This study aims to assess the effects of different routes of chronic nicotine administration on
gastric morphology and hormonal secretion; mainly gastrin, ghrelin, histamine and
prostaglandin E2 (PGE2). Forty adult male albino rats were randomly assigned into four
groups (10 rats/ group) as following: control group (given standard rat pellets and water
only), oral nicotine treated group (50 μg/ml drinking water), intra-peritoneal (IP) nicotine
treated group (0.5 mg/kg b.w.) and inhaled nicotine treated group (0.5 mg/kg b.w.) for 21
days. Levels of gastrin, ghrelin, PGE2, and histamine in serum and gastric tissue
homogenates were assessed by ELISA kits. Stomach fundus was processed for
histopathology and immunohistochemistry using light and electron microscopes. Different
routes of chronic nicotine administration result in significant increase in serum and
homogenate gastrin and ghrelin levels and significant decrease in serum and homogenate
PGE2 levels compared to control. Moreover,, nicotine administration via oral and inhalation
routes caused gastric erosion, transformation of peptic cells into mucous variety, significant
increase in parietal cells number and increase in gastrin expression. In conclusion, the negative impact of nicotine administration on gastric structure that is associated with
increased level of gastrin and decreased level PGE2 might be the leading cause of
gastric/peptic ulcers in heavy smokers. Increase ghrelin level and its effect following
nicotine chronic administration needs further investigation.Upon these findings we suggest that the gastric structure alteration following chronic
administration of nicotine can be prevented by reducing gastrin secretion and/or targeting its
receptors