Figure 1: Activation of apoptosis in HCT-8 cells by G. intestinalis. Cells were submitted to different treatments and incubated for 16 h to evaluate the number of apoptotic cells and caspase-3 activation. a YO-PRO/PI fluorescent staining. Green, apoptotic cells; red, dead cells. Live cells are unstained. b The percentage of apoptotic cells. CTR, control cells; ACT, actinomycin D-treated cells; G, G. intestinalis-infected cells. Results are expressed as mean ± SD of five different experiments. **P < 0.01 compared to CTR.