Potentiating effect of passive cigarette smoking on gastrointestinal damage induced by indomethacin in rats

Cigarette smoking and nonsteroidal antiinflammatory drugs (NSAIDs) have bee n associated with gastroduodenal ulcers. The present study aimed to clarify the ulcerogenic mechanisms of passive cigarette smoking on gastrointestina l damage induced by indomethacin in fasted or in fasted and refed rats. Rat s were exposed to cigarette smoke (0%, 1%, 2%, or 4%, v/v) before and/or af ter indomethacin administration. Cigarette smoke dose-dependently potentiat ed indomethacin-induced gastric mucosal lesions in the fasted animals and f urther lowered gastric blood flow. The gastric myeloperoxidase activity (a marker enzyme for neutrophils) was also potentiated. In addition, passive c igarette smoking increased the mortality and aggravated duodenal ulceration and also the reduction of duodenal blood flow in the fasted and refed rats after indomethacin treatment. The results indicated that the potentiating effect of passive cigarette smoking on indomethacin-induced gastroduodenal lesions is probably due to the depression of blood flow in the gastroduoden al mucosa and to the aggravation of neutrophil infiltration in the gastric mucosa.