经气管灌注血管紧张素Ⅱ导致凋亡性急性肺损伤
庄甲举, 李小鹏, Uhal B D, Yian K R
白求恩军医学院生理教研室.河北,石家庄 050081;美国密歇根州立大学生理学系.密歇根州东兰辛市 48824
摘要
为研究外源性血管紧张素Ⅱ(angiotensinⅡ,ANG)在急性肺损伤和肺泡上皮细胞凋亡中的作用,经气管分别给雄性Wistar大鼠(175---200g)灌注ANG、ANG加caspase抑制剂ZVAD--fmk、ANG加ANG受体1阻断剂losartan和仅灌注磷酸盐缓冲溶液(PBS)。6或20h后在体灌洗动物肺脏,测定灌洗液中血红蛋白(hemoglobin,Hb)和荧光物质(BODIPY)标定的白蛋白含量(在灌洗前15min静脉注入BODIPY--白蛋白)。TUNEL测定显示,灌注ANG6h后,支气管和肺泡上皮细胞内标定的DNA片断显著增加({sl P}<0.05);ANG所致的DNA片断增加可被同时灌注ZVAD--fmk或losartan阻断。灌注ANG后免疫标定caspase3阳性细胞数量显著增多({sl P}<0.01),ZVAD--fmk或losartan同样显著减少caspase3阳性细胞的数量。灌注ANG显著增加肺泡灌洗液中荧光标定的白蛋白({sl P}<0.01)和Hb的含量({sl P}<0.05);ZVAD--fmk或losartan亦显著抑制荧光白蛋白和Hb含量的变化。结果表明,肺泡上皮细胞在体暴露于外源性ANG足以引起ANG受体1介导的上皮细胞凋亡和肺泡屏障损伤。
关键词: 凋亡; 肺泡上皮细胞; 急性肺损伤; Ⅱ型肺泡细胞
Apoptosis--dependent acute pulmonary injury after intratracheal instillation of angiotensin Ⅱ
Zhuang Jiaju, Li Xiaopeng, Uhal B D, Yian K R
Department of Physiology,Bethune Military Medical College.Shijiazhuang 050081,Hebei;USA
Abstract
To test the hypothesis that exogenous purified angiotensin Ⅱ(ANG) might cause apoptosis of alveolar epithelial cells(AECs) and acute lung injury,male Wistar rats were intratracheally instilled with purified ANG(10 #mu#mol/L),ANG plus the caspase inhibitor ZVAD-fmk(60 #mu#mol/L),ANG plus the ANG receptor AT1 antagonist losartan(LOS,100 #mu#mol/L) or sterile phosphate-buffered saline(PBS) vehicle alone.Six or 20 h later,the lungs were lavaged in situ for determination of bronchoalveolar lavage(BAL) fluid content of hemoglobin(Hb) and fluorescent(BODIPY)-albumin,a bolus of which was injected intravenously 15 min prior to BAL.Terminal deoxynucleotidyl transferase-mediated nick-end labeling(TUNEL) revealed that instillation of ANG,but not PBS alone,increased labeling of fragmented DNA in bronchiolar epithelial cells and in AECs(P<0.05) at 6 h post-ANG.Increased TUNEL was abrogated by concurrent instillation of ZVAD-fmk or LOS.Significant increased numbers of caspase-positive cells were observed by anti-caspase 3 immunolabeling after instillation of ANG(P<0.01);the same doses of LOS or ZVAD-fmk that blocked TUNEL also blocked the activation of caspase 3(P<0.01).Intratracheal instillation of ANG also remarkably increased BAL BODIPY-albumin(P< 0.01) and Hb(P<0.05),both of which were eliminated by ZVAD-fmk or LOS.These data indicate that exposure of AECs to ANG in vivo is sufficient to induce apoptosis and alveolar epithelial barrier injury mediated by ANG receptor AT1.
Key words: Apoptosis;alveolar epithelial cell;acute pulmonary injury;type Ⅱ pneumocyte
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引用本文:
庄甲举, 李小鹏, Uhal B D, Yian K R. 经气管灌注血管紧张素Ⅱ导致凋亡性急性肺损伤[J]. 生理学报 2008; 60 (6): 715-722.
Zhuang Jiaju, Li Xiaopeng, Uhal B D, Yian K R. Apoptosis--dependent acute pulmonary injury after intratracheal instillation of angiotensin Ⅱ. Acta Physiol Sin 2008; 60 (6): 715-722 (in Chinese with English abstract).