Sepsis does not alter red blood cell glucose metabolism or Na⁺ concentration: A ²H-,²³Na-NMR study

The effects of sepsis on intracellular Na⁺ concentration ([Na⁺](i)) and glucose metabolism were examined in rat red blood cells (RBCs) by using ²³Na- and ²H-nuclear magnetic resonance (NMR) spectroscopy. Sepsis was induced in 15 halothane-anesthetized female Sprague-Dawley rats by using the cecal ligation and perforation technique; 14 control rats underwent cecal manipulation without ligation. The animals were fasted for 36 h, but allowed free access to water. At 36 h postsurgery, RBCs were examined by ²³Na-NMR by using dysprosium tripolyphosphate as a chemical shift reagent. Human RBCs from 17 critically ill nonseptic patients and from 7 patients who were diagnosed as septic were also examined for [Na⁺](i). Five rat RBC specimens had [Na⁺](i) determined by both ²³Na-NMR and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). For glucose metabolism studies, RBCs from septic and control rats were suspended in modified Krebs-Henseleit buffer containing [6,6-²H₂]glucose and examined by ²H-NMR. No significant differences in [Na⁺](i) or glucose utilization were found in RBCs from control or septic rats. There were no differences in [Na⁺](i) in the two groups of patients. The [Na⁺](i) determined by NMR spectroscopy agreed closely with measurements using ICP-AES and establish that 100% of the [Na⁺](i) of the RBC is visible by NMR. Glucose measurements determined by ²H-NMR correlated closely (correlation coefficient = 0.93) with enzymatic analysis. These studies showed no evidence that sepsis disturbed RBC membrane function or metabolism.