gms | German Medical Science

124. Kongress der Deutschen Gesellschaft für Chirurgie

Deutsche Gesellschaft für Chirurgie

01. - 04.05.2007, München

Zinc and wound healing: a new molecular mechanism explaining the effects of an old remedy

Meeting Abstract

  • corresponding author M.M. Cortese - Klinik für plastische Chirurgie, Hand- und Verbrennungschirurngie, RWTH Uniklinikum Aachen, Aachen, Deutschland
  • V. Kolb-Bachofen - Institut für Molekulare Medizin, Forschungsgruppe Immunbiologie, Heinrich Heine Universität Düsseldorf, Düsseldorf, Deutschland
  • N. Pallua - Klinik für plastische Chirurgie, Hand- und Verbrennungschirurngie, RWTH Uniklinikum Aachen, Aachen, Deutschland
  • C.V. Suschek - Klinik für plastische Chirurgie, Hand- und Verbrennungschirurngie, RWTH Uniklinikum Aachen, Aachen, Deutschland

Deutsche Gesellschaft für Chirurgie. 124. Kongress der Deutschen Gesellschaft für Chirurgie. München, 01.-04.05.2007. Düsseldorf: German Medical Science GMS Publishing House; 2007. Doc07dgch7726

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter: http://www.egms.de/de/meetings/dgch2007/07dgch626.shtml

Veröffentlicht: 1. Oktober 2007

© 2007 Cortese et al.
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Gliederung

Text

Introduction: Malnutrition and micronutrients deficiencies can have a severe impact on the outcome of traumatic and surgical wounds. Zinc is the most well known micronutrient playing a central role in the wound healing and has been used empirically in dermatologic conditions for centuries. Zinc is involved DNA synthesis, protein synthesis and cell proliferation, all fundamental processes for wound healing. The antioxidant and protective activity exerted by zinc supplementation has been recently taken in consideration.

Materials and methods: A primary culture of rat endothelial cells was treated with peroxide for 24 hours. Cell viability was determined by neutral red staining and by fluorescent microscopy (hoechst staining). Gene expression was determined by real time RT PCR. The increase in protein level was determined by western blot. The silencing RNA experiments were performed by transfecting endothelial cells with specific silencing RNA sequences and verified by real time PCR. The promotor activity was determoned by using a reporter cell line transfected with a fragment of the human promoter for iNOS. omoter sequence of human iNOS

Results: Using a 24-hour treatment with H2O2 (LD50= 1 mM) as a model for inflammation-derived oxidative stress (which is a typical condition during wound healing) we have found that zinc supplementation fully protects endothelial cells against peroxide-induced toxicity. Vice versa zinc depletion increases the cell death rate (LD50<0.4 mM). We also investigated the molecular mechanisms of zinc-mediated protection and we found that zinc exerts antioxidant activity mainly via inducing the transcription of glutamate-cysteine ligase (GCL), catalysing the de novo synthesis of glutathione (GSH), the most abundant endogenously-produced antioxidant in eukaryotic cells, as verified by real time RT-PCR and western blot. The increase in GCL corresponds to an increase of the GSH levels of the cells. On the other hand the inhibition of GCL corresponds to a decreased GSH levels and decreased cell viability after the treatment with peroxide. By using the RNA silencing technique we also found that the antioxidant transcription factor Nrf2 is involved in the zinc-mediated up-regulation of GCL.The addition of zinc in the presence of pro-inflammatory cytokines (IL-1beta + IFNgamma) limits the inflammatory response, as verified by measuring the expression (mRNA and protein level) of the inducible nitric oxide synthase (iNOS), which is the key enzyme expressed in inflammation. By measuring the promoter activity of the human iNOS, we found that zinc inhibits the activation of the gene transcription.

Discussion: To conclude we verified that zinc exerts antioxidant and anti-inflammatory activity on endothelial cells. The identification of the molecular mechanism responsible for the zinc-mediated effects may contribute to the elaboration of new nutritional and/or clinical approaches to promote the wound healing.