重症急性胰腺炎肺损伤发病机制中的肺泡Ⅱ型上皮细胞凋亡的作用及乌司他丁干预的实验研究

The role of apoptosis of alveolar typeⅡepithelial cells in the pathogenesis of severe acute pancreatitis lung injury and the intervention of ulinastatin

目的探讨重症急性胰腺炎(SAP)发病机制中其肺泡Ⅱ型上皮细胞凋亡的作用并对乌司他丁对其干预的作用进行分析。方法将42只健康大鼠随机分为3组,分别为假手术组、模型组与乌司他丁干预组,每组14只,以向大鼠十二指肠乳头内侧胰胆管注射脱氧胆酸钠建立SAP大鼠模型,假手术组大鼠仅打开大鼠腹腔轻轻翻动其胰腺后关闭腹腔,乌司他丁干预组于大鼠建模后给予乌司他丁注射。对几组大鼠术后肺组织及胰腺组织的病理变化及相关指标差异进行分析。结果与假手术组比较,SAP组及乌司他丁干预组TNF⁃α、AMY及MDA水平明显更高,乌司他丁干预组与SAP组比较,TNF⁃α、AMY及MDA水平明显更低(P<0.05)。SAP大鼠伴随着明显的肺损伤状况,假手术组、SAP组、乌司他丁干预组肺湿/干比值分别为3.62±0.56、6.48±0.77、4.69±0.63,血气指标PaCO_(2)、PaO_(2)分别为(31.25±1.03)mmHg、(106.52±2.03)mmHg,(48.67±2.01)mmHg、(73.57±2.44)mmHg和(35.22±1.32)mmHg、(90.22±3.01)mmHg),SAP组及乌司他丁干预组大鼠肺湿/干比值及PaCO_(2)明显上升,PaO_(2)明显下降,相较于SAP组,乌司他丁干预组大鼠的肺湿/干比值及PaCO_(2)更低,PaO_(2)更高(P<0.05)。假手术组大鼠肺泡Ⅱ型上皮细胞凋亡率[(3.58±0.57)%]及Ca^(2+)浓度[(34.52±2.35)%]均显著低于SAP组凋亡率[(29.67±4.52)%]及Ca^(2+)浓度[(82.66±4.66)%]及乌司他丁干预组凋亡率[(14.62±3.67)%]及Ca^(2+)浓度[(46.77±5.02)%],乌司他丁干预组大鼠肺泡Ⅱ型上皮细胞凋亡率及Ca^(2+)浓度显著低于SAP组(P<0.05)。假手术组大鼠Caspasee⁃8、BaxmRNA表达均显著低于SAP组及乌司他丁干预组,乌司他丁干预组大鼠Caspasee⁃8、BaxmRNA表达显著低于SAP组(P<0.05)。SAP肺损伤大鼠线粒体细胞破坏明显,乌司他丁对减少线粒体细胞破坏数量具有明显作用。结论SAP肺损伤中肺泡Ⅱ型上皮细胞凋亡可能参与了其作用机制,TNF⁃α、AMY、MDA、Caspasee⁃8、BaxmRNA在肺损伤机制中存在重要作用,乌司他丁干预有利于缓解SAP肺损伤状况,有利于控制病情进展。

Objective To explore the role of type II alveolar epithelial cell apoptosis in the pathogenesis of severe acute pancreatitis(SAP)and analyze the intervention effect of ulinastatin.Methods 42 healthy rats were randomly divided into 3 groups:sham operation group,model group and ulinastatin intervention group,with 14 rats in each group.The sap rat model was established by injecting sodium deoxycholate into the medial pancreaticobiliary duct of duodenal papilla of rats.The rats in sham operation group only opened the abdominal cavity of rats,gently flipped the pancreas and then closed the abdominal cavity.The rats in ulinastatin intervention group were injected with ulinastatin after modeling.The pathological changes of lung tissue and pancreas tissue and the differences of re⁃lated indexes were analyzed.Results Compared with the sham surgery group,the levels of TNF⁃α,AMY and MDA in SAP group and the ulinastatin intervention group were significantly increased(P<0.05).Compared with the SAP group,the levels of TNF⁃α,AMY and MDA in ulinastatin intervention group were significantly decreased(P<0.05).The lung wet/dry ratio of the sham surgery group,SAP group,and ulinastatin intervention group were 3.62±0.56,6.48±0.77,and 4.69±0.63,respectively.The blood gas indicators PaCO_(2)and PaO_(2)were(31.25±1.03)mmHg,(106.52±2.03)mmHg,(48.67±2.01)mmHg,(73.57±2.44)mmHg,and(35.22±1.32)mmHg,(90.22±3.01)mmHg,respectively.The SAP group and ulinastatin intervention group showed a significant increase in lung wet/dry ratio and PaCO_(2),while PaO_(2)decreased significantly.Compared with the SAP group,the ulinastatin intervention group showed lower lung wet/dry ratio and PaCO_(2),while PaO_(2)was higher(P<0.05).The apoptosis rate[(3.58±0.57)%]and Ca^(2+)concentration[(34.52±2.35)%]of alveolar type II epithelial cells in the sham surgery group were significantly lower than those in the SAP group[(29.67±4.52)%]and Ca^(2+)concentration[(82.66±4.66)%],as well as the apoptosis rate[(14.62±3.67)%]and Ca^(2+)concentration[(46.77±5.02)%]in the ulinastatin interven⁃tion group.The apoptosis rate and Ca^(2+)concentration of alveolar type II epithelial cells in the ulinastatin intervention group were significantly lower than those in the SAP group(P<0.05).The expression of Caspasee⁃8 and Bax mRNA in rats of the sham surgery group was significantly lower than that of the SAP group and the ulinastatin intervention group.The expression of Caspasee⁃8 and Bax mRNA in rats of the ulinastatin intervention group was significantly low⁃er than that of the SAP group(P<0.05).The damage of mitochondrial cells in SAP lung injury rats is significant,and ulinastatin has a significant effect on reducing the number of mitochondrial cell damage.Conclusion Apoptosis of alveolar type II epithelial cells is involved in the mechanism of SAP lung injury.TNF⁃α,Amy,MDA,Caspase⁃8 and Bax mRNA play an important role in the mechanism of SAP lung injury.Ulinastatin intervention is beneficial to alleviate SAP lung injury and control the progress of the disease.