Caspase-1 Involves In Bilirubin-induced Injury Of Cultured Rat Cortical Neurons

Objection: The purpose of this study was to investigate whether caspase-1 is involved in bilirubin-induced neuronal injury and what the possible mechanisms are.Methods: VX-765,a highly potent and selective inhibitor of caspase-1,was used to investigate the effects of unconjugated bilirubin(UCB)on rat cortical neurons,including cell viability,morphological changes in the cell membrane,and nuclear factor-kappa B(NF-?B)activation.The rat cortical neurons were cultured in vitro and were randomly divided into three groups: the control group,the UCB group and the VX-765+UCB group.The modified MTT method was used to detect the survival of neurons.Caspase-1 activity was measured by using a bioluminescent method.The membrane permeability change was detected by lactate dehydrogenase release and EtBr/EthD2 staining.The activation of GSDMD was detected by Western blot.The levels of pro-inflammation cytokines were detected by PCR and ELISA.The expression and activation of NF-?B were detected by Western blot and EMSA.Results: Neurons treated with UCB showed increased caspase-1 and GSDMD activities without the secretion of interleukin(IL)-1? and IL-18,and caspase-1 was significantly inhibited by pretreatment with VX-765.The cell viability of the VX-765-pretreated neurons was improved,and cellmembrane rupture was prevented,as detected by lactate dehydrogenase release and EtBr uptake.Moreover,NF-?B was activated,which was attenuated by VX-765 pretreatment.Conclusions: Caspase-1 activation is involved in the neuronal damage induced by UCB.This complicated process involved the activation of caspase-1 and NF-?B,specific membrane pore formation and programmed cell death,independently of IL-1? and IL-18.