Modulatory effect of lycopene on oxidative injury, related proteins and gene expression in gastric cancer tissue

The aim of this study was to the in vivo antioxidant properties of lycopene and its role in gastric carcinogenesis. Male Fischer 344 rats were used in this study. The animals were randomized into experimental and control groups and divided into 4 groups of 15 animals each. Group 1 animals received basic diet and served as control. Rats in group 2 were given MNNG (150 mg/kg bw) by intragastric intubation three times with a gap of two weeks in between the treatments. Rats in group 3 and 4 administered MNNG as in group 1 received in addition, intragastric administration of lycopene at 50 or 100 mg/kg bw, three times per week starting on the day following the first exposure to MNNG and continued until the end of the experimental period. The experiment was terminated at the end of 26 weeks and all animals were sacrificed by cervical dislocation after an overnight fast. An increase in serum IL-2, IL-4 and IL-10 levels and a decrease in serum IL-6 and TNF-α levels was observed in rats fed the lycopene diet. In addition, lycopene diet treatment significantly decreased gastric tissue oxidative injury, HIF-1α, Cyr61 proteins expression levels, NDRG1, BNIP3, STAT2 mRNA expression and enhanced antioxidant enzymes activities, SOD2 mRNA expression. Based on these results it is concluded that dietary lycopene may play an important role in protecting against oxidative stress and gastric carcinogenesis by enhancing antioxidant enzyme activities and immunity activities. RT-PCR and Western blot confirm that lycopene inhibited HIF-1α, Cyr61 proteins expression levels, NDRG1, BNIP3, STAT2 mRNA expression and stimulated SOD2 mRNA expression in gastric cancer tissue. This partly explains molecular mechanism of antitumour activity of lycopene in MNNG-induced gastric cancer rats.