Effect of Peiminine on MEK1/2， ERK1/2 and the Phosphorylatioin in Lung Tissue of Pulmonary Fibrosis in Rats

OBJECTIVE To investigate the effect of peiminine on MEK1/2， ERK1/2 and the phosphorylatioin of bleomycin-induced pulmonary fibrosis in rats. METHODS Bleomycin of 5 mg/kg was instilled into the rats with a microliter injector to induce the acute lung injury. Shamoperated group and control group were given distilled water of 1 mL/100 g. Dexamethasone group was given equal volume of dexamethasone distilled water solution. Peiminine A and B group were given equal volume of peiminine distilled water solution of 5 mg/kg and 2.5 mg/kg， respectively. After consecutive daily gavage for 28 d， the rats were anesthetized and killed by carotid exsanguination. Lungs were fixed and embedded， and 4 μm sections were prepared. MEK1/2 and ERK1/2 in the lung tissues were detected by immunohistochemistry. The p-MEK1/2 and p-ERK1/2 were detected by Western blot. RESULTS Peiminine significantly reduced the levels of ERK1/2 and MEK1/2 in lung tissues of rats with bleomycin-induced pulmonary fibrosis(P<0.01)， and the effects was similar to dexamethasone (P>0.05). No significant difference was observed between peimine A group and B group(P>0.05). Compared to the model group and dexamethasone group， peiminine significantly reduced the level of p-MEK1/2 and p-ERK1/2 in lung tissue of bleomycin-induced pulmonary fibrosis rats(P<0.01). Compared to peimine A group， the B group displayed more significant efficacy(P<0.01). CONCLUSION Peiminine attenuates the level of MEK1， ERK1 / 2 and the phosphorylation in lung tissues of bleomycin-induced pulmonary fibrosis rats， which may be one of the mechanism of antifibrosis.