Inhalation carcinogenicity study with nickel metal powder in Wistar rats

Journal Article · Mon Dec 01 04:00:00 EST 2008 · Toxicology and Applied Pharmacology

DOI:https://doi.org/10.1016/j.taap.2008.08.017· OSTI ID:21180493

Kirkpatrick, Daniel T; Radovsky, Ann ^[1]; Bates, Hudson K ^[2]

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1. WIL Research Laboratories, LLC, 1407 George Road, Ashland, OH 44805 8946 (United States)
2. NiPERA, 2605 Meridian Parkway, Suite 200, Durham, NC 27713 (United States)

Epidemiological studies of nickel refinery workers have demonstrated an association between increased respiratory cancer risk and exposure to certain nickel compounds (later confirmed in animal studies). However, the lack of an association found in epidemiological analyses for nickel metal remained unconfirmed for lack of robust animal inhalation studies. In the present study, Wistar rats were exposed by whole-body inhalation to 0, 0.1, 0.4, and 1.0 mg Ni/m{sup 3} nickel metal powder (MMAD = 1.8 {mu}m, GSD = 2.4 {mu}m) for 6 h/day, 5 days/week for up to 24 months. A subsequent six-month period without exposures preceded the final euthanasia. High mortality among rats exposed to 1.0 mg Ni/m{sup 3} nickel metal resulted in the earlier termination of exposures in this group. The exposure level of 0.4 mg Ni/m{sup 3} was established as the MTD for the study. Lung alterations associated with nickel metal exposure included alveolar proteinosis, alveolar histiocytosis, chronic inflammation, and bronchiolar-alveolar hyperplasia. No increased incidence of neoplasm of the respiratory tract was observed. Adrenal gland pheochromocytomas (benign and malignant) in males and combined cortical adenomas/carcinomas in females were induced in a dose-dependent manner by the nickel metal exposure. The incidence of pheochromocytomas was statistically increased in the 0.4 mg Ni/m{sup 3} male group. Pheochromocytomas appear to be secondary to the lung toxicity associated with the exposure rather than being related to a direct nickel effect on the adrenal glands. The incidence of cortical tumors among 0.4 mg Ni/m{sup 3} females, although statistically higher compared to the concurrent controls, falls within the historical control range; therefore, in the present study, this tumor is of uncertain relationship to nickel metal exposure. The lack of respiratory tumors in the present animal study is consistent with the findings of the epidemiological studies.

• OSTI ID: 21180493
• Journal Information: Toxicology and Applied Pharmacology, Journal Name: Toxicology and Applied Pharmacology Journal Issue: 2 Vol. 233; ISSN TXAPA9; ISSN 0041-008X
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
ADENOMAS
ADRENAL GLANDS
HEALTH HAZARDS
INFLAMMATION
INHALATION
LUNGS
MORTALITY
NICKEL
RATS
TOXICITY