Fig. 2.

Effects of HO-1 inducer/inhibitor on MAPK in the lungs in murine silicosis. a Expression levels of phospho-ERK (pERK), phospho-p38 (p-p38), and phospho-JNK (pJNK) were determined in 20 μg of lung nuclear extractions by using relevant antibodies. pERK was upregulated 1 day after silica instillation without pretreatment. pERK was hardly detected following pretreatment with hemin, whereas the expression was enhanced by ZnPP. There were no differences in expression levels of p-p38 and pJNK with or without pretreatment with either inducer or inhibitor of HO-1. b Densitometric analysis of band intensity representing the mean ± SD level of pERK to ERK (n = 4/group). The ratio of pERK/ERK was significantly decreased at days 1, 2, and 7 in the lungs in murine silicosis pretreated with HO-1 inducer compared to no pretreatment group (silica alone), whereas those pretreated with HO-1 inhibitor showed a sustained increase in the pERK/ERK ratio over time. Densitometric data were analyzed by one-way analysis of variance with the post hoc Student-Newman-Keuls test. ** P < 0.01