| Objective:Cardiovascular disease has become one of the major diseases threating human health. At present the researches about the mechanism of anti-ischemic have become an important task of medical research in the world. In this research, we studied the rats of acute myocardial ischemia caused by abdominal rapid injection of pituitrin induction method. We adopted morphological and biochemical technology to observe the effect that applied by of needling "Neiguan" to acute myocardial ischemia in rat myocardial ultrastructure of hypothalamus, CRH, blood ACTH and CORT content. From the perspective of hypothalamus-pituitary-adrenal axis stress change, this essay studied the mechanism of action of pre needling "Neiguan" point on acute myocardial ischemia in, so as to further elucidate the mechanism of acupuncture in preventing and treating ischemic heart disease, which provides a reliable basis for clinical acupuncture treatment.This study selected50Sprague-Dawley rats about3months old, male and female of informality, weight in200-250g. All the normal experimental animals that tested by electrocardiographic were marked by numbers according to the weight of numbers, divided into5groups:normal group, sham operation group, model group, electroacupuncture group and binding group,10rats in each group. We used abdominal rapid injection method of pituitrin at the dose of20u/kg to produce acute myocardial ischemia model and used RM6280four polygraphs to record the lead II electrocardiogram. The standard of successful modelling was that significant towered T waves, elevated S-T part (≥0.1mV) and slowed down heart rate. In the sham-operation group, we used equivalent saline to replace the pituitrin. The binding group rats were tied up for five days, once per day and30minutes per time. We began modeling60minutes after the last binding ended. Electro-acupuncture group rats were stabbed at bilateral Neiguan into0.5-1cm, then stimulated using G6805-II electro-acupuncture treatment instrument with2Hz continuous waves. The standard was animal limb shaking, electrified for once per day and30minutes per time for5days continuously. We began modeling60minutes after the last electro-acupuncture ended. The electrocardiograms of rats in each group were recorded, besides, the contents of ACTH and CORT in serum, changes of myocardial ultrastructure and the expression of hypothalamic CRH protein were detected respectively.Results:1. Changes of electrocardiogram:The S-T part’s potential in ECG of all the rats was not significant different before the experiment. The S-T part’s potential in ECG of the sham-operation group increased after the injection of saline, but that was not significant from the normal group (P>0.05). It was shown that the sham-operation group had no significant effect on the S-T part’ s potential in ECG. The S-T part’s potential in ECG of the model group, binding group and electro-acupuncture group significantly increased immediately after the modeling, and they were all very significant different from the normal group and the sham-operation group (P<0.01). It suggested that acute myocardial ischemia model was successful.2. Changes of myocardial ultrastructure:The myocardial ultrastructure in normal group was not unusual. Light and dark stripes were visible from the longitudinal section of myofibrils. All the lines of the sarcomere were clear, and Z line was straight. Lots of mitochondrias with even sizes and distinct cristaes were visible in the myocardial cells. Sham-operation group was similar to normal group. There were different degrees of abnormal of the structure of myofibril within the myocardial cells in model group. Z line was buckling, and the thin myofilament moved with it. The myofilaments disordered and the gaps widened. Obvious fracture and dissolution occured to the myofilament in some areae and many blank areae appeared. Mitochondria accumulated and swelled, cristaes disintegrated in different degrees, some mitochondria membrane even dissolved. Binding group was similar to model group. Transverse bands of myofibril were basically clear in electro-acupuncture group. Each stripe was neatly, Z line was straight, myofilament fracture occured accidentally. There were accumulation and swelling in parts of the mitochondria with occasionally cristae dissolution.3. Expression of hypothalamic CRH protein:Expression of CRH in model group increased compared with the normal group and sham-operation group, and the difference was very significant (P<0.01). In electro-acupuncture group, it was very significant lower than in model group (P<0.01). CRH expression was not significant different between model group and binding group (P>0.05). No obvious CRH-positive neurons were seen in normal group or sham group, there was no significant difference (P>0.05).4. Contents of ACTH and CORT in serum:The levels of ACTH and CORT in serum in model group were very significant different from the normal group and sham-operation group (P<0.01). In electro-acupuncture group the levels of ACTH and CORT in serum were very significant lower than in model group (P<0.01). There was no significant difference between binding group and model group (P>0.05). The levels of ACTH and CORT in serum in sham-operation group were not significant different from the normal group (P>0.05).Conclusion:1. Stress response of HPA axis was concerned with body changes caused by acute myocardial ischemia, which might be one of the important factors causing myocardial ischemia and reperfusion injury.2. Acupuncture at Neiguan has a protective effect on myocardium of the myocardial ischemia rats. It could reduce the damage caused by myocardial ischemia and hypoxia on myocardial. Further confirmed Neiguan and heart were correlative.3. Electro-acupuncture may reduce ACTH and CORT contents in serum via the inhibition of the increase of hypothalamic CRH after acute myocardial ischemia, to adjust stress response induced by acute myocardial ischemia, reduce body cell damage and played the role of myocardial protection. |
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