地塞米松对内毒素致急性肺损伤大鼠肺的保护作用

目的:探讨在急性肺损伤(acute lung injury,ALI)病程不同阶段给予小剂量地塞米松干预,对ALI是否具有保护性差异.方法:根据腹腔注射内毒素(lipopolysacharide,LPS)后不同时间肺组织病理改变程度的不同将实验动物分为LPS组、LPS后1 h地塞米松干预组、LPS后3 h地塞米松干预组和生理盐水对照组,对比各组间组织病理学改变、动脉血气、肺湿/干重比、肺泡灌洗液蛋白含量、肺通透指数、IL-8含量及肺内水通道蛋白1(aquaporin-1,AQP1)表达的差异.结果:LPS组、LPS后1 h组、LPS后3 h组和生理盐水对照组的肺湿/干重比例分别为(4.92±0.23),(4.89±0.21),(4.57±0.14)和(4.48±0.23),肺泡灌洗液蛋白含量分别为(291.60±58.58) g/L,(140.36±32.45)g/L,(121.80±40.68)g/L和(194.6±60.36)g/L,肺通透指数分别为(5.73±1.37),(2.40±0.51),(2.15±0.63)和(3.94±1.28),肺内AQP1表达水平分别为(19.92±6.47),(33.47±9.41),(40.70±9.18)和(47.16±10.88).试验结果显示两组地塞米松干预组与内毒素组相比均可显著改善肺湿/干重比、肺泡灌洗液蛋白含量、肺通透指数及肺内AQP1表达水平,差异具有统计学意义;在LPS后3 h地塞米松干预组上述指标改善趋势更明显,但与LPS后1 h地塞米松干预组结果相比差异不具有统计学意义.上述4组的病理评分分别为(12.00±2.22)分,(6.75±2.28)分,(8.00±2.66)分和(2.75±0.79)分,两组地塞米松干预组与LPS组3组间比较差异无统计学意义.结论:ALI典型病理改变出现后再给予糖皮质激素治疗可以改善肺通透性和减轻肺水肿.

Effects of dexamethasone on acute lung injury in rats induced by lipopolysacharide

OBJECTIVE: To study the difference between the preventive and therapeutic effects of dexamethasone on acute lung injury models induced by lipopolysacharide (LPS) in different phases. METHODS: Forty adult male Wistar rats were randomly divided into four groups: (1)control group to receive intraperitoneal NS injection (2 mL/kg). (2)LPS group to receive intraperitoneal LPS injection (5 mg/kg). (3)one-hour group to receive intraperitoneal dexamethasone injection (2 mg/kg) one hour after LPS injection. (4)three-hour group to receive intraperitoneal dexamethasone injection (2 mg/kg) three hours after LPS injection. Then histopathology, arterial blood gases, lung permeability, wet-to-dry weight ratio and immunohistochemistry AQP1 were performed 24 hours later. RESULTS: Dexamethasone could improve biological indexes. Lung permeability, wet-to-dry weight ratio and immunohistochemistry AQP1 were (5.73+/-1.37), (4.92+/-0.23), (19.92+/-6.47) in LPS group, (2.4+/-0.51), (4.89+/-0.21), (33.47+/-9.41) in one-hour group and (2.15+/-0.63), (4.57+/-0.14), (40.69+/-9.18) in three-hour group, respectively. Dates in three-hour group were prior to those of one-hour group, and there was slight but no significant difference between the two groups. CONCLUSION: Dexamethasone can improve lung permeability and reduce lung edema. There is no need to be treated with glucocorticoids in advance.