Effect Of Different Tidal Volume Ventilation On Expression Of IL-6 And STAT3 In Lung And Lung Injury In The Rats

Objective:The mechanism of ventilator-induced lung injury(VILI) is complicated,Which is inflammation participated by many inflammatory factors and pathways.The inflammatory pathway that Interleukin -6(IL-6)activated signal transducers and activators of transcription-3(STAT3)plays an important role in many lung diseases, but whether it participates the process of VILI remains unknown.Our study produces lung injury by mechanical ventilation,to explore the effects of different tidal volume on lung injury and the expression of lung IL-6 and STAT3 in the rats,and the relationship between the lung injury and the expression of lung IL-6 and STAT3.Methods:24 Sprague-Dawley rats were randomly divided into 4 groups:A group(control),B group(10ml/kg ventilated),C group (20ml/kg ventilated),D group(40ml/kg ventilated).The rats accepted tracheotomy after anesthesia,A group kept breathing for 2 hour,B,C and D groups accepted ventilation for 2 hour,the inhalation of oxygen concentration was 1.0,recording vital sign of rats and doing blood gas analysis.The rats recovered 24 hour after ventilated,the lung wet/dry ratio,WBC counts in bronchoalveolar lavage fluid(BALF),lung tissue morphological change,the expression of lung IL-6 and STAT3 were tested. Result:1.Compared with A group,B group had no significant difference in wet/dry ratio,WBC counts in BALF,and the lung morphological change(P＞0.05).C group and D group had obviously lung injury,the wet/dry ratio,WBC counts in BALF,lung morphological change were higher or more serious than A and B group(P＜0.05),D group was serious than C group(P＜0.05).2.The expression of IL-6 and STAT3 had no difference between A and B group(P＞0.05),C group and D group were higher than A and B group (P＜0.05),and D group was higher than C group(P＜0.05).The IL-6 and STAT3 was direct correlation among 4 groups.Conclusions:1.The high tidal volume mechanical ventilation can induce lung inflammation and injury,while reduced tidal volume diminished lung injury and inflammation,which is one of protecting lung ventilation method.2.The inflammatory pathway that IL-6 activated STAT3 participates the process of VILI.