Change in expression of macrophage migration inhibitory factor mRNA in a rat model of ventilator-induced lung injury / 中华麻醉学杂志

ABSTRACT

Objective To investigate the changes in the expression of macrophage migration inhibitory factor (MIF) mRNA in a rat model of ventilator-induced lung injury.Methods Thirty adult male Sprague-Dawley rats,weighing 2β5-260 g,were randomly divided into 3 groups (n =10 each) using a random number tablecontrol group (group C),small tidal volume (VT) mechanical ventilation group (group S) and large tidal volume mechanical ventilation group (group L).The animals were anesthetized with intraperitoneal ketamine 100 mg/kg,midazolam 0.2 mg/kg and atropine 1.0 mg/kg.The rats were tracheostomized and spontaneous breathing was maintained in group C,while the rats were tracheostomized and mechanically ventilated for 4 h in groups S and L.The tidal volume was 7 ml/kg (group S) or 40 ml/kg (group L),I ∶ E was 1 ∶ 1,RR was 80 bpm and FiO2 was 100％.At 4 h of spontaneous breathing or mechanical ventilation,broncho-alveolar lung lavage fluid (BALF) was collected for determination of the total protein concentration,white blood cell (WBC) counts and concentrations of MIF,IL-6 and IL-1β (by ELISA).Then the rats were sacrificed and the lungs removed for microscopic examination and for determination of wet to dry lung weight ratio (W/D ratio) and expression of MIF mRNA (by RT-PCR).Results Compared with C and S groups,WBC counts,concentrations of total protein,MIF,IL-6 and IL-1β in BALF,and W/D ratio and expression of MIF mRNA in lung tissues were significantly increased in group L (P ＜ 0.05).There was no significant difference in the indexes mentioned above between group C and group S (P ＞ 0.05).The pathological changes occurred in group L.Conclusion The up-regulation of MIF mRNA expression in lung tissues may be involved in the development of ventilator-induced lung injury in rats.