusion Chronic sleep deprivation leads to gut microbiota disorder in mice,which mediates the cognitive decline caused by chronic sleep deprivation and NLRP3 inflammasome plays an important role. Altered gut microbiota is a driver of chronic sleep deprivation,leading to disruption of the intestinal barrier by activating NLRP3 inflammasome in the colon,which in turn leads to the release of inflammatory cytokines.Peripheral inflammatory factors further activate NLRP3 inflammasome and microglia in the central nervous system through the impaired blood-brain barrier,resulting in cognitive dysfunction.