1.
Scuba diving induces nitric oxide synthesis and the expression of inflammatory and regulatory genes of the immune response in neutrophils.
Sureda, A, Batle, JM, Capó, X, Martorell, M, Córdova, A, Tur, JA, Pons, A
Physiological genomics. 2014;(17):647-54
Abstract
OBJECTIVE Scuba diving, characterized by hyperoxia and hyperbaria, could increase reactive oxygen species production which acts as signaling molecules to induce adaptation against oxidative stress. The aim was to study the effects of scuba diving immersion on neutrophil inflammatory response, the induction of oxidative damage, and the NO synthesis. DESIGN Nine male divers performed a dive at 50 m depth for a total time of 35 min. Blood samples were obtained at rest before the dive, after the dive, and 3 h after the diving session. MEASUREMENTS Markers of oxidative and nitrosative damage, nitrite, and the gene expression of genes related with the synthesis of nitric oxide and lipid mediators, cytokine synthesis, and inflammation were determined in neutrophils. RESULTS The mRNA levels of genes related with the inflammatory and immune response of neutrophils, except TNF-α, myeloperoxidase, and toll-like receptor (TLR) 2, significantly increased after the recovery period respect to predive and postdive levels. NF-κB, IL-6, and TLR4 gene expression reported significant differences immediately after diving respect to the predive values. Protein nitrotyrosine levels significantly rose after diving and remained high during recovery, whereas no significant differences were reported in malondialdehyde. Neutrophil nitrite levels as indicative of inducible nitric oxide synthase (iNOS) activity progressively increased after diving and recovery. The iNOS protein levels maintained the basal values in all situations. CONCLUSION Scuba diving which combines hyperoxia, hyperbaria, and acute exercise induces nitrosative damage with increased nitrotyrosine levels and an inflammatory response in neutrophils.
2.
Hypoxia/reoxygenation and vitamin C intake influence NO synthesis and antioxidant defenses of neutrophils.
Sureda, A, Batle, JM, Tauler, P, Aguiló, A, Cases, N, Tur, JA, Pons, A
Free radical biology & medicine. 2004;(11):1744-55
Abstract
Oxidative stress induced by hypoxia/reoxygenation mediates the pathophysiological consequence of ischemia/reperfusion and human diseases. Diving apnea could be a good model of oxidative stress induced by hypoxia/reoxygenation. We studied the influence of vitamin C diet supplementation on the response of neutrophil antioxidant defenses, NO production, and redox status to diving apnea. Seven professional apnea divers participated in a double-blind cross study. Divers were assigned to either vitamin C-supplemented (1 g/d for a week) or placebo groups. Blood samples were taken under basal conditions, immediately after diving apnea for 4 h and after 1 h of recovery. Plasma vitamin C increased only in the supplemented group after diving and was maintained high in recovery. Diving apnea decreased neutrophil GSH/GSSG ratio in both groups, but maintained protein carbonyl derivates. Neutrophil catalase activity and levels and glutathione peroxidase activity were lower in the supplemented group than in the placebo group after diving. iNOS and nitrite levels decreased only in the supplemented group after diving and recovery. Diving apnea induced oxidative stress and initiated neutrophil reactions that resemble the acute-phase immune response with increased myeloperoxidase activity in neutrophils. Diet supplementation with vitamin C reduced neutrophil iNOS levels and NO production.