Fig. 6.

Activation of caspase-9 by cyclic stretch and the role of selective inhibitors on apoptosis. a The effect of cyclic stretch on caspase-8, 9 activities in rat AF cells. Cyclic stretch significantly increased the activity of caspase-9 after 24 h but not caspase-8 (n = 5). *P < 0.05 vs. control. b Z-LEHD-FMK and Z-ATAD-FMK suppressed of apoptosis induced by cyclic stretch for 36 h in rat AF cells (n = 5). *P < 0.05 vs. stretch alone. ^#P < 0.05 vs. stretch + Z-LEHD-FMK + Z-ATAD-FMK group. c Z-ATAD-FMK significantly inhibited caspase-9 activity induced by cyclic stretch for 36 h in rat AF cells (n = 5). *P < 0.05 vs. stretch alone. d Representative western blots for caspase-12 after 36 h cyclic stretch in rat AF cells pretreated with Z-LEHD-FMK or not. e Quantitative analysis of caspase-12 protein levels. The values from treated cells have been normalized to values in static control cells