Abstract: AIM: To study the expression of PTEN and the intervention effect of dexamethasone(DXM) in the asthma rat model .METHODS: Twenty-four (200 ±10) g SD rats were randomly divided into three groups:control group(Group C) , asthma group(Group A) and DXM group(Group DXM) .The lung tissue was sampled from the left lung .The bronchoalveolar lavage fluid (BALF) was collected from the right lung .The differential count of cells in BALF was measured.The concentration of IL-13 in BALF wasmeasured by Sand-wich ELISA .The expression of PTEN protein and the changes of PTEN level in lung homogenate of each groupwere detected by immunohistochemical and West-ern blot method. RESULTS: The expression of bron-chial PTEN protein in Group C and Group DXM were 7.87±0.80, 1.80±0.23 which were higher than that in Group A(0.92 ±0.23, all P<0.01) , and the bronchial epithelial cell was the main expression cell. The expression of IL-13 in BALF of Group A was sig-nificantly increased, and which was higher than that in Group C (P<0.01) , and which in Group DXM was significantly decreased, compared with Group A, there was significant difference .There were significantly negative correlations between the expression of PTEN protein in lung homogenate and the level of IL-13 in BALF(r =-0.675, P<0.01) .CONCLUSION: The PTEN chief expression cell was tracheal epithelial cell .The expressions of PTEN protein in Group A were decreased.PTEN could decrease the expression of Th₂ factor.Dexamethasone could promote the expression of PTEN,which may be an important mechanism of inhib-iting asthmatic airway inflammation formation.

Key words: asthma, PTEN, airway inflammation, dexamethasone