Reactive oxygen spesies production from BALF cells was assessed ex vivo under PDB-stimulated conditions (A). Relative light units (RLU)/second per 1,000 cells was calculated. Protein expression of gp91 and HO-1 in lung tissue was assessed using Western blot and representative bands were shown (B). The intensity of each band was adjusted according to the value of the backgroud and normalized to β-actin housekeeping protein. Data are shown as mean ± S.E.M for n = 14–16 mice (C and D). Statistical significance was assessed using two-way ANOVA with Sidak post hoc test; **P<0.01.