Diffuse and continuous cell proliferation enhances radiation-induced tumorigenesis in hamster lung.
Cancer Lett 1991 Dec; 60(3):193-197
This study examined to what extent radiation carcinogenesis may be susceptible to modulation by an inhalant. Outbred male LVG-Syrian-Golden-hamsters received 8 weekly instillations of 0.2 microcuries of polonium-210 (13981527) (Po-210) intratracheally while being kept continuously in a chamber ventilated with an atmosphere of 65% oxygen. A second group of animals received similar instillations of Po-210 but was kept in air throughout the study. Hamsters treated with Po-210 and kept in air gained weight and survived until the scheduled sacrifice 3 months after the beginning of the study. Hamsters treated with Po-210 and exposed to the hyperoxide environment kept their initial weight during the first 6 weeks and then began to loose weight rapidly. Seven of 24 died or were killed because of poor condition; ten of 24 developed lung tumors. The lung tumors formed were highly cellular with little stroma. The tumor cells were spindle shaped with a large nucleus/cytoplasmic ratio, a morphology frequently found in small cell lung cancers. The results indicated that hyperoxia is able to accelerate lung tumor development in hamsters. The authors conclude that diffuse cell hyperplasia in the lung, caused by an inhalant, may constitute an additional risk factor in the pathogenesis of alpha radiation induced lung cancer.
Respiratory-system-disorders; Laboratory-animals; Lung-cells; Lung-cancer; Radiation-effects; Cancer-rates; Inhalation-studies; Radioisotopes
University of California - Davis