title: Cardiovascular and thermoregulatory responses of unrestrained rats exposed to filtered or unfiltered diesel exhaust.
abstract: Diesel exhaust has been associated with adverse cardiovascular and pulmonary health effects. The relative contributions of the gas phase and particulate components of diesel exhaust are less well understood. We exposed telemetered Wistar-Kyoto rats to air or diesel exhaust that was either filtered (F) or unfiltered [gas-phase plus diesel exhaust particles (DEP)], containing ~1.9 mg/m³ of particulate matter for 5 h/day; 5 days/week for 4 consecutive weeks. Blood pressure (BP), core temperature (T(c)), heart rate (HR), and cardiac contractility (CC) estimated by the QA interval were monitored by radiotelemetry during exposure as well as during a 2-week period of recovery. Pulmonary injury and inflammation markers were analysed after 2-day, and 4 weeks of exposure, and 2-week recovery. Exposure to F or DEP was associated with a trend for a reduction in BP during weeks 1, 2 and 4. A reduction in HR in the DEP group was apparent during week 4. Exposure to DEP but not F was associated with significant reduction in CC over weeks 1-4. There was also a slight elevation in T(c) during DEP exposure. All telemetry parameters were normal during recovery at night and a 2-week recovery period. Neutrophilic inflammation in bronchoalveolar lavage fluid was evident after 2 days and 4 weeks of exposure to F and DEP. There were no signs of inflammation after 2-week recovery. We found a significant decrease in CC and slight reduction in BP. Exposure to DEP and F is associated with pulmonary inflammation, and mild effects on HR, BP, and T(c) but there is a marked effect of DEP on CC.
authors.affiliation: Toxicity Assessment Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27709, USA. Gordon.christopher@epa.gov
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Gordon
authors.forename: Mette C
authors.initials: MC
authors.lastname: Schladweiler
authors.forename: Todd
authors.initials: T
authors.lastname: Krantz
authors.forename: Charly
authors.initials: C
authors.lastname: King
authors.forename: Urmila P
authors.initials: UP
authors.lastname: Kodavanti
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000166:cytology; D002452:Cell Count; D005374:Filtration; D006321:Heart / Q000187:drug effects* / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects; D006813:Humidity; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D052638:Particulate Matter / Q000633:toxicity*; D011014:Pneumonia / Q000139:chemically induced* / Q000378:metabolism / Q000503:physiopathology; D051381:Rats; D011921:Rats, Inbred WKY; D013696:Temperature; D014409:Tumor Necrosis Factor-alpha / Q000097:blood; D001335:Vehicle Emissions / Q000633:toxicity*; D005723:gamma-Glutamyltransferase / Q000378:metabolism
chemical_list: D000393:Air Pollutants; D015850:Interleukin-6; D052638:Particulate Matter; D014409:Tumor Necrosis Factor-alpha; D001335:Vehicle Emissions; D005723:gamma-Glutamyltransferase