双光气致急性损伤对兔肺泡Ⅱ型细胞形态学的影响

Study of changes of pulmonary alveolar type Ⅱ epithelial cells of lung in the experiment rabbits exposured to diphosgene

目的 :通过对日本大耳兔双光气肺损伤后肺泡Ⅱ型细胞内磷脂和形态学变化的观察 ,探讨双光气对肺Ⅱ型细胞的损伤及其机制 .方法 :将纯种日本大耳白兔 3 5只随机分为对照组 (n =10 )、染毒即刻组 (n =5 )、染毒 2h组 (n =5 )染毒4h组 (n =5 )、染毒 8h组 (n =5 )、染毒 12h组 (n =5 ) ;采用浓度—时间法动态式染毒 ,染毒后按不同时间点对实验动物进行颈总动脉插管放血处死 ,取肺并用肺灌洗液对支气管肺泡进行灌洗 ,然后取肺组织作冰冻切片 ,进行电镜观察 ,并测定细胞内磷脂含量 .结果 :肺Ⅱ型细胞内磷脂含量在染毒即刻开始时较正常组含量下降 (P <0 0 1) ;在染毒 2h时降到最低 ,之后上升 (P <0 0 5 ) ,而在 4h后又下降 (P <0 0 5 ) .染毒终止后 ,损伤逐渐加重 ,染毒后 2h磷脂因消耗而降低 .染毒后 4h ,由于代偿功能启动 ,磷脂短暂升高 ,出现致伤性代偿期 .从染毒 2h后开始 ,细胞损伤加重 ,磷脂合成进入失代偿期 ,合成逐渐减少 .到染毒后 8h ,肺泡Ⅱ型细胞内细胞处于致伤性和致死性细胞改变的临界点 ,细胞出现致死性改变 ,磷脂合成、分泌停止 ,细胞出现死亡 .结论 :兔在双光气染毒 12h内 ,肺泡表面活性物质磷脂的改变有差异 ,随细胞损伤程度发生改变 ,出现明显中毒分期 :即致伤性改变期、致伤性代偿期、

AIM:To study the changes of pulmonary alveolar type Ⅱ epithelial cells in rabbit lung injured by diphosgene acutely and to find out the mechanism of the lung injury by diphosgene. METHODS: Japanese rabbits were chosen as the experimental animals and were randomly divided into six groups: Negative control group ( n =10) and 0, 2, 4, 8 and 12 h groups after diphosgene exposure ( n =5 in each group). Following exposure to diphosgene, rabbits were killed, lungs were taken out and lavaged and the content of phospholipid in pulmonary alveolar type Ⅱ epithelial (PATE) cells was detected. The changes of pulmonary alveolar type Ⅱ epithelial cells were also observed under electron microscope. RESULTS: The PATE cells changed morphologically in groups exposed to diphosgene. After exposure to diphosgene, the content of phospholipid in PATE cells in the exposed groups was remarkably lowered than that in normal control group ( P <0 01). Compared with that of the control group, the content of phospholipid in PATE cells in the exposed groups decreased greatly 2 hours after the exposure and increased 4 hours after the exposure ( P <0 05). 8 hours after the exposure, it gradually descended again. CONCLUSION: Our results indicate that diphosgene can indirectly injure the pulmonary alveolar type Ⅱ epithelial cells by injuring PATE cell surfactant and cell shapes. The injury process can be divided into four phases: non lethal phase, compensatory phase, decompensatory phase and lethal phase.