Figure 4

Soybean trypsin inhibitor (SBTI) augments H. pylori -induced cell death and DNA fragmentation in gastric epithelial cells concentration-dependently. (A) AGS cells were treated with SBTI (0.2 μM, 0.5 μM) and cultured in the absence or the presence of H. pylori at a bacterium/cells ratio of 150: or 300:1 for 24 hours. Viable cell numbers were determined by trypan blue exclusion test. The results represent mean ± SE of four different experiments. *P < 0.05 compared to none (the cells without treatment and cultured in the absence of H. pylori). ⁺P < 0.05 compared to the corresponding none (the cells without treatment and cultured in the presence of H. pylori at a bacterium/cells ratio of 150: or 300:1). (B) AGS cells were treated with SBTI (0.5 μM) and cultured in the absence or the presence of H. pylori at a bacterium/cells ratio of 300:1 for 24 hours. DNA fragmentation was determined by the amount of oligonucleosome-bound DNA in the cell lysates. The relative increase in oligonucleosome-bound DNA was determined at 405 nm and expressed as an enrichment factor. The results represent mean ± SE of four different experiments. *P < 0.05 compared to none control (the cells without treatment and cultured in the absence of H. pylori). ⁺P < 0.05 compared to H. pylori control (the cells without treatment and cultured in the presence of H. pylori).