title: Disinfection of ocular cells and tissues by atmospheric-pressure cold plasma.
abstract: BACKGROUND
  Low temperature plasmas have been proposed in medicine as agents for tissue disinfection and have received increasing attention due to the frequency of bacterial resistance to antibiotics. This study explored whether atmospheric-pressure cold plasma (APCP) generated by a new portable device that ionizes a flow of helium gas can inactivate ocular pathogens without causing significant tissue damage.
  
  
  RESULTS
  We tested the APCP effects on cultured Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Candida albicans, Aspergillus fumigatus and Herpes simplex virus-1, ocular cells (conjunctival fibroblasts and keratocytes) and ex-vivo corneas. Exposure to APCP for 0.5 to 5 minutes significantly reduced microbial viability (colony-forming units) but not human cell viability (MTT assay, FACS and Tunel analysis) or the number of HSV-1 plaque-forming units. Increased levels of intracellular reactive oxygen species (ROS) in exposed microorganisms and cells were found using a FACS-activated 2',7'-dichlorofluorescein diacetate probe. Immunoassays demonstrated no induction of thymine dimers in cell cultures and corneal tissues. A transient increased expression of 8-OHdG, genes and proteins related to oxidative stress (OGG1, GPX, NFE2L2), was determined in ocular cells and corneas by HPLC, qRT-PCR and Western blot analysis.
  
  
  CONCLUSIONS
  A short application of APCP appears to be an efficient and rapid ocular disinfectant for bacteria and fungi without significant damage on ocular cells and tissues, although the treatment of conjunctival fibroblasts and keratocytes caused a time-restricted generation of intracellular ROS and oxidative stress-related responses.
authors.affiliation: Histology Unit, Department of Biomedical Sciences, University of Padua, Padua, Italy. paola.brun@unipd.it
authors.forename: Paola
authors.initials: P
authors.lastname: Brun
authors.forename: Paola
authors.initials: P
authors.lastname: Brun
authors.forename: Maria
authors.initials: M
authors.lastname: Vono
authors.forename: Paola
authors.initials: P
authors.lastname: Venier
authors.forename: Elena
authors.initials: E
authors.lastname: Tarricone
authors.forename: Velika
authors.initials: V
authors.lastname: Deligianni
authors.forename: Emilio
authors.initials: E
authors.lastname: Martines
authors.forename: Matteo
authors.initials: M
authors.lastname: Zuin
authors.forename: Silvia
authors.initials: S
authors.lastname: Spagnolo
authors.forename: Roberto
authors.initials: R
authors.lastname: Cavazzana
authors.forename: Romilda
authors.initials: R
authors.lastname: Cardin
authors.forename: Ignazio
authors.initials: I
authors.lastname: Castagliuolo
authors.forename: Alvise La Gloria
authors.initials: AL
authors.lastname: Valerio
authors.forename: Andrea
authors.initials: A
authors.lastname: Leonardi
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000111:Acetylcysteine / Q000494:pharmacology; D000328:Adult; D001274:Atmospheric Pressure; D002453:Cell Cycle / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003228:Conjunctiva / Q000166:cytology; D060527:Corneal Keratocytes / Q000166:cytology* / Q000378:metabolism; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000378:metabolism; D004203:Disinfection / Q000379:methods*; D005089:Exocytosis / Q000187:drug effects; D005123:Eye / Q000166:cytology* / Q000187:drug effects*; D005347:Fibroblasts / Q000166:cytology* / Q000187:drug effects; D006801:Humans; D050296:Microbial Viability / Q000187:drug effects; D010718:Phosphatidylserines / Q000378:metabolism; D058626:Plasma Gases / Q000494:pharmacology*; D014176:Protein Biosynthesis / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D016897:Respiratory Burst / Q000187:drug effects; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects; D038301:Virus Inactivation / Q000187:drug effects
chemical_list: D010718:Phosphatidylserines; D058626:Plasma Gases; D017382:Reactive Oxygen Species; D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine; D000111:Acetylcysteine