Study On The Protective Effect Of Alda-1 On Sepsis-associated Acute Kidney Injury

Background Acute kidney injury(AKI)is often secondary to patients with sepsis.Ischemia-reperfusion injury,inflammatory immune disorders and renal tubular injury are all important pathogenesis.Studies have shown that nucleotide binding oligomerization domain(NOD)-like receptor family 3(NLRP3)inflammasomes is composed of NLRP3,apoptosis-associated speck like protein(ASC)and pro-caspase-1,which can be activated by reactive oxygen species(ROS)to produce various inflammatory cytokines(such as interleukin-1β and interleukin-18)and play a role in S-AKI.Aldehyde Dehydrogenase-2(ALDH2)plays an important role in removing toxic substances from the body.Its agonist Alda-1 played a protective role by enhancing ALDH2 activity and reducing the level of 4-Hydroxy-2-Nonenal(4-HNE)to alleviate lung damage in severe hemorrhagic shock and resuscitation rat models.Several researches have revealed that Cyanamine,a non-specific inhibitor,can weaken the activity of ALDH2 and aggravate the accumulation of toxic aldehydes.Objective To investigate the role of Alda-1 in the cecal ligation and puncture(CLP)model of sepsis-induced AKI and its possible mechanism.Methods(1)This experiment uses healthy male SD rats for experiments.All rats were randomlydivided into four groups: sham operation group(sham group)(n= 10);CLP +Dimathyl sulfoxide group(DMSO)(n = 10);CLP + Alda-1 Group(n= 10);CLP +Cyanamine group(n= 10).(2)Rats in groups 2,3,and 4 were successfully established CLP models,and givenDMSO or Alda-1(10 mg/kg)or Cyanamine(25 mg/kg)drugs 30 minutes aftersurgery.(3)Arterial blood was drawn from the catheter to detect Lactate(LAC),creatinine(Cr),4-HNE,ALDH2 levels at baseline(BL),CLP 6h,CLP 12 h and kidney tissueretained to detect expression of NLRP3,ASC and renal histopathology at CLP 6h,CLP 12 h.Results(1)There were no significant differences in the parameters of body weight,MAP,LAC at baseline in four groups rats(P > 0.05).(2)Compared with sham group,MAP of rats in rest groups showed a decrease trend after CLP 6 hrs,in which CLP + Cyanamine group was significantly lower than CLP + DMSO group and its level in CLP + Alda-1 group was significantly higher than that in CLP + DMSO group(P < 0.05).(3)Compared with sham group,Cr of rats in rest groups showed an increase trend after CLP 6hrs.Its level in CLP + Cyanamine group was significantly higher than that in CLP + DMSO group and the level of rats in CLP + Alda-1 group was significantly lower than that in CLP + DMSO group(P < 0.05).(4)The renal pathological injury scores of rats in three groups were significantly increased compared with the sham group after CLP 12 hrs,which showed swollen renal epithelial cells,detachment of the brush border,vacuolar degeneration and cavity expansion.Among them,after administration of Alda-1 or Cyanamine,the tissue damage was significantly improved/ worsened than that in CLP+DMSO group and the renal tubular injury score was significantly reduced/ increased(P < 0.05).(5)Compared with the sham group,the 4-HNE level of rats in rest groups showed an increase trend after CLP 6hrs.Its level was significantly higher in CLP + Cyanamine group than CLP + DMSO group,and the level in CLP + Alda-1 group was significantly lower than CLP + DMSO group(P < 0.05).The activity of ALDH2 in CLP + DMSO group was not significantly changed compared with the sham group(P > 0.05).After CLP 6 hrs,the ALDH2 activity in CLP + Cyanamine group was significantly lower than that in CLP + DMSO group and its level was higher in CLP + Alda-1 group than CLP + DMSO group(P < 0.05)(6)The expressions of NLRP3 and ASC protein of rats in three groups showed an increase trend after CLP 12 hrs.Both expressions in CLP + Cyanamine group were significantly higher than CLP + DMSO group,and their levels were lower in CLP + Alda-1 group than CLP + DMSO group(P <0.05).Conclusions 1.The CLP model was used to establish a stable sepsis model.2.After CLP insult,it can cause the decrease of MAP,the increase of LAC,Cr level and the accumulation of 4-HNE in rats.3.The expression of NLRP3 and ASC protein increased after CLP injury.4.CLP can cause renal dysfunction and acute kidney injury,which was manifested by increased Cr levels,increased renal tubular injury and pathological injury scores.5.The mechanism may be that Alda-1 reduced renal tubular damage,alleviated Cr levels to protect renal function by enhancing ALDH2 activity,accelerating the clearance of 4-HNE and inhibiting the expression of NLRP3/ ASC protein.While administration of Cyanamine inhibited ALDH2 activity,weakened the clearance of 4-HNE,up-regulated the expression of NLRP3/ASC protein and aggravated renal tissue damage.