Abstract
The usefulness of pulmonary carcinogenicity data from rats exposed to high concentrations of particles for quantitatively predicting lung cancer risk in humans exposed to much lower environmental or occupational concentrations has been questioned. The results of several chronic inhalation bioassays of poorly soluble, nonfibrous particles have suggested that rats may be more prone than other rodent species to develop persistent pulmonary epithelial hyperplasia, metaplasia, and tumors in response to the accumulation of inhaled particles. In addition, rats and primates differ in their pulmonary anatomy and rate of particle clearance from the lung. This paper reviews results of recent Lovelace Respiratory Research Institute (Albuquerque, NM) investigations that directly compared the anatomical patterns of particle retention and the lung tissue responses of rats and monkeys exposed chronically to high occupational concentrations of poorly soluble particles. Lung sections from male cynomolgus monkeys and F344 rats exposed 7 hr/day, 5 days/week for 24 months to filtered ambient air, diesel exhaust (2 mg soot/m3), coal dust (2 mg respirable particulate material/m3), or diesel exhaust and coal dust combined (1 mg soot and 1 mg respirable coal dust/m3) were obtained from a study conducted at the U.S. National Institute for Occupational Safety and Health and examined histopathologically and morphometrically. Within each species, the sites of particle retention and lung tissue responses were the same for diesel soot, coal dust, and combined material. Rats retained a significantly greater portion of the particulate material in the lumens of alveolar ducts and alveoli than monkeys. Conversely, monkeys retained a significantly greater portion of the particulate material in the interstitium than rats. Rats, but not monkeys, had significant alveolar epithelial hyperplastic, inflammatory, and septal fibrotic responses to the retained particles. These results suggest that anatomic patterns of particle retention and lung tissue reactions in rats may not be predictive of retention patterns and tissue responses in primates that inhale poorly soluble particles at concentrations representing high occupational exposures.
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Selected References
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- Green F. H., Laqueur W. A. Coal workers' pneumoconiosis. Pathol Annu. 1980;15(Pt 2):333–410. [PubMed] [Google Scholar]
- Kapanci Y., Tosco R., Eggermann J., Gould V. E. Oxygen pneumonitis in man., Light- and electron-microscopic morphometric studies. Chest. 1972 Aug;62(2):162–169. doi: 10.1378/chest.62.2.162. [DOI] [PubMed] [Google Scholar]
- Kapanci Y., Weibel E. R., Kaplan H. P., Robinson F. R. Pathogenesis and reversibility of the pulmonary lesions of oxygen toxicity in monkeys. II. Ultrastructural and morphometric studies. Lab Invest. 1969 Jan;20(1):101–118. [PubMed] [Google Scholar]
- Leak L. V., Jamuar M. P. Ultrastructure of pulmonary lymphatic vessels. Am Rev Respir Dis. 1983 Aug;128(2 Pt 2):S59–S65. doi: 10.1164/arrd.1983.128.2P2.S59. [DOI] [PubMed] [Google Scholar]
- Mauderly J. L., Jones R. K., Griffith W. C., Henderson R. F., McClellan R. O. Diesel exhaust is a pulmonary carcinogen in rats exposed chronically by inhalation. Fundam Appl Toxicol. 1987 Aug;9(2):208–221. doi: 10.1016/0272-0590(87)90044-3. [DOI] [PubMed] [Google Scholar]
- Mauderly J. L. Relevance of particle-induced rat lung tumors for assessing lung carcinogenic hazard and human lung cancer risk. Environ Health Perspect. 1997 Sep;105 (Suppl 5):1337–1346. doi: 10.1289/ehp.97105s51337. [DOI] [PMC free article] [PubMed] [Google Scholar]
- McLaughlin R. F., Jr, Tyler W. S., Canada R. O. Subgross pulmonary anatomy of the rabbit, rat, and guinea pig, with additional notes on the human lung. Am Rev Respir Dis. 1966 Sep;94(3):380–387. doi: 10.1164/arrd.1966.94.3.380. [DOI] [PubMed] [Google Scholar]
- Nikula K. J., Avila K. J., Griffith W. C., Mauderly J. L. Lung tissue responses and sites of particle retention differ between rats and cynomolgus monkeys exposed chronically to diesel exhaust and coal dust. Fundam Appl Toxicol. 1997 May;37(1):37–53. doi: 10.1006/faat.1997.2297. [DOI] [PubMed] [Google Scholar]
- Nikula K. J., Snipes M. B., Barr E. B., Griffith W. C., Henderson R. F., Mauderly J. L. Comparative pulmonary toxicities and carcinogenicities of chronically inhaled diesel exhaust and carbon black in F344 rats. Fundam Appl Toxicol. 1995 Apr;25(1):80–94. doi: 10.1093/toxsci/25.1.80. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pathology standards for coal workers' pneumoconiosis. Report of the Pneumoconiosis Committee of the College of American Pathologists to the National Institute for Occupational Safety and Health. Arch Pathol Lab Med. 1979 Jul 6;103(8):375–432. [PubMed] [Google Scholar]
- Pinkerton K. E., Barry B. E., O'Neil J. J., Raub J. A., Pratt P. C., Crapo J. D. Morphologic changes in the lung during the lifespan of Fischer 344 rats. Am J Anat. 1982 Jun;164(2):155–174. doi: 10.1002/aja.1001640206. [DOI] [PubMed] [Google Scholar]
- Snipes M. B. Long-term retention and clearance of particles inhaled by mammalian species. Crit Rev Toxicol. 1989;20(3):175–211. doi: 10.3109/10408448909017909. [DOI] [PubMed] [Google Scholar]
- Tyler W. S. Comparative subgross anatomy of lungs. Pleuras, interlobular septa, and distal airways. Am Rev Respir Dis. 1983 Aug;128(2 Pt 2):S32–S36. doi: 10.1164/arrd.1983.128.2P2.S32. [DOI] [PubMed] [Google Scholar]
- Weibel E. R. Morphometric estimation of pulmonary diffusion capacity. I. Model and method. Respir Physiol. 1970;11(1):54–75. doi: 10.1016/0034-5687(70)90102-7. [DOI] [PubMed] [Google Scholar]