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OBJECTIVE@#To observe the effects of electroacupuncture (EA) pretreatment on cardiac function, sympathetic nerve activity, indexes of myocardial injury and GABAA receptor in fastigial nucleus in rats with myocardial ischemia reperfusion injury (MIRI), and to explore the neuroregulatory mechanism of EA pretreatment in improving MIRI.@*METHODS@#A total of 60 male SD rats were randomly divided into a sham operation group, a model group, an EA group, an agonist group and an agonist+EA group, 12 rats in each group. The MIRI model was established by ligation of the left anterior descending coronary artery. EA was applied at bilateral "Shenmen" (HT 7) and "Tongli" (HT 5) in the EA group and the agonist+EA group, with continuous wave, in frequency of 2 Hz and intensity of 1 mA, 30 min each time, once a day for 7 consecutive days. After intervention, the MIRI model was established. In the agonist group, the muscone (agonist of GABAA receptor, 1 g/L) was injected in fastigial nucleus for 7 consecutive days before modeling, 150 μL each time, once a day. In the agonist+EA group, the muscone was injected in fastigial nucleus 30 min before EA intervention. The data of electrocardiogram was collected by PowerLab standard Ⅱ lead, and ST segment displacement and heart rate variability (HRV) were analyzed; the serum levels of norepinephrine (NE), creatine kinase isoenzyme MB (CK-MB) and cardiac troponin I (cTnI) were detected by ELISA; the myocardial infarction area was measured by TTC staining; the morphology of myocardial tissue was observed by HE staining; the positive expression and mRNA expression of GABAA receptor in fastigial nucleus were detected by immunohistochemistry and real-time PCR.@*RESULTS@#Compared with the sham operation group, in the model group, ST segment displacement and ratio of low frequency to high frequency (LF/HF) of HRV were increased (P<0.01), HRV frequency domain analysis showed enhanced sympathetic nerve excitability, the serum levels of NE, CK-MB and cTnI were increased (P<0.01), the percentage of myocardial infarction area was increased (P<0.01), myocardial fiber was broken and interstitial edema was serious, the positive expression and mRNA expression of GABAA receptor in fastigial nucleus were increased (P<0.01). Compared with the model group, in the EA group, ST segment displacement and LF/HF ratio were decreased (P<0.01), HRV frequency domain analysis showed reduced sympathetic nerve excitability, the serum levels of NE, CK-MB and cTnI were decreased (P<0.01), the percentage of myocardial infarction area was decreased (P<0.01), myocardial fiber breakage and interstitial edema were lightened, the positive expression and mRNA expression of GABAA receptor in fastigial nucleus were decreased (P<0.01). Compared with the EA group, in the agonist group and the agonist+EA group, ST segment displacement and LF/HF ratio were increased (P<0.01), HRV frequency domain analysis showed enhanced sympathetic nerve excitability, the serum levels of NE, CK-MB and cTnI were increased (P<0.01), the percentage of myocardial infarction area was increased (P<0.01), myocardial fiber breakage and interstitial edema were aggravated, the positive expression and mRNA expression of GABAA receptor in fastigial nucleus were increased (P<0.01).@*CONCLUSION@#EA pretreatment can improve the myocardial injury in MIRI rats, and its mechanism may be related to the inhibition of GABAA receptor expression in fastigial nucleus, thereby down-regulating the excitability of sympathetic nerve.
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Masculino , Animais , Ratos , Ratos Sprague-Dawley , Núcleos Cerebelares , Eletroacupuntura , Traumatismo por Reperfusão Miocárdica/terapia , Receptores de GABA-A/genética , RNA MensageiroRESUMO
OBJECTIVE@#To observe the effect of electroacupuncture (EA) pretreatment on hippocampal oxidative stress in aged mice with postoperative cognitive dysfunction (POCD) and explore the relevant mechanism of EA pretreatment on the improvement of learning and memory in POCD aged mice.@*METHODS@#A total of 72 healthy male aged mice were randomized into a blank group, a model group, a medication group and an EA group, 18 mice in each one. In each group, 1-day, 3-day and 7-day subgroups were divided separately, 6 mice in each subgroup. In the EA group, "Baihui" (GV 20) and "Dazhui" (GV 14) were selected and stimulated with EA, using continuous wave (15 Hz, 1 mA), continuously for 30 min, once a day, for 5 days consecutively. In the medication group, 10% minocycline was injected intraperitoneally, 40 mg/kg, once a day, consecutively for 5 days. In the blank and the control group, intraperitoneal injection of 0.9% sodium chloride solution was given with equal dosage. Except the blank group, at the end of intervention, partial hepatectomy was conducted to establish POCD model in the rest groups. Morris water maze test was adopted to evaluate the learning and memory ability of the aged mice. ELISA was used to determine the contents of reactive oxygen species (ROS) and malondialdehyde (MDA) in the hippocampal tissue. Western blot method was applied to detect the protein expressions of superoxide dismutase 1 (SOD 1) and superoxide dismutase 2 (SOD 2) in the hippocampal tissue.@*RESULTS@#Compared with the blank group, the percentage of platform quadrant residence time was obviously reduced in the mice in the model group (@*CONCLUSION@#Electroacupuncture pretreatment at "Baihui" (GV 20) and "Dazhui" (GV 14) may increase the learning and memory ability of POCD aged mice, which is probably related to the decrease of oxidative stress and the strengthening of hippocampal antioxidant capacity.
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Animais , Masculino , Camundongos , Eletroacupuntura , Hipocampo , Memória , Estresse Oxidativo , Complicações Cognitivas Pós-OperatóriasRESUMO
OBJECTIVE: To observe the effect of "Neiguan" (PC6)-electroacupuncture (EA) or moxibustion (Moxi) pretreatment on myocardial apoptosis and expression of autophagy related proteins light chain (LC) 3-Ⅰ and LC3-Ⅱ in rats with myocardial ischemia/reperfusion injury (MIRI), so as to explore their mechanisms underlying improvement of MIRI. METHODS: Forty SD rats (half male and half female) were randomly divided into sham operation, model, ischemic preconditioning (IP), EA and Moxi groups (n＝8 in each group). EA (10 Hz/50 Hz, 1 mA) or Moxi (ignited moxa stick) was respectively applied to bilateral "Neiguan" (PC6) for 20 min, once daily for 7 days. The MIRI model was established by occlusion of the anterior descending branch of the left coronary artery for 40 min, followed by reperfusion for 60 min. The ultrastructural changes and autophagy of myocardial cells were observed by electron microscopy (EM), and the myocardial cellular apoptosis [apoptotic index ＝ (number of apoptotic cells/total number of cardiomyocytes)×100%] was detected by the terminal deoxyribonucleotidyl transferase mediated dUTP nick end labelling (TUNEL) method. The expressions of LC3-Ⅰ and LC3-Ⅱ proteins (markers for autophagy) in myocardial tissue were detected by Western blot. RESULTS: Following MI, EM observation revealed a vague structure of cardiomyocytes and muscular horizontal grain, dissolution of myofibers, mitochondrial swelling, some autophagic vacuoles and autophagic lysosomes at different degrees and surrounded by a double membrane in the model group, these situations were apparently milder in the EA and Moxi groups. The apoptosis index, myocardial LC3-Ⅰ and LC3-Ⅱ protein expression levels, and the ratio of LC3-Ⅱ/Ⅰ were significantly increased in the model group relevant to the sham operation group (P0.05), and no significant differences were observed in the apoptosis index and levels of LC3-Ⅱ and LC3-Ⅱ/Ⅰ between the IP and Moxi groups (P>0.05)．. CONCLUSION: Both EA and moxibustion pretreatments, similar to IP, have a positive role in reducing myocardiocyte apoptosis and regulating autophagy-related protein expression in MIRI rats, which maybe contribute to their protective effects on ischemic myocardium.
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OBJECTIVE: To observe the effect of electroacupuncture (EA) and moxibustion (Moxi) pretreatment on myocardial pathological and structural changes and expression of autophagy related protein LC 3 Ⅰ/Ⅱ and Beclin 1 in rats with myocardial ischemia-reperfusion injury (MI/RI), so as to explore their mechanisms underlying improving MI/RI. METHODS: Forty SD rats were randomly divided into sham operation, model, ischemic preconditioning (IP), EA and Moxi groups (n＝8 in each group). EA (10 Hz/50 Hz，1 mA) or Moxi (ignited moxa stick) was respectively applied to bilateral "Neiguan"(PC 6) for 20 min, once daily for 7 days. The MI/RI model was established by occlusion of the anterior descending branch of the left coronary artery for 40 min, followed by reperfusion for 60 min. The left ventricular (LV) tissue samples were collected and analyzed for pathological (H.E. staining) and ultrastructural changes, for myocardial apoptosis (apoptotic index＝ number of apoptotic cells/total number of cardiomyocytes×100%) with terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) method, and for the expression of LC 3 and Beclin 1 in myocardial cells with Western blot. RESULTS: Following MI/RI, H．E. staining revealed a disorder of arrangement of cardiomyocytes with vague border, inflammatory cell infiltration, intracellular swelling with bleeding, necrosis and dissolution of partial striated muscles of the left ventricle under light microscope, and dual staining of Uranyl acetate and leadnitrate showed atrophy, arrangement disorder, dissolution, necrosis, and interstitial edema of partial myocardial fibers, mitochondrial structural disorder, vacolation, and large body of autophagosomes with bilayers, etc. in ultrastructure, which was relatively lighter in both EA and Moxi groups. The apoptosis index, expression levels of myocardial LC 3 Ⅱ and Beclin 1 and the ratio of LC 3 Ⅱ/LC 3 Ⅰ were significantly higher in the model group than those in the sham operation group (P<0.01), but the expression level of LC 3 Ⅰ was considerably down-regulated in the model group relevant to the sham operation group (P<0.01). Following the intervention and MI preconditioning, the increased apoptosis index and expression levels of LC 3Ⅱ and Beclin 1 proteins and the ratio of LC 3Ⅱ/LC 3 Ⅰ were obviously down-regulated in the IP, EA and Moxi groups relevant to the model group (P<0.01), and the decreased expression of LC 3 Ⅰ protein was up-regulated obviously in the 3 treatment groups (P<0.05，P<0.01). The effects of EA were significantly superior to those of IP and Moxi groups in down-regulating apoptosis index and expression of LC 3 Ⅱ and Beclin 1 and the ratio of LC 3 Ⅱ/LC 3 Ⅰ and in up-regulating expression of LC 3 Ⅰ (P<0.05, P<0.01). CONCLUSION: Both EA and Moxi preconditioning of PC 6 have a protective effect on ischemic myocardium in MI/RI rats, which is probably related to their effects in regulating expression of myocardial autophagy proteins as LC 3 Ⅰ/Ⅱ and Beclin 1.
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Objective To investigate the protective effect of electroacupuncture pretreatment on myocardial ischemia/reperfusion (I/R) injury and its influence on high mobility group box 1 (HMGB1) expression in rats. Methods Sixty Wistar rats were randomly divided into sham operation group, myocardial I/R model group and electroacupuncture pretreatment group by random number table (each n = 20). Myocardial I/R injury model was reproduced by ligating the left ventricular branch coronary artery at about 0.5 cm below the atrial appendage lower margin for 10 minutes to occlude the blood flow, then the ligature was relaxed for 1 hour reperfusion; in electroacupuncture pretreatment group, 7 days before I/R, the electroacupuncture at Neiguan acupoint was applied once daily for 20 minutes till the 7th day when I/R was established. Under light microscope, the pathological changes of myocardial specimen stained by hematoxylin-eosine (HE) method were observed. The myocardial histopathological integral was detected by semi quantitative integral method, and the changes of histological scores in three groups were investigated. The levels of plasma HMGB1, tumor necrosis factor-α (TNF-α), cardiac troponin T (cTnT) were detected by enzyme-labeled immunosorbent assay (ELISA). The expressions of HMGB1, monocyte chemotactic protein-1 (MCP-1), TNF-αmRNA and protein in myocardium were detected by reverse transcription-polymerase chain reaction (PT-PCR) and Western Blot. Results Under light microscope, the myocardial tissue in myocardial I/R model group showed partial fracture of myocardial fibers, large patches of myocardial cell necrosis, hazy boundary, cellular condensation, rupture and dissolution or even disappearance, interstitial edema with a lot of inflammatory cell infiltration; the above myocardial tissue injury in electroacupuncture pretreatment group was significantly milder than that in myocardial I/R model group. Compared with sham operation group, in myocardial I/R model group the HMGB1, TNF-α, cTnT contents and histological score were significantly increased [HMGB1 (μg/L):9.64±1.16 vs. 2.15±0.31, TNF-α(μg/L):91±22 vs. 19±5, cTnT (μg/L):1.50±0.35 vs. 0.07±0.03, histological score:2.5±0.3 vs. 0.0±0.0, all P<0.01], HMGB1, MCP-1, TNF-α mRNA and protein expressions were increased obviously (HMGB1 mRNA: 1.42±0.16 vs. 0.02±0.00, MCP-1 mRNA:0.46±0.06 vs. 0.01±0.00, TNF-αmRNA:0.75±0.04 vs. 0.03±0.00;HMGB1 protein:1.08±0.01 vs. 0.20±0.01, MCP-1 protein:0.92±0.03 vs. 0.40±0.01, TNF-αprotein:1.10±0.02 vs. 0.35±0.01, P<0.05 or P<0.01);compared with myocardial I/R model group, in electroacupuncture pretreatment group, HMGB1 (6.58±0.73), TNF-α (63±19), cTnT (1.15±0.31) levels were significantly decreased (all P < 0.01), HMGB1, MCP-1, TNF-αmRNA and protein expressions were markedly reduced (mRNA expression was 0.74±0.12, 0.18±0.02, 0.10±0.03, and protein expression was 0.40±0.01, 0.36±0.02, 0.50±0.02, respectively all P<0.05), and histological score (1.2±1.0) was remarkably lowered (P < 0.01). Conclusion Electroacupuncture pretreatment may reduce the myocardial I/R injury in rats, and the mechanism may be related to the amelioration of inflammatory response mediated by HMGB1 at late stage.