Fig. 2.
RPTC lysate induces fibroblast cell death in a caspase-3-dependent and -independent manner. Confluent NRK-49F cells were treated with RPTC lysate (prepared from 6.6 × 105 cells) for the indicated time period (A and B) or pretreated with Z-VAD-fmk (50 μM) for 1 h followed by exposed to RPTC lysate for 20 h (C). Cell lysate were subjected to immunoblot analysis for cleaved poly(ADP-ribose) polymerase (PARP), cleaved caspase 3, and actin (A). The levels of the indicated proteins were quantified by densitometry and normalized with actin (B). Cell viability was assessed by the MTT assay (C). Values are means ± SD of 3 independent experiments and expressed as the percentage of control. Bars with different letters (a–d) are significantly different from one another (P < 0.05).