Study on the effect of fisetin on alleviating cognitive impairment after sepsis by inhibiting the activation of microglial NLPR3 inflammasome
Objective To investigate the mechanism of fisetin inhibiting the activation of microglia NOD-like receptor family protein 3(NLRP3)inflammasome in microglia and alleviating cognitive impairment after sepsis.Methods C57BL/6 mice were used to establish the sepsis model by cecal ligation and puncture.Mice were divided into four groups:the sham group,the sepsis group,the sepsis+caspase-1 knockout group(sepsis+Cas-1-/-group)and the sepsis+fisetin group.Evans blue was used to detect the permeability of blood-brain barrier(BBB).Morris water maze was used to evaluate the cognitive function of mice.Western blot assay and immunofluorescence double staining were used to detect the expression of NLRP3 inflammasome-related proteins including caspase-1,N-terminal fragment of the GSDMD(GSDMD-N),interleukin(IL)-1β,IL-18 and mitophagy-related proteins(Pink1,Parkin and LC3-Ⅱ)in brain tissue and microglia.Results Compared with the sham group,expression levels of caspase-1,GSDMD-N,IL-1β and IL-18 were significantly increased in the sepsis group(P＜0.05).Compared with the sepsis group,expression levels of caspase-1,GSDMD-N,IL-1β and IL-18 were significantly decreased in the sepsis+Cas-1-/-group(P＜0.05).The expression levels of Pink1,Parkin and LC3-Ⅱ were significantly higher in the sepsis+fisetin group than those of the sepsis group(P＜0.05),and expression levels of caspase-1,GSDMD-N,IL-1β and IL-18 were significantly lower(P＜0.05).After fisetin intervention,the permeability of BBB was decreased and the cognitive impairment(decreased escape latency and increased frequencies of crossing the platform)was alleviated in the sepsis+fisetin group compared with those of the sepsis group(P＜0.05).Conclusion Fisetin may alleviate central inflammation and cognitive impairment after sepsis by inhibiting the activation of microglial NLRP3 inflammasome through activating mitophagy.
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