N-nitrosobis(2-hydroxypropyl)amine(BHP)によるラット肺と食道発癌に対するbovine lactoferrinの影響

Abstract

Effects of bovine lactoferrin (bLF) on lung and esophageal carcinogenesis by N-nitrosobis(2-hydroxypropyl)amine (BHP) were studied in rats. Male Wistar rats received 2000 ppm BHP in drinking water for 12 weeks, followed by 0.5% or 2% bLF for 8 weeks or the same doses of bLF for the entire experimental period of 20 weeks. Lung and esophageal lesions were histopathologically analyzed. No toxic signs including growth retardation and decreased amount of food intake of bLF were observed. The diet containing 0.5% bLF given after BHP inhibited lung adenoma development and the diets containing 0.5 or 2% bLF given with BHP for 12 weeks followed by without BHP for 8 weeks reduced the numbers of alveolar hyperplasias and of lung lesions including alveolar hyperplasia, squamous metaplasia, adenoma, adenocarcinoma and adenosquamous carcinoma. The diets containing two doses of bLF did not affect esophagial carcinogenesis. No promoting effects of bLF on lung and esophagial carcinogenesis by BHP in rats were observed. These results suggest that bLF is a possible candidate as a chemopreventive agent for lung carcinogenesis.