Abstract: Objective: To observe the effects of calcitonin gene-related peptide (CGRP) on epithelial-mesenchymal transition (EMT) of alveolar epithelial cells and its mechanism.Methods: The RLE-6TN cell were divided into 6 groups as follows:control group, cells were incubated with double distilled water (TGF-β1 solvent) for 48 h; transforming growth factor-β1(TGF-β1) group, cells were incubated with TGF-β1 (5 ng/ml) for 48 h; +CGRP (1, 10,100 nmol/L) group, cells were pre-treated with CGRP (1, 10,100 nmol/L) for 1 h, and then subjected to TGF-β1 for 48 h; CGRP 100 nmol/L + CGRP8-37 1 μmol/L group, cells were pre-treated with CGRP 100 nmol/L + CGRP8-37 1 μmol/L for 1 h, and then subjected to TGF-β1 for 48 h. RLE-6TN cell vitality was determined by MTT. The mRNA or protein expression levels of Notch1, eIF3a, α-SMA, E-cadherin and collagen Ⅲ were detected by real-time PCR or Western blot.Results: Compared with the TGF-β1 group, cell vitality and the expression of E-cadherin were significantly increased, and the expression of Notch 1, eIF3a, α-SMA and collagen Ⅲ were markedly decreased in CGRP (1, 10, 100 nmol/L) group. The effects of CGRP above mentioned could be abolished by CGRP 8-37.Conclusion: These results suggest that CGRP inhibits TGF-β1-induced EMT process, and down-regulation of the expressions of Notch1and eIF3a may be involved in its mechanisms.

Key words: calcitonin gene-related peptide, epithelial-mesenchymal transition, Notch1, eIF3a, rat