粒细胞集落刺激因子对于血管紧张素Ⅱ所致小鼠心室肥厚的保护作用

Cardioprotective Effects of Granulocyte Colony-Stimulating Factor in Mice Cardiac Hypertrophy Induced by Angiotensin Ⅱ

背景以往研究表明粒细胞集落刺激因子(G-CSF)对于心肌梗死和阿霉素所致心肌病的心功能不全有改善作用。目的研究 G-CSF 对于血管紧张素Ⅱ(AngⅡ)所致心室肥厚过程中心室重塑的作用。方法雄性野生型(WT)小鼠36只随机分为4组:空白对照组(n=9),或小鼠皮下注射G-CSF(10μg/kg,n=9),或给药 AngⅡ(2.88 mg/kg,n=9),或给药 Ang Ⅱ同时皮下注射 G-CSF(Ang Ⅱ 2.88 mg/kg+G-CSF 10μg/kg,n=9)。测量各组小鼠的血压和心功能。处死动物后测量心室质量/体质量,心肌细胞横截面积和纤维化面积。采用 RT-PCR的方法检测心肌组织中骨桥蛋白的 mRNA 表达量。采用 Western-Blot 的方法检测心肌组织中血管紧张素转换酶(ACE),ACE2和磷酸化 p70S6激酶蛋白的表达量。结果 Ang Ⅱ使 WT 小鼠血压显著升高[收缩压,Ang Ⅱ给药组:(139.7±1.6)mmHg 比 WT 组:(108.7±2.3)mmHg,P<0.05]并出现心室肥大和纤维化。G-CSF 不影响血压,却明显减少了心肌细胞横截面积[AngⅡ+G-CSF 组:(181.06±0.11)比 AngⅡ给药组:(202.02±0.16)μm^2,P<0.05]、纤维化面积[Ang Ⅱ+G-CSF 组:(2.87±0.12)%比 AngⅡ给药组:(3.91±0.06)%,p<0.05]、心室质量体质量比[Ang Ⅱ+G-CSF 组:(3.7±0.2)mg/g 比 Ang Ⅱ给药组:(4.2±0.1)mg/g,P<0.05],以及左心室舒张功能[等容舒张时间,Ang Ⅱ+G-CSF 组:(0.11±0.02)ms 比 Ang Ⅱ给药组:(0.16±0.01)ms,P<0.05]。Western-Blot 和 RT-PCR 的结果表明 G-CSF 降低了 ACE、骨桥蛋白、磷酸化 p70S6激酶的表达量,同时增加了ACE2的表达量。结论这些结果说明 G-CSF 能够防止 Ang Ⅱ所致心室肥厚。G-CSF 治疗增加 ACE2的表达量,抑制了 Ang Ⅱ引起心室肥厚。抑制 OPN 表达和 p70S6K 磷酸化,这些因素可能介导了 G-CSF 抑制心室肥厚、改善心室重塑的治疗作用。

Background Granulocyte colony-stimulating factor （G-CSF） has been reported to have beneficial effect on cardiac dysfunction in post-infarction and doxorubicin-induced cardiomyopathy. Objective To. investigate the effects of G-CSF on cardiac remodeling in cardiac hypertrophy induced by angiotensin Ⅱ （Ang Ⅱ ）. Methods Thirty-six male wild type mice （WT） were allocated randomly to receive subcutaneously G-CSF （10 μg/kg per day, n=9） , or Ang Ⅱ （2.88 mg/kg per day, n=9） , or Ang Ⅱ plus G-CSF （Ang Ⅱ 2.88 mg/kg＋G-CSF 10μg/kg, n = 9） for 4 weeks with untreated WT（n = 9） as controls. Blood pressure and cardiac function were measured. Heart weight/body weight ratio, myoeyte cross-sectional area and fibrosis area were determined. The mRNA expression of osteopontin （ OPN ） in myocardium was detected by RT-PCR. The expressions of angiotensin converting enzyme （ACE）, ACE2 and phosph-p70S6 kinase protein in myocardium were assessed by Western-Blot. Results Ang Ⅱ significantly elevated blood pressure （SBP, Ang Ⅱ ： 139.7± 1.6 vs WT： 108.7±2.3 mmHg, P〈0. 05） and caused cardiac hypertrophy and fibrosis. G-CSF treatment did not prevent the Ang Ⅱ -induced elevation of blood pressure （SBP, Ang Ⅱ ＋G-CSF： 140.1±2.6 vs Ang Ⅱ ： 139.7±1.6 mmHg, P〉0.05）, but significantly attenuated the myocyte cross-sectional area （Ang Ⅱ ＋G-CSF： 181.06±0. 11 vs Ang Ⅱ ： 202.02±0.16 μm^2 , P〈 0.05）, fibrosis area （Ang Ⅱ ＋G-CSF： 2.87%±0.12% vs Ang Ⅱ ： 3.91%±0.06%, P〈0.05）, heart weight/body weight ratio （Ang Ⅱ ＋G-CSF; 3.7±0.2 vs Ang Ⅱ ： 4.2±0.1 mg/g, P〈0.05）, and left ventricular diastolic function （cardiac isovolumic relaxation time, Ang Ⅱ ＋G-CSF： 0.11±0.02 vs Ang Ⅱ ： 0.16±0.01 ms, P〈0. 05）.Further more, G-CSF reduced cardiac levels of ACE, OPN, phosph p70S6 kinase and increased the expression of ACE2. Conclusion These data suggest that G-CSF reduces Ang Ⅱ induced hypertrophy. The effect of G-CSF on the prevention of cardiac fibrosis and hypertrophy was associated with the inhibition of OPN and phosph-p70S6 kinase expression.