Corticosteroid administration modifies ozone-induced increases in sheep airway blood flow

Journal Article · Tue Sep 01 00:00:00 EDT 1992 · American Review of Respiratory Disease (New York); (United States)

DOI:https://doi.org/10.1164/ajrccm/146.3.660· OSTI ID:7249515

Gunther, R A; Yousef, M A; Schelegle, E S; Cross, C E ^[1]

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1. Department of Surgery, School of Medicine, University of California, Davis (United States)

Recently, we have shown that exposure of intubated conscious sheep to 3 to 4 ppm ozone (O3) for 3 h increases bronchial blood flow (Qbr). The purpose of the present study was to assess the potential role of corticosteroids in modulating this increase. Six nasally intubated sheep were exposed to filtered room air, 3.5 ppm O3 on two separate occasions, and 3.5 ppm O3 plus methyl-prednisone, for 3 h. Qbr was measured using a chronically implanted 20 MHz pulsed Doppler flow probe. Qbr, mean aortic pressure, cardiac output, pulmonary artery pressure, arterial blood gases, and core temperature were monitored. After 3 h of 3.5 ppm O3, Qbr increased from 3.2 +/- 0.5 (mean +/- SEM) to 8.5 +/- 1.6 KHz, whereas bronchial vascular resistance (BVR) decreased from the baseline value of 43.6 +/- 8.0 to 15.0 +/- 3 mm Hg/KHz. With corticosteroids, baseline Qbr was 3.2 +/- 0.6 and BVR was 44.2 +/- 9.7; after 3 h of 3.5 ppm O3, Qbr was 3.3 +/- 0.5 KHz and BVR was 39.0 +/- 8.0 mm Hg/KHz. The two 3.5-ppm O3 exposures without corticosteroids were impressively reproducible. Except for Qbr and BVR, no other measured cardiovascular parameters were affected by O3. The results indicate that corticosteroids are capable of interfering with mediator, neurohumoral, or inflammatory cell mechanisms responsible for vasodilation of the airway microcirculation after O3 exposure, but do not specifically address the specific processes whereby this attenuation occurs.

• OSTI ID: 7249515
• Journal Information: American Review of Respiratory Disease (New York); (United States), Vol. 146:3; ISSN 0003-0805
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BRONCHI
BLOOD FLOW
CORTICOSTEROIDS
BIOLOGICAL EFFECTS
OZONE
TOXICITY
DOSE-RESPONSE RELATIONSHIPS
SHEEP
VASODILATION
ADRENAL HORMONES
ANIMALS
DOMESTIC ANIMALS
HORMONES
HYDROXY COMPOUNDS
KETONES
MAMMALS
ORGANIC COMPOUNDS
PREGNANES
RESPIRATORY SYSTEM
RUMINANTS
STEROID HORMONES
STEROIDS
VERTEBRATES
560300* - Chemicals Metabolism & Toxicology