ABSTRACT
Objective To investigate the role of c-Jun N-terminal kinase (JNK) signal transduction pathway in IL-8 and TNF-α secretion from alveolar macrophages induced by mechanical ventilation with large-tidal volume in rabbits. Methods Thirty male New Zealand white rabbits weighing 210-260 g were randomly divided into 330-40 bpm, PEEP 0), and SB203580 group (group S). The animals were anesthetized with iv pentobarbital sodium 40 mg/kg, traeheostomized and mechanically ventilated. Group C received no mechanical ventilation. The animals were mechanically ventilated for 3 days in group V. The animals were mechanically ventilated for 3 days and SB203580 (a specific JNK inhibitor) 6 mg/kg was injected via the ear vein every day during ventilation (the ventilation parameters were the same as those in group V). The animals were then sacrificed by exsanguination. The concentrations of IL-8 and TNF-α in bronchoalveolar lavage fluid (BALF) were determined by ELISA and the alveolar macrophages were collected. After the macrophages were cultured for 2 h in vitro, the expression of IL-8 mRNA and TNF-α mRNA was determined by RT-PCR. Results Compared with group C, the levels of IL-8 , TNF-α,IL-8 mRNA and TNF-α mRNA were significantly increased in group V (P＜0.05). Compared with group V, the levels of TNF-α and TNF-α mRNA were significantly decreased ( P ＜ 0.01 ), but no significant change was found in the levels of IL-8 and IL-8 mRNA in group S ( P ＞ 0.05). Conclusion JNK signal transduction pathway plays an important role in TNF-α secretion from alveolar macrophages induced by mechanical ventilation with large-tidal volume in rabbits, but is not involved the secretion of TNF-α.