Effects Of Glycyrrhizin On The Expression Of TNF-α, IL-10, IL-18 MRNA In Alveolar Macrophages Of Rats With Acute Lung Iujury Induced By Trauma Combined With Hemorrhagic Shock

Acute Lung Injury ( abbreviated as ALI) is described as a syndrome with progressive expiratory dyspnea and continuous hypoxia induced by serious trauma, shock and infection. Although the pathogen-esis of ALI had not been understood completely, in recent years more and more researchers had confirmed that uncontrolled inflammatory reaction might play an important role for the onset of ALI, and different drugs and pharmaceutics had been used to prevent or therapy for this diseases, but experiment and clinical results were controversy. Glycyrrhizin (abbreviated as GLY) is a drug coming from Chinese medical herb " glycyrrhiza" , which has immunmodulative function as steroid hormone, and now is using for therapying hepatitides and has got effective results. To understand the pathogenic mechanism of ALI better and find more effective drug for its therapy, we try to structure rat model of ALI induced by trauma combined with hemorrhagic shock and detect the expression levels of tumor necrosis factor - alpha (TNF - a) , interleukin -10(IL-10) and interleukin -18(IL-18) message RNA(mRNA) in alveolar macrophages(abbreviated as AM) of rats using semi - quantitative reverse transcription polymerase chainreaction(RT - PCR) technology, and try to evaluate the therapeutic effectiveness of GLY for ALI and its probably mechanism of action.Materials and methods1 The experiment animals and groupingMale Wistar rats altogether 40, and their body weights were from 240 to 270 g. They were randomly divided into 5 grouped with eight in every group. That is: Group A: normal control group; Group B; sham - operation group; Group C: sham - treated group of ALI; Group D: dexamethasone ( abbreviated as DXM ) - treated group of ALI; Group E: GLY - treated group of ALI.2 The establishment of ALI modelExperiment rats were anesthetized with chloral hydrate (300 mg/ kg, ip). Carotid inducted and connected with arterial blood pressure monitor, and femora fracture were done with surgical bone rongeur. Hemorrhagic shock was induced 30 minutes later by withdrawing blood into a heparinized syringe until a mean arterial blood pressure between 40 mm Hg to 50 mm Hg was obtained and was maintained for 60 minutes by continued withdrawals. Shed blood was then reinfused within 5 minutes and different additional fluids were administered intraperito-neally according to different groups. We detected rats'lung water content , arterial blood oxygen pressure ( Pa02 ) , lung x - ray checking and the pathologic changes of lung with light microscope to know the degree of ALI.3 The treatment intervention and preparation and assay for the lung tissue, cells and blood specimenGroup A; animals did not accept any treatment intervention;Group B: animals underwent carotid puncture under chloral hydrate anesthesia without blood removal. After surgeon, 5 ml glucose saline was injected intraperitoneally; Group C: animals underwent anesthesia and femora fracture by bone rongeur, and then bleed to achieve a mean arterial blood pressure between 40 mm Hg to 50 mm Hg for 60 minutes. Resuscitation was induced by reinjecting shed blood, and 5 ml glucose saline was injected intraperitoneally; Group D; all procedures were done as Group C except that 5 ml glucose saline mixed with DXM(10 mg/kg) was injected intraperitoneally in the end; Group E: all procedures were done as Group C except that 5 ml glucose saline mixed with GLY(50 mg/kg) was injected intraperitoneally in the end.After 6 hours from resuscitation, all animals be death to get blood specimen, lung tissue and AM to detect.4 Statistical AnalysisAll data are presented as means ?standard error of the mean ( SEM) and analysis of variance and paired t test were taken for testing. P values < 0. 05 were considered significant.Experiment Results1 After femora fracture combined with hemorrhagicshock, experiment animals showed expiratory dyspnea and levels of Pa02 decreased badly(P <0.01) , attaining hypoxia. When treated with DXM or GLY respectively, levels of Pa02 increased in...