Experimental studies in rats on the effects of asbestos inhalation coupled with the inhalation of titanium dioxide.

Details

• Personal Author:
  Davis JM ; Jones AD ; Parker I
• Description:
  The inhalation toxicity of asbestos (1332214) and titanium-dioxide (13463677) mixtures was studied in rats. AF/HAN-rats were exposed to respirable dusts containing 10mg/m3 chrysotile (12001295) or amosite (12172735), plus 10mg/m3 titanium-dioxide for 1 year. They were maintained for lifespan observation. Selected rats were killed at the end of exposure and at 6 months post exposure and the lungs were removed. The left lung was analyzed for asbestos and titanium- dioxide. The right lung was analyzed for histopathological changes. At the end of exposure deposits of asbestos and titanium-dioxide were found in lesions containing macrophages, giant cells, and fibroblast containing collagenous fibers. These lesions were more pronounced in rats examined 6 months after exposure ended. Pulmonary fibrosis occupying 9.5 to 12.9% of the lung parenchyma was observed. The extent and severity of fibrosis induced by asbestos was not increased by titanium-dioxide. Rats exposed to chrysotile plus titanium-dioxide had a significantly increased incidence of pulmonary tumors compared to those exposed to chrysotile only. A similar nonsignificant trend was seen for rats exposed to amosite plus titanium-dioxide. The lung burdens of chrysotile or amosite in rats simultaneously exposed to titanium-dioxide were significantly increased relative to those exposed to chrysotile or amosite only. The authors conclude that inhalation of titanium-dioxide, a particulate dust normally considered to be innocuous, may enhance the carcinogenicity of amosite and chrysotile. This may reflect increased pulmonary retention of chrysotile and amosite in animals exposed to titanium-dioxide.
• Subjects:
  Accident Prevention Accidents Accidents, Occupational Age Factors Agriculture Construction Industry Food-Processing Industry Mining Occupational Exposure Occupational Health Safety

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• Keywords:
  Asbestos Fibers Chronic Exposure Histopathology Inhalation Studies In Vivo Studies Laboratory Animals Lung Burden Lung Cancer Lung Fibrosis Mineral Dusts Synergism

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• Publisher:
  National Institute for Occupational Safety and Health
• Document Type:
  Text
• Genre:
  Conference/Symposia Proceedings
• Place as Subject:
  OSHA Region 3 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  159-162
• NIOSHTIC Number:
  nn:00198423
• Citation:
  Proceedings of the VIIth International Pneumoconioses Conference, August 23-26, 1988, Pittsburgh, Pennsylvania, USA. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 90-108, 1990 Sep; (Part I):159-162
• CAS Registry Number:
  Asbestos (CAS RN 1332-21-4) ; Titania (CAS RN 13463-67-7) ; Chrysotile (CAS RN 12001-29-5) ; Amosite asbestos (CAS RN 12172-73-5)
• Federal Fiscal Year:
  1990
• Peer Reviewed:
  False
• Part Number:
  I
• Source Full Name:
  Proceedings of the VIIth International Pneumoconioses Conference, August 23-26, 1988, Pittsburgh, Pennsylvania, USA
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:3f388a378c02c104c8a522c34a0ab0b3d551e96e08dba34d79ba0ca1e04063396c8824581bef79887449584d353c4f71012ddf62ab7c93c5ed25230807aebb18
• Download URL:
  https://stacks.cdc.gov/view/cdc/180486/cdc_180486_DS1.pdf
• File Type:
  [PDF - 148.54 KB ]