Dynamic changes and significance of calcitonin gene-related peptide in juvenile rats with hyperoxia-induced lung injury
AIM: To observe the dynamic changes and the effects of calcitonin gene-related peptide (CGRP) on the process of hyperoxia-induced lung injury. METHODS: Sixty-four SD rats were randomly divided into hyperoxia groups and air inhalation control groups, (1,3,7 and 14 d, respectively), with 8 animals in each group. At the end of the exposure time, the rats were sacrificed. The lung histopathologic changes were examined with hematoxylin and eosin (HE) staining and the wet/dry weight ratio was measured. The changes of CGRP and α-CGRPmRNA and β-CCRPmRNA expression were detected by radioimmunity technique and RT-PCR. RESULTS: After hyperoxia exposure for 3 and 7 d, a large number of inflammatory cells infiltrated into the alveolar space, and congestion and edema were found in the lung tissues. At the 14th day of hyperoxia exposure, expansion of alveolar space and proliferation of lung fibroblast were observed in the lung tissues and the lung wet/dry ratio increased after hyperoxia exposure for 7 and 14 d. With prolonged hyperoxia exposure, the CGRP concentration increased gradually in the lung tissue homogenate, peaked on the 3rd day and gradually declined to the normal level in the 14 d. RT-PCR study showed the expression of two different subtypes of CGRP mRNA in the lung tissues, namely, α-CGRP and β-CGRP. α-CGRP mRNA expression increased within 24 h of hyperoxia exposure. The high expression continued to the 7th day and then decreased significantly. β-CGRP mRNA expressed Liter than α-CGRP mRNA. The expression of β-CGRP mRNA began to increase from 3 d after hyperoxia exposure and the high expression maintained until the 14th d. CONCLUSION: CGRP may participate in the development of hyperoxia-induced lung injury and play an important role in mitigating the inflammatory reaction of hyperoxia-induced lung injury.
NETL
NSTL
万方数据
维普
