Wu Yun-hu, Zhang Xuan, Wang Dian-hua
Kunming Medical University, Kunming 650031, China.
Nan Fang Yi Ke Da Xue Xue Bao. 2011 Aug;31(8):1289-94.
To determine the role of asymmetric dimethylarginine (ADMA) in acute lung injury induced by cerebral ischemia/reperfusion (I/R) injury in rats.
Adult male SD rats were randomly divided into 4 groups, namely the sham-operated group (S), cerebral I/R model group, ADMA+I/R group, and dimethylarginine dimethylaminohydrolase (DDAH)+I/R group. In the latter 3 groups, acute lung injury was induced by left middle cerebral artery occlusion for 120 min. After a 24-h reperfusion, the rats were sacrificed and the activities of nitric oxide synthase (NOS) and contents of nitric oxide (NO) were measured using reductase and colorimetric assay. The mRNA and protein expressions of protein kinase C (PKC) and myosin light chain kinase (MLCK) in the lung tissues were detected with RT-PCR and Western blotting, respectively. The contents of ADMA in the bronchoalveolar lavage fluid (BALF) and blood flowing into and out of the lungs were measured by ELISA.
Cerebral I/R injury caused significantly elevated ADMA levels in the BALF and blood flowing into the lungs, and obviously lowered the NO concentration and NOS activity in the lung tissues (P<0.05). Following cerebral I/R injury, MLCK and PKC mRNA and protein expressions were significantly upregualted in the lung tissues (P<0.05). Exogenous DDAH obviously decreased the levels of ADMA in the BALF and blood flowing into the lungs, increased NO concentration and NOS activity, and down-regulated MLCK and PKC mRNA and protein expressions in lung tissues of rats with cerebral I/R injury (P<0.05).
ADMA contributes to the development of acute lung injury following cerebral I/R injury in rats by upregulating MLCK and PKC expression. ADMA may serve as a novel therapeutic biomarker and a potential therapeutic target for acute lung injury induced by cerebral I/R injury.
确定不对称二甲基精氨酸（ADMA）在大鼠脑缺血/再灌注（I/R）损伤所致急性肺损伤中的作用。
成年雄性SD大鼠随机分为4组，即假手术组（S）、脑I/R模型组、ADMA+I/R组和二甲基精氨酸二甲胺水解酶（DDAH）+I/R组。后3组通过左侧大脑中动脉闭塞120分钟诱导急性肺损伤。再灌注24小时后，处死大鼠，采用还原酶法和比色法测定一氧化氮合酶（NOS）活性和一氧化氮（NO）含量。分别用RT-PCR和蛋白质印迹法检测肺组织中蛋白激酶C（PKC）和肌球蛋白轻链激酶（MLCK）的mRNA和蛋白表达。采用ELISA法测定支气管肺泡灌洗液（BALF）及进出肺的血液中ADMA的含量。
脑I/R损伤导致BALF和流入肺的血液中ADMA水平显著升高，肺组织中NO浓度和NOS活性明显降低（P<0.05）。脑I/R损伤后，肺组织中MLCK和PKC的mRNA及蛋白表达显著上调（P<0.05）。外源性DDAH明显降低了脑I/R损伤大鼠BALF和流入肺的血液中ADMA水平，增加了NO浓度和NOS活性，并下调了肺组织中MLCK和PKC的mRNA及蛋白表达（P<0.05）。
ADMA通过上调MLCK和PKC表达促进大鼠脑I/R损伤后急性肺损伤的发展。ADMA可能作为一种新的治疗生物标志物及脑I/R损伤所致急性肺损伤的潜在治疗靶点。
