Abstract: AIM: To investigate the effect of dexamethasone on eosinophil apoptosis and expression of interleukin-5 mRNA and interleukin-10 mRNA in bronchoalveolar lavage fluid (BALF) of asthmatic guinea pig.METHODS: 30 Hartley male guinea pigs were divided into 3 groups randomly:dexamethasone group, asthma grouPand control group.The EOS apoptosis, IL-5mRNA and IL-10 mRNA expressions were measured by the techniques of TUNEL and RT-PCR.RESULTS: The EOS in BALF of dexamethasone grouPdecreased prominently compared with the asthma grouP(P<0.01) ;the EOS apoptosis increased (P<0.01) significantly.The level of IL-5 mRNA was prominently lower than that of the asthma grouP(P<0.05).The level of IL-10mRNA increased markedly compared with the asthma grouP(P<0.05).CONCLUSION: Dexamethasone can restrain the EOS ascending, increase EOS apoptosis effectively through reducing the expression of IL-5 mRNA and increasing the expression of IL-10 mRNA in asthmatic guinea pigs'respiratory passage.

Key words: asthma, dexamethasone, eosinophils, apoptosis, interleukin