The disruption of Bim and Bid prevented spontaneous hepatocyte apoptosis in the absence of Bcl-xL. The offspring from the mating of bim+/−bid−/−bcl-xflox/floxalb-cre mice with bim+/−bid−/−bcl-xflox/flox mice were examined at 6 weeks of age. Bcl-xL+/+ and Bcl-xL−/−, bcl-xflox/flox and bcl-xflox/floxalb-cre, respectively. A, Western blot analysis of whole liver lysates for the expression of BimEL, Bid, Bcl-xL, Mcl-1, Bak, Bax, and β-actin. B, representative images of liver histology stained with hematoxylin-eosin (HE) and TUNEL (original magnifications, ×100 (large panels) and ×400 (insets)). Black arrows indicate apoptotic bodies. C, TUNEL-positive cell ratio; more than 5 mice/group; *, p < 0.05 versus all. D, serum caspase-3/7 activity; more than 6 mice/group; *, p < 0.05 versus all. E, serum ALT levels; more than 6 mice/group; *, p < 0.05 versus all. Error bars, S.D. RLU, relative light units; I/U, international units.