Antioxidant Supplementation (AOxS) Prevents the Renal Damage Induced by the Continue Exposure to Mild Heat Stress and Rehydration with a Fructose‐Containing Beverage (FCB)

Experimental studies have shown that rehydration with an FCB, in the setting of continuous exposure to mild heat stress further aggravates the renal alterations. In those studies, it was observed that a principal component of the renal damage is an increase in intrarenal oxidative stress. Therefore, the objective of the present study was to evaluate the potential protective role of supplementing the rehydration and/or fluids of the day (tap water) with water‐soluble antioxidants on the renal alterations induced by mild heat stress with rehydration with an FCB. Four groups of male Wistar rats were studied (230–260 g, n=9). Mild heat stress was induced by exposing rats to 37°C during 1 h in a closed chamber from Monday to Friday during 4 weeks. The supplementation with the water‐soluble antioxidants (AOxS), l‐ascorbic acid (1%) plus n‐acetylcysteine (600 mg/L) was done either in the 10% FCB used as rehydration fluid for 2 h immediately after heat stress (Fructose 10%+Antiox), or tap water (Water+Antiox) for fluid intake during the remaining of the day, or in the two fluids. At the end of the study, urine was collected in metabolic cages, and systolic blood pressure was measured by a non‐invasive method in conscious animals. Rats were euthanized by deep anesthesia and kidneys were washed by perfusion with cold PBS, excised and renal cortex and medulla separated and stored in liquid nitrogen until further processing. The following measurements were done: In plasma, creatinine, BUN, and total antioxidant capacity; in urine, creatinine and thiobarbituric acid reactive substances and NAG activity. Creatinine clearance was also calculated to evaluate renal function. In renal cortex, NOX activity and lipid peroxidation as well as the expression (western‐blot) of Nrf2, Keap‐1, Superoxide dismutase‐1, catalase, glutathione peroxidase, glutamate cysteine ligase, Nox4, and beta‐actin. In nuclear extracts, the translocation of Nrf2 was evaluated by western blot using the proliferation cell nuclear antigen (PCNA) antibody as load control. AOxS in tap water preserved the expression of antioxidant enzymes and reduced systemic and renal oxidative stress induced by mild heat stress and rehydration with an FCB. The beneficial effect was further amplified when AOxS were also present in FCB. In conclusion, the therapeutic effect of AOxS was accomplished when provided before the exposure to mild heat stress and rehydration with an FCB. The effect was partially mediated by the translocation of the Nrf2 transcription factor to nuclei allowing the expression of antioxidant enzymes, and by preserving the capacity to synthesize glutathione. Support or Funding Information Danone Nutricia ResearchResults: AOxS prevented renal alterations and preserved antioxidant defenses by stimulating Nrf2 pathway and preserving glutathione intracellular poolThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .