Chronic Exposure to Cigarette Smoke Inhibits the Stimulating Effects of Mineral Fibers on the Production of Tumor Necrosis Factor by Alveolar Macrophages of Rats
Authors: Morimoto, Yasuo; Nambu, Ziro; Hori, Hajime; Tsuda, Tohru; Yamato, Hiroshi; Higashi, Toshiaki; Yokosaki, Yasuyuki; Kido, Masamitsu; Tanaka, Isamu
Source: International Journal of Occupational and Environmental Health, Number 2, April/June 1996 , pp. 95-98(4)
Publisher: Maney Publishing
Abstract:The objective of this study was to evaluate the chronic combined effects of mineral fibers and cigarette smoke on the production of tumor necrosis factor (TNF) by alveolar macrophages. The authors chronically exposed ten rats to cigarette smoke in vivo and measured the production of TNF by alveolar macrophages in the presence of mineral fibers in vitro. For smoke exposure, rats were divided into two groups. Five rats were exposed daily to a concentration of 10 mg/m3 of cigarette smoke for six hours a day, five days a week, for four weeks, and five rats (control) were not exposed to smoke. A broncho-alveolar lavage was performed after the smoke exposure, and the recovered alveolar macrophages were incubated with either chrysotile or ceramic fibers on a microplate for 24 hours. TNF activity in the supernatant was determined by the L929 bioassay. When alveolarmacrophages were not stimulated by mineral fibers, TNF production tended to be lower in smoke-exposed alveolar macrophages than in unexposed ones, although the difference was not significant statistically. When alveolar macrophages were stimulated in vitro by chrysotile or ceramic fibers, both fibers stimulated TNF production, but TNF production in smoke-exposed alveolar macrophages was lower than that in unexposed macrophages. These results revealed that long-term exposure to cigarette smoke inhibited the stimulating effect of mineral fibers on the production of TNF.
Document Type: Research Article
Publication date: 1996-04-01