磷脂酰肌醇-3-激酶参与过度机械通气诱导的核因子-κB激活

Phosphatidylinositol-3-kinase participates in the activation of NF-κB induced by hyperventilation

目的通过观察磷脂酰肌醇-3-激酶(PI3K)抑制剂(ly294002)对不同潮气量机械通气中NF-κB活性的影响,探讨机械通气肺损伤发生机制。方法40只SD大鼠随机分为对照组(A组)、正常通气组(B组)、过度通气组(C组)、正常通气+ly294002组(D组)、过度通气+ly294002(E组),每组8只。分别采用Western blot测定磷酸化蛋白激酶B(Akt)的活性、免疫组化观察I-κBβ、NF-κB在肺细胞中的分布及表达;电泳迁移率测定NF-κB的DNA结合活性。结果C组大鼠肺组织中Akt的磷酸化水平较其他各组增加(P<0.05),NF-κB的DNA结合活性较A、D、E组显著提高(P<0.01),肺组织中I-κBβ表达显著降低,NF-κB表达增加,且主要表达于肺内巨噬细胞和肺上皮细胞。ly294002可明显抑制Akt磷酸化,降低NF-κB的活性及在肺组织中的表达。结论PI3K参与了过度机械通气导致的NF-κB激活。

Objective To investigate the effects of phosphatidylinositol-3-kinase （PI3K）on the activation of NF-κB induced by hyperventilation and the possible mechanism of ventilation- induced lung injury. Methods Forty SD rats were randomly divided into five groups：control group（group A）, normal ventilation group（group B）, hyperventilation group （group C）, normal ventilation＋ ly294002 group（group D） and hyperventilation＋ly294002 group（group E） with eight animals each. Activation of Akt kinase and NF-κB were detected by Western blot and electrophoretic mobility shift assay respectively. The expression and location of NF-κB and I-κB β in the lung cells were detected by immunohistochemical technique. Results The level of phosphorylation Akt kinase was elevated significantly in group C than that in the other groups （P〈0.05）. NF-κB was activated in both group B and C, but displayed stronger DNA-binding activity in group C as compaired with that in groups of A, D and E （P〈0.05） ; The expression of NF-κB was upregulated and the number of positive cells in the nuclear was increased significantly in group C as well; Ly294002 suppressed the activation of Akt and NF-κB and downregulated the expression of NF-κB in the lung tissues （P〈0.05）. Conclusion This result suggested that PI3K participates the activation of NF-κB induced by hyperventilation.