Abstract: Objective To explore the protection of calcitonin gene-related peptide(CGRP) on typeⅡ alveolar epithelial cells(AECⅡ) injuries induced by 95% oxygen, and influence on Gli1 protein in Sonic hedgehog(Shh) signal pathway. Methods AECⅡs were isolated and purified from premature rats and exposed to air, air+CGRP, air+CGRP+CGRP antagonists(CGRP8-37), hyperoxia(95% oxygen), hyperoxia+CGRP and hyperoxia+CGRP+CGRP8-37 for 24 h respectively. Morphologic change of AECⅡs were observed under electron microscope. The apoptosis ratio of AECⅡs were detected by flow cytometry. The level of cellular reactive oxygen species (ROS) were measured by fluorescence molecular probes, malondialdehyde (MDA) and superoxide dismutase(SOD) in AECⅡs were determined by spectrophotography. The expression of surfactant protein C (SPC) mRNA and protein of Gli11 in AECⅡs were also detected by real-time quantitative polymerase chain reaction(RT-qPCR) or western blot. Results Under the 95% oxygen condition, the apoptosis ratio of AECⅡs were increased 3.6-fold, the level of ROS increased 1.5-fold , and the activation of MDA and SOD also up-regulated sharply, SPC mRNA and Gli11 protein were decreased significantly comparison with air group. Administration of CGRP before hyperoxia could attenuate these changes induced by 95% hyperoxia. Conclusion CGRP can alleviate AECII injuries induced by 95% oxygen, which might be associated with the activation of Gli1 in Shh signal pathway.

Key words: Calcitonin Gene-Related Peptide, hyperoxia, type Ⅱ alveolar epithelial cell, Gli1 protein