NO AND INFLAMMATION AS EFFECTORS OF CARDIAC MITOCHONDRIAL DYSFUNCTION AND ROS PRODUCTION IN LOW-GRADE AND SEVERE ENDOTOXEMIA.

VICO, TAMARA; VANASCO, VIRGINIA; MARCHINI, TIMOTEO; ADÁN AREÁN, JUAN; CALABRO, VALERIA; GARCES, MARIANA; CATUOGNO, FRANCO; LORENZETTI, MARIO; FERRERO, MARIANA; GONZALEZ MAGLIO, DANIEL; BALDI, PABLO; EVELSON, PABLO; ALVAREZ, SILVIA

Congreso; Reunión Conjunta de Sociedades de Biociencias.; 2017

Myocardial dysfunction is a complication of severe sepsis and endotoxemia. Previously, we described cardiac mitochondrial dysfunction in this syndrome. Mechanisms of how systemic inflammation could damage heart function remains still unknown. Cytokines, NOand bioenergetics derangements are thought to be involved. The aim was to analyse systemic NO and ROS in a model of low-grade and severe endotoxemia. Female Sprague-Dawley rats (55 days) were injected i.p. with a single dose of LPS 0.5 mg/kg, 8 mg/kg or vehicle (control), 6h later animals were sacrificed. White blood cells (WBC) and differential count were analysed. DFC-DA and DAF-2-DA were used to estimate intracellular ROS and NO concentration by polymorphonuclear cells (PMN), respectively. Nitrite/nitrate content and proinflammatory cytokines levels (TNFα and IL-6) were analysed in plasma samples. Mitochondrial H2O2 production was measured using Amplex Red probe. WBC count showed difference between groups: control 2638 cells/mm3 (N:17%/L:77%/M:5%/E:1%/B:0%), LPS 0.5: 6771 cells/mm3 (N:61%/L:28%/M:7%/E:0%/B:4%) and LPS 8: 1021 cells/mm3 (N:58%/L:40%/M:2%/E:0%/B:0%). PMN cells from LPS-treated animals increased intracellular NO by 147% (LPS 0.5) and 164% (LPS 8) compared with control (p<0.05). ROS production showed a partial increase at LPS 0.5 and LPS 8 treated animals. Nitrite/nitrate content in plasma increased 4-fold (LPS 0.5) and 7-fold (LPS 8) compared to control group (p<0.05). TNF-α and IL-6 levels increase was related to the severity of endotoxemia. Cardiac mitochondrial H2O2 production (control: 0.128±0.01) increased140% in LPS 0.5 and 160% in LPS 8 treatment compared with control group (p<0.05). Our results show that the severity of the endotoxemic process is correlated to ROS and NO levels in blood, and to cardiac mitochondrial dysfunction previously reported. These resultsstrongly suggest the importance of restoring NO and ROS levels, and cardiac mitochondrial function in inflammatory pathologies.