The Effect Of Mechanical Ventilation In The Acute Lung Injury And The Role Of Glucocorticoid In The Ventilator-Induced Lung Injury In Rats

Objective:To evaluate the effect of different tidal volume and the role of glucocorticoid in the acute lung injury with LPS by observing the pathologic alterations;the expressions of MIP-1α, MIP-1α-mRNA and NF-κBp65-mRNA in the ventilated rats.Methods:1 Thirty-two normal Wistar rats were randomly divided into four groups: Control group. LPS group , LPS+conventional tidal volume group(C-V_T) and LPS+low tidal volume group(L-V_T).2 Forty normal Wistar rats were randomly divided into five groups:Control group,LPS group,LPS+C-V_T group,Dexamethasone(Dex)+LPS+C-V_T group and Budesonide (Bud)+LPS+C-V_T group Then the pathologic alterations of the lungs of each group were observed under light microscope, and the content of MlP-1α in plasma and bronchoalveolar lavage fluid(BALF)was measured with ELISA,and the expression of MIP-1α-mRNA and NF-κBp65-mRNA on lung tissue was measured with RT-PCR respectively.Results:1 (1) Apart from the control group,different levels of interstitial and alveolar edema, infiltration and activation of inflammation cells could be seen. Compared the LPS+L-V_T group,there were more obvious pathologic alterations in the LPS+C-V_T group.(2) The contents of MlP-1α in plasma and BALF were significantly higher in rats in the LPS+C-V_T group than it in the LPS+L-V_T group(P<0.01).there was no statistical difference between the LPS group and the LPS+L-V_T group(P>0.05).(3) The expression of MIP-1α-mRNA in lung tissue was significantly higher in rats in the LPS+C-V_T group than it in the LPS+L-V_T group(P<0.05).There was no statistical difference between the LPS group and the LPS+L-V_T group(P>0.05).(4) The expression of NF-κBp65-mRNA in lung tissue was significantly higher in rats in the LPS+C-V_T group than it in the LPS+L-V_T group(P<0.05).There wasno statistical difference between the LPS group and the LPS+L-V_T group(P>0.05).(5) The expression of NF-κBp65-mRNA correlated with the expression of MIP-1α-mRNA in the LPS+C-V_T group and the LPS+L-V_T group, respectedly. (r=0.881, P<0.05, r=0.806, P<0.05).2(1) Different levels of interstitial and alveolar edema,infiltration and activation of...