The Effects Of Dially Trisulfide On Anti-oxidative Function And ICAM-1 Expression Of Acute Lung Injury Induced By Lipopolysaccharide In Mice

Objective: Acute lung injury(ALI) is an acute, diffused injury of alveoli and lung vascular induced by different causes. It's characterized by aggregation and action of polymorphonuclear neutrophil (PMN) in the lung ,which conglutinate with vascular endothelial and release reactive oxygen species (ROS) and proteinase so that contribute to excessive inflammatory reaction with pulmonary vascular permeability increased. In the end, it will develop the acute respiratory distress syndrome(ARDS)and multiple organ dysfunction syndrome (MODS). ALI is an early stage of ARDS. The mortality and clinical prognosis of ALI/ARDS is very disadvantaged. Therefore, it's important to explore the pathogenesis and further strategy of prevention for ALI.So far, complicated pathogenesis of ALI has not been fully clarified. Most of scholars suggested that the unbalance of oxidation/antioxidation play an important role in the process of ALI. When the lung under sepsis, trauma and shock or other risk factors, severe oxidative stress will be occurred in the lung. A large quantity of sequestrated and activated PMN in lung were in state of respiratory burst, oxygen consumption increased significantly beside of releasing excessive oxygen free radical. They can make protein and nucleic acid denatured as well as insult lung directly and further promote the process of ALI.We can choose some objective indicators to evaluate the damage process. Myeloperoxidase(MPO), which can reflect accumulation and activity of PMN in lung. Meanwhile, lipid peroxidation product malondialdehyde(MDA), superoxide dismutase(SOD) and total antioxidant capacity(T-AOC) are closely related with oxidative stress. In addition, intercellular adhesion molecule-1 (ICAM-1) is an important indicator which mediated the adhesion of PMN and vascular endothelial. It will further promote the inflammatory reaction of ALI.Garlic is also known as Hu."Ben Cao Gang Mu"said there are a lot of functions in garlic. Modern science have found that diallyl trisulfide(DATS) is the main active and effective component in garlic extract. It had been reported that garlic extract has strong antioxidant capacity and has a function of getting rid of oxygen free radical. Some studies had suggested that DATS maybe have chemoprevention effects on ALI. But it is unclear that DATS can reduce oxidative stress reaction and the expression of ICAM-1 in ALI. Well, in this study, we duplicated lipopolysaccharide (LPS)-induced ALI mice model in order to provide theoretical basis for prevention of ALI/ARDS in clinic.Methods:Forty-eight healthy kun-ming mice were randomly divided into four groups:(1)ALI group: mice were infused the same bulk as DATS of sodium chloride intraperitoneally for 7 days, and then received LPS 10mg/kg injection;(2)DATS pretreatment group: mice were infused (3mg/ml)DATS 30mg/kg intraperitoneally for 7 days and then received LPS 10mg/kg injection;(3)DATS treatment group: mice were infused the same bulk as DATS of sodium chloride intraperitoneally for 7 days, then received LPS 10mg/kg injection, and after 30 minutes they received(3mg/ml)DATS 30mgl/kg injection; (4)Control group: mice were infused the same bulk as DATS sodium chloride intraperitoneally for 7 days and without LPS injection. Mice in each group(n=6) were executed by taking off the neck at 2 hour and 6 hour. The degree of pulmonary edema was assessed with the lung coefficient and the left lung wet/dry weight(W/D). The right middle lobe was fixed in 4% paraformaldehyde solution and detected ICAM-1 after that. Then lavaged the remaining right lung with saline, dried it with filter paper, stored immediately in liquid nitrogen at -70℃for the determination of MPO, MDA, SOD, and T-AOC. Then we observed morphological changes and the expression of ICAM-1 in lung tissues by means of immunohistochemistry staining and image analytical system.SPSS13.0 statistical analysis software was used for statistical analysis. Data were presented as mean±standard deviation ( x±s) and analyzed with analysis of variance (ANOVA). Least significant difference(LSD)and independent-samples t Test were also used to analyze statistical difference. A level of P <0.05 was considered to be statistically significant.Results:1 The changes of the lung coefficient and the lung W/D ratio in ALI miceAt 2 hour of ALI group, no changes were detected in the lung coefficient and lung W/D compared with that in control group(P>0.05).At 6 hour of ALI group, the lung coefficient and lung W/D were significantly elevated (P<0.05 vs control group),and pulmonary edema was visable, while it was reduced in DATS pretreatment group (P<0.05 vs ALI group). But no decrease was observed in DATS treatment group(P>0.05 vs ALI group).2 The changes of data which were reflection of oxidation/antioxidationMPO activity and MDA content in lung tissues increased significantly at 2 hour ALI group and 6 hour ALI group compared with control group respectively (P<0.05 vs control group), MPO activity and MDA content in lung tissues reduced significantly at DATS pretreatment group compared with 2 hour ALI group and 6 hour ALI group respectively (P<0.05 vs ALI group), but it is still higher than that of control group(P<0.05 vs ALI group). No decrease was observed in DATS treatment group (P>0.05 vs ALI group).SOD and T-AOC activity in lung tissues reduced significantly at 2 hour ALI group and 6 hour ALI group compared with control group respectively(P<0.05 vs control group), SOD and T-AOC activity in lung tissues increased significantly at DATS pretreatment group compared with 2 hour ALI group and 6 hour ALI group respectively(P<0.05 vs ALI group), but it is still lower than that of control group(P<0.05 vs ALI group). No increase was observed in DATS treatment group(P>0.05 vs ALI group).3 Observation of immunohistochemistry staining of lung tissuesAt 6 hour, in control group, positive expression of ICAM-1 resided only in endothelial cell of airway mucosa. The positive singal was weaker, but positive expression hadn't been found in vascular endothelial cell; Compared with control group, positive expression was very obvious in ALI group which mainly resided in vascular endothelial cell and endothelial cell of airway mucosa, and both of them are positive. The positive expression of DATS pretreatment group and DATS treatment group had located between control group and ALI group. Analyzed of image analytical system, the mean optical density value of ICAM-1 increased significantly at ALI group compared with control group(P<0.05 vs control group), while mean optical density value of ICAM-1 reduced significantly at DATS pretreatment group compared with ALI group (P<0.05 vs ALI group), No decrease was observed in DATS treatment group(P>0.05 vs ALI group).Conclusion:1 Pretreatment with DATS could alleviate the degree of pulmonary edema.2 Pretreatment with DATS could decrease MPO activity and MDA content in ALI mice induced by LPS and contribute to alleviate oxidative stress of lung tissue.3 Pretreatment with DATS could elevate SOD and T-AOC activity in ALI mice induced by LPS and contribute to remove oxygen free radical.4 Pretreatment with DATS could reduce expression of ICAM-1 and maybe play an protective role in ALI.