海马齿状回在针刺心经抗心肌缺血中的作用

目的 观察海马齿状回（dentate gyrus,DG）区在针刺心经干预大鼠急性心肌缺血损伤中的作用。方法 将60只大鼠随机分为伪手术组、模型组、针刺组、损毁组,每组15只。通过开胸结扎心脏冠状动脉左前降支复制大鼠急性心肌缺血模型,其中针刺组和损毁组选取手少阴心经“神门-通里”经脉段,给予电针干预,电流强度为1 mA,频率为2 Hz,每日电针30 min,连续干预3 d,伪手术组和模型组不予电针处理。观察各组大鼠心电图、海马DG区细胞形态以及神经细胞放电频率的变化。结果 与伪手术组比较,模型组心率和ST段电压均显著升高（P<0.05）;与模型组比较,针刺组心率和ST段电压均显著降低（P<0.05）;与针刺组比较,损毁组心率和ST段电压均显著升高（P<0.05）。伪手术组大鼠海马DG区神经细胞排列紧密,细胞核大而圆,胞质色浅而均匀,尼氏体丰富;模型组大鼠海马DG区神经细胞排列较为稀疏,细胞体积变小,尼氏体减少;针刺组大鼠海马DG区神经细胞排列相对较为紧密,细胞体积较大,尼氏体相对增多。与伪手术组比较,模型组海马DG区神经细胞放电频率显著增加（P<0.05）;与模型组比较,针刺组海马DG区神经细胞放电频率显著减少(P<0.05)。结论 海马DG区可能是针刺改善急性心肌缺血损伤的关键中枢之一。

Role of the Hippocampal Dentate Gyrus in Acupuncture at the Heart Meridian in Treatment of Myocardial Ischemia

Objective To investigate the role of the hippocampal dentate gyrus (DG) in acupuncture at the heart meridian in the treatment of myocardial ischemia. Methods A total of 60 rats were randomly divided into sham-operation group, model group, acupuncture group, and damage group, with 15 rats in each group. A rat model of acute myocardial ischemia was established by thoracotomy and ligation of the left anterior descending branch of the coronary artery. The rats in the acupuncture group and the damage group were given electroacupuncture at the "Shenmen-Tongli" section of the Shaoyin heart meridian with an intensity of electric current of 1 mA and a frequency of 2 Hz for 3 consecutive days with 30 minutes per day. The rats in the sham-operation group and the model group were not given such treatment. All groups were observed in terms of the changes in electrocardiographic findings, cell morphology in the hippocampal DG, and neuronal discharge frequency. Results Compared with the sham-operation group, the model group had significant increases in heart rate and ST segment (P<0.05). Compared with the model group, the acupuncture group had significant reductions in heart rate and ST segment (P<0.05). Compared with the acupuncture group, the damage group had significant increases in heart rate and ST segment (P<0.05). In the sham-operation group, the neurons in the hippocampal DG were arranged closely with large and round nuclei, and the cytoplasm was uniform and light in color with rich Nissl bodies; in the model group, the neurons in the hippocampal DG were sparse with reductions in cell volume and Nissl bodies; in the acupuncture group, the neurons in the hippocampal DG were arranged closely with relative increases in cell volume and Nissl bodies. Compared with the sham-operation group, the model group had a significant increase in neuronal discharge frequency in the hippocampal DG (P<0.05); compared with the model group, the acupuncture group had a significant reduction in neuronal discharge frequency (P<0.05). Conclusion The hippocampal DG may be one of the key centers for improving acute myocardial ischemia by acupuncture.