US EPA

16431 

Journal Article 

Induction of lung cancer in rats by intratracheal insufflation of cancerogenic hydrocarbons 

Pylev, LN 

1962 

Yes 

International Journal of Cancer
ISSN: 0020-7136
EISSN: 1097-0215 

NIOSH/00135943 

19 

688-691 

A procedure to induce tumors that are similar to lung cancer in humans was tested in rats. Wistar-rats and random bred rats were tested with 9,10-dimethyl-1,2-benzanthracene (57976) (DMBA) or 3,4-benzpyrene (50328) (BP). The carcinogen was added to a colloidal protein solution containing 0.2 milligrams (mg) of india-ink. Three groups of rats were treated with DMBA: 56 rats received a single injection containing 2.5mg DMBA, 82 rats received 3 monthly injections of 2mg DMBA, and 78 rats received 5 monthly injections of 2mg DMBA. Two groups of rats were treated with BP: 16 rats received 5 monthly injections containing 5mg BP and 38 rats received 7 monthly injections containing 5mg BP. A group of 39 controls were treated with 5 monthly injections of colloidal protein solution containing 2.0mg india-ink. All injections were administered by intubation in the trachea under visual control. Tumors started to appear 5 months after the start of the experiments. Tumor development was preceded by certain morphological changes in the lungs. Adenomatous growths developed from bronchial and alveolar epithelium, adenomas, foci of proliferation of multilayered squamous epithelium, and papillomas. Lung cancer occurred in 27.8 percent of rats treated with DMBA. In 40 rats, the tumors were squamous carcinomas and in 2 rats they were adenocarcinomas. Lung cancer was found in 12 of 19 rats treated with BP that had died. Tumors of the lungs were not found in any controls. The majority of precancerous changes and many of the tumors appeared in tissue marked by the deposition of india-ink. The author concludes that the type of lung cancer which is induced experimentally is morphologically, etiologically, and pathogenetically similar to that which occurs in humans.