The Role And Mechanism Of Interleukin-1β In Vascular Dysfunction Of Sepsis

Objective:To study the role of interleukin-1β（IL-1β）in vascular dysfunction of sepsis and its possible mechanism.Methods:1.Vivo experiments:the vascular dysfunction of sepsis was induced by cecal ligation and puncture（CLP）in C57BL/6 mice.The mice were randomly divided into sham operation group（SO）,CLP group,CLP+MCC950（IL-1βinhibitor）group,CLP+Diacerein（IL-1βinhibitor）group,CLP+MG132（proteasome inhibitor）group,SO+BMY7378(α_1D-adrenergic receptor inhibitor)group,CLP+BMY7378 group,CLP+BMY7378+MCC950 group,CLP+BMY7378+Diacerein group（n≥5）.One-week survival rates of septic mice were observed.Mean arterial pressures（MAP）were measured by tail cuff method,vasodilation and vasoconstriction function of superior mesenteric arteries were measured by vascular reactivity experiments,proteins expression of endothelial nitric oxide synthase（eNOS）andα₁-adrenergic receptor（α₁-AR）in mesenteric arteries were observed by Western blot,and mRNA levels of three subtypes ofα₁-AR(α_1A-AR,α_1B-AR,α_1D-AR)in mesenteric arteries were detected by RT-qPCR at 24 hours after CLP.2.Vitro experiments:primary culture of HUVECs was established,HUVECs were randomly divided into control group,IL-1βtreatment group（treat with different concentrations and different time）,MG132+IL-1βtreatment group（n≥5）.eNOS protein expression in HUVECs was tested by Western blot.Results:1.Vivo experiments:the decrease of one-week survival rate,the decrease of mean arterial pressure,the impairment of relaxation and contraction function of superior mesenteric arteries,the decline of eNOS andα₁-AR expression in mesenteric arteries,the decline of three subtypes ofα₁-AR(α_1A-AR,α-_1B-AR,α_1D-AR)mRNA in mesenteric arteries in CLP group could be improved by MCC950 or Diacerein.The one-week survival rate,the relaxation function of superior mesenteric arteries,the protein expression of eNOS in mesenteric arteries were significantly improved in the mice pretreated with MG132.The improvement of MCC950 or Diacerein on one-week survival rate in CLP mice could be significantly inhibited by BMY7378.2.Vitro experiments:compared with the control group,IL-1βsignificantly down-regulated the expression of eNOS protein in HUVECs in a concentration-dependent and time-dependent manner.MG132 pretreatment could significantly block the down-regulation of eNOS in HUVECs induced by IL-1β.Conclusion:IL-1βmay participate in the endothelial dysfunction and contraction dysfunction of sepsis by down-regulating the expression of eNOS andα_1D-AR respectively,the down-regulation of eNOS may be caused by ubiquitin-proteasome degradation pathway.