Cardiac bioenergetics and mitochondrial pathways in a rat model of low and severe endotoxemia.

VICO, TAMARA; VANASCO, VIRGINIA; MARCHINI, TIMOTEO; ADAN AREAN, JUAN; EVELSON, PABLO; ALVAREZ, SILVIA

Mar del Plata

Congreso; LXI Reunión Científica Anual de la Sociedad Argentina de Investigación Clínica; 2016

Sociedad Argentina de Investigación Clinica

Despite being the major source of energy in the cell, mitochondria participate in multiple cell signaling pathways. Besides, mitochondria dysfunction is suggested to play a central role in inflammatory pathologies like metabolic, cardiovascular and neurological diseases, and also in acute endotoxemia and sepsis. The aim of this study was to analize cardiac bioenergetics and mitochondrial function in low and severe endotoxemia. Female Sprague-Dawley rats (45 days old) were separated in three experimental groups and i.p. injected with a single dose of LPS (0.5 or 8 mg/kg) or vehicle. After 6 h of treatment, mitochondria were isolated from left ventricle. O2 uptake in state 4 (rest respiration state) and state 3 (active state) was measured and a 15% and 24% decrease in state 3 was observed in LPS 0.5 and LPS 8 mg/kg groups, respectively (Control: 74.8±22 ng-atO/min.mg protein). Complex I-III activity showed a 15% decrease at the highest dose of LPS (Control: 92.1±14 nmol/min.mg protein). Complex II-III and IV activities showed no statistical differences. ATP production was observed decreased by 33% at the highest dose (Control: 186.2±55 nmol ATP/min.mg protein, p˂0.05). The calculated P/O ratios were 2.8; 2.2 and 2 for control, LPS 0.5 and 8 mg/kg; respectively. Mitochondrial membrane potential was measured by flow cytometry and showed a 17% decrease in LPS 8 mg/kg dose (Control IFM: 234±25). To evaluate NO role in this inflammatory processes, iNOS and eNOS expression were measured by Western Blott in left ventricle tissue, showing an increase in both enzyme expressions for LPS 8 mg/kg treatment. These results correlated with nitrite/nitrate levels in plasma. These results suggest that mitochondrial dysfunction occurs in different levels of endotoxemia, setting the mitochondria as a potential therapeutic target to treat inflammatory diseases.