Changes in Ki-67 and Bcl-2 Expression in Rat Gastric Mucosa Secondary to Soybean Feeding: An Assessment of Proliferative and Apoptotic Activity of Flavonoids.

Background: Gastric cancer is a common malignancy and nutritional factors are believed to play an important role in its development. Isoflavones in soybean products are an important nutritional source, especially in some Asian Countries, having protective role against development of gastric cancer.In our study, we have prepared soybean extracts via different methodologies and assessed their apoptotic role and proliferation index in gastric mucosa of the rodents. Methodology: We have fed 2 months old 64 rats for a period of 1 month with soybean extracts prepared by 3 different methodologies and in 6 different concentrations. Subsequently, the rodents were subjected to euthanasia and their gastric mucosal linings were processed accordingly for H & E, Bcl-2, and Ki 67 staining. Thereafter, the specimens were evaluated under light microscopy. Results: In all the experimental groups fed with soybean extracts, weak staining was observed with Bcl-2, more significantly in the group of rodents fed with 100 mg/kg and 200 mg/kg ethanol extract as well as in the group fed with high ethyl acetate extract (p<0.05). There was no difference between the groups with respect to Ki 67 staining and inflammation rate (p>0.05). Conclusions: We have discovered that soybean extracts and specifically genistin and daidzein induces apoptosis at high concentrations. This observation makes us believe that soybeans have a protective role in the development of gastric cancer