High doses of in vitro beta-carotene, alpha-tocopherol and ascorbic acid induce oxidative stress and secretion of IL-6 in peripheral blood mononuclear cells from healthy donors.
BACKGROUND
Oxidative stress represents an imbalance between the production and manifestation of reactive oxygen species (ROS) and a biological system's ability to readily detoxify the reactive intermediates or repair the resulting damage. Our objective was to verify the existence of an in vitro dual effect of alpha-tocopherol, beta-carotene and ascorbic acid in peripheral blood mononuclear cells (PBMNC) of healthy donors and the inflammatory capacity by IL-6 production.


METHODS
PBMNC were incubated with two concentrations of vitamin complex: [A] = Ascorbic Acid = 0.08μM, α- tocopherol = 0.04μM, β-carotene = 0.0008 μM and [20A] = Ascorbic Acid = 1.6μM, α-tocopherol = 0.82μM, β-carotene = 0.016μM. Oxidizing and reducing response were measured by chemiluminescence and MTT assays, respectively. IL-6 production was measured by sandwich ELISA.


RESULTS
Ours results demonstrated that PBMNC (from 20-39-year-old donors) incubated with vitamins activated free radical production only in [20A] concentration. However, in the age groups of 40-59 and 60-80 years old, there was a significant reduction and activation of the oxidizing response with both concentrations, respectively. The inflammatory profile showed an elevation of IL-6 production in pro-oxidant and a decrease in antioxidant conditions. Correlation between ROS production and IL-6 releasing was observed.


CONCLUSIONS
With this experiment we concluded that vitamins can exert an antioxidant effect and a pro-oxidant effect according to their concentration, and could be an inductor of an inflammatory process in vitro generating severe complications to the body in cellular levels.
Departamento de Bioquimica e Imunologia, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais - Caixa Postal, Belo Horizonte, Minas Gerais, Brazil.
Barbara Fonseca
BF
de Oliveira
Clara Araujo
CA
Veloso
Jose Augusto
JA
Nogueira-Machado
Miriam
M
Martins Chaves
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism; D000975:Antioxidants / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism*; D007963:Leukocytes, Mononuclear / Q000187:drug effects* / Q000378:metabolism; D008163:Luminescent Measurements; D008297:Male; D008875:Middle Aged; D016877:Oxidants / Q000494:pharmacology*; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000378:metabolism; D055815:Young Adult; D024502:alpha-Tocopherol / Q000494:pharmacology*; D019207:beta Carotene / Q000494:pharmacology*
D000975:Antioxidants; C508600:IL6 protein, human; D018836:Inflammation Mediators; D015850:Interleukin-6; D016877:Oxidants; D017382:Reactive Oxygen Species; D019207:beta Carotene; D024502:alpha-Tocopherol; D001205:Ascorbic Acid