Effect Of Scalp Acupuncture On Myocardial Ischemia-reperfusion Arrhythmia In Rats And Its Mechanism

ObjectiveThis project aims to observe the effect of scalp acupuncture on myocardial ischemia-reperfusion arrhythmia in rats by testing ECG, myocardial ischemic and infarct range, myocardial ultrastructure and LDH. Myocardial ischemia-reperfusion preparation model was induced by ligation of the left anterior descending coronary artery 30min and 15min reperfusion. To SOD, MDA, Na+-K+-ATPase, Ca2+-Mg2+-ATPase and nitric oxide synthase, nitric oxide index for observation, this research tried to investigate anti-arrhythmic effect of scalp acupuncture molecular mechanism. By detecting nNOS expression of in Hypothalamic paraventricular nucleus (PVN) and Rostral ventrolateral medulla(RVLM), peripheral sympathetic nerve discharge,norepinephrine content and the expression ofβ1-AR protein levels, this paper explored the sympathetic regulation of MIRI arrhythmia in rats.This reseach provided modern scientific basis for clinical acupuncture treatment.MethodsWe divided the rats into five groups according to the principles of random. The experiments were performed as follows: A. normal group. B. sham group (rats without ligation of left anterior desending artery). C. model group (rats with ligation of left anterior descending artery for 30 min followed by 15min reperfusion). D. scalp acupuncture group. E. western medicine group (verapamil group). Groups of five adopt standard II to record electrocardiogram (ECG), all the signals were input BL-420E+ experimental system of biological functions. We took the abdominal aorta blood samples, then monitored NO, SOD, and MDA content. We took ischemic myocardium specimens, then analysed myocardial ischemic range and myocardial ultrastructural changes and detected myocardial Na+-K+-ATPase, Ca2+-Mg2+-ATPase and total NOS(TNOS), inducible nitric oxide synthase (iNOS) and constitutive nitric oxide synthase (cNOS) biological activity. B, C and D group with BL-420E+ experimental system biological function recorded ECG, sympathetic nerve discharge.We detected serum NE levels by Elisa method and ischemic myocardiumβ1-AR protein expression by using Western blot. After the end of experiment,we derived the brain slice and detected the nNOS expression of PVN and RVLM by immunohistochemistry method.Results1 Compared with the normal group,model group were significantly changed (P<0.01). The incidence of arrhythmia was significantly reduced after Scalp acupuncture (P<0.01). It was not obvious between scalp acupuncture group and western medicine group (P> 0.05).2 Myocardial ischemic and infarct range in Scalp acupuncture group was significantly reduced compared with model group(P<0.05). There is no significant difference between scalp acupuncture group and western medicine group (P> 0.05).3 Myocardial structure of model group seriously damaged than normal group. The mypcardial cells were swelling obxiously, the arrangement of myofibril was in disorder with vague light and dark.Mitochondria was markly swollen. Part of the nucleus edema was seen, nuclear condensatedion, reduction of euchromatin, heterochromatin increased. The damage of myocardial ultrastructure in scalp group significantly reduced compared with model group. The arrangement of some myofibrils was in slightly disordered, mitochondria being slightly swelling4 LDH activity in model group was significantly increased (P<0.01). LDH activity in the scalp acupuncture group was significantly lower than model group (P<0.01). The LDH activity was not significantly different between scalp acupuncture group and western medicine group (P>0.05).5 Compared with normal group, serum SOD activity decreased significantly (P<0.01), MDA concentration increased in model group (P<0.01). SOD activity in the scalp acupuncture group were significantly higher than model group (P<0.05), MDA concentration in the scalp acupuncture group decreased significantly compared with model group (P<0.01). Scalp acupuncture group and western medicine group were no significant difference (P>0.05).6 The activity of Na+-K+-ATPase,Ca2+-Mg2+-ATPase in model group was significantly less than normal group(P<0.01). scalp acupuncture group increased the Na+-K+-ATPase,Ca2+-Mg2+-ATPase activity(P<0.01). However, it was not a apparent diffierence between scalp acupuncture group and western medicine group (P> 0.05).7 Myocardial total NOS (TNOS) and constitutive NOS(cNOS) activity in model group was significantly lower (P<0.01), iNOS activity was significantly higher (P<0.01). TNOS and cNOS activity in scalp acupuncture group was significantly higher than model group (P<0.01), iNOS activity in scalp acupuncture group was significantly lower than model group (P<0.05). The three NOS activity between scalp acupuncture group and western medicine group was not significantly different (P>0.05)NO production was reduced during MIRI in model group (P<0.01). NO level increased significantly in scalp acupuncture group (P<0.01).The level of NO between scalp acupuncture group and western medicine group was not a obvious discrepancy (P>0.05).8 The nNOS gray value of PVN in model group significantly decreased than sham group (P<0.01). This suggests nNOS expression of PVN in model group increased. The nNOS gray value in scalp acupuncture group was significantly higher than model group (P<0.01). This suggests nNOS expression of PVN in scalp acupuncture group was decreased.9 The nNOS gray value of RVLM in model group significantly increased than sham group (P<0.01). This suggests nNOS expression of RVLM in model group decreased. nNOS gray value of scalp acupuncture group was significantly lower than model group (P<0.05). This suggests nNOS expression of RVLM in scalp acupuncture group was increased.10 Compared with sham group, sympathetic nerve activity in model group after reperfusion was significantly higher (P<0.01). Sympathetic nerve discharge in scalp acupuncture group was significantly lower than model group (P<0.05).11 Serum NE concentration and myocardialβ1-AR expression in model group significantly increased than sham group (P<0.01). Serum NE concentration and myocardialβ1-AR protein expression in the scalp acupuncture group significantly decreased (P<0.05).Conclusion Our results show that scalp acupuncture can induce the incidence of arrhythmia,lessen myocardial ischemic and infarct range,significantly reduce the damage of myocardial ultrastructure and lower serum LDH, indicating a clear protection of myocardial cells and anti-arrhythmic effect of scalp acupuncture.Scalp acupuncture increased serum SOD activity, decreased MDA and NO levels in the serum, increased myocardial total NOS, cNOS and Na+-K+-ATPase, Ca2+-Mg2+-ATPase activity, indicating that Scalp acupuncture may clear oxygen free radical oxygen, reduce the intracellular Ca2+ overload and adjust the biological activity of NOS and NO levels. So Scalp acupuncture can inhibit the MIRI of myocardial cells and make electrical activity tend to stability for prevention the occurrence of myocardial ischemia-reperfusion arrhythmia. This may be biological mechanism of scalp acupuncture against arrhythmia.Scalp acupuncture decreased the nNOS expression of PVN and increased that of RVLM in reperfusion arrhythmias rats. Sympathetic nerve activity, serum concentrations of NE and the expression of cardiacβ1-AR protein were significantly decreased by Scalp acupuncture. This indicates that scalp acupuncture prevention of myocardial ischemia -reperfusion arrhythmia may be related to regulate sympathetic system pathways.