Сomparative study of chemopreventive activity of lycopene on experimental model of esophagus cancer induced by N-methyl-N-benzylnitrosourea in rats

Abstract

Background. Cancer of the esophagus is the sixth most common malignancy worldwide and there is a remarkable variation in the incidence of esophageal cancer in different parts of the world. Objective: The present study was designed to evaluate chemopreventive activity of lycopene on esophagus carcinogenesis induced by N-methyl-N-benzylnitrosourea in rats. Methods. The study was conducted on male Wistar rats with body weight at the beginning 160-180g. Tumors of esophagus were induced by N-methyl-N-benzylnitrosourea in dose of 0.5 mg/kg body weight in 10 % ethanol given daily with drinking water during 8 weeks. Results. Lycopene given in dose of 50 mg/kg reduced incidence of tumors of esophagus from 100 % in N-methyl-N-benzylnitrosourea group to 44 % (р < 0.05). Lycopene also inhibited tumor multiplicity, the standard end point in this tumor model 2,4 times in comparison with N-methyl-N-benzylnitrosourea group (p < 0.005). The average score of neoplastic changes decreased 2.4 times in lycopene group (р < 0.001) and indicates inhibition of malignization of neoplastic changes in target organ. Additionalfeeding of N-methyl-N-benzylni- trosourea-treated rats with lycopene preventedformation of the imbalance in lipid peroxidation - antioxidant defense system by prevention of inhibition of antioxidant enzymes and accumulation of malonic dialdehyde. Conclusion. At this stage of our study, we can conclude that lycopene appears to be worthy of consideration as an antioxidant, and antitumor medicine.