Figure 6.

Caspase 3 protein expression and enzymatic activity. Caspase-3 was assayed in lung extracts from wild-type (WT) and GGT^enu1 mice in normoxia (N) and hyperoxia (H) as described in Materials and Methods. A: Caspase-3 protein expression by Western analysis in GGT^enu1 mouse lung showed a twofold induction at 48 hours (GGT^enu1_H48) and a threefold induction at 72 hours (GGT^enu1_H72), as compared with the normoxia control (GGT^enu1_N). In contrast, the wild-type mouse lung showed a twofold induction of caspase 3 protein expression at 72 hours of hyperoxia (WT_H72) compared with the wild-type normoxia control (WT_N). B: Caspase 3 activity was increased at baseline in GGT^enu1 mouse lung compared with wild-type mouse lung. In hyperoxia, caspase 3 enzymatic activity in GGT^enu1 mouse lung increased fourfold at 48 hours and 11-fold at 72 hours compared with baseline. In the wild-type mouse lung, induction of caspase 3 activity was only significant at 72 hours as compared with baseline and was sixfold less at 48 hours, and threefold less at 72 hours as compared with the GGT^enu1 mouse lung. *P < 0.05 compared with baseline.