Sulfuric acid-induced changes in the physiology and structure of the tracheobronchial airways

Journal Article · Wed Feb 01 04:00:00 EST 1989 · Environ. Health Perspect.; (United States)

DOI:https://doi.org/10.1289/ehp.8979127· OSTI ID:5900719

Gearhart, J M; Schlesinger, R B

Sulfuric acid aerosols occur in the ambient particulate mode due to atmospheric conversion from sulfur dioxide (SO2). This paper describes the response of the rabbit tracheobronchial tree to daily exposures to sulfuric acid (H2SO4) aerosol, relating physiological and morphological parameters. Rabbits were exposed to filtered air (sham control) or to submicrometer-sized H2SO4 at 250 micrograms/m3 H2SO4, for 1 hr/day, 5 days/week, with sacrifices after 4, 8, and 12 months of acid (or sham) exposure; some rabbits were allowed a 3-month recovery after all exposures ended. H2SO4 produced a slowing of tracheobronchial mucociliary clearance during the first weeks of exposure; this change became significantly greater with continued exposures and did not improve after exposures ended. Airway hyperresponsiveness was evident by 4 months of acid exposure; the condition worsened by 8 months of exposure and appeared to stabilize after this time. Standard pulmonary mechanics parameters showed no significant trends with repeated acid exposure, except for a decline in dynamic lung compliance in animals exposed to acid for 12 months. Lung tissue samples obtained from exposed animals showed a shift toward a greater frequency of smaller airways compared to control, an increase in epithelial secretory cell density in smaller airways, and a shift from neutral to acidic glycoproteins in the secretory cells. The effect on airway diameter resolved after the exposures ceased, but the secretory cell response did not return to normal within the recovery period. No evidence of inflammatory cell infiltration was found due to H2SO4 exposure. Thus, significant alterations in the physiology of the tracheobronchial tree have been demonstrated due to repeated 1-hr exposures to a concentration of H2SO4 that is one-fourth the current 8-hr threshold limit value for exposure in the work environment.

• Research Organization: New York Univ. Medical Center, NY (USA)
• OSTI ID: 5900719
• Journal Information: Environ. Health Perspect.; (United States), Journal Name: Environ. Health Perspect.; (United States) Vol. 79; ISSN EVHPA
• Country of Publication: United States
• Language: English

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ACID RAIN
AEROSOLS
AIR POLLUTION
ANIMAL TISSUES
ANIMALS
ATMOSPHERIC PRECIPITATIONS
BODY
BRONCHI
CLEARANCE
COLLOIDS
DISPERSIONS
DOSE-RESPONSE RELATIONSHIPS
EPITHELIUM
EXCRETION
GLYCOPROTEINS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
LUNG CLEARANCE
MAMMALS
ORGANIC COMPOUNDS
PATHOLOGICAL CHANGES
POLLUTION
PROTEINS
RABBITS
RAIN
RESPIRATORY SYSTEM
SOLS
SULFURIC ACID
TISSUES
TOXICITY
TRACHEA
VERTEBRATES