The effects of mechanical ventilation-induced lung injury on concentration of proinflammatory cytokines in rats

Objective To investigate the effects of mechanical ventilation on lung pathology and concentration of proinflammatory cytokines in rats.Methods Forty-five healthy Sprague-Dawley rats were randomly divided into three groups with 15 rats each group,ie.a control group(No mechanical ventilation),a high tidal volume group(VT 34 mL/kg,RR 30 bpm)and low tidal volume group(VT 8 mL/kg,RR 60 bpm).Results There were enlarged alveolar spaces,interalveolar septum collapse,swollen and spotty hemorrhages,inflammatory cell infiltration in the ventilation groups,which were more serious in the high tidal volume group.Lung wet-to-dry weight ratio of high tidal volume group was significantly higher than that of other groups(all P0.05).The concentrations in both macrophage-inflammatory protein-2(MIP-2)and tumor necrosis factor-α(TNF-α)of bronchoalveolar lavage fluid(BALF)and blood samples was significantly higher in two ventilation groups than the control group(all P0.05),which were higer in the high tidal volume group than in the low tidal volume group(P0.05).Conclusions These results indicate that mechanical ventilation can cause lung injury,which is more serious in high tidal volume ventilation.And mechanical ventilation-induced lung injury can cause proinflammatory cytokines release,with different levels in bronchoalveolar lavage fluid and blood samples.