ISBN: 978-83-60043-10-3 - eurobic9

Eurobic9, 2-6 September, 2008, Wrocław, Poland
P52. Interference of Zinc in the Activation of Human Neutrophils and
Subsequent Oxidative Burst
M. Freitas a , G. Porto b , J.L. Fontes Costa Lima a , E. Fernandes a
a
Química-Física, Faculdade de Farmácia da Universidade do Porto, Rua Aníbal Cunha, 164, 4099-030, Porto,
Portugal
e-mail: marisafreitas@ff.up.pt
b
Serviço de Hematologia Clínica, Hospital Geral de Santo António, Largo Professor Abel Salazar, 4099-001,
Porto, Portugal
Zinc is considered a non-toxic metal. Nevertheless, in spite of its safety, some reports suggest that zinc may
disturb the innate host defense response, by interfering in the activation of neutrophils and subsequent oxidative
burst. However, the exact role of zinc still needs clarification since some authors reported an activation effect
while in turn, others revealed that zinc inhibits superoxide radical (O2 -. ) formation. Thus, the main objective of
the present study was to provide clarification on the role of zinc on the activation human neutrophils and the
consequent oxidative burst. For this purpose, different detection methods [luminol amplified
chemiluminescence, cytochrome c reduction (UV/Vis spectrometry), Amplex Red and 2-[6-(4'-amino)phenoxy-
3H-xanthen-3-on-9-yl]benzoic acid (APF) (fluorescence)] were used to evaluate the interference of zinc in the
neutrophils's oxidative burst in order to understand the apparent contradictory results reported in literature. It was
clearly demonstrated that zinc, at physiologic concentrations (5-12.5 µM) activate NADPH oxidase leading to
the formation of O2 -. . On the other hand, higher concentrations of zinc may originate misleading results due to its
catalytic role on the interconversion among reactive oxygen species.
Acknowledgement: Marisa Freitas acknowledges Fundação para a Ciência e Tecnologia (FCT) and Fundo
Social Europeu (FSE) her PhD grant (SFRH/BD/28502/2006).
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