title: Effects of ambient levels of traffic-derived air pollution on the ocular surface: analysis of symptoms, conjunctival goblet cell count and mucin 5AC gene expression.
abstract: OBJECTIVE
  To quantify ocular symptoms, goblet cells (GC) and mucin 5AC (MUC5AC) gene expression on the conjunctiva of healthy subjects exposed to ambient levels of traffic-derived air pollution and to estimate its correlation with NO2 and particulate matter smaller than 2.5 μm (PM2.5) levels.
  
  
  METHODS
  Twenty-one taxi drivers or traffic controllers were assessed with the Ocular Surface Disease Index (OSDI) questionnaire and conjunctival impression cytology. MUC5AC mRNA levels were determined based on the cytology of the right eye, and GC density was assessed based on the cytology of the left eye. Mean individual levels of 24-h NO2 and PM2.5 exposure were assessed the day before examination. Possible associations between NO2 or PM2.5 levels, OSDI scores, GC densities and MUC5AC mRNA levels were verified.
  
  
  RESULTS
  The subjects were exposed to mean PM2.5 levels of 35±12 μg/m(3) and mean NO2 levels of 189±47 μg/m(3). OSDI scores were low (7.4±8) and GC densities were 521±257 and 782±322 cell/mm(2) on the bulbar and tarsal conjunctivas, respectively. The mean GC-derived MUC5AC mRNA expression was 14±7 fM/μg of total RNA. A significant and positive correlation was observed between MUC5AC mRNA levels and tarsal GC density (p=0.018). A trend toward association between PM2.5 levels and tarsal GC cell density (p=0.052) was found.
  
  
  CONCLUSIONS
  Exposure to ambient levels of air pollution impacts conjunctival GC density. An increase in MUC5AC mRNA levels may be part of an adaptive ocular surface response to long-term exposure to air pollution.
authors.affiliation: Division of Ophthalmology and the Laboratory for Investigation in Ophthalmology (LIM-33), University of São Paulo Medical School, Av. Dr. Arnaldo 455, 5th floor, 01246-903 São Paulo, Brazil. Electronic address: torricelli.andre@yahoo.com.br.
authors.forename: André Augusto Miranda
authors.initials: AA
authors.lastname: Torricelli
authors.affiliation: Division of Ophthalmology and the Laboratory for Investigation in Ophthalmology (LIM-33), University of São Paulo Medical School, Av. Dr. Arnaldo 455, 5th floor, 01246-903 São Paulo, Brazil.
authors.forename: Monique
authors.initials: M
authors.lastname: Matsuda
authors.affiliation: Division of Ophthalmology and the Laboratory for Investigation in Ophthalmology (LIM-33), University of São Paulo Medical School, Av. Dr. Arnaldo 455, 5th floor, 01246-903 São Paulo, Brazil.
authors.forename: Priscila
authors.initials: P
authors.lastname: Novaes
authors.affiliation: Environmental Epidemiology Study Group, Laboratory of Experimental Air Pollution, University of São Paulo Medical School, São Paulo, Brazil.
authors.forename: Alfésio Luiz Ferreira
authors.initials: AL
authors.lastname: Braga
authors.affiliation: Environmental Epidemiology Study Group, Laboratory of Experimental Air Pollution, University of São Paulo Medical School, São Paulo, Brazil.
authors.forename: Paulo Hilário Nascimento
authors.initials: PH
authors.lastname: Saldiva
authors.affiliation: Division of Ophthalmology and the Laboratory for Investigation in Ophthalmology (LIM-33), University of São Paulo Medical School, Av. Dr. Arnaldo 455, 5th floor, 01246-903 São Paulo, Brazil.
authors.forename: Milton Ruiz
authors.initials: MR
authors.lastname: Alves
authors.affiliation: Division of Ophthalmology and the Laboratory for Investigation in Ophthalmology (LIM-33), University of São Paulo Medical School, Av. Dr. Arnaldo 455, 5th floor, 01246-903 São Paulo, Brazil.
authors.forename: Mário Luiz Ribeiro
authors.initials: ML
authors.lastname: Monteiro
mesh_terms: D000328:Adult; D000397:Air Pollution / Q000009:adverse effects*; D003228:Conjunctiva / Q000187:drug effects* / Q000378:metabolism; D020397:Goblet Cells / Q000187:drug effects; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D055271:Mucin 5AC / Q000235:genetics / Q000378:metabolism*; D001335:Vehicle Emissions / Q000633:toxicity*
chemical_list: D055271:Mucin 5AC; D001335:Vehicle Emissions
keywords: Air pollution; Goblet cell; Mucin; Ocular surface