Trans‐sodium crocetinate does not affect oxygen uptake in rats during treadmill running

Abstract

Trans‐sodium crocetinate (TSC), the isomer of the carotenoid compound crocetin, is found markedly to increase survival in hemorrhagic shock subsequent to 50–60% blood loss, mainly via restored resting oxygen consumption (VO₂), blood pressure and heart rate. The proposed mechanism is that TSC increases oxygen diffusivity, and thus availability, in plasma. If this were found to be a prominent feature in the oxygen transfer from blood to skeletal muscle fiber mitochondria, increased VO₂ during exercise would be expected because of reduced partial pressure of venous oxygen (increased utilization), which we aimed to elucidate in this study. Male Sprague‐Dawley rats were intravenously injected with 0.3 mL kg⁻¹ TSC (40 µg mL⁻¹) or placebo and immediately thereafter tested on a ramped treadmill test protocol. Rats were introduced to the experimental protocols beforehand. Administration of TSC had a neutral effect on submaximal and maximal VO₂ (VO_2max) as well as running performance measured as maximal running time and maximal aerobic running velocity. Thus, in this study we cannot report any effects of TSC on steady‐state submaximal VO₂ or VO_2max at exhaustive exercise.

• Exercise
• TSC
• VO₂

Acknowledgements

We thank Professor Duan Chen, the Norwegian University of Science and Technology, and Veterinarian Ingolf Hanssen for help with immobilization of the rats and administration of TSC, and Research Technician Ingerid Arbo for randomization and blinding procedures. Furthermore, we express our gratitude to Professor John L. Gainer, the School of Engineering and Applied Science, University of Virginia, Charlottesville, Va., for kindly providing us with the substance as a gift. Ole Johan Kemi is the recipient of a research fellowship from the Norwegian University of Science and Technology.