The HOCl dry fog-is it safe for human cells?

• Published in: PloS one Vol. 19; no. 5; p. e0304602
• Main Authors: Lewandowski, Rafał Bogdan, Stępińska, Małgorzata, Osuchowski, Łukasz, Kasprzycka, Wiktoria, Dobrzyńska, Monika, Mierczyk, Zygmunt, Trafny, Elżbieta Anna
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 29.05.2024; Public Library of Science (PLoS)
• Subjects: Acids; Aerosols; Apoptosis; Bioassays; Biology and Life Sciences; Cell death; Cell membranes; Cell Survival - drug effects; Cells; Cells, Cultured; Comet Assay; Cytology; Cytotoxicity; Damage detection; Disinfection & disinfectants; DNA damage; DNA Damage - drug effects; Earth Sciences; Ethylenediaminetetraacetic acid; Experiments; Exposure; Fibroblasts; Fibroblasts - drug effects; Flow cytometry; Fog; Fogging; Genotoxicity; Homeostasis; Humans; Humidity; Hypochlorous Acid - toxicity; Medicine and Health Sciences; Morphology; Pathogens; Photographic industry; Physical Sciences; Physiology; Research and Analysis Methods; Skin - cytology; Skin - drug effects; Toxicity; Japan
• DOI: 10.1371/journal.pone.0304602
• ISSN: 1932-6203

This study aims to investigate if high-concentration HOCl fogging disinfection causes cytotoxicity and genotoxicity to cultured primary human skin fibroblasts. The cells were exposed to a dry fog of HOCl produced from solutions with a concentration of 300 ppm (5.72 mM) or 500 ppm (9.53 mM). After four times when fibroblasts were exposed to aerosolized HOCl at a concentration of 500 ppm for 9 minutes, significant cytotoxicity and genotoxicity effects were observed. Significant changes in the morphology of fibroblasts and cell death due to membrane disruption were observed, independent of the number of exposures. Flow cytometry analyses performed under these experimental conditions indicated a decrease in the number of cells with an intact cell membrane in the exposed samples compared to the sham samples, dropping to 49.1% of the total cells. Additionally, under the same conditions, the neutral comet assay results demonstrated significant DNA damage in the exposed cells. However, no analogous damages were found when the cells were exposed to aerosolized HOCl generated from a 300-ppm solution for 3 minutes, whether once or four times. Therefore, we have concluded that aerosolized HOCl in dry fog, with a concentration exceeding 300 ppm, can cause cytotoxic and genotoxic effects on human skin fibroblasts.