Influence Of Dexamethasone On Foxm1 Gene Expression In Pulmonary Cells Types Following Acute Lung Injry

Objective:To investigate the expression and the effect of protection of Foxm1 transcription factor and foxm1 gene in the lungs of mice with lipopolysaccharide(LPS), and the effect of dexamethasone on acute lung injury(ALI)induced by LPS.Methods: 72 mice were randomly devided into 3 groups: control group (A, n=24), model group(B, n=24), DEX treatment group(C, n=24 ). In the control group, mice were given 0.9% sline intraperitoneally(0.3ml). In the model group, mice were given i.p. injected with LPS at a dosage of 5mg/kg. In the DEX treatment group, the mice were given i.p. injected with LPS at a dosage of 5mg/kg, after 6 hours the mice were i.p. administered dexame- thasone at a dosage of 5mg/kg. Then the 3 groups respectively included 24h, 48h, 72h after LPS lung injury and DEX treatment. The level of foxm1 mRNA expression in lung was detected by reverse transcription polymerase chain reaction (RT-PCR). Foxm1 transcription factor in lung was detected by Immunocytochemica (IHC). Pathological changes in the lung were observed after the establishment of model.Results:When group comparison, at 24h, the expression levels of Foxm1 tanscription factor(8.881±0.817) in the mice lungs of the DEX treatment group were remarkably higher than model group(6.883±1.172) (P<0.05), and DEX treatment group also remarkably higher than control group(2.585±0.557)(P<0.05); the expression levels of foxm1 mRNA (0.608±0.094) in the mice lungs of the DEX treatment group were remar- kably higher than model group(0.268±0.015)(P<0.05), and model group also remarkably higher than control group(0.126±0.047)(P<0.05). At 48h, the expression levels of Foxm1 transcription factor(55.163±3.019) in the mice lungs of the DEX treatment group were remarkably higher than model group (15.804±1.555)(P<0.05), and model group also remarkably higher than control group (2.387±0.539)(P<0.05); the expression levels of foxm1 mRNA(1.190±0.087) in the mice lungs of the DEX treatment group were remarkably higher than model group (0.433±0.208)(P<0.05), and model group also remarkably higher than control group(0.133±0.119) (P<0.05). At 72h, the expression levels of Foxm1 transcription factor (36.773±1.610) in the mice lungs of the DEX treatment group were remarkably higher than model group(13.064±1.1641)(P<0.05), and model group also remarkably higher than control group(2.047±0.095)(P<0.05); the expression levels of foxm1 mRNA(0.894±0.010) in the mice lungs of the DEX treatment group were remarkably higher than model group (0.335±0.097)(P<0.05), and model group also remarkably higher than control group (0.097±0.095) (P<0.05). When comparison within group, for DEX treatment group, the expression levels of Foxm1 transcription factor (55.163±3.019) in the mice lungs at 48h were remarkably higher than 72h (36.773±1.610)(P<0.05), and 72h also remarkably higher than 24h (8.881±0.817)(P<0.05); the expression levels of foxm1 mRNA(1.190±0.087) in the mice lungs at 48h were remarkably higher than 72h(0.894±0.010) (P<0.05), and 72h also remark- ably higher than 24h(0.608±0.094)(P<0.05). For model group, the expres- sion levels of Foxm1 transcription factor (15.804±1.555) in the mice lungs at 48h were remarkably higher than 72h(13.064±1.164)(P<0.05), and 72h also remarkably higher than 24h (6.883±1.172)(P<0.05);the expression levels of foxm1 mRNA(0.433±0.208) in the mice lungs at 48h were remarkably higher than 72h(0.335±0.097) (P<0.05), and 72h also remark- ably higher than 24h(0.268±0.015)(P<0.05); For control group, the expression levels of Foxm1 transcription factor in the mice lungs at 48h (2.387±0.539) have no significantly variation compared with those at 72h(2.047±0.095) and 24h(2.585±0.557)(P<0.05), the expression levels of foxm1 mRNA in the mice lungs at 48h(0.133±0.119) have no significantly variation compared with those at 72h(0.097±0.095) and 24h(0.216±0.047) (P<0.05). The pathologic changes of the lung in mice of the DEX treatment group were wilder than those in mice of the model group.Conclusion: The expression levels of foxm1 mRNA and Foxm1 transcription factor increased significantly in lung in LPS-induced acute lung injury and LPS+DEX group. Administration of dexamethasone reduces injury of lung by protecting vascular endothelial cells (VECs) and alveolar epithelial cells (AECs) and increasing the expression of Foxm1 taranscri- ption factor.