Figure 4.

HO-1 overexpression by infection of a recombinant HO-1 adenovirus decreases iNOS protein in response to IL-1β. (A). Modified adenoviral vectors expressing HO-1 or β-galactosidase transduced in hepatocytes at the indicated multiplicity of infection (12.5, 25, 50, 100 PFU/cell). The infected hepatocytes were recovered overnight prior to changing to fresh medium and initiating iNOS expression by treatment with IL-1β (500 U/ml) for 24h. Monolayers were harvested after being washed with ice-cold PBS, and lysed by three cycles of freeze and thaw. Cytosolic fractions were prepared by centrifugation at 12,000×g for 20min and then western blot was performed using non-denaturing SDS-PAGE. (B) Accumulated nitrite was measured in the culture medium using Griess reagent. Data represent the mean ± S.D. of more than three independent experiments