急性呼吸窘迫综合征大鼠多器官中Gq/11蛋白表达的变化及意义

目的 探讨急性呼吸窘迫综合征(ARDS)大鼠肺、脑、心、肾、肝、小肠中Gq/11蛋白表达及作用.方法 40只Wistar大鼠按随机数字表法分为5组,每组8只.由大鼠尾静脉注射油酸(OA)0.2 ml/kg复制ARDS模型,对照组从尾静脉注射等量生理盐水.模型组分别于制模后30、60、90和120 min检测血浆和各器官中乳酸脱氢酶(LDH)、丙二醛(MDA)、血管紧张素转换酶(ACE);蛋白质免疫印迹法(Western blotting)检测各器官中Gq/11蛋白α活性亚基Gαq/11蛋白表达.结果 与对照组相比,LDH活性于30 min后在血浆和心呈进行性升高血浆(kU/L):9.69±1.66比6.27±1.70,心(kU/g):0.81±0.12比0.59±0.09],60 min后在肺、脑、肾、小肠呈进行性升高肺(kU/g):1.15±0.19比0.87±0.11,脑(kU/g):2.27±0.37比1.53±0.61,肾(kU/g):1.13±0.26比0.64±0.09,小肠(kU/g):0.72±0.10比0.60±0.13],90 min后在肝(kU/g)呈进行性升高(0.50±0.14比0.39±0.05,P<0.05或P<0.01);MDA含量于30 min后在心(μmol/g)呈进行性升高(2.20±0.47比1.45±0.27),60 min后在血浆、肺、肾呈进行性升高血浆(μmol/L):3.10±0.58比2.33±0.35,肺(μmol/g):5.56±1.30比2.05±0.52,肾(μmol/g):1.61±0.27比0.98±0.42],90 min后在脑、肝、小肠呈进行性升高脑(μmol/g):6.78±1.38比5.83±1.58,肝(μmol/g):2.58±0.68比2.11±0.42,小肠(μmol/g):2.14±0.51比0.81±0.26,P<0.05或P<0.01];ACE活性于60 min后在血浆和肺呈进行性降低血浆(μmol·min-1·L-1):15.47±1.68比19.87±3.11,肺(μmol·min-1·g-1):20.61±1.81比26.26±1.93],在肾(μmol·min-1·g-1)呈进行性升高(15.92±1.20比13.67±2.26),90 min后在小肠(μmol·min-1·g-1)呈进行性升高(4.42±0.34比3.29±0.24,均P<0.01);Gαq/11蛋白表达于30 min后在肺、小肠呈进行性升高肺:(119.24±2.38)%比(100.00±18.74)%,小肠:(138.91±23.03)%比(100.00±19.43)%],60 min后在脑、心、肾呈进行性升高脑:(141.85±33.82)%比(100.00±16.81)%,心:(124.72±24.05)%比(100.00±16.04)%,肾:(123.98±25.74)%比(100.00±8.50)%],90 min后在肝呈进行性升高(134.34±19.14)%比(100.00±13.04)%,P<0.05或P<0.01].Gαq/11蛋白表达与各器官中LDH的变化呈正相关(r=0.584,P<0.05).结论 ARDS过程中肺、脑、心、肾、肝、小肠中Gq/11蛋白表达有不同程度上调,引发肌醇磷脂信号转导通路活性异常,参与了各器官的损伤发生.

The dynamic alteration in Gq/11 protein expression in multiple organs during acute respiratory distress syndrome in rat

Objective To observe the dynamic alteration in Gq/11 protein expression in the lung, brain, heart, kidney, liver and small intestine of rats suffering from acute respiratory distress syndrome (ARDS), and to explore the pathophysiological mechanism of ARDS in terms of signal transduction. Methods Forty male Wistar rats were randomly divided into oleic acid (OA) groups (n=32) and control group (n=8). OA groups included four subgroups: 30, 60, 90, 120 minutes (each n=8). An ARDS model in rats was reproduced by intravenous injection of OA 0.2 ml/kg in 2 minutes, and control group was given normal saline by the same way. Lactate dehydrogenase (LDH), malondialdehyde (MDA) and angiotensin converting enzyme (ACE) in the plasma and the above-mentioned organs were measured. Gαq/11 protein expression in these organs was examined by Western blotting. Results Compared with control group, LDH activity in the plasma and the heart 30 minutes after injection of OA gradually increased (plasma (kU/L): 9.69±1.66 vs. 6.27±1.70, heart (kU/g): 0.81±0.12 vs. 0.59±0.09), and in the lung, brain, kidney, and small intestine 60 minutes after injection of OA also gradually increased (lung (kU/g): 1.15±0.19 vs. 0.87±0.11, brain (kU/g): 2.27±0.37 vs. 1.53±0.61, kidney (kU/g): 1.13±0.26 vs. 0.64±0.09, small intestine (kU/g): 0.72±0.10 vs. 0.60±0.13), and in the liver (kU/g) 90 minutes after injection of OA gradually increased (0.50±0.14 vs. 0.39±0.05, P<0.05 or P<0.0１). MDA concentration in the heart (μmol/g) 30 minutes after injection of OA gradually increased (2.２0±0.4７ vs. 1.4５±0.27), and in the plasma, lung and kidney 60 minutes after injection of OA gradually increased (plasma (μmol/L): 3.10±0.58 vs. 2.33±0.35, lung (μmol/g): 5.56±1.30 vs. 2.05±0.52, kidney (μmol/g): 1.61±0.27 vs. 0.98±0.42), and in the brain, liver and small intestine 90 minutes after injection of OA gradually increased (brain (μmol/g): 6.78±1.38 vs. 5.83±1.58, liver (μmol/g): 2.58±0.68 vs. 2.11±0.42, small intestine (μmol/g): 2.14±0.51 vs. 0.81±0.26, P<0.05 or P<0.01). ACE activity was reduced in the plasma and lung 60 minutes after injection of OA (plasma (μmol·min-１·L-１): 15.47±1.68 vs. 19.87±3.11, lung(μmol·min-１·g-１): 20.61±1.81 vs. 26.26±1.93), but in the kidney (μmol·min-１·g-１) it was gradually increased (15.92±1.20 vs. 13.67±2.26), and in the small intestine (μmol·min-１·g-１) 90 minutes after injection of OA it gradually increased (4.42±0.34 vs. 3.29±0.24, all P<0.01). Gαq/11 protein expression in the lung and small intestine obviously increased 30 minutes after injection of OA (lung: (119.24±2.38)% vs. (100.00±18.74)%, small intestine: (138.91±23.03)% vs. (100.00±１9.43）%), and in the brain, heart and kidney increased 60 minutes after injection of OA (brain: （141.85±33.82）% vs. (100.00±16.81)%, heart: (124.72±24.0５)% vs. (100.00±16.04)%, kidney: (123.98±25.74)% vs. (100.00±8.50)%), and in the liver increased 90 minutes after injection of OA ((134.34±19.14）％ vs. (100.00±13.04)%, P<0.05 or P<0.0１). A positive correlation between the change in Gαq/11 protein expression and LDH in these organs (r=0.584, P<0.05) was found. Conclusion Up-regulation of Gq/11 protein expression in the lung, brain, heart, kidney, liver and small intestine may induce abnormal activity of phosphatidyl inositol signal transduction and thus plays a role in the production of multiple organ injury during ARDS.