| In recent years, plenty of clinical research verified that acupuncture could improve cardiac function of patients with myocardial hypertrophy. Experimental studies on electroacupuncture (EA) were discussed from the regulation of ischemic myocardial function, change of myocardial cell structure and vasoactive substances, regulation of energy metabolism, reduction of oxygen free radicals, central nervous mechanisms and molecular biological mechanisms of anti-ischemic and many other aspects, EA was generally considered positive and effective to protect myocardial cells. However, the comparative study of EA effects has not been reported from the perspective of extracellular signal regulated kinase (ERK). This experiment tries to give a contrast research that Neiguan acupoint and Shenmen, Hegu at the same anatomical level adjust to myocardial hypertrophy injure.Objective:This subject is intended under the guidance of Chinese acupuncture theory "for heart and chest, it is point Neiguan", draw on the academic characteristic of acupuncture on prevention of disease, in order to study the pathology morphological structure of myocardial tissue, regulatory mechanisms of cardiac electrophysiology, catecholamine neurotransmitter, angiotensin II and endothelin in neuroendocrine system and ERK signaling pathway in cardiac hypertrophic model rats from the cellular and molecular levels; Try to have a comparative study between H7, PC6 and LI4at the same anatomical level on heart meridian, pericardium meridian and large intestine meridian; To explore specificity of the correlation between meridians (acupoint) and viscera, and provide the experimental basis.Methods:One hundred and five clean three-month-old female SD rats, weigh about171±4.2g, were randomly divided into seven groups by random number table method:normal group, model group, H7group, PC6group, LI4group, inhibitor group and PC6added inhibitor group, with fifteen rats in each group respectively. Rats were treated in a classic method with injection of isoprenaline hydrochlorid in the back skin to prepare left ventricular hypertrophy model, three sets of acupuncture effect (PC6, H7and LI4) were compared. Acupuncture operating method:the acupuncture needle,15mm long and0.3mm in diameter, was penetrated into the subcutis and rotated for1minute. The bilateral acupoints were interconnected with a Hans acupoint nerve stimulator (HANS) EA apparatus, and the following stimulus parameters were selected: continuous-wave at2Hz and1mA,20minutes a day for14days, and inhibitor intervention was used in the experiment with a calculate of3mg/kg/d through intraperitoneal injection. All rats were weighed the body weight after the end of the experiment, and then were taken tissue biopsy after electrocardiogram (ECG). After obtained blood plasma by heart picks, cardiac were gathered and weighted, myocardial hypertrophy indexes were calculated, and then the central ventricle muscle of LVFW (left ventricle free wall) was separated from the cardiac. The muscle was inspected the myocardial cell pathological structure under microscope; Content of plasma catecholamine neurotransmitters and metabolin were detected through HPLC (High Performance Liquid Chromatography); The cardiac tissue Ang Ⅱ (Angiotensin Ⅱ) and ET (Endothelin) was analyzed by radioimmunoassay; Protein expression of left ventricular ERK1/2and p-ERK was detected by western blot, and the data were analyzed through a statistical analysis system at last.Results:1. Effect of acupuncture on the pathological structure of myocardial tissue: normal rats’cardiac muscle fibers arranged in neat rows, with abundant capillaries, without edema in endothelial cells; Myocardial cells appeared morphological integrity, the nucleus electronic density distribute homogeneous, with complete nucleoli and rare apoptosis; Myofilament and sarcomere structure was clearly visible, with abundant and intact mitochondria, and cytoplasmic organelle structure is clearly visible without edema and vacuolization. After modeling, rats’myocardial cells under an optical microscope appeared mainly for the following three aspects:including disorganized cardiac muscle fibres, proliferating myocardial interstitium, and fiberized myocardial interstitium. For the following six areas under transmission electron microscopy:including mitochondria swelling, increasing cell apoptosis, endothelial cell interstitial hyperplasia, muscle plasma nets expansion, out-sync contraction of contraction band, and intercalated disc deformation. Rats in the other five groups were improved to some degree in the above six aspects;2. Effect of acupuncture on myocardial hypertrophy index in rats: abtained from the experiment, the rats’heart weight in model group were increased significantly while compared with normal group (P<0.01), but no significant differences were found in other groups (P>0.05); Compared with the normal group, HWIs and LVWIs in the model group were significantly higher after modeling for14days (P<0.01); After the inhibitor intervention and electro-acupuncture treatment, the HWIs and LVWIs were significantly lower than modle group (P<0.05), especially LI4group was significantly changed while compared between three EA groups (P<0.05), but no significant differences were found in other groups (P>0.05);3. Effect of acupuncture on ECG in rats:abtained from the experiment, compared with those in the normal group, ST segment and R-R interval were significantly higher, and the heart rate was lower in the model group after modeling for14days (P<0.05; P<0.01); After the inhibitor intervention and electro-acupuncture treatment, the heart rate, ST segment and R-R interval significantly tended to be normal while compared with modle group (P<0.05), but no significant differences were found in other groups (P>0.05);4. Effect of acupuncture on plasma catecholamine neurotransmitter in rats: compared with those in the normal group, content of plasma catecholamine neurotransmitters (NE, E and DA) and metabolin (MHPG, HVA and DOPAC) was significantly higher in the model group after modeling for14days (P<0.05); After the inhibitor intervention and electro-acupuncture treatment, content of plasma catecholamine neurotransmitters and metabolin was significantly lower than modle group (P<0.05), but no significant differences were found in other groups (P>0.05);5. Effect of acupuncture on the cardiac tissue AngⅡand ET in rats: compared with those in the normal group, content of the cardiac tissue Ang Ⅱ and ET was significantly higher in the model group after modeling for14days (P<0.05); After the inhibitor intervention and electro-acupuncture treatment, content of the cardiac tissue Ang Ⅱ and ET was significantly lower than modle group (P<0.05), but no significant differences were found in other groups (P>0.05);6. Effect of acupuncture on the left ventricular myocardial tissue ERK1/2and p-ERK in rats:compared with those in the normal group, protein expression of the left ventricular myocardial tissue ERK1/2and p-ERK was significantly higher in the model group after modeling for14days (P<0.05); After the inhibitor intervention and electro-acupuncture treatment, ERK1/2and p-ERK expression was significantly lower than modle group (P<0.05), but no significant differences were found in other groups (P>0.05).Conclusion1. Contrast myocardial hypertrophy index, there’s a difference between PC6, H7and LI4on the protective effect on myocardium, LI4group was significant, and was superior in other targets while compared with PC6and H7groups. Possibly LI4analgesic effect played a protective effect in myocardial hypertrophy.2. Acupuncture had a significant protective effect on myocardial cells, which provided experimental evidence on the relation between meridians (acupoints) and viscera; Meanwhile LI4was found effective on MH, which also provided an experimental basis for clinical selection of acupoints.3. We were able to verify that acupuncture indeed improve cardiac function in MH, and this effect had a close relation with ERK signaling pathways through regulating the role of neuroendocrine-cytokines to promote the organization forms and myocardial ultrastructure of rehabilitation, improve ECG activities. |
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