Fig. 4.
A: effect of PKR inhibition on caspase-8 protein levels. Top: procaspase-8 and active caspase-8 protein for representative diaphragm samples. Bottom: α-tubulin protein levels (loading control). LPS administration elicited a large increase in active cleaved caspase-8 protein compared with the control, and administration of a PKR chemical inhibitor, 2AP, prevented this increase. B: mean data examining the effect of 2AP on diaphragm caspase activation. Left: procaspase-8 levels were similar for the four experimental groups. Right: in contrast, diaphragm active caspase-8 protein levels increased dramatically for endotoxin (LPS)-treated animals (P < 0.01), and administration of 2AP to endotoxin-treated animals prevented this increase (P < 0.01 for comparison between endotoxin and endotoxin plus 2AP groups). Values are means ± SE. *Significant statistical difference between endotoxin and all other groups. DU, densitometry units.