RESUMEN
Objective To investigate the role of O-linked N-acetylglutamine (O-GlcNAc) modification in glutamine-induced myocardial heat shock protein (HSP70) expression in a rat model of endotoxic shock. Methods Thirty-two 8 weeks old male SD rats weighing 250-300 g were randomly divided into 4 groups (n = 8 each):group Ⅰ control (group C); group Ⅱ LPS; group Ⅲ G+ LPS and group glutamine + LPS (group A + G + LPS). Endotoxic shock was induced by iv administration of LPS 10 mg/kg in group Ⅱ , Ⅲ and Ⅳ.Glutamine 0.75 g/kg was administered iv at 1 h before iv LPS in group Ⅲ and Ⅳ . Alloxan (an inhibitor ofO-linked N-acetylglucosamine transferase) 50 mg/kg was administered iv together with glutamine at 1 h before LPS in group Ⅳ. The animals were sacrificed at 6 h after iv LPS administration. Their hearts were removed for determination of the expression of O-GlcNAc and HSP70 in myocardium. Results Intravenous LPS significantly up-regulated the expression of O-GlcNAc and HSP70. Glutamine pretreatment further increased the expression of O-GlcNAc and HSP70. The glutamine pretreatment induced increase in O-GlcNAc and HSP70 expression was abolished by concomitant administration of alloxan. Conclusion O-GlcNAc modification may be involved in glutamine-induced myocardial HSP70 expression in endotoxic shock.