心梗大鼠持续和间歇运动干预的心肌血管新生相关miRNAs表征与EGFL7/miR126-PIK3R2/SPRED1通路激活的心脏保护效应

    Continuous and Interval Exercise Intervention on the Expression of Myocardial mi RNAs Related to Angiogenesis and Activitation of EGFL7/mi R126-PIK3R2/SPRED1 on Protecting the Hearts of MI Rats

    • 摘要: 目的:探讨持续和间歇运动对心梗大鼠心脏血管新生相关mi RNAs表征及可能的效应机制。方法:3月龄雄性SD大鼠, 随机分为假心梗组 (S) 、心梗组 (MI) 、心梗持续运动组 (MCE) 、心梗间歇运动组 (MIE) , 每组10只。采用左脉前降支结扎制备心梗模型。MCE和MIE组术后1周进行跑台适应性训练 (15 m/min, 30 min/天×5天) , 之后MCE组以16 m/min (50%~60%O2max) 速度持续运动64 min/天, 5天/周×8周;MIE组以25 m/min×4 min (85%~90%O2max) 和15 m/min×3 min (50%~60%O2max) 速度依次交替运动49 min/天, 5天/周×8周, 训练结束后次日测定心功能。Masson染色观察分析心肌胶原容积分数 (CFV) , 免疫组化观察心肌CD31和α-SMA表达, RT-q PCR检测心肌血管新生相关mi RNAs、egfl7、pik3r2和spred1表达, Western Blotting检测心肌PIK3R2、SPRED1和VEGF表达。结果:与S组比较, MI组心肌mi R-222表达显著上调, mi R-126表达显著下调, 心肌CFV显著增加, 心功能下降;与MI组比较, MIE组心肌mi R-17-5p、mi R-126表达均显著上调, MCE和MIE组CD31、α-SMA阳性颗粒显著增加, VEGF和egfl7 m RNA表达显著上调, 且egfl7 m RNA与mi R-126表达呈高度正相关, PIK3R2、SPRED1蛋白及其m RNA表达均显著下调, 心功能显著提升, 且间歇运动优于持续运动。结论:间歇运动可显著上调心梗心脏mi R-126和mi R-17-5p表达, 且mi R-126表达的变化率更大;持续和间歇运动显著激活心梗心脏EGFL7/mi R126-PIK3R2/SPRED1通路, 抑制其下游靶蛋白PIK3R2/SPRED1表达, 促进心脏梗死边缘区血管新生, 产生心脏保护效应, 且间歇运动的保护效应优于持续运动。

       

      Abstract: Objectives: This study was carried out to investigate the continuous and interval exercise intervention on the expression of myocardial mi RNAs related to angiogenesis and possible mechanism. Methods: 40 three-month-old male SD rats were randomly divided into four groups:sham-operated group (S) , myocardial infarction group (MI) , MI with continuous exercise group (MCE) and MI with interval exercise group (MIE) . MI model was induced by ligation of the left anterior descending (LAD) coronary artery. After five days' adaptive training (15m/min, 30min/d×5d) , rats in MCE group performed continuous exercise for 64min/d, 5d/wk×8wk at the speed of16m/min (50% ~60% V̇O2 max) , and MIE intervals alternated between 4min at 25m/min (85%~90% V̇O2 max) and 3min at 15m/min (50%~60% V̇O2 max) for 49min/d, 5d/wk×8wk. Cardiac function was measured the next day after 8wk training. CFV was analyzed through Masson' trichrome staining; CD31 and α-SMA were evaluated by immunohistochemistry. The expression of mi RNAs related to angiogenesis, egfl7、pik3r2, spred1 were determined by RT- q PCR, while PIK3R2, SPRED1, VEGF were measured by Western Blotting. Results: Compared with S group, cardic function in MI was impaired with mi R- 222'upregulation and mi R- 126'downregulation; Compared with MI group, levels of mi R-17-5p and mi R-126 increased in MIE; meanwhile, in either MIE or MCE, positive granules of CD31 and α- SMA, VEGF, egfl7 m RNA were elevated andmi R-126 was found to have a highly positive correlation with egfl7 m RNA. in addition, the protein levels of PIK3R2、SPRED1 and their m RNA decreased, and rats in MIE group shows better performance than their counterparts in MCE group. Conclusions: Interval exercise training promotes an increase in the expression of mi R-126 and mi R-17-5p, and an even bigger change rate in mi R-126. Continuous and interval exercise could suppress the protein expression of PIK3R2/SPRED1 through the activation of EGFL7/mi R126- PIK3R2/SPRED1, promote angiogenesis in peri- infarct zone, all of which result in the protection of the MI hearts in the end. The protective effect of interval exercise was better than continuous exercise.

       

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