title: A new guinea-pig model for acute inhalation studies on combined effects of cold air and pollutants.
abstract: We have developed a new small animal model for acute inhalation studies on combined effects of cold air and gaseous urban air pollutants. The anaesthetised, tracheostomised and paralysed guinea-pig was placed inside a small, sealed whole-body-box, in which it was ventilated mechanically by using cyclic negative pressure (Pbox) for active expansion of the chest. During a 2-h normal ventilation with warm humid air (n=6), there was a need for increasing Pbox with time to maintain the fixed tidal volume (VT) of 11 ml/kg. No such need was seen in the experiments with 15-min periods of isocapnic hyperventilation at 80 and 120 breaths/min (n=13). During the 2-h normal ventilation and in experiments with hyperventilation, there was a gradual increase in heart rate and small gradual decreases in PaCO2 and pH with time. Cold air + SO2 2.5 ppm produced a significantly stronger bronchoconstriction (deltaVT=-30.3+/-7.2%, n=6, P < 0.05) than clean cold dry air (deltaVT=-10.6+/-1.3%, n=6) and cold air + NO2 2.5 ppm (deltaVT=-13.2+/-3.3%, n=6), although these three exposure conditions produced similar decreases in tracheal air and retrotracheal tissue temperatures. With the present guinea-pig model, the combined respiratory effects of cold air and gaseous urban air pollutants can be investigated in a highly controlled manner.
authors.affiliation: National Public Health Institute, Department of Environmental Medicine, Kuopio, Finland. raimo.salonen@ktl.fi
authors.forename: R O
authors.initials: RO
authors.lastname: Salonen
authors.forename: A I
authors.initials: AI
authors.lastname: Hälinen
authors.forename: A S
authors.initials: AS
authors.lastname: Pennanen
authors.forename: K
authors.initials: K
authors.lastname: Hyvönen
authors.forename: J
authors.initials: J
authors.lastname: Ruuskanen
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D000818:Animals; D001784:Blood Gas Analysis; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D003080:Cold Temperature / Q000009:adverse effects*; D006168:Guinea Pigs; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D008297:Male; D008954:Models, Biological; D012121:Respiration, Artificial; D012129:Respiratory Function Tests; D015656:Respiratory Mechanics / Q000187:drug effects / Q000502:physiology*
chemical_list: D000393:Air Pollutants