干扰PALM3表达对小鼠内毒素性急性肺损伤的影响

Effect of downregulation of paralemmin-3 on LPS-induced acute lung injury in mice

目的研究干扰paralemmin-3(PALM3)表达对小鼠内毒素(LPS)性急性肺损伤(ALI)的影响。方法雄性BALB/c小鼠30只,随机分成3组:正常小鼠组、PALM3 shRNA组(在体转染PALM3 shRNA质粒)及Control shRNA组(在体转染Control shRNA质粒)。转染48 h后,免疫组化及逆转录聚合酶链反应(RT-PCR)检测肺内PALM3表达水平,检验PALM3 shRNA的干扰效率。雄性BALB/c小鼠40只,随机分4组:正常小鼠组、ALI模型组、PALM3 shRNA+ALI组及Control shRNA+ALI组,腹腔注射LPS(15 mg/kg)4 h后处死小鼠,观察各组肺组织病理学改变及肺组织匀浆中NO含量、MPO活性。结果与正常小鼠组及Control shRNA组比较,PALM3shRNA组肺内PALM3表达下调(P<0.05)。注射LPS后,与正常小鼠组比较,ALI模型组及Control shRNA+ALI组小鼠出现典型ALI病理改变,肺损伤评分升高(P<0.05),肺组织匀浆中NO含量及MPO活性增加(P<0.05);与ALI模型组及Control shRNA+ALI组比较,PALM3 shRNA+ALI组小鼠肺损伤程度减轻(P<0.05),肺组织匀浆中NO含量及MPO活性下降(P<0.05)。结论经滴鼻方式转染PALM3 shRNA质粒,成功下调PALM3在小鼠肺内的表达;干扰小鼠肺内PALM3表达可减轻LPS性ALI程度及炎性反应。

Objective To investigate the effect of downregulation of paralemmin - 3 （ PALM3 ） expression on LPS -induced acute lung injury （ALl） in mice. Methods Thirty BALB/c mice were randomly divided into 3 groups （ normal group, PALM3 shRNA group and control shRNA group）. At 48 h after transfection, protein expression level of PALM3 in lung tissues was detected by immunohistochemistry and mRNA level of PALM3 in lung tissues was analyzed by RT - PCR. A second cohort of forty BALB/c mice were randomly divided into 4 groups （ normal group, ALI model group, PALM3 shRNA ＋ALI group and control shRNA ＋ALI group）. Lung tissues of all 4 groups were collected at 4 h ＇after introperito-neal injection of LPS （ 15 mg/kg）. Levels of nitric monoxide （NO） and activity of myeloperoxidase （MPO） in lung tissue homogenates, as well as pathological changes in the lung were detected. Results Compared with the normal and control shRNA groups, the PALM3 mRNA and protein expressions were suppressed in the PALM3 shRNA group （ P 〈 0. 05 ）. After intraperitoneal injection of LPS, typical pathological features of ALI were observed in the control shRNA ＋ALI and ALI model groups, as well as higher lung injury score （P 〈 0. 05 ） and marked increases in pulmonary NO level and MPO activity （P 〈0. 05）. However, in mice given PALM3 shRNA, pathological changes in lung tissues were attenuated （P 〈 0. 05 ）. NO production and MPO activity in lung tissue homogenates of the PALM3 shRNA group were significantly reduced （ P 〈 0. 05 ）. Conclusion PALM3 expression in mice lungs was significantly down - regulated by intranasal transfection with PALM3 shRNA. Downregulation of pulmonary PALM3 expression in mice could significantly suppress the inflammatory reaction to LPS and reduce severity of LPS - induced ALI.