Feature of Ventilation Induced Lung Injury with Different Tidal Volume in Neonatal Rats

Objective To investigate the feature of ventilation induced lung injury(VILI) with different tidal volume in neonatal rats.Methods Thirty-two neonatal rats were assigned to control group(without ventilation),conventional ventilation group(tidal volume 0.010 L·kg-1 for 5 h),hyperventilation 5 h group(tidal volume 0.025 L·kg-1 for 5 h),hyperventilation 3 h group(tidal volume 0.025 L·kg-1 for 3 h) randomly.After ventilation,the lungs were obtained to weigh,score about the degree of lung pathologic injury was count.The levels of IL-6 and IL-10 of lung tissue were detected by enzyme-linked immunosorbent assay.Results The VILI histopathology score in hyperventilation 5 h group,hyperventilation 3 h group,conventional ventilation group and control group were 9.63±1.40,4.40±1.06,6.50±1.85 and 0.00,respectively,the differences were significant among the 4 groups(P=0.000).IL-6 in hyperventilation 5 h group,hyperventilation 3 h group,conventional ventilation group and control group were(785.33±39.06) pg·g-1,(656.78±48.82) pg·g-1,(701.6±33.65) pg·g-1 and(635.02±65.78) pg·g-1,there were significant differences among the 4 groups(P=0.000).The IL-6 level was positively correlated with VILI histopathology score(r=0.78,P0.01).There was no significant difference of IL-10 level among the 4 groups(P=0.940).The ratio of IL-6/IL-10 was significantly higher in hyperventilation 5 h group compared with the other groups(P0.05).Conclusions VILI in neonatal rats is related with tidal volume and duration of ventilation,hyperventilation may induce serious lung injury.The level of IL-6 in lung tissue is correlated with the degree of lung injury positively.The imbalance of inflamm-antiflam cytokine is one of mechanism of biotrauma in VILI.