| Objective: Nucleotide binding oligomerization domain-like receptor protein 3(NLRP3)inflammasome has been implicated in the pathogenesis of neurodegenerative diseases.This study aimed to explore the effects of inhibition of NLRP3 on blood-brain barrier and oxidative stress after surgery in aged mice.Methods: Eighteen-month-old male C57BL/6 mice(30～50 g)were randomly divided into four groups: control + vehicle group(Con + Veh group),control + MCC950group(Con + MCC950 group),surgery + vehicle group(Sur + Veh group),surgery +MCC950 group(Sur + MCC950 group).MCC950(40 mg/kg,NLRP3 specific inhibitor)or vehicle was injected intraperitoneally 30 min before laparotomy.24 h after operation,the hippocampal tissues were collected for measuring the protein levels of NLRP3,ASC,cleaved caspase-1,Iba-1,GFAP,MMP-2,MMP-9,IL-1β,IL-18 and IL-10,content of malondialdehyde(MDA)and activity of superoxide dismutase(SOD).Results: Compared to the Con + Veh group,the levels of MMP-2,MMP-9,NLRP3,cleaved caspase-1,Iba-1,GFAP,IL-1β and IL-18,and content of MDA were increased while IL-10 level and SOD activity were decreased in the Sur + Veh group.Compared to the Sur + Veh group,the levels of NLRP3,cleaved caspase-1,GFAP,Iba-1,MMP-2,MMP-9,IL-1β and IL-18,and content of MDA were significantly decreased,while IL-10 level and SOD activity was significantly increased(P<0.05)in the Sur + MCC950 group.Conclusions: The blood-brain barrier was damaged after surgery,inducing neuroinflammation and oxidative stress in the aged mice.The NLRP3 specific inhibitor MCC950 protected the blood-brain barrier from surgery-induce damage,alleviating oxidative stress and neuroinflammation.Objective: Sepsis-associated encephalopathy(SAE)is a serious complication in the central nervous system of septic patients.However,the pathogenesis of SAE is still not fully understood,and effective pharmacologic agents are lacking.In this study,we hypothesized that the NLRP3/caspase-1 pathway is involved in the pathogenesis of SAE,and inhibiting NLRP3/caspase-1 pathway attenuates sepsis-induced pyroptosis activation,inflammatory cytokines maturation,and cognitive deficits in the SAE mice.Methods: Four-month-old male C57BL/6 mice(20~30 g)were randomly divided into six groups: sham + saline,sham + MCC950,sham + Ac-YVAD-CMK,cecal ligation and puncture(CLP)+ saline,CLP + MCC950 and CLP + Ac-YVAD-CMK.According the grouping,saline,MCC950(NLRP3 inhibitor)or Ac-YVAD-CMK(caspase-1 inhibitor)was intraperitoneally injected 30 min before surgery,and on day1,2,4,and 6 after surgery,respectively.On day 7,six mice in each group were deeply anesthetized and the brain of each mouse was separated into two halves for histochemical analysis and biochemical assays.Cell morphology in hippocampal CA1 region was observed by hematoxylin and eosin staining.Protein levels of NLRP3,ASC,cleaved caspase-1,cleaved GSDMD,IL-1β and IL-18 were measured by western blot and enzyme-linked immunosorbent assay.The remaining mice in each group were used for behavioral tests 2 weeks after surgery.Results: Compared to the sham + saline group,the 7-days mortality,levels of NLRP3,cleaved caspase-1,cleaved GSDMD,IL-1β,and IL-18 and the number of NLRP3 and caspase-1 positive cells in the hippocampal CA1 area were increased in the CLP + saline group.Compared to CLP + saline group,the 7-day mortality,protein levels of NLRP3,cleaved caspase-1,cleaved GSDMD,IL-1β and IL-18,and the number of NLRP3 and caspase-1 positive cells were decreased in the CLP + MCC950 group,while the 7-day mortality,levels of cleaved caspase-1,cleaved GSDMD,IL-1β and IL-18,and the number of caspase-1 positive cells were decreased in the CLP + Ac-YVAD-CMK group(P<0.05).Conclusions: The NLRP3/caspase-1 pathway-induced pyroptosis mediates cognitive deficits in a mouse model of SAE.Administration of MCC950 or Ac-YVAD-CMK inhibits sepsis-induced pyroptosis activation and pro-inflammatory cytokines releasing and rescues cognitive deficits in the SAE mice. |
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