Antioxidant supplementation alters cytokine production from monocytes

We studied in 10 healthy subjects the effect of chronic enteral supplementation of antioxidants (vitamins E, C, A, allopurinol, and N-acetylcysteine) on cytokine production by monocytes at rest, end exercise (60-min cycling at 60 of maximum oxygen consumption), and 60 min post-exercise (recovery). The percentage and the mean fluorescent intensity (MFI) of both unstimulated and lipopolysaccharide (LPS)-stimulated tumor necrosis factor (TNF)-, interleukin (IL)-1, and IL-6-producing monocytes were detected using flow cytometry. Antioxidants decreased the percentage of unstimulated IL-6-producing monocytes following exercise, while their MFI increased at rest. The percentage of LPS-stimulated monocytes increased after exercise and they produced more IL-6 both at rest and following exercise. The percentage of unstimulated and LPS-stimulated IL-1-producing monocytes was not affected by antioxidants. The MFI of IL-1-produced unstimulated monocytes was increased after antioxidants both at rest and following exercise. After antioxidants, LPS-stimulated monocytes produced more IL-1 following exercise. Antioxidants decreased the percentage of TNF- spontaneously-produced monocytes following exercise, which produced more TNF- at recovery. Antioxidants did not affect the percentage of LPS-stimulated monocytes producing TNF-, while LPS-stimulated production of TNF- increased both at rest and following exercise. Antioxidants differentially affect TNF-, IL-1, and IL-6 production by monocytes, with a general tendency of augmenting cytokine production.