降钙素基因相关肽对家兔急性肺损伤的治疗作用及其可能机制

Effect of Calcitonin gene-related peptide on the acute lung injury of rabbits and the possible mechanism

目的:研究降钙素基因相关肽(CGRP)对家兔急性肺损伤的治疗作用及其可能机制。方法:18只家兔随机等分为生理盐水对照组、脂多糖(LPS)模型组、CGRP治疗组。通过耳缘静脉给药4 h后颈动脉放血处死,收集动脉血及肺泡灌洗液(BALF),测定动脉血氧分压(PaO2)及BALF表面张力、总磷脂含量(TPL)、乳酸脱氢酶(LDH)、碱性磷酸酶(AKP)、总蛋白(TP)含量。结果:与对照组比较,给予LPS后BALF中LDH、AKP活性升高、TP含量升高、动脉血PaO2下降、TPL含量下降、表面张力升高,CGRP可显著减轻LPS引起的上述各项指标的变化。结论:CGRP能显著减轻LPS引起的急性肺损伤,其机制可能与CGRP减轻LPS对肺泡Ⅱ型上皮细胞(AT-Ⅱ)的损伤,促进PS的合成、分泌有关。

Objective： To study the curative effect of Calcitonin gene -related peptide （CGRP） on the acute lung injuries （ALI） and the possible mechanisms. Methods： 18 rabbits were randomly divided into 3 groups： Control group were injected physiological saline through auricular vein; LPS group were injected LPS and physiological saline; CGRP group were injected LPS and CGRP. All rabbits were sacrificed after four hour. The arterial blood samples and bronchoalveolar lavage fluid （BALF） were collected. The surface tension, total phospholipids （TPL） and total protein （TP） in BALF were measured, The partial pressure of oxygen （PaO2 ） in arterial blood was detected. The activities of lactate dehydrogenase （LDH） and alkaline phosphatase （AKP） in BALF were measured. Results： Comparing with the control group, LPS increased the TP content and LDH activity in BALF and decreased PaO2 （P〈 0 . 05 ）, which was reversed by CGRP. TPL level was increased and the surface tension was decreased in LPS group （P〈0.05 ）, but no significant difference was found between the CGRP group and the control. CGRP inhibited the increase of AKP activity in BALF （P〈 0.05 ） induced by LPS. Conclusion： CGRP protects lungs from injured by LPS in ALI. One of the most important possible mechanisms is that CGRP protects the alveolar type Ⅱ cells （AT - Ⅱ ） and facilitates the synthesis and secretion of pulmonary surfactants.