Roles Of VEGF And Dexamethasone In The Expressions Of SP-B And Tgf-β1 In Type 2 Alveolar Epithelial Cells

Objective:To investigate the effects of recombinant rat VEGF and Dexamethasone on the expression of SP -B and TGF-β1 of AECⅡs.Methods:rat AECⅡs were isolated from the fetal SD rats lung tissues, and cultured with recombinant VEGF and Dexamethasone. Analyze the effects of VEGF and Dexamethasone on the expression of SP-B mRNA and TGF-β1 mRNA by using real-time PCR and expressions of the TGF-β1 by Immunocytochemistry.Results:25 ng/ml VEGF and Dexamethasone groups stimulate the mRNA expression of SP-B significantly (P<0.05). 25 ng/ml VEGF, 50 nmol/ml, 100 nmol/ml and 200 nmol/ml Dexamethasone groups restrain the expression of TGF-β1 mRNA significantly (P<0.05), other groups compared with the control group having no significant change (P>0.05).The result of immunocytochemistry showed that the expressions of TGF-β1 in 25 ng /ml VEGF, 50 nmol/ml, 100 nmol/ml, 200 nmol/ml Dexamethasone groups are negative in most of the AECⅡs and positive of the AECⅡs about 26℅. In the control group the the expressions of TGF-β1 is positive in about 80℅ of the AECⅡs and the number of negative AECⅡs are small. Conclusion : Both of VEGF and Dexamethasone can promoting the expression of SP-B on mRNA levels significantly at the appropriate concentration. When they stimulated the expression of SP-B mRNA, the expression of TGF-β1 mRNA was inhibited significantly (P <0.05).We surmise that both VEGF and Dexamethasone provoke the mRNA expression of SP-B by controlling the expression of TGF-β1 directly or indirectly.