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目的 探讨地塞米松对大鼠光气急性肺损伤(ALI)血管生成素-1、2(Ang-1,2)表达的影响.方法 采用大鼠光气吸入性肺损伤动物模型.36只SD大鼠随机(随机数字法)分为3组:正常对照组(吸入与光气染毒组同等流量的空气)、光气染毒组(吸入8.33 mg/L纯度为100％的光气5min)、地塞米松处理组(尾静脉注入2.5 mg/kg地塞米松1h后,吸入同等剂量的光气).染毒2h后收集支气管肺泡灌洗液(BALF)测定中性粒细胞细胞数、蛋白含量和肺湿/干质量比(W/D).采用双抗体夹心酶标免疫分析法(ELISA法)测定各组血清和BALF中Ang-1,2水平.RT-PCR法对肺脏组织中Ang-1,2和Tie-2mRNA的水平进行半定量研究.Western blot技术检测肺脏组织中Ang-1,2和Tie-2蛋白含量.结果 与正常对照组比较,光气染毒组肺W/D、BALF中中性粒细胞数和蛋白含量明显升高,差异具有统计学意义(P＜0.01);与光气染毒组比较,地塞米松处理组的肺W/D、BALF中中性粒细胞数和蛋白含量明显降低,差异具有统计学意义(P＜0.01).与正常对照组比较,光气染毒组血清、BALF及肺组织中Ang-1和Tie-2表达明显下降,差异具有统计学意义(P＜0.01);与光气染毒组比较,地塞米松处理组Ang-1和Tie-2表达明显升高,差异具有统计学意义(P＜0.01).与正常对照组比较,光气染毒组血清、BALF及肺组织中Ang-2表达明显升高,差异具有统计学意义(P＜0.01);与光气染毒组比较,地塞米松处理组Ang-2表达明显下降,差异具有统计学意义(P ＜0.05,P＜0.01).结论 地塞米松可能通过抑制Ang-2表达并促进Ang-1和Tie-2表达来有效地保护大鼠光气吸入性急性肺损伤.“,”Objective To investigate the effect of dexamethasone on expressions of angiopoietin-1,2 (Ang-1,2) in rats with acute lung injury induced by phosgene.Methods A total of 36 SD rats were randomly (random number) divided into 3 groups:normal control group that consisted of the rats with air exposure,phosgene group that consisted of the rats with exposure to 8.33 mg/L phosgene (purity 100％,of the same volume as the inhaled air in the normal control group) for 5 minutes and dexamethasone group that consisted of the rats with caudal vein injection of 2.5 mg/kg dexamethasone an hour before exposure to the same dose of phosgene.Wet and dry ratio of the lung (W/D) was calculated,and leukocyte count and total protein content of bronchoalveolar lavage fluid (BALF) were recorded 2 hours later.The concentrations of Ang-1,2 in the serum and BALF were measured by enzyme-linked immunosorbent assay (ELISA).Reverse transcription-polymerase chain reaction (RT-PCR) was used to determine the mRNA levels of Ang-1,2 and Tie-2 in the lung tissue.The protein expression of Ang-1,2 and Tie-2 in the lung tissue were quantified by Western blot.Results Compared with phosgene group,the lung W/D,protein content of BALF and WBC count in dexamethasone group were significantly decreased (P ＜ 0.01).Compared with normal control group,Ang-1 and Tie-2 expressions in phosgene group were significantly decreased (P ＜ 0.01).Compared with phosgene group,the serum,BALF and lung tissue of Ang-1 and Tie-2 expressions in dexamethasone group was significantly increased (P ＜0.01).Compared with normal control group,the serum,BALF and lung tissue of Ang-2 expressions in phosgene group were significantly increased (P ＜ 0.01).Compared with phosgene group,the serum,BALF and lung tissue of Ang-2 expressions in dexamethasone group were significantly decreased (P ＜ 0.05,P ＜ 0.01).Conclusion Dexamethasone has a beneficial effect on acute lung injury induced by phosgene in rats by inhibition of Ang-2 and increase in Ang-1 and Tie-2 expressions.