重症急性胰腺炎肺损伤时磷脂酰肌醇3激酶/蛋白激酶B信号转导通路的表达

目的 探讨磷脂酰肌醇3激酶/蛋白激酶B(PI3K/PKB)信号转导通路在重症急性胰腺炎肺损伤的表达和意义. 方法 健康雄性长白猪24只,随机分为假手术组、急性肺损伤(ALI)组、ALI+内毒素(LPS)组和ALI+Wortmannin(P13K抑制剂)组,每组6只.逆行聚合酶链反应(RT-PCR)、免疫印迹方法检测肺组织PI3K/PKB mRNA和PKB蛋白活性,凝胶电泳迁移滞留试验(EMSA)法检测核转录因子-κB(NF-κB)活性变化,酶联免疫法检测肺泡灌洗液(BALF)中肿瘤坏死因子-α(TNF-α)、白介素-1β(IL-1β)含量变化,并观察肺组织病理学变化. 结果 ALI组较假手术组肺组织PI3K、PKB mRNA表达及PKB磷酸化水平明显增强PDK mRNA(43.7±14.3)%vs(20.7±9.1)%,P<0.05;PKB mRNA(52.2±22.2)%vs(22.2±10.2)%,P<0.01;p-PKB/PKB(0.547±0.036)vs(0.348±0.029),P<0.05],NF-κB活性变化同步增强(10.5±2.1 vs 2.4±0.5,P<0.01),BALF中TNF-α、IL-1β高表达,且尤以注射LPS后表现更显著,差异有统计学意义(P<0.05,P<0.01).ALI+Woamannin组PI3K、PKB mRNA及PKB磷酸化水平较ALI组和ALI+LPS组明显下降PDK mRNA(31.3±8.5)%vs(43.7±14.3)%,(75.7±17.2)%,P<0.05,P<0.01;PKB mRNA(27.5±9.8)%vs(52.2±22.2)%,(69.7±14.3)%,P<0.05,P<0.01;p-PKB/PKB(0.380±0.031)vs(0.547±0.036),(0.695±0.042),均P<0.01)],NF-κB活性、TNF-α及IL-1β含量也明显降低,差异有统计学意义(P<0.05,P<0.01). 结论 PI3K/PKB信号转导通路的活化参与了重症急性胰腺炎肺损伤的病理过程,PDK/PKB信号转导通路可被LPS激活并通过上调NF-κB活性、TNF-α及IL-1β水平而发挥作用.

Expression and significance of phosphtidylinositol 3-kinase/protein kinase B signal transduction pathway in severe acute pancreatitis-associated lung injury

Objective To investigate the expression and significance of phosphtidylinositol 3-kinase/protein kinase B (PI3K/PKB) signal transduction pathway in severe acute pancreatitis-associated lung injury. Methods Twenty-four healthy male Changbai pigs were randomized into four groups: sham operation group (n = 6), ALI group (n = 6), ALI plus LPS (lipopolysaccharide) group (n = 6) and ALI plus Wortmannin group (n =6). The expression levels of PI3K and PKB were determined by both RT-PCR and Western blot. Activity changes of NF-κB were detected by electrophoretic mobility shift assay (EMSA). Contents of TNF-α and IL-1β in bronchoalveolar lavage fluid (BALF) were examined by ELLSA. The histopathological changes of lung were observed. Results The expressions of mRNA and protein PI3K and PKB, NF-κB activity and TNF-α, IL-1β3 in BALF in ALI group were higher than those in sham operation group(P <0.05 or P <0.01). In ALI plus LPS group, they increased significantly in comparison with ALI group and sham operation group after injection of LPS(P <0.05 or P <0.01). In ALI plus Wortmannin group, these parameters were significantly inhibited by Wortmannin in comparisons with ALI group and ALI plus LPS group (P < 0.05 or P < 0.01). Conclusion The phosphtidylinositol 3-kinase/protein kinase B signal transduction pathway is found to participate in the pathological process of severe acute pancreatitis-associated lung injury through the up-regulations of NF-κB activity, TNF-α and IL-1β.