Histopathological changes in rat lung following intratracheal instillation of silicon carbide whiskers and potassium octatitanate whiskers.
We evaluated the pattern of pulmonary inflammation for the assessment of the biological hazards of two man-made mineral fibers. Rats were exposed by intratracheal instillation to a 2 mg dose of each of two kinds of man-made mineral fibers (PT1, potassium octatitanate whisker; and SiCW, silicon carbide whisker), or three kinds of comparable respirable particles (crystalline silica, crocidolite asbestos, and titanium dioxide, TiO(2)). The lung tissue was evaluated at 3 day, 1 wk, and 1, 3 and 6 mo after exposure. Digital images taken of the lung sections were examined by morphometric point counting method (PCM). PT1 and SiCW showed a similar inflammatory pattern, which contains temporal inflammation such as moderate alveolitis within 1 wk after the exposure, and in later phase aggregation foci of instilled fibers. Differences in repair patterns of these two man-made mineral fibers showed that the toxicity of these two fibers is less toxic than for crocidolite or crystalline silica. Although SiCW showed a higher inflammation score than TiO(2) within 1 mo after instillation, the inflammation scores and fibrotic changes of PT1 and SiCW were not significant as TiO(2) at 3 mo and 6 mo in this study. Careful use should be recommended when these materials are used in the workplace.
Ogami
Akira
A
Department of Occupational Pneumology, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, Yahatanishi-ku, Kitayushu, Japan.
Morimoto
Yasuo
Y
Myojo
Toshihiko
T
Oyabu
Takako
T
Murakami
Masahiro
M
Nishi
Kenichiro
K
Kadoya
Chikara
C
Tanaka
Isamu
I
D000818:Animals; D017554:Carbon Compounds, Inorganic / Q000633:toxicity*; D005355:Fibrosis / Q000139:chemically induced; D008168:Lung / Q000473:pathology*; D008171:Lung Diseases / Q000139:chemically induced* / Q000473:pathology*; D008297:Male; D019016:Mineral Fibers / Q000633:toxicity; D052638:Particulate Matter; D051381:Rats; D017208:Rats, Wistar; D017655:Silicon Compounds / Q000633:toxicity*; D013997:Time Factors; D014025:Titanium / Q000633:toxicity*
D017554:Carbon Compounds, Inorganic; D019016:Mineral Fibers; D052638:Particulate Matter; D017655:Silicon Compounds; C021028:potassium octatitanate; D014025:Titanium; C022088:silicon carbide