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Objective To investigate the effects of different tidal volumes and positive end expiratory pressures on cell apoptosis in lung tissue of rats with acute lung injury.Methods Forty healthy male Sprague-Dawley rats were randomly(random number)divided into five groups,namely low tidal volume group(LV,VT 8 mL/kg),high tidal volume group(HV,VT 30 mL/kg),low tidal volume group with PEEP 2cmH2O(LV2P,VT 8 mL/kg,PEEP 2 cmH2O),low tidal volume group and PEEP 5cmH2O (LV5P,VT 8 mL/kg,PEEP 5 cmH2O)and low tidal volume group and PEEP 8 cmH2O(LV8P,VT 8 mL/kg,PEEP 8 cmH2O).After intravenous administration of oleic acid(OA,0.1 mL/kg),the rat model of acute lung injury was made.Mechanical ventilation was employed in rats of the experiment groups.Rats were sacrificed and their whole lungs were taken after mechanical ventilation for 2 hours.The transferase d-UTP end labeling assay(TUNEL)was used to define the extent and distribution of apoptotic cells in bronchus and lung tissues.The level of caspase-3 protein was determined by immunohistochemistry.Results The apoptotic cells on both alveolar septum and bronchial epithelium obviously increased with high level of caaspase-3 protein in HV group.The number of apoptotic cells obviously decreased with decrease in caspase-3 protein after PEEP ventilation.These changes were more significant in LV5P than those in other groups(P ＜ 0.01).Conclusions The mechanical ventilation with low tidal volume and PEEP produces protective effects on lung from injury.The cell apoptosis plays an important role in the course of VILI.
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OBJECTIVE To investigate the effect of ventilation on the changes in TNF-? concentration of BALF on acute lung injury model.METHODS Forty healthy male Sprague-Dawley rats were randomly divided into five groups LV,HV,LV2P,LV5P,LV8P and the rat model of acute lung injury was built.Mechanical ventilation was employed in the test groups.Rats were sacrificed after 2 hours ventilation when the serum acquired.The supernatant of BALF was detected for TNF-? concentration.RESULTS The changes in TNF-? content of serum:the TNF-? contentration of serum was higher in HV group than that in LV group(P