Figure 8.

Elimination of iron dextran-mediated caspase 3 activation and apoptosis by adiponectin (APN) through AMPK-mediated PPARα activation and subsequent heme oxygenase (HO)−1 induction. A: Cells were pretreated with compound C, GW6471, or DMSO as the control for one hour before another one hour of APN or phosphate-buffered saline administration, followed by iron dextran challenge for 18 hours. Additionally, cells were treated with WY-14643 as a positive control for HO-1 induction. B: Effect of HO-1 on APN-mediated protection against iron-mediated hepatic injury. Cells were pretreated with SnPP for one hour to block HO-1 activity before APN administration. Fifty micrograms of total cell lysate was analyzed for the protein level of apoptotic-related molecules by Western blotting. Membranes were probed with an anti-GAPDH antibody to verify equivalent loading. Bar charts in the lower panel show the band intensities of indicated molecules by densitometry. Data were derived from three independent experiments and are presented as the mean ± SEM. Significantly different (*P < 0.01, and **P < 0.005 vs. the control; ^†P < 0.05 vs. iron dextran alone; ^‡P < 0.01 vs. APN and iron dextran-treated group). C: Cells grown on coverslips with the above-mentioned various pretreatments, then challenged with 20 μmol/L of iron dextran for two days. Nuclei with positive stains are indicated as having undergone cell apoptosis by the TUNEL assay. Representative results of three separate experiments are shown.