Effects Of Dexmedetomidine On Monocytes Pyroptosis In Peripheral Blood In Patients With Cardiac Valve Replacement Under Cardiopulmonary Bypass

Objective:The study was aimed to determine the effects and mechanism of dexmedetomidine（Dex）on inflammatory response and peripheral blood monocytes pyroptosis in patients with cardiac valve replacement under cardiopulmonary bypass.Methods:44 American Society of Anesthesiologists physical statusⅡorⅢpatients of both sexesp of New York Heart AssociationⅡorⅢp aged45-64 yrp BMI 18-25 kg/m²p receiving elective cardiac valve replacement with cardiopulmonary bypassp were randomly divided into 2 groups（n=22）according to the random number table method:dexmedetomidine group（Group Dex）and normal saline group（Group NS）.Patients in Group Dex received an infusion of 0.5μg/kg（initial dose）within 10 min after anesthesia induced intubationp followed by continuous infusion at 0.5μg·kg^-1·h^-1until the end of the operationp while patients in Group NS were injected with the equal volume of normal saline.The blood samples of internal jugular vein were collected before skin incision（T1）p 30 min after the initiation of CPB（T2）p immediately after the end of CPB（T3）and 24 h after CPB（T4）.The concentrations of plasma IL-18 and IL-1βwere determined by ELISAp mononuclear cells were extracted by Ficoll density gradient separationp and NLRP3p Caspase-1 and GSDMD protein expression in monocytes was detected by Western blot.Propofolp sufentanil and norepinephrine consumption during operationp the time of postoperative mechanical ventilation and the stay time of ICU were recorded.Results:The levels of plasma IL-18 and IL-1βin the two groups at T2-4were significantly higher than those at T1（P<0.05）.Compared to Group NSp the levels of plasma IL-18 and IL-1βin Group Dex decreased at T2-4（P<0.05）.Compared with T1p the protein expression of NLRP3p Caspase-1and GSDMD in peripheral blood monocytes of the two groups increased at T2-4（P<0.05）.Compared to Group NSp NLRP3p Caspase-1 and GSDMD protein expression in Group Dex decreased at T2-4（P<0.05）.Compared with Group NSp the time of postoperative mechanical ventilation in Group Dex decreased（P<0.05）.Conclusion:Dex alleviates the inflammatory response in patients undergoing cardiac valve replacement with cardiopulmonary bypassp the anti-inflammatory mechanism may be related to the inhibition of the expression of NLRP3 and Caspase-1 proteins and the decrease of the levels of downstream inflammatory cytokines IL-18 and IL-1βp thus inhibiting pyroptosis.