中文摘要：

目的探讨静脉注射血管紧张素Ⅱ（AngⅡ）和血管紧张素Ⅱ1型受体（AT1R）阻断药氯沙坦对大鼠肺组织AT2R表达的影响及AT2R与急性肺损伤（ALI）的相关性。方法24只SD大鼠被随机分为4组，每组6只。正常对照组和AngⅡ组：持续皮下注射生理盐水或AngⅡ1μg·kg^-1·min^-1 72h；AngⅡ＋氯沙坦组：注射AngⅡ前24h及注射过程中给予氯沙坦10mg·kg^-1·d^-1灌胃，连用4d；氯沙坦组：仅用氯沙坦10mg·kg^-1·d^-1灌胃，连用4d。给药后活杀大鼠，分别用逆转录-聚合酶链反应（RT—PCR）和蛋白质免疫印迹法（Western blotting）检测肺组织AT2R的mRNA和蛋白表达，并行组织损伤病理评分。结果AngⅡ组肺组织病理评分[（3．33±1．14）分]明显高于正常对照组[（0．73±0．09）分]；AngⅡ＋氯沙坦组评分降至（1．98±0．30）分，而氯沙坦组为（0．95±0．20）分，各组间比较差异均有统计学意义（P〈0．05或P〈0．01）。AngⅡ组AT2R mRNA表达[（47．90±9．88）％]明显低于正常对照组[（86．33±5．90）％]；AngⅡ＋氯沙坦组AT2R mRNA表达上调[（90．63±19．66）％]，而氯沙坦组为（68．65±4．88）％，各组间比较差异均有统计学意义（P〈0．05或P〈0．01）。正常对照组肺组织AT2R蛋白表达为（78．80±41．26）％，AngⅡ组为（68．98±23．93）％，AngⅡ＋氯沙坦组为（68．13±23．23）％，氯沙坦组为（70．15±17．16）％，各组间比较差异均无统计学意义。结论AngⅡ可以诱导大鼠ALI并下调AT2R mRNA在肺组织中的表达，此时应用氯沙坦可上调AT2R mRNA表达，改善肺损伤；AT2R可能在ALI中发挥肺保护作用。

英文摘要：

Objective To study the effect of angiotensin Ⅱ （Ang Ⅱ ） and losartan, which is an angiotensin Ⅱ type 1 receptor （ATIR） antagonist, on expression of AT2R in rat lung and the relationship between AT2R with acute lung injury （ALI）. Methods Twenty-four Sprague-Dawley （SD） rats were randomly divided into normal group, Ang Ⅱ group, Ang Ⅱ ＋losartan group and losartan group, with 6 rats in each group. Normal group and Ang Ⅱ group were treated with continuous subcutaneous injection of normal saline （NS, 1 μg · kg^-1 · min^-1） or Ang Ⅱ （1 μg · kg^-1 · min^-1） for 72 hours respectively. Ang Ⅱ ＋losartan group was gavaged with losartan （10 mg· kg^-1 · d^-1） 24 hours before and during the 72 hours＇ continuous subcutaneous injection of Ang Ⅱ for a duration of 4 days. In losartan group rats were gavaged with losartan （10 mg · kg^-1 · d^-1） for 4 days only. Reverse transcription-polymerase chain reaction （RT-PCR） and Western blotting were employed to measure AT2R mRNA and protein. The pathology of the rat pulmonary was scored. Results Smith＇s score of pathology in Ang Ⅱ group [（3.33± 1.14） scores] was significantly higher than that of the normal group [（0. 73±0.09） score ], while it was significantly lower in Ang Ⅱ ＋ losartan group [（1.98± 0.30） scores] than that of Ang Ⅱ group. Smith＇s score of pathology in losartan group was [（0.95 ± 0.20） scores]. The differences among four groups showed significant statistical difference （P〈0.05 or P〈0.01）. AT2R mRNA in Ang Ⅱ group [（47.90±9.88）%] was significantly lower than that of normal group [（86.33±5.90）%], while it was significantly higher in Ang Ⅱ ＋losartan group [（90.63 ± 19.66）%] than Ang Ⅱ group. AT2R mRNA of losartan group was （68.65±4.88）%. The differences among four groups had significant statistical difference （P〈0.05 or P〈0. 01）. While on protein level showed no statistically significant difference among the four groups. The values o