Yamato H, Oyabu T, Ogami A, Morimoto Y, Higashi T, Tanaka I, Ishimatsu S, Hori H, Kasai T. Pulmonary effects and clearance after long-term inhalation of potassium octatitanate whiskers in rats.
Inhal Toxicol 2004;
15:1421-34. [PMID:
14648357 DOI:
10.1080/08958370390248969]
[Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The pulmonary effects of long-term inhalation of potassium octatitanate whisker (PT1), one of the durable man-made fibers (MMFs), were examined in rats. Male Wistar rats were exposed to PT1 by inhalation for 6 h/day, 5 days/wk for 1 yr. The daily average exposure concentration of PT1 aerosol was 2.2 +/- 0.7 mg/m3 (111 +/- 34 fiber/ml) during the exposure. Rats were sacrificed at 3 days, 6 mo, and 12 mo after 1 yr of inhalation exposure. The amount of deposited PT1 in rat lungs (lung burden) was 2.4 +/- 0.7 mg and the deposition fraction was 7.2% at 3 days after 1 yr. The clearance of inhaled PT1 after 1-yr inhalation was prolonged so that the biological half-life time (BHT) was difficult to estimate. The histopathological findings showed that mild fibrotic changes were observed around the macrophages that had engulfed the PT1 in the 3-day, 6-mo, and 12-mo rat sacrifice groups. As for pulmonary tumors, no malignant tumors were observed, although 2 adenomas at 6 mo and 1 adenoma and 1 squamous metaplasia at 12 mo after the exposure were found in the rat lungs.
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