Introduction & Objective: Nicotine could directly act as a cancer promoter. The purpose of this study was to evaluate effects of nicotine on mitotic index in esophagus epithelium.

Materials & Methods: In the present study 30 adult male mice were used. Animals were randomly divided into three groups. Group A or the control group received vehicle, groups B and C received nicotine intraperitoneally at doses of 0.2 and 0.4 mg/kg once daily for 14 days, respectively. Evaluations were made using kI-67 immunohistochemistry and Hematoxilin& Eosin for proliferative activity and morphometric study on esophagus mucosa, respectively.

Results: Administration of nicotine in group C, showed a significant increase (P<0.05) in KI-67 index 34.15±2.50vs. 10.41±1.4 compared with the control subjects.  The other parameters such as epithelial height, lamina propria, muscular mucosa and mucosa height in nicotine- treated groups were not affected. Nicotine at dose of 0.2 mg/kg did not change the mitotic index in epithelium when compared with the control group.

Conclusion: This study indicates nicotine at dose of 0.4 mg/kg increases mitotic activity in basal cells in esophagus epithelium.