| （1.西藏民族大学 体育学院，陕西 咸阳 712082；2.陕西师范大学 运动生物学研究所 运动与心血管研究室，陕西 西安 710062） 摘 要：探讨心脏β2-AR/β1-AR变化在运动减轻心梗后心肌纤维化中的作用。将雄性SD大鼠36只，随机分为假手术组(S)、心肌梗死组(MI)、心梗后有氧运动组(ME)，每组12只。MI组采用结扎心脏左冠状动脉前降支(LAD)法，建立MI模型。S组仅穿线而不结扎LAD，ME组在MI后1周进行4周跑台运动。第1周适应性训练(速度10 m/min，坡度0)，第2周运动速度15 m/min，坡度3%，第3周速度20 m/min，坡度3%，第4周速度25 m/min，坡度5%。运动总时间均为60 min，每周训练5 d，连续4周。训练结束后开胸摘取心脏，免疫组化法检测左心室β2-AR蛋白表达；荧光免疫组化法检测左心室Nox4蛋白表达；Western Blot法检测β1-AR，β2-AR及Nox4蛋白水平；DHE法检测心肌超氧阴离子水平；Masson染色测定心肌胶原容积百分比(CVF)。结果：与S组比较，MI后可见心肌β2-AR、Nox4阳性染色，大面积超氧阴离子红色荧光及蓝色心肌胶原纤维。MI后LV中β2-AR/β1-AR比例显著上调(P<0.01)，心肌Nox4蛋白表达、超氧阴离子水平、CVF值显著增加(P<0.05、P<0.01、P<0.01)。与MI组比较，ME组可见心肌β2-AR、Nox4阳性染色，而超氧阴离子红色荧光及蓝色胶原纤维明显减少。运动后LV中β2-AR/β1-AR比例显著下调(P<0.01)，心肌Nox4蛋白表达、超氧阴离子水平及CVF显著降低(P<0.05、P<0.05、P<0.01)。且LV中β2-AR/β1-AR与心肌CVF呈显著正相关(r=0.419，P<0.05)。结果表明：有氧运动可下调左心室β2-AR/β1-AR比例，抑制Nox4-ROS通路，减轻心梗大鼠心肌纤维化程度。运动对心梗后心肌纤维化的抑制和β2-AR/β1-AR比例降低有关。 |
CHEN Ting1，2，TIAN Zhen-jun2
| （1.School of Physical Education，Xizang Minzu University，Xianyang 712082，China；2.Exercise＆Cardiovascular Lab，Institute of Sports and Exercise Biology，Shaanxi Normal University，Xi’an 710062，China) Abstract: In order to probe into the roles of the changing of cardiac β2-AR/β1-AR in exercise alleviating myocardial fi-brosis after myocardial infarction, the authors divided 36 male SD rats randomly into a sham surgery group (S), a myocar-dial infarction group (MI), and an aerobic exercise after myocardial infarction group (ME), each of which consisted of 12 rats, established a MI mode on the rats in group MI by means of ligation of the left anterior descending (LAD) coronary artery, stitched but not ligated the LAD of the rats in group S, let the rats in group ME exercise on a treadmill for 4 weeks, 1 week after MI, according to the following plan: week 1: adaptive training (speed: 10m/min, gradient: 0%); week 2: speed: 15mmin, gradient: 3%; week 3: speed: 20m/min, gradient: 3%; week 4: speed: 25m/min, gradient: 5%; total exer-cise time: 60min, training: 5 days a week, 4 weeks consecutively. After the training was finished, the authors opened the rats’ chest and took out their hearts, measured left ventricular β2-AR protein expression by means of immunohistochemis-try, measured left ventricular Nox4 expression by means of fluorescent immunohistochemistry, measured β1-AR, β2-AR and Nox4 protein levels by means of Western Blot, measured myocardial superoxide anion level by means of DHE, meas-ured myocardial collagen volume fraction (CVF) by means of Masson staining, and revealed the following findings: as compared with the rats in group S, the rats after MI could be seen having myocardial β2-AR and Nox4 positive staining, large areas of superoxide anion red fluorescence and blue myocardial collagen fibers; in LV after MI, the radio of β2-AR/β1-AR increased significantly (P<0.01), myocardial Nox4 protein expression, superoxide anion level and CVF value increased significantly (P<0.05, P<0.01, P<0.01); as compared with the rats in group MI, the rats in group ME could be seen having myocardial β2-AR and Nox4 positive staining, but significantly decreased superoxide anion red fluores-cence and blue collagen fibers; in LV after exercise, the radio of β2-AR/β1-AR was down-regulated significantly (P<0.01), myocardial Nox4 protein expression, superoxide anion level and CVF value decreased significantly (P<0.05, P<0.05, P<0.01); and in LV, β2-AR/β1-AR was significantly positive correlative with myocardial CVF (r=0.419, P<0.05). The said findings indicate the followings: aerobic exercise can down-regulate the ratio of left ventricular β2-AR/β1-AR, restrain the pathway of Nox4-ROS, and alleviate the degree of myocardial fibrosis of rats with myocardial infarction; exercise is re-lated to the restraint of myocardial fibrosis and the decrease of the ratio of β2-AR/β1-AR after myocardial infarction. |
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