Study On The Protective Effect Of Cx43 Inhibition On Intestinal Injury In Sepsis By Recducing Oxidative Stress

Sepsis is a life-threatening syndrome that often causes multi-organ impairment or failure and is the most common cause of death in intensive care units.The gastrointestinal tract is the most commonly involved organ in sepsis,and the mechanisms of sepsis-induced intestinal injury in humans are still unclear,so we investigate the potential mechanisms and develop new therapeutic strategies to improve the prognosis of patients with sepsis.Gap junction(GJ)function plays an important role in injury amplification and tissue deterioration,and it has been shown that intracellular accumulation of reactive oxygen species(ROS)induces intestinal mucosal cell injury in sepsis.In the present study,we focused on the relevance of the GJ function regulatory protein gap-linked protein 43(connexin43,Cx43)to sepsis intestinal injury and the specific mechanism of the role of Cx43 in sepsis-induced intestinal injury through the transfer of reactive oxygen species(ROS).Objective1.To explore the possible mechanisms of septic bowel injury and to clarify the role of Cx43,ROS,and JNK1/Sirtl/FOXO3a signaling pathway-mediated apoptosis in the development of septic bowel injury.2.To verify whether the hypothesis that Cx43 channels mediate ROS translocation during septic bowel injury regulates JNK1/Sirtl/FoxO3a signaling pathway activity,which in turn leads to transcriptional translation of the pro-apoptotic proteins Bim and Puma and exacerbation of sepsis-induced bowel injury.Methods1.A rat model of sepsis was constructed by cecum ligation puncture(CLP),small intestinal tissues and serum were collected,and Cx43 protein expression levels in small intestinal tissues were measured at different time points,and the injury pathology scores of corresponding rat small intestinal tissues and the levels of intestinal injury indicators LDH,DAO and IFABP were measured to explore the correlation between Cx43 expression levels and intestinal injury in sepsis.2.select IEC-6 cells,establish a sepsis cell model by pretreatment with lipopolysaccharide LPS,transfect IEC-6 using small interfering RNA,and observe the correlation between Cx43 expression levels and the levels of LDH,DAO and IFABP,indicators of intestinal injury,in the cell model3.Cx43 inhibitors(18-?-GA)and antioxidants(NAC)were used to intervene in vivo and in vitro models,and the levels of intestinal injury indicators LDH,DAO and IFABP were measured,and the effects of Cx43 and ROS on intestinal injury were observed.4.In sepsis cell models,dual luciferase and chromatin immunoprecipitation ChIP were used to detect the binding area between FoxO3 and Bim or Puma.Results1.In an in vivo rat model of sepsis,the expression level of Cx43 showed a positive correlation with the severity of intestinal injury and peaked around 24 hours postoperatively,and was coordinated with changes in LDH,DAO,and IFABP levels.2.In ex vivo sepsis models,Cx43 can promote the transfer and intracellular accumulation of ROS,thus activating the JNK1/Sirtl/FoxO3a signaling pathway leading to septic bowel injury.3.Dual luciferase and ChIP-seq assays demonstrated that FoxO3a,a downstream regulator of Cx43,could directly bind apoptosis-related proteins Bim and Puma to induce apoptosis leading to septicemia intestinal injury.ConclusionCX43 can promote ROS translocation and intracellular accumulation,thereby activating the JNK1/Sirtl/FoxO3a signaling pathway and thereby inducing apoptosis to aggravate sepsis-induced intestinal injury.