Mechanism Of Protection Of Hexarelin On Ischemia-Reperfusion Induced Acute Renal Injury

Objective: Acute Kidney Injury(AKI)is a transient reversible clinical complication with low diagnosis rate and high mortality rate and is closely related to the prognosis of patients.Kidney structure can be permanently changed even if the kidney function returns to normal,so the prevention of AKI was of vital importance both in clinical and in society.In this study,in vivo experiments,reverse docking and clinical data analysis approaches were used to explore the effect and the underlying mechanism of Hexarelin on IRI Ischemia Reperfusion Injury Induced Acute Kidney Injury(IRI-AKI)and to construct a visual Nomogram prediction model in patients with cardiac surgery,with a view to provide a theoretical basis for early identification of AKI high-risk patients,guiding clinical medication and preventing their occurrence.Methods: To investigate whether Hexarelin has the protective effect of renal ischemiareperfusion injury and the possible protective mechanism,a rat model of IRI-AKI was constructed was constructed with Hexarelin pretreatment;further,inverse virtual screening(IVS)and molecular docking methods were used to explore the potential targets and mechanism underlying protection.In addition,in order to predict the individuals with highrisk of AKI after cardiac surgery,a Nomogram prediction model of cardiac surgeryassociated acute kidney injury(CSA-AKI)based on the 2012 KDIGO guidelines was built to identify high-risk populations of CSA-AKI for providing theoretical basis for clinical administration.Results: The experimental results showed that Hexarelin pretreatment can significantly improve the renal tubular dilation caused,loss of brush border,tube formation,inflammatory cell and erythrocyte infiltration and other pathological changes by IRI-AKI,and can reduce concentration of blood creatinine(P <0.001)urea nitrogen(P <0.001).The expression of Kidney injury molecule 1(KIM-1)(P <0.001)and pro-apoptotic factor Caspase3(P <0.05),BAX(P <0.001),BAD(P<0.001)can also be inhibited after Hexarelin pretreatment.However,Hexarelin did not increase the concentration of growth hormone in the process(P> 0.05),indicating that Hexarelin pretreatment can significantly antagonize IRI-AKI,reduce IRI-AKI-induced apoptosis,whose protection has nothing to do with growth hormone.Accordingly,differential genes of AKI were controlled by transcription factors such as Nuclear factor erythroid 2-related factor 2(NFE2L2),Activating Transcription Factor 3(ATF3),FOS,and caudal type homeobox 2(CDX2)Regulation.Inverse docking results showed that in AKI,mitogen-activated protein kinase-1(MAPK1),cyclin-dependent kinase-2(CDK2),Glucocorticoid receptor gene(Homo sapiens nuclear receptor subfamily 3 group C member 1,NR3C1),signal transduction and transcription activator 1(Signal Transducer And Activator Of Transcription 1,STAT1),nuclear receptor subfamily 1,group H,member 2(Recombinant Human Nuclear Receptor Subfamily 1 Group H,Member 2,NR1H2)may be target transcriptional regulators of Hexarelin.Further,analysis of molecular docking showed that MAPK1 and CDK2 played a key role in transcriptional regulation of AKI protection of Hexarelin.Finally,the Nomogram prediction model was constructed,and the results showed that the incidence rate of CSAAKI was 49.05%(932/1900),among which the incidence rates of AKI in phases 1,2 and 3 were 74.89%(698/932)and 16.96%(158 / 932),8.15%(76/932).Multivariate logistic regression analysis showed that age(OR = 1.679,95% CI 1.396-2.020),perioperative estimated glomerular filtration rate(OR = 0.528,95% CI 0.471-0.591),lactate dehydrogenase(OR = 1.764,95% CI 1.366-2.278),chronic kidney disease(OR = 2.982,95 CI 1.186-7.497),surgical history(OR = 8.655,95% CI 4.703-15.928)are all predictors of CSA-AKI.the nomogram demonstrated good accuracy in estimating CSA-AKI,with a C-index and a bootstrap-corrected one of 0.796 and 0.789,respectively.Moreover,calibration plots showed optimal agreement with the actual presence of CSA-AKI.Conclusion: Hexarelin can protect against IRI-AKI,and its mechanism may be related to the direct binding of transcription regulators MAPK1,CDK2,NR3C1 etc.to regulate downstream genes.Transcription regulators There are intermolecular forces between MAPK1 and CDK2 at Asp109,Asp104,Lys112 and Val163,Glu12,Arg199 and Hexarelin,which is the key transcription regulator of Hexarelin to protect AKI.The CSA-AKI Nomogram prediction model has good predictive ability and can be used to guide preoperative medication.