title: Photochemically altered air pollution mixtures and contractile parameters in isolated murine hearts before and after ischemia.
abstract: BACKGROUND
  The cardiopulmonary effects of the individual criteria air pollutants have been well investigated, but little is known about the cardiopulmonary effects of inhaled multipollutant mixtures that more realistically represent environmental exposures.
  
  
  OBJECTIVE
  We assessed the cardiopulmonary effects of exposure to photochemically altered particle-free multipollutant mixtures.
  
  
  METHODS
  We exposed mice to filtered air (FA), multipollutant mixtures, or ozone (O3) for 4 hr in a photochemical reaction chamber. Eight hours after exposure, we assessed cardiac responses using a Langendorff preparation in a protocol consisting of 20 min of global ischemia followed by 2 hr of reperfusion. Cardiac function was assessed by measuring the index of left-ventricular developed pressure (LVDP) and contractility (dP/dt) before ischemia. On reperfusion after ischemia, recovery of postischemic LVDP and size of infarct were examined. We used bronchoalveolar lavage (BAL) cell counts to assess lung inflammation.
  
  
  RESULTS
  Exposure to the multipollutant mixtures decreased LVDP, baseline rate of left ventricular contraction (dP/dtmaximum), and baseline rate of left ventricular relaxation (dP/dtminimum) compared with exposure to FA. Exposure to O3 also decreased heart rate and dP/dtminimum. Time to ischemic contracture was prolonged in the multipollutant-mixture group relative to that in the FA group. Mice in the multipollutant-mixture group had better recovery of postischemic LVDP and smaller infarct size. Exposure to multipollutant mixtures and to O3 exposure increased numbers of macrophages in the BAL fluid.
  
  
  CONCLUSIONS
  Exposure to photochemically altered urban air pollution appears to affect cardiac mechanics in isolated perfused hearts. Inhalation of acute multipollutant mixtures decreases LVDP and cardiac contractility in isolated non-ischemic murine hearts, prolongs ischemic contracture, increases postischemic recovery of LVDP, and reduces infarct size.
authors.affiliation: Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Rachel
authors.initials: R
authors.lastname: McIntosh-Kastrinsky
authors.forename: David
authors.initials: D
authors.lastname: Diaz-Sanchez
authors.forename: Kenneth G
authors.initials: KG
authors.lastname: Sexton
authors.forename: Corey M
authors.initials: CM
authors.lastname: Jania
authors.forename: Jose
authors.initials: J
authors.lastname: Zavala
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Tilley
authors.forename: Ilona
authors.initials: I
authors.lastname: Jaspers
authors.forename: M Ian
authors.initials: MI
authors.lastname: Gilmour
authors.forename: Robert B
authors.initials: RB
authors.lastname: Devlin
authors.forename: Wayne E
authors.initials: WE
authors.lastname: Cascio
authors.forename: Haiyan
authors.initials: H
authors.lastname: Tong
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000528:radiation effects* / Q000633:toxicity*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D018893:Bronchoalveolar Lavage; D004781:Environmental Exposure / Q000032:analysis*; D008027:Light; D051379:Mice; D009200:Myocardial Contraction / Q000187:drug effects*; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology*; D010126:Ozone; D018709:Statistics, Nonparametric; D016277:Ventricular Function, Left / Q000187:drug effects / Q000502:physiology
chemical_list: D000393:Air Pollutants; D010126:Ozone