Experimental design
40 rats were randomly divided into 4 groups: Control (untreated with carcinogen or MRN-100); MRN-100 treated (MRN-100-treated only), MNNG treated (carcinogen-treated only), and MNNG plus MRN-100 treated (MRN-100 and carcinogen-treated). In order to induce gastric/esophageal cancer, rats were given carcinogen MNNG at dose 200 mg/kg body weight once daily by oral gavage for 2 weeks, followed by oral administration of NaCl (1ml/rat) once every 3 days for 4 weeks. Concomitantly with chemical induction, the rats were given MRN-100-free water (groups 1 and 3) or MRN-100 water (groups 2 and 4) for a total of 33 weeks. All animals were weighed at different time intervals. At the end of experimental period (33 weeks), animals were killed and examined for the following: histopathological changes in the esophageal and gastric tissues, changes in the weight of livers and spleens, and redox status in the blood and stomach tissues.