Abstract: AIM: The purpose of this study is to explore the effects of erythromycin on the expressions of phosphorylation P38 and Th2 cytokines in asthmatic rats. METHODS: Thirty male Sprague-Dawley adult rats were randomly divided into normal, asthma and erythromycin-treated group (n =10 for each group). Peripheral blood monouclear cells(PBMCs) of rats were collected and cultured in each group.The concentrations of IL-4, IL-5 and IL-13 in cell supernatant were detected by ELISA.The mRNA and phosphor protein of P38 in PBMCs were detected by reverse transcription polymerase chain reaction (RT-PCR) and Western blotting (WB), respectively. RESULTS: The expression of mRNA and phosphor protein of P38 in PBMCs and the concentrations of IL-4, IL-5 and IL-13 in cell supernatant were higher in asthmatic group than those in normal group (P <0.05).Compared with the asthmatic group, the above indexes were significantly decreased in erythromycin-treated group (P <0.05). There were positive correlations between the expression of phosphor-P38 in PBMCs and the concentrations of IL-4, IL-5 and IL-13 in cell supernatant (r =0.75, 0.82 and 0.70, all P <0.05). CONCLUSION: The P38 may be involved in the pathogenesis of bronchial asthma.Erythromycin playing its role in the treatment of asthma may be achieved by acting on the P38.

Key words: asthma, peripheral blood mononuclear cell, P38, erythromycin