Objective: To investigate the Smads proteins localization in lung tissue of chronic bronchial asthma rats lung tissue and its mRNA expression

and to explore the TGF-β/Smad signaling pathway

thus in the chronic bronchial asthma. Method: Twenty-four Sprague-Dawley rats were randomly divided into two groups:normal control group was treaded by 0.9% saline; model group treaded by the mixture(10%ovalbumin+10%aluminum hydroxide). HE staining was used to observe the pathomorphological changes;Smad proteins localization in lung tissue was determined by immunofluorescence; Smads mRNA expression was determed by RT-PCR. Result: HE staining showed the model group was obviously bleeding

expanding of lung alveolar andinflammatory cell. The results showed Smads proteins were located in the bronchial wall or alveolar wall by immunofluorescence assay;RT-PCR showed that the Smad2 mRNA expression were higher significantly in model group than that in normal group (P<0.05); Smad7 mRNA expression were significantly lower in model group than that in normal expression (P<0.05); Smad4 mRNA expression was no difference between the two groups. Conclusion: Smads proteins had closely related to chronic asthma

Smad proteins were located in lung tissue of both normal rats and chronic bronchial asthma rats. In the course of asthma

receptor type Smad2 mRNA was increased in expression

inhibitory type Smad7 mRNA was decreased in expression

and thus TGF-β/Smad signaling pathways that might be activated.