NIX在机械牵张诱导的急性肺损伤中的表达及其严重程度的相关性

Expression of Nix after mechanical stretch-induced acute lung injury and its correlation with injury severity

目的急性肺损伤的本质是各种内外因素引起的全身失控性炎症反应,胸部撞击伤是急性肺损伤的常见原因之一。Nix作为Bcl-2的家族成员,研究发现,Nix在多种人组织细胞的凋亡途径中发挥着重要的作用。本研究旨在探讨NIX在机械牵张诱导的急性肺损伤中的表达及其严重程度的相关性;方法小生物撞击仪器精准控制建立不同严重程度大鼠胸部撞击伤模型,分组轻伤、重伤、严重伤组,对照组(n=10)不做处理;各模型组(n=10)分别于精准撞击后0.5、2、12、24、48、72 h后无伤取其肺组织,利用HE染色观察其病理学变化。取不同损伤程度的AT-Ⅱ型细胞培养株,RT-PCR技术检测各模型组各个时间点肺泡细胞Nix的表达情况,Western blot检测蛋白表达情况。结果撞击伤大鼠模型组肺组织出现不同程度的出血、水肿并大量炎性细胞浸润。与对照组相比,在撞击0.5、2、12、24、48、72 h后,各模型组大鼠肺组织中Nix mRNA都存在较为明显增高,Nix mRNA在伤后0.5 h已经开始增高,并在撞击48 h后Nix mRNA的表达达到峰值,撞击伤后72 h已有显著下降(P<0.05),接近伤后0.5 h水平,并随着撞击伤的严重程度Nix mRNA表达水平也呈相应的增高(P<0.05)。与对照组相比,各模型组大鼠肺组织Nix蛋白表达水平也与Nix mRNA表达水平呈现相同的变化曲线(P<0.05),且同样随撞击伤严重程度的增高而增高(P<0.05)。结论在机械牵张诱导的急性肺损伤中,肺组织中Nix基因的表达情况与肺损伤严重程度呈正相关(P<0.05)。这为我们通过Nix作为靶点进行肺组织相关疾病的研究提供理论依据。

Objective To investigate the correlation between the expression and injury severity of Nix after acute lung injury induced by mechanical stretch.Methods A small biological impact instrument accurately controlled the establishment of rat chest impact injury models with different injury severities:10 rats with minor injury(the minor injury group),10 with moderate injury(the moderate injury group),and 10 with serious injury(the serious injury group).And 10 rats received no treatment as the control group.Then lung tissues of all the groups were taken with no injury 0.5,2,12,24,48,and 72 h after the precise impact,respectively,and HE staining was employed to observe the pathological changes.The AT-Ⅱcell culture strains with different degrees of injury were taken and RT-PCR was used to detect the expression of Nix in the alveolar cells at each time point.The expression levels of proteins were detected by Western blotting method.Results The lung tissues of the injury groups showed different degrees of hemorrhage,edema and massive inflammatory cell infiltration.Compared with the control group,after the impact for 0.5,2,12,24,48,and 72 h,the expression of Nix mRNA in the lung tissues of each injury group was significantly increased,and Nix mRNA expression began to increase 0.5 h after injury.The expression of Nix mRNA peaked at 48 h after impact,and decreased significantly at 72 h after impact(P<0.05),which was close to that of 0.5 h after injury.And the expression levels of Nix mRNA increased correspondingly with the severity of impact injury(P<0.05).Compared with the control group,the expression of Nix proteins in the lung tissues of each injury group also showed the same change curve with the expression level of Nix mRNA(P<0.05),and also increased with the severity of impact injury(P<0.05).Conclusion In the rats with acute lung injury induced by mechanical stretch,the expression of Nix gene in the lung tissues was positively correlated with the severity of lung injury(P<0.05).This provides a theoretical basis for our study on lung tissue-related diseases through Nix as a target.