Objective       To determine the effects of calcitonin gene related peptide (CGRP) and Wnt on type Ⅱ alveolar epithelial cells (AECⅡ) upon the exposure of hyperoxia.       Methods       AECⅡ were isolated and purified from premature rats and exposed to air

hyperoxia

hyperoxia+CGRP (10

-7

mol/L) and hyperoxia+CGRP+hCGRP

8-37

(10

-6

mol/L) respectively. The proliferation of AECⅡ was measured by M

TT cell proliferation assay. Cell apoptosis was measured by flow cytometry. The activation of Wnt7b

β-catenin and p-β-catenin was assessed by Western blot analysis.       Results       Cell proliferation was significantly decreased and apoptosis was increased upon the treatment of hyperoxia (P0.01). Compared with hyperoxia exposure alone

additional CGRP treatment promoted cell proliferation and reduced the apoptosis of AECⅡ（P0.01）. Hyperoxia exposure resulted in significant decrease of Wnt7b and β-catenin (P0.01) and increased expression of p-β-catenin (P0.01)

while CGRP treatment reversed above results significantly (P0.01).       Conclusion       CGRP decreases cell death and attenuates the inhibited proliferation of hyperoxia exposure

and improves the survival of AECⅡ exposed to hyperoxia

which might be associated with the activation of Wnt7b/β-catenin.