The expression of Egr-1, C-jun and IL-1? in the lung injured by mechanical ventilation in rats / 中华麻醉学杂志

ABSTRACT

Objective To investigate the changes in the expression of Egr-1, C-jun and IL-1? mRNA and protein in the lung injured by mechanical ventilation. Methods Forty male SD rats weighing 250-320 g were randomly divided into 5 groups (n = 8 each) group A received no mechanical ventilation; group B-E received mechanical ventilaion for 30 (B), 60 (C), 90 (D) and 120 (E) minutes. The animals were anesthetized with intraperitoneal 3% pentobarbital 35 mg?kg-1 , tracheostomized and mechnically ventilated (VT =42 ml?kg-1 , RR = 40 bpm, I E = 12, FiO2 = 21 % ) . Arterial blood samples were taken for blood gas analysis. The animals were killed at the end of mechanical ventilation in group B-E and after tracheostomy in group A. The lungs were removed for microscopic examination using HE staining. The expression of Egr-1, C-jun and IL-1? mRNA and protein was detected by RT-PCR and immuno-histochemical technique respectively. Results There was no significant difference in PaO2 and SaO2 among the 5 groups while PaCO2 was significantly decreased in group B and C but increased in group E as compared with group A. The expression of Egr-1, C-jun and IL-1? mRNA and protein was significantly increased by mechanical ventilation in a duration - dependent manner. Histological studies demonstrated that the damage to the lung was correlated with the duration of mechanical ventilation in terms of perivascular inflammatouy cell infiltration, exudates and hemorrhage in the alveoli and thickening of alveolar walls. Conclusion The results of our study show that mechanical ventilation activates and upregulates the expression of the early response genes in a duration - dependent manner. The upregulation of the expression of these genes might be involved in the underlying mechanism of lung damage induced by mechanical ventilation.