Reduction of oxidative DNA fragmentation by ascorbic acid, zinc and N-acetylcysteine in nasal mucosa tissue cultures.
Oxidative stress is one major factor in upper aerodigestive tract carcinogenesis. Reactive oxygen species derived from environmental sources, cigarette smoke or cellular metabolism, constantly attack large molecules within the cell. While damaged lipids and proteins can be replaced, oxidative DNA damage needs to be repaired. Damage exceeding DNA repair capacity might lead to permanent mutations. Ascorbic acid, zinc and N-acetylcysteine are widely used as supplementations during upper aerodigestive tract infections. Therefore we chose to investigate their potential in DNA protection. We produced so called "mini-organ" cultures of nasal mucosa, three-dimensional tissue cubes coated with ciliated epithelium, for repeated incubation with ascorbic acid, zinc and N-acetylcysteine at different concentrations. This model has several advantages with respect to repeated incubations, metabolic competence of cells and standardized conditions compared to cell line experiments or animal models. After washing twice, oxidative damage was induced by hydrogen peroxide. Resulting DNA fragmentation was analyzed using the FPG-comet assay, a special modification of the alkaline single-cell microgel electrophoresis for the detection of the most prevalent oxidative DNA base modification. DNA damage was reduced within a range of 45-60%. Cell viability after incubations with hydrogenperoxide was >90%. Our results show strong DNA protective effects of the substances tested in accordance with epidemiological studies linking a diet rich in antioxidative micronutrients with a lowered risk for cancer development. The reasons for the failure of large antioxidant supplementation interventional trials need to be further investigated.
Baumeister
Philipp
P
Department of Otolaryngology, University of Munich, Marchioninistr. 15, 81377 Munich, Germany. philipp.baumeister@med.uni-muenchen.de
Huebner
Thomas
T
Reiter
Maximilian
M
Schwenk-Zieger
Sabina
S
Harréus
Ulrich
U
D000111:Acetylcysteine / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D053938:DNA Fragmentation / Q000187:drug effects*; D006801:Humans; D009297:Nasal Mucosa / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D009924:Organ Culture Techniques; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D015032:Zinc / Q000494:pharmacology*
D015032:Zinc; D001205:Ascorbic Acid; D000111:Acetylcysteine