Original Article Toxicity of Nicotine by Repeated Intratracheal Instillation to F344 Rats

Abstract: In vivo, nicotine in cigarette smoke induces various effects not only on the respiratory system but also the central and periph-eral nerve systems, circulatory organs and digestive organs, and there is a possibility of promotion of lung tumorigenesis. The present experiment was conducted to examine histopathological changes caused by nicotine in the lung with repeated intratracheal instilla-tion (i.t.). Six-week-old male F344 rats were administered nicotine by i.t. at doses of 0.05, 0.1 and 0.2 mg nicotine/rat every 3 weeks beginning at week 4, for up to a total of 9 times and were then sacrificed at week 30. The total number of administrations, total dos