Exogenous ketone salts inhibit superoxide production in the rat caudal solitary complex during exposure to normobaric and hyperbaric hyperoxia.
Level 5 - mechanism / opinion, no new human data
Ex vivo animal tissue experiment
PubMed 33661724 · doi:10.1152/japplphysiol.01071.2020
What was done
Cellular superoxide production was measured in the caudal solitary complex (cSC) of rat brain slices using the fluorogenic dye dihydroethidium (DHE). Tissue slices were exposed to baseline control oxygen (0.4 ATA) followed by 1–2 hours of normobaric oxygen (0.95 ATA) or hyperbaric oxygen (1.95 and 4.95 ATA), with or without co-exposure to 5 mM ketone salts (a 50:50 mixture of dl-β-hydroxybutyrate and acetoacetate).
What was found
All tested levels of hyperoxia stimulated superoxide production in cSC cells. Co-exposure to 5 mM ketone salts significantly blunted the increase in DHE fluorescence during hyperoxia. This inhibition was selective: cells exhibiting a >25% increase in superoxide production during hyperoxia relative to baseline were significantly inhibited by ketone salts, whereas cells failing to reach that 25% threshold were unaffected. Specific quantitative rate values and baseline numbers were not reported in the abstract.
Why it matters
These findings suggest a direct cellular mechanism—suppression of superoxide generation in oxygen-sensitive brainstem neurons—by which exogenous ketone supplementation may mitigate central nervous system oxygen toxicity during hyperbaric exposure.
Limits
The study is restricted to ex vivo rat medullary slices, meaning systemic physiological effects, whole-organism metabolism, and direct clinical applicability to humans were not evaluated. Exact sample sizes (number of animals, slices, and individual cells) are not reported in the abstract.
Cited by
- supports Beta-hydroxybutyrate and ketone molecules reduce mitochondrial reactive oxygen species (ROS) and superoxide anion production.