Objective: To observe the effect of Chaipu decoction on ovalbumin(OVA) -induced asthma in rats and the dynamic expression of alpha-smooth muscle actin(α-SMA). Method: Seventy sprague dawley(SD) rats were randomly divided into control group

model group(two weeks

four weeks and eight weeks)

chaipu decoction-treated group(two weeks

four weeks and eight weeks). Asthma rat model was established by sensitization and stimulation with ovalbumin(OVA) conjuncted with Al(OH)3. The rat airway morphological parameters changes

the gene and protein expression of α-SMA in bron-chopulmonary tissue at different time points were observed by HE staining

RT-PCR and immuno-histochemical method. Result: ①The WAt/Pbm

WAi/ Pbm

and WAm/ Pbm were significantly increased in the asthma group on the two weeks

four weeks

and eight weeks compared with that in normal group(all P<0.05)

and the WAt/ Pbm

WAi/ Pbm

and WAm/ Pbm were showed the trend of gradually increasing with the days of stimulation

the asthma group on the four weeks was higher than that on the two weeks

the asthma group on the eight weeks was higher than that on the four weeks (all P<0.05). The WAt/Pbm

WAi/ Pbm

and WAm/ Pbm on the two weeks

four weeks

eight weeks in the chaipu decoction-treated group. And that on the two weeks

four weeks in the asthma group were lower than eight weeks in the asthma group (all P<0.05).But that in the all chaipu-treated group were higher than the control group. ②The gene and protein expression of α-SMA on the two weeks

four weeks and eight weeks were significantly increased in the asthma group compared with that on the two weeks

four weeks

eight weeks in the chaipu decoction-treated group and control group(all P<0.05)

and showed the trend of gradually increasing with the days of stimulation (all P<0.05); there was little expression of the gene and protein expression of α-SMA in the lung tissue of chaipu decoction-treated two weeks group compared with the control group;but all the chaipu decoction-treated groups were increased compared with that in the same week of asthma model group (P<0.05). Conclusion: α-SMA of asthmatic lung tissue is dynamic over expression in the onset of asthmatic. Our study suggest that chaipu decoction involve in the pathogenesis of asthmatic airway remodeling by downregulating the expression of α-SMA inhibiting the airway smooth muscle constriction and hyperplasia.