Biopersistence of inhaled organic and inorganic fibers in the lungs of rats
| Autor: | Mark A. Hartsky, Kristen A. Kellar, Tim A. McHugh, David B. Warheit |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
Male
Lung Inhalation Metabolic Clearance Rate Polymers Chemistry Silicates Health Toxicology and Mutagenesis Public Health Environmental and Occupational Health Calcium Compounds Pharmacology Rats medicine.anatomical_structure Metabolic clearance rate Administration Inhalation medicine Animals Bioassay Fiber Bronchoalveolar Lavage Fluid Research Article |
| Zdroj: | Environmental Health Perspectives |
| ISSN: | 1552-9924 0091-6765 |
| DOI: | 10.1289/ehp.94102s5151 |
| Popis: | Fiber dimension and durability are recognized as important features in influencing the development of pulmonary carcinogenic and fibrogenic effects. Using a short-term inhalation bioassay, we have studied pulmonary deposition and clearance patterns and evaluated and compared the pulmonary toxicity of two previously tested reference materials, an inhaled organic fiber, Kevlar para-aramid fibrils, and an inorganic fiber, wollastonite. Rats were exposed for 5 days to aerosols of Kevlar fibrils (900-1344 f/cc; 9-11 mg/m3) or wollastonite fibers (800 f/cc; 115 mg/m3). The lungs of exposed rats were digested to quantify dose, fiber dimensional changes over time, and clearance kinetics. The results showed that inhaled wollastonite fibers were cleared rapidly with a retention half-time of < 1 week. Mean fiber lengths decreased from 11 microns to 6 microns over a 1-month period, and fiber diameters increased from 0.5 micron to 1.0 micron in the same time. Fiber clearance studies with Kevlar showed a transient increase in the numbers of retained fibrils at 1 week postexposure, with rapid clearance of fibers thereafter, and retention half-time of 30 days. A progressive decrease in the mean lengths from 12.5 microns to 7.5 microns and mean diameters from 0.33 micron to 0.23 micron was recorded 6 months after exposure to inhaled Kevlar fibrils. The percentages of fibers > 15 microns in length decreased from 30% immediately after exposure to 5% after 6 months; the percentages of fibers in the 4 to 7 microns range increased from 25 to 55% in the same period.(ABSTRACT TRUNCATED AT 250 WORDS) Images Figure 4. A Figure 4. B Figure 6. A Figure 6. B |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|