Role of microRNA-125b in ventilator-induced lung injury in mice / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the role of microRNA-125b (miR-125b) on ventilator-induced lung injury (VILI) in mice.Methods Forty healthy male C57BL/6 male mice,weighing 25-30 g,aged 2-3 months,were divided into 4 groups (n=10 each) using a random number table method:sham operation group (group Sham),group VILI,VILI plus miR-125b negative control group (group VILI+NC),and VILI plus miR-125b overexpression group (group VILI+miR-125b agomir).In VILI+NC and VILI+miR-125b agomir groups,miR-125b negative control and miR-125b agomir transfection complex 50 μl were intratracheally instilled,respectively,and 48 h later VILI model was established.The animals were mechanically ventilated for 4 h with high tidal volume (40 ml/kg) to induce VILI.Blood samples were obtained from the femoral artery at 4 h of mechanical ventilation for detection of PaO2,then animals were sacrificed,lungs were removed for determination of wet to dry weight ratio (W/D ratio) and for examination of pathological changes (with a light microscope),and lung injury was scored.In VILI+NC and VILI+miR-125b agomir groups,bronchoalveolar lavage fluid (BALF) was collected to measure the concentrations of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) by enzyme-linked immunosorbent assay.The cell apoptosis of lung tissues was measured using TUNEL,apoptosis index was calculated,the caspase-3expression was detected by Western blot,and the miR-125b expression was detected by real-time polymerase chain reaction.Results Compared with Sham group,PaO2 was significantly decreased,and W/D ratio and lung injury score were increased in VILI,VILI+NC and VILI+miR-125b agomir groups,and the expression of miR-125b was down-regulated in VILI and VILI+NC groups (P＜0.05).Compared with VILI group,PaO2 was significantly increased,W/D ratio and lung injury score were decreased,the expression of miR-125b was up-regulated (P＜0.05),the pathological changes of lung tissues were significantly attenuated in group VILI+miR-125b agomir,and no significant change was found in the parameters mentioned above in group VILI+NC (P＜0.05).Compared with group VILI+NC,the concentrations of TNF-α and IL-6 in BALF and apoptotic index were significantly decreased,and the expression of caspase-3 was down regulated in group VILI+miR-125b agomir (P＜0.05).Conclusion MiR-125b is involved in the endogenous protective mechanism of VILI in mice.