Induction of pancreatic acinar pathology via inhalation of nicotine.

This study was conducted to determine the effects of nicotine inhalation on the onset, progression, and sequential development of pancreatic lesions. Male Sprague-Dawley rats in groups of five were exposed to saline or nicotine aerosol twice daily for 15, 30, 45, and 60 min for 21 days. After sacrifice, blood samples were analyzed for plasma levels of nicotine, glucose, gastrin, and cholecystokinin. Pancreatic tissues were examined for pathological lesions. While there were no significant differences in plasma levels of glucose, gastrin, and cholecystokinin in all groups, there was a steady increase in plasma levels of nicotine with increased exposures to nicotine. Histopathological examination of pancreatic tissue revealed definitive pancreatic injuries that also appeared to be directly correlated with increased duration of nicotine exposure. The pathological changes of the pancreas were confined only to acinar cells of the exocrine pancreas. Two main types of cellular changes were observed: cellular swelling/vacuolation and nuclear condensation/cellular pyknosis. Both of these changes indicated tissue injuries in the pancreas. Transformation of the glandular acini to solid masses of epithelial cells was also observed. The results from our present study strongly suggest that the exocrine pancreas is very sensitive and susceptible to nicotine toxicity. Our data further indicate that early morphological changes in the pancreas induced by nicotine may occur without functional or metabolic alterations; however, such changes could occur at a later stage, when tissue and cellular changes become more extensive.