阿米洛利预先给药对大鼠内毒素性急性肺损伤的影响

目的 探讨阿米洛利预先给药对大鼠内毒素性急性肺损伤的影响.方法 清洁级雄性SD大鼠32只,体重200～250 g,随机分为4组(n=8):对照组(C组)、急性肺损伤组(ALI组)、阿米洛利组(A组)和阿米洛利预先给药组(AL组).C组股静脉输注生理盐水3 ml,ALI组股静脉输注生理盐水1 ml、内毒素6 mg/kg,A组股静脉输注阿米洛利10 mg/kg、生理盐水2 ml,AL组股静脉输注阿米洛利10 mg/kg、内毒素6 mg/kg,输注速率均为0.05 ml/rain,给药间隔均为30 min.于输注内毒素结束后6 h时处死大鼠取肺,观察肺组织病理学,并行病理学评分,称重后计算肺湿干重比,检测髓过氧化物酶(MPO)活性,测定支气管肺泡灌洗液总蛋白、TNF-α和巨噬细胞炎性蛋白-2(MIP-2)的浓度,采用Western blot法检测肺组织钠氢交换体1(NHE1)、p38丝裂原活化蛋白激酶(p38MAPK)和细胞外信号调节激酶(ERK)的表达水平.结果 与C组比较,ALI组和AL组肺组织病理学评分、肺湿干重比、MPO活性、支气管肺泡灌洗液总蛋白、TNF-α和MIP-2浓度、肺组织NHE1、p38MAPK和ERK的表达水平明显升高(P＜0.01),A组上述指标差异无统计学意义(P＞0.05);与ALI组比较,AL组肺组织病理学评分、肺湿干重比、MPO活性、支气管肺泡灌洗液总蛋白、TNF-α和MIP-2浓度、肺组织NHE1和ERK的表达水平明显降低(P＜0.01),p38MAPK表达差异无统计学意义(P＞0.05).结论 阿米洛利预先给药可减轻大鼠内毒素性急性肺损伤,其机制可能与抑制ERK信号转导通路激活有关.

Effect of amiloride pretreatment on lipopolysaccharide-induced acute lung injury in rats

Objective To investigate the effect of amiloride pretreatment on the acute lung injury (ALI)induced by lipopolysaccharide (LPS) in rats. Methods Thirty-two pathogen-free male SD rats weighing 200-250 g were randomly divided into 4 groups (n = 8 each); group Ⅰ received iv normal saline (group C); group Ⅱ ALI received iv LPS 6 mg/kg (group ALI); group Ⅲ received iv amiloride 10 mg/kg (group A) and group Ⅳ received amiloride 10 mg/kg iv 30 min before iv LPS ( group AL). The animals were killed by exsanguination at 6 h after iv LPS infusion. The lungs were immediately removed. Microscopic examination of lung tissue was performed. The left lung was lavaged. The total protein (TP), TNF-α and macrophage inflammatory protein-2 (MIP-2)concentrations in broncho-alveolar lavage fluid (BALF) were measured. The W/D weight ratio and the myeloperoxidase (MPO) activity and expression of Na-H exchanger-1 ( NHE1 ), p38MAPK and extracellular signal-regulated kinase (ERK) in lung tissue were determined. Results LPS significantly increased ALI score (0 = slightest, 4 = severest), W/D lung weight ratio, TP, TNF-α and MIP-2 concentrations in BALF and MPO activity and the expression of NHE1, p38MAPK and ERK in the lung as compared with. control group. Amiloride pretreatment significantly attenuated LPS-induced changes except p38MAPK expression. Conclusion Pretreatment with amiloride can attenuate LPS-induced ALI by inhibition of ERK activation.