The Effect Of Glutamine By Promoting Heat Shock Protein 90 On Cardiac Myocyte Apoptosis In Sepsis Rats

BackgroundMyocardial cell injury and cardiac myocyte apoptosis are associated with sepsis.Previous researches demonstrate that Glutamine(Gln)play a key role in repairation of myocardial cell injury.The aim of this study was to explore the role of Gln on cardiac myocytes in a cecal ligation and puncture(CLP)model of sepsis in Wistar rats.Materials and methodsThe male Wistar rats were divided randomly into 12 groups(n = 6 in each group): the normal group;the CLP model group;the Hsp90 overexpression(Adv-Hsp90)group;the Hsp90 overexpression + CLP model(Adv-Hsp90+ CLP)group;the Hsp90 silenced(Adv-Hsp90dsDNA)group;the Hsp90 silence + CLP model(Adv-Hsp90dsDNA+CLP)group;the Gln,Gln + CLP model(Gln + CLP)group;the Gln + Hsp90 overexpression(Gln + Adv-Hsp90)group;the Gln + Hsp90 overexpression + CLP model(Gln + Adv-Hsp90 + CLP)group;the Gln + Hsp90silence(Gln + Adv-Hsp90dsDNA)group;and the Gln + Hsp90 silence + CLP model(Gln + Adv-Hsp90 dsDNA + CLP)group.Following induction of sepsis in a CLP rat model,viral encoding of heat shock protein 90(Hsp90)gene and Hsp90 dsDNA were designed to express and knockdown Hsp90,respectively.Gln was dissolved in saline and injected intravenously at a dose of 0.75 g/kg once,2 h after surgery.Myocardial tissues were sampled 48 h after treatment from rats in each group.Rat cardiac tissues were examined histologically,and apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling staining.The expression of Bcl-2,Bcl-2-associated X protein,Hsp90,p53 upregulated modulator of apoptosis,and p53 was measured by western blotting and quantitative real-time polymerase chain reaction.Caspase-3,caspase-8,and caspase-9 were detected by enzyme-linked immunosorbent assay.ResultsCompared with controls,the degree of cardiac pathological damage and apoptosis of cells with green fluorescence in the CLP group and the Adv-Hsp90dsDNA+CLP group were more serious while that of the Gln+Adv-Hsp90+CLP group was relieved significantly.Compared with controls,the activity of Bcl-2 protein decreased(p<0.05),the activity of Bax protein increased(p<0.05),and the m RNA expression of p53 and PUMA increased(p<0.05)in the CLP group.Compared with the CLP group,the concentration of Bcl-2 protein increased(p<0.05),the concentration of Bax protein decreased(p<0.05),and the mRNA expression of p53 and PUMA decreased(p<0.05)in the Adv-Hsp90+CLP group,the Gln+CLP group and the Gln+Adv-Hsp90DNA+CLP group.Compared with controls,caspase-8,caspase-9,and caspase-3 activities were increased in rat cardiac myocytes in the CLP model(p<0.05),which were reversed by Gln treatment and/or Hsp90 overexpression(p<0.05).ConclusionsGln reduced apoptosis of cardiac myocytes in a rat model of sepsis,by promoting Hsp90 expression.Further studies are needed to determine the possible therapeutic action of Gln in sepsis in human tissue.