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目的观察机械通气介导肺损伤(VILI)过程中丝裂原蛋白激酶(MAPK)的活性变化以及对细胞因子的影响,从中探讨VILI发生机制和MAPK的作用。方法 72只SD大鼠随机分为未处理的对照组(不行机械通气)、正常通气组、过度通气组和采用MAPK抑制剂SP600125 (JNK)、SB203580(p38)、PD98059(ERK)分别预处理上述3组。机械通气4 h后取大鼠肺组织采用 Western blot方法测定各组的总JNK、ERK、p-38蛋白激酶的表达及其磷酸化水平变化。同时以酶联免疫吸附试验(ELISA)方法测定大鼠肺组织、支气管肺泡灌洗液(BALF)和血浆中的肿瘤坏死因子-α(TNF-α)、巨噬细胞炎性蛋白-2(MIP-2)浓度。结果正常和过度机械通气4 h后均能激活 JNK、ERK、p38激酶,但以过度通气组为著(P<0．01)。过度通气组大鼠肺组织、BALF、血浆中的 TNF-α、MIP-2含量显著高于其他组(P<0．01)。JNK、ERK、p38抑制荆显著降低肺组织、BALF中的TNF-α、MIP-2含量(P<0．05或0．01),且JNK和ERK抑制剂作用强于p38抑制剂。结论过度机械通气激活了肺细胞中的JNK、ERK、p38激酶,且JNK、ERK、p38参与了VILI细胞因子的产生,即MAPK信号转导通路的激活可能是VILI发生机制之一。
Objective To investigate the changes of mitogen-activated protein kinase (MAPK) activity and cytokines in the process of mechanical ventilation-induced lung injury (VILI), and to explore the mechanism of VILI and MAPK. Methods Seventy-two SD rats were randomly divided into untreated control group (no mechanical ventilation), normal ventilation group, hyperventilation group and preconditioning with MAPK inhibitor SP600125 (JNK), SB203580 (p38) and PD98059 (ERK) 3 groups. After 4 h of mechanical ventilation, the expression of JNK, ERK and p-38 protein kinases and the phosphorylation level in the lungs of rats were determined by Western blot. The levels of tumor necrosis factor-α (TNF-α) and macrophage inflammatory protein-2 (MIP) in the lung tissue, bronchoalveolar lavage fluid (BALF) and plasma were determined by enzyme-linked immunosorbent assay (ELISA) -2) concentration. Results Both JNK, ERK and p38 kinases were activated after 4 h of normal and hyperventilation, but hyperventilation was the most important (P <0.01). The levels of TNF-α and MIP-2 in pulmonary tissue, BALF and plasma in hyperventilation group were significantly higher than those in other groups (P <0.01). JNK, ERK and p38 inhibitors significantly decreased the levels of TNF-α and MIP-2 in lung tissue and BALF (P <0.05 or 0.01), and the effect of JNK and ERK inhibitors was stronger than that of p38 inhibitors. Conclusion Excessive mechanical ventilation activates JNK, ERK and p38 kinases in lung cells. JNK, ERK and p38 are involved in the production of VILI cytokines. The activation of MAPK signal transduction pathway may be one of the mechanisms of VILI.