Early EPR Detection of HbNO in the Hearts of Rats with Induced Septic Shock

Septic shock is characterized by an excess of reactive oxygen and nitrogen species. The induction of nitric oxide (NO) synthesis has been related to vasoplegia, myocardial depression, and decompensated shock. Decompensation cannot be diagnosed in its early phases and is associated with high mortality. The goal of this study was to detect the NO radical, by electron paramagnetic resonance (EPR), in organs isolated from septic male Wistar rats to establish a time course of septic shock and to detect the onset of decompensation. The heme-nitrosyl (HbNO) adduct was detected in hearts and livers 1 h after lipopolysaccharide (LPS) administration. Advantage was taken of the heme group which acts as endogenous spin-trap. Three hours after the LPS dosing, HbNO was evident in the lung and ileum. The early increase of HbNO in the heart, a new finding, could indicate that cardiovascular dysfunction begins earlier that it was thought before.