Testosterone suppresses oxidative stress in human neutrophils

Abstract

The in vitro effect of testosterone on human neutrophil function was investigated. Blood neutrophils from healthy male subjects were isolated and treated with 10 nM, 0.1 and 10 microM testosterone for 24 h. As compared with untreated cells, the testosterone treatment produced a significant decrease of superoxide production as indicated by the measurement of extra- and intracellular superoxide content. An increment in the production of nitric oxide was observed at 0.1 and 10 microM testosterone concentrations, whereas no effect was found for 10 nM. Intracellular calcium mobilization was significantly increased at 10 nM, whereas it was reduced at 10 microM testosterone. There was an increase in phagocytic capacity at 10 nM and a decrease of microbicidal activity in neutrophils treated with testosterone at 10 microM. Glutathione reductase activity was increased by testosterone treatment, whereas no effect was observed in other antioxidant enzyme activities. An increase in the content of thiol groups was observed at all testosterone concentrations. Lipid peroxidation in neutrophils evaluated by levels of TBARS was decreased at 10 nM and 0.1 microM testosterone. These results indicate the antioxidant properties of testosterone in neutrophils as suggested by reduction of superoxide anion production, and lipid peroxidation, and by the increase in nitric oxide production, glutathione reductase activity and the content of thiol groups. Therefore, the plasma levels of testosterone are important regulators of neutrophil function and so of the inflammatory response.

Supra-physiological doses of testosterone affect membrane oxidation of human neutrophils monitored by the fluorescent probe C11-BODIPY581/591

“…After centrifugation, isolated neutrophils were maintained in RPMI--1640 medium supplemented with 2 mM glutamine, 20 mM HEPES, 10 % fetal calf serum, 10 U/mL penicillin, and 10 mg/mL streptomycin. The number of viable cells (>95 %) was determined in a Neubauer chamber under an optical microscope by Trypan blue exclusion (Marin et al 2010). Alternatively, a second set of human neutrophils were isolated from blood samples by including a pre--cleaning treatment with Dextran 500.…”

“…All materials used for blood collection (syringes, needles, bottles) were disposable and handled by health/medical professionals of the ICAFE/Universidade Cruzeiro do Sul to prevent any potential physical complication. Testosterone treatment Neutrophils (2 × 10 6 cell/mL), in a RPMI--1640 medium, were treated with 0.1 and 10 μM testosterone (1.0 mg/mL in 1,2--dimethoxyethane, T5411--1ML, Sigma--Aldrich), and incubated in a humidified atmosphere of 5 % CO2 at 37 °C for 24 h, in accordance with preliminary studies (Marin et al 2010). Control cultures (treated with same volumes of the drug vehicle, 1,2--dimethoxyethane or DMSO) were simultaneously incubated under the same experimental conditions.…”

“…However, we cannot confirm if this effect was caused by baseline overproduction of ROS/RNS in resting neutrophils and/or by TES--mediated increase of antioxidant defenses. Marin et al (2010) elegantly reported that pre--incubation with 10 nM, 0.1 and 10 μM TES clearly inhibited superoxide radical (O 2 ·− ) production in of human neutrophils after PMA activation (albeit, at a fivefold lower concentration). Under these circumstances, the authors reported lower indexes of lipid oxidation (using the thiobarbituric--acid reactive substances assay; TBARS) in 10 nM and 0.1 μM TES--treated cells, but not after 10 μM TES incubation.…”

Antioxidation improves in puberty in normal weight and obese boys, in positive association with exercise-stimulated growth hormone secretion

“…In addition, in adults with GH deficiency, endothelial dysfunction is common and associated with the increased levels of prooxidation markers, which decrease following GH replacement therapy (11). Furthermore, physiological concentrations of testosterone have been shown in vitro to suppress neutrophil prooxidative capability (12). Also, the increasing testosterone levels during puberty in young Japanese boys correlated negatively with prooxidation markers (13).…”

Effects of Intramuscular or Bioadhesive Buccal Testosterone Treatment on Antioxidant Systems in Secondary Hypogonadism

“…No significant effects of androgens were reported on antioxidant enzymes in erythrocytes [18]; conflicting results have also been reported about regulation of nitric oxide (NO) synthesis in immune system [19]; however antioxidant properties of testosterone in human neutrophils have been recently demonstrated, as indicated by suppression of superoxide anion and thiobarbituric acid-reactive substances (TBARS) levels, increase of NO levels, glutathione reductase activity and thiol groups; so testosterone administration at physiological concentrations had a greater antioxidant potential than higher concentrations [20].…”