降钙素基因相关肽对急性肺损伤幼鼠水通道蛋白1、5表达的影响

Effects of calcitonin gene - related peptide on aquaporin 1 and aquaporin 5 expressions in young rats with acute lung injury

目的 探讨降钙素基因相关肽（CGRP）对脂多糖（LPS）诱导的幼鼠肺水肿及水通道蛋白（AQP）的影响。方法 84只SD幼鼠按随机数字表法随机分为对照组（12只）、急性肺损伤（ALI）组（36只）和CGRP组（36只）。对照组不做任何干预；ALI组腹腔注射LPS（5 mg/kg），分别处理2、6、12、24 h；CGRP组在LPS注射1 h后进行腹腔注射CGRP（1 mg/kg）。于2、6、12、24 h处死幼鼠，取出肺组织，苏木精－伊红染色对肺组织进行病理分析，称重法计量各组湿/干质量比值，荧光定量PCR和Western blot分别检测各组幼鼠肺组织中AQP1和AQP5的mRNA和蛋白表达水平。结果 病理切片显示：与对照组相比，ALI组幼鼠组织肺泡腔明显变窄；肺泡壁毛细血管扩张，肺间质出现炎性细胞浸润。CGRP组肺水肿和炎症浸润程度明显减轻。荧光定量PCR结果显示：24 h后，ALI组AQP1和AQP5 mRNA（0.009±0.001和0.055±0.006）与对照组（0.035±0.002和0.167±0.006）相比均明显降低（均P〈0.001），CGRP处理后两者水平增高（0.024±0.002和0.134±0.012），与ALI组相比，差异均有统计学意义（均P〈0.001）。Western blot结果显示：24 h ALI组AQP1和AQP5蛋白水平（0.397±0.041和0.215±0.029）均低于对照组（0.850±0.020和0.741±0.032）（均P〈0.001），而CGRP组AQP1和AQP5蛋白水平（0.593±0.065和0.461±0.039）亦低于对照组（均P〈0.001），但明显高于ALI组（均P〈0.001）。结论 CGRP能够增加AQP1和AQP5的表达，减轻肺水肿，对ALI幼鼠肺损伤具有保护作用。

Objective To explore the effect of calcitonin gene-related peptide （CGRP） on expressions of aquaporin （AQP）1 and AQP 5 in young rats with acute lung injury（ALI） caused by lipopolysaccharide（LPS）.Methods Eighty-four young rats were randomly divided into control group, ALI model group and CGRP group.The rats in ALI model group were given intraperitoneal injection of LPS （5 mg/kg）for 2, 6, 12, 24 hours; while the rats in CGRP group were given intraperitoneal CGRP （1 mg/kg） after 1 h injection of LPS.At 2 h, 6 h, 12 h and 24 h, all rats were sacrificed and lung tissues were obtained.The histopathological changes in lung tissues were evaluated by adopting hematoxylin-eosin staining, and wet/dry（W/D） was measured.The mRNA and protein levels of AQP1 and AQP5 in lung tissues were detected by adopting fluorogenic quantitative PCR（qPCR） and Western blot.Results Pathological stain showed that rats in control group had a normal lung tissue structure, and LPS made lung tissue edema, narrowing the alveolar cavity and inflammatory cell infiltration.CGRP attenuated the effect of LPS on rat′s lung.The W/D ratio of lung tissue was significantly higher than that in the control group, and CGRP reduced the W/D ratio of lung tissue.qPCR showed that the mRNA levels of AQP1 and AQP5 from rats in ALI group （0.009±0.001 and 0.055±0.006） decreased compared with those in the control group （0.035±0.002 and 0.167±0.006） and CGRP group （0.024±0.002 and 0.134±0.012） （all P〈0.001）. Western blot results showed after 24 h injection of LPS, both AQP1 and AQP5 levels from ALI group （0.397±0.041 and 0.215±0.029） were significantly lower than those in the control group （0.850±0.020 and 0.741±0.032） （all P〈0.001）, and their levels in CGRP group （0.593±0.065 and 0.461±0.039） were also lower than those in the control group, but higher than those in ALI group （all P〈0.001）.Conclusion CGRP can enhance AQP1 and AQP5 levels and reduce pulmonary edema, and it has a protective effect on rats with acute lung injury.