TY - JOUR
T1 - Dual effect of chronic nicotine administration
T2 - Augmentation of jejunitis and amelioration of colitis induced by iodoacetamide in rats
AU - Eliakim, R.
AU - Karmeli, F.
AU - Cohen, P.
AU - Heyman, S. N.
AU - Rachmilewitz, D.
PY - 2001
Y1 - 2001
N2 - Smoking has a dichotomous effect on inflammatory bowel disease, ameliorating disease activity in ulcerative colitis but having a deleterious effect on Crohn's disease. This effect is thought to be due to nicotine. We investigated the effect of chronic nicotine administration on the small and large bowel in iodoacetamide-induced jejunitis and colitis. Jejunitis was induced in Sprague-Dawley rats by intrajejunal administration of 0.1 ml 2% iodoacetamide and colitis by intrarectal administration of 0.1 ml 3% iodoacetamide. Nicotine was dissolved in drinking water (12.5 or 250 μg/ml), rats drinking ad libitum. Nicotine administration started 10 days prior to damage induction and throughout the experiment and had no effect on weight gain or daily food intake of rats. Rats were killed 5 days after iodoacetamide-induced colitis and 7 days after induction of jejunitis. The jejunum and colon were resected, rinsed, weighed, damage assessed macroscopically and microscopically and tissue processed for myeloperoxidase and nitric oxide synthase (NOS) activities and prostaglandin E2 (PGE2) generation. Effects of nicotine on gut microcirculation were also assessed. Nicotine by itself caused no damage to the colon. Nicotine had a dichotomous effect on jejunitis and colitis. At a dose of 12.5 μg/ml nicotine improved the macroscopic damage of colitis from 252±66 to 70±31 mm2, and segmental weight also declined significantly in the colon (from 1.7±0.2 to 1.2±0.1 g/10 cm). In contrast, the same dose of nicotine had a deleterious effect on iodoacetamide-induced jejunitis, increasing the macroscopic damage from 368±38 to 460±97 mm2 in rats treated with injury escalating to 970±147 in rats treated with 250 μg/ml nicotine. Nicotine treatment also significantly increased jejunal segmental weight. By itself nicotine did not change NOS activity or PGE2 generation compared to control rats, but it enhanced microcirculation in the colon, whereas in the jejunum nicotine decreased PGE2 generation and increased NOS activity but not jejunal microcirculation. Nicotine has opposite effects on iodoacetamide-induced colitis and jejunitis, which may be partly explained by decreased PGE2 generation and increased NOS activity in the jejunum and an increase in the colonic microcirculation.
AB - Smoking has a dichotomous effect on inflammatory bowel disease, ameliorating disease activity in ulcerative colitis but having a deleterious effect on Crohn's disease. This effect is thought to be due to nicotine. We investigated the effect of chronic nicotine administration on the small and large bowel in iodoacetamide-induced jejunitis and colitis. Jejunitis was induced in Sprague-Dawley rats by intrajejunal administration of 0.1 ml 2% iodoacetamide and colitis by intrarectal administration of 0.1 ml 3% iodoacetamide. Nicotine was dissolved in drinking water (12.5 or 250 μg/ml), rats drinking ad libitum. Nicotine administration started 10 days prior to damage induction and throughout the experiment and had no effect on weight gain or daily food intake of rats. Rats were killed 5 days after iodoacetamide-induced colitis and 7 days after induction of jejunitis. The jejunum and colon were resected, rinsed, weighed, damage assessed macroscopically and microscopically and tissue processed for myeloperoxidase and nitric oxide synthase (NOS) activities and prostaglandin E2 (PGE2) generation. Effects of nicotine on gut microcirculation were also assessed. Nicotine by itself caused no damage to the colon. Nicotine had a dichotomous effect on jejunitis and colitis. At a dose of 12.5 μg/ml nicotine improved the macroscopic damage of colitis from 252±66 to 70±31 mm2, and segmental weight also declined significantly in the colon (from 1.7±0.2 to 1.2±0.1 g/10 cm). In contrast, the same dose of nicotine had a deleterious effect on iodoacetamide-induced jejunitis, increasing the macroscopic damage from 368±38 to 460±97 mm2 in rats treated with injury escalating to 970±147 in rats treated with 250 μg/ml nicotine. Nicotine treatment also significantly increased jejunal segmental weight. By itself nicotine did not change NOS activity or PGE2 generation compared to control rats, but it enhanced microcirculation in the colon, whereas in the jejunum nicotine decreased PGE2 generation and increased NOS activity but not jejunal microcirculation. Nicotine has opposite effects on iodoacetamide-induced colitis and jejunitis, which may be partly explained by decreased PGE2 generation and increased NOS activity in the jejunum and an increase in the colonic microcirculation.
KW - Colitis
KW - Iodoacetamide
KW - Jejunitis
KW - Nicotine
KW - Prostaglandin E
UR - http://www.scopus.com/inward/record.url?scp=0035100614&partnerID=8YFLogxK
U2 - 10.1007/s003840000262
DO - 10.1007/s003840000262
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AN - SCOPUS:0035100614
SN - 0179-1958
VL - 16
SP - 14
EP - 21
JO - International Journal of Colorectal Disease
JF - International Journal of Colorectal Disease
IS - 1
ER -