Figure 7.

Cell death and DNA fragmentation induced by trypsin in the presence or absence of Ca²⁺ influx antagonist. Two-hundred-fifty-microliter aliquots of cultures containing nascent TE were pretreated for 15 min with either 4 mg/mL soybean trypsin inhibitor (TI), 500 μm EGTA, 150 μm LaCl₃, or 50 μm ruthenium red (RRed) before treatment with 0.5% trypsin. The percentage of dead cells was determined 1 h later using fluorescein diacetate staining; the percentage of cells exhibiting DNA fragmentation was determined 4 h after treatment with TUNEL. Error bars represent the se of two samples treated in parallel.