Objective      To investigate the effect of macrolides combined with glucocorticoids on the expression of cleaved caspase-9 and Bak in eosinophil (EOS) of bronchoalveolar lavage fluid (BALF) from the lung tissues of asthmatic rats.       Methods      Asthmatic rat models were established by repeated ovalbumin sensitization of Spra

gue-Dawley rats

and the rats were divided into five groups including a control group

a model group

an interference group A

1

(erythromycin)

an interference group A

2

(dexamesone) and an interference group A

3

(erythromycin + dexamesone). The percentage of EOS in BALF was counted

and EOS apoptosis was detected by TUNEL method. The levels of IL-8 and IL-5 in BALF were detected by ELISA

and the expression levels of cleaved caspase-9 and Bak in EOS from BALF were detected by Western blotting.       Results      The total cell number and the percentage of EOS in the model group were significantly higher than those in the control group and interference groups (P0.01)

and the EOS apoptosis rate was lower in the model group than in the control group and interference groups (P0.01). The expression of IL-8 and IL-5 in the BALF of the model group increased significantly as compared with the control group and interference groups (P0.01)

and the expression of IL-8 and IL-5 in the BALF was significantly lower in the interference group A

3

than in the interference group A

1

and interference group A

2

. The OD values of cleaved caspase-9 in the model group

interference groups and control group were 0.32±0.05

0.45±0.08

0.48±0.10

0.66±0.15 and 0.75±0.10

respectively

and the OD values of Bak in the model group

interference groups and control group were 0.40±0.05

0.54±0.09

0.57±0.06

0.78±0.10 and 0.92±0.12

respectively. The levels of cleaved caspase-9 and Bak were significantly higher in the interference groups and control group than in the model group (P0.01)

and those in the interference group A

3

were significantly higher than those in the interference group A

1

and interference group A

2

(P0.01).       Conclusion      Macrolides combined with glucocorticoids may play an anti-inflammatory role by up-regulating cleaved caspase-9 and Bak expression to promote EOS apoptosis in the lung tissues of asthmatic rats.