生长激素对急性肺损伤大鼠Clara细胞的影响

The effect of growth hormone on Clara cell in acute lung injury of rats

目的探讨应激反应期生长激素（Gh）对急性肺损伤（ALI）大鼠Clara细胞的影响。方法将112只雄性SD大鼠随机均分为ALI组和重组人生长激素（rhGh）组，两组大鼠根据致伤与否及致伤后的观察时间不同又随机均分为0、0．5、1、2、4、6和24h共7个亚组。通过免疫组织化学染色、透射电镜分析，观察ALI大鼠Clara细胞数量和形态学方面的变化。结果静脉注射内毒素脂多糖（LPS）后0．5hALI组大鼠开始出现ALI病理改变，随着时间的延长，肺损伤程度逐渐加重，于6h达最重，6h后逐渐恢复。rhGh组大鼠静脉注射LPS后肺部病理变化趋势与ALI组大鼠相似，但各时间点肺损伤程度进一步加重。LPS致伤后1hALI组大鼠Clara细胞数量开始明显减少，6h达最少，24h逐渐恢复，差异有统计学意义（P均〈0．01）。与ALI组同期比较，LPS致伤后rhGh组大鼠Clara细胞数均有不同程度减少，以24h减少更明显。LPS致伤后24h，ALI组大鼠Clara细胞的超微结构明显受损，rhGh组大鼠Clara细胞超微结构损害较ALI组更为严重。结论应激反应期应用rhGh可加重内毒素血症所致ALI大鼠Clara细胞受损。

Objective To study the effect of growth hormone （Gh） on Clara cell in acute lung injury （ALI） rats during stress responsive stage. Methods One hundred and tweleve male Sprague-Dawley（SD） rats were randomly divided into ALI group and recombinant human Gh （rhGh） group. The rats in two groups were subdivided into seven subgroups of different time intervals after lipopolysaccharide （LPS） injection：0 （pre-injection of LPS, acted as control group）, 0.5, 1, 2, 4, 6 and 24 hours subgroups respectively. Immunohistochemstry and electron microscope were used to investigate the number and morphological changes in Clara cells in ALI rats. Results Half of an hour after LPS injection, ALI was induced. The extent of lung injury increased with the time increased after LPS injection,peaked at 6 hours, then the extent of lung injury began to recess. The dynamic changes in lung injury of rats in rhGh group were similar to those in ALI group, but the extent of injury was more severe than that in ALI group at different time intervals. The Clara cell counts decreased significantly 1 hour after LPS injection, reaching the lowest at 6 hours, then began to recover 24 hours after LPS injection with statistically significant difference （all P〈0. 01）. The counts of Clara cells in rhGh group decreased more significantly than that in ALI group at different time intervals after LPS injection, especially at 24 hours. The ultrastructure of Clara cell showed significant damage 24 hours after LPS injection. Compared with ALI group,the ultrastructure of Clara cell in rhGh group were more damaged 24 hours after LPS injection. Conclusion rhGh could deteriorate the damage of Clara cell in acute lung injury rats induced by endotoxemia during stress response stage.