大鼠机械通气相关性肺损伤与肺组织细胞凋亡的关系

Relationship between cell apoptosis and mechanical ventilation -induced lung injury on rats

目的观察不同机械通气潮气量对大鼠肺细胞凋亡的影响，探讨细胞凋亡在机械通气所致肺损伤中的作用机制及意义。方法将30只健康雄性SD大鼠随机分成A、B、C三组，分别给予不同潮气量（VT）：A组7ml／kg，B组20ml／kg，C组40ml／kg，各组大鼠通气时间均为4h。凋亡细胞的检测使用末端脱氧核苷酸转移酶介导的dUTP缺口标记技术（TUNEL），用免疫组织化学技术检测肺组织核转录因子-κB（NF—κB）的表达；观察各组肺组织的病理改变，用湿／干重比值来比较肺水肿的程度。结果A、B、C三组大鼠肺组织病理改变依次加重，肺湿／干重比值依次增加，肺组织凋亡细胞逐渐增加，NF—κB的表达也逐渐增强。结论三组大鼠肺组织病理改变、细胞凋亡及NF—κB的表达一致，细胞凋亡在大潮气量机械通气所致肺损伤中起重要作用。

Objective To investigate the changes in bronchial and alveolar epithelial cell apoptosis after mechanical ventilation with different tidal volumes explore the mechanism and to explore the mechanism and significance of cell apoptosis in ventilation - induced lung injury （VILI）. Methods Thirty healthy male Sprague - Dawley rats were randomly divided into groups A, B and C to receive tracheotomy under anesthesia for with different volumes （VT） for 4 h （VT of 7 ml/kg in group A, 20 ml/kg in group B and 40 ml/kg in group C）. Lung biopsies were used for examination of dry/wet ratio to compare the levels of lung edema. The Nuclear factor - κB （ NF - κB） expression in pulmonary endothelium was assessed by immunohistochemistry staining. Apoptosis was investigated by TdT- mediated dUTP nick end labeling（TUNEL）. Results The expression of the NF - κB, the apoptosis index alveolar and bronchial epithelial cells were found to increase in group A, B and C. Conclusions Different tidal volume mechanical ventilation causes consistent changes in histopathology, cell apoptosis and NF-κB expression in rats, which support the presumption that cell apoptosis plays an important role in the pathogenesis of high VT ventilation - induced lung injury.