Recovery from changes in the blood and nasal cavity and/or lungs of rats caused by exposure to methanol-fueled engine exhaust

Journal Article · Thu Jul 01 00:00:00 EDT 1993 · Journal of Toxicology and Environmental Health; (United States)

DOI:https://doi.org/10.1080/15287399309531755· OSTI ID:6121934

Maejima, K; Suzuki, T; Numata, H; Maekawa, A; Nagase, S; Ishinishi, N ^[1]

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1. Japan Automobile Research Institute, Inc., Ibaraki (Japan)

One group of male, pathogen-free, Fischer 344 rats was exposed to about 17-fold diluted exhaust generated by an M85 methanol-fueled engine (methanol with 15% gasoline) without catalyst for 8 h, and then the rates of recovery from the resulting increased levels of plasma formaldehyde and carboxyhemoglobin in their erythrocytes were measured. The carboxyhemoglobin level in the erythrocytes was restored within 4 h, whereas the plasma formaldehyde level was still elevated after 4 h but was restored to the normal level within 8 h. No methanol or formic acid was detected in the plasma. Another group of rats was exposed to the same dilution of exhaust for 8 h/d for 7 d, and then the recovery from histopathological damage of the nasal cavity and lungs was also examined. Hyperplasia/squamous metaplasia and erosion of the respiratory epithelium lining the nasoturbinate, maxilloturbinate, or nasal septum, and infiltration of neutrophils into the submucosa at level 1 (level of the posterior edge of the upper incisor teeth) were observed immediately after the exposure period. Lesions of the respiratory epithelium at level 2 (incisive papilla) were less than those at level 1. Slight lesions at levels 1 or 2 were still noticed 1 wk after exposure, but not 4 wk after exposure. Just after exposure, decreases of Clara cells in the terminal bronchiolus and of cilia in the bronchial/bronchiolar epithelium were also observed. Moreover, focal hypertrophy of alveolar walls and increase of macrophages were observed in parts adjacent to respiratory bronchiolus. One week after the exposure period, these changes were no longer seen. These results indicate that changes in the blood and in the nasal cavity and lungs caused by methanol-fueled engine exhaust are reversible. However, complete recovery from damage of the nasal cavity caused by 7-d exposure takes 4 wk, and recovery from elevated plasma formaldehyde and erythrocyte carboxyhemoglobin levels caused by a single 8-h exposure takes 4-8 h.

• OSTI ID: 6121934
• Journal Information: Journal of Toxicology and Environmental Health; (United States), Vol. 39:3; ISSN 0098-4108
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
59 BASIC BIOLOGICAL SCIENCES
BLOOD PLASMA
BIOLOGICAL RECOVERY
EXHAUST GASES
BIOLOGICAL EFFECTS
ORAL CAVITY
BLOOD
CARBOXYHEMOGLOBIN
EPITHELIUM
ERYTHROCYTES
FORMALDEHYDE
FORMIC ACID
GASOLINE
HYPERTROPHY
LUNGS
MACROPHAGES
METHANOL
NEUTROPHILS
RATS
ALCOHOLS
ALDEHYDES
ANIMAL CELLS
ANIMAL TISSUES
ANIMALS
BIOLOGICAL MATERIALS
BLOOD CELLS
BODY
BODY FLUIDS
CARBOXYLIC ACIDS
CONNECTIVE TISSUE CELLS
DIGESTIVE SYSTEM
FLUIDS
FUELS
GASEOUS WASTES
GASES
HYDROXY COMPOUNDS
LEUKOCYTES
LIQUID FUELS
MAMMALS
MATERIALS
MONOCARBOXYLIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PATHOLOGICAL CHANGES
PETROLEUM PRODUCTS
PHAGOCYTES
RESPIRATORY SYSTEM
RODENTS
SOMATIC CELLS
TISSUES
VERTEBRATES
WASTES
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