Parenteral succinate reduces levels of reactive oxygen species without changing serum caspase-3 levels in septic rats

Introduction
Sepsis is a syndrome of physiological, pathological, and biochemical disorders with several processes co-occurring; reactive oxygen species (ROS) production and apoptosis are 2 of them. Succinate is a Krebs cycle intermediate that is oxydized in complex II of the mitochondria. This study aims to investigate the influence of succinate infusion on these processes.

Material and methods
Sepsis was induced with caecal ligation and puncture in 200 gr Sprague Dawley rats. Four groups were formed with 10 animals (1 – control, 2 – succinate, 3 – sepsis, and 4 – sepsis + succinate). 5 mmol kg–1 of intraperitoneal succinate were administered twice in groups 2 and 4. ROS and caspase-3 levels were measured.

Results
Overall, ROS levels (P = 0.017), but not caspase-3 levels (P = 0.89) differed significantly between the groups. The succinate administration reduced serum ROS levels (group 4 vs. 3) in a statistically significant way [0.0623 units (95% CI: 0.0547-0.0699) vs. 0.0835 (0.06-0.106), P = 0.017)], but it did not reduce serum caspase-3 levels (P = 0.39). There was no correlation between serum ROS levels and serum caspase-3 levels.

Conclusions
In this model, ROS levels were reduced with succinate infusion, but caspase-3 levels were not. In addition, ROS levels and apoptosis levels are not correlated, which suggests that those processes occur at different times.