[Key words] Mesenchymal stem cells; Extracellular signal-regulated kinases; Apoptosis; Alveolar type Ⅱ epithelial cells; Lipopolysaccharide

    急性呼吸窘迫综合征(acute respiratory distress syndrome，ARDS)常继发于脓毒症，死亡率高(30%～40%)，发病机制复杂，尚缺乏有效的治疗措施[1-2]。脓毒症释放大量炎症因子，肺泡上皮细胞损伤甚至凋亡是ARDS的病理、生理基础[3-4]。ARDS中肺泡Ⅱ型上皮细胞(alveolar epithelial type Ⅱ cell，AECⅡ)的凋亡是AEC死亡的主要机制之一[5]。细胞外信号调节激酶(extracellular regulated protein kinases，ERK)在细胞的分化、增殖及凋亡中起关键作用[6-7] ......