Electroacupuncture improves myocardial fibrosis in heart failure rats by attenuating ECM collagen deposition through modulation of TGF-β1/Smads signaling pathway

Background: To explore the effects of electroacupuncture on cardiac function and myocardial fibrosis in rat models of heart failure, and to elucidate the underlying mechanism of electroacupuncture in heart failure treatment. Methods: Healthy male Sprague-Dawley rats were allocated into three groups: Sham group, Model group, and electroacupuncture (Model + EA) group, with each group comprising 8 rats. The model underwent a procedure involving the ligation of the left anterior descending coronary artery to induce a model of heart failure. The Model + EA group was used for 7 consecutive days for electroacupuncture of bilateral Shenmen (HT7) and Tongli (HT5), once a day for 30 min each time. Left ventricular parameters in rats were assessed using a small-animal ultrasound machine to analyze changes in left ventricular end-diastolic volume, left ventricular end-systolic volume, left ventricular ejection fraction, and left ventricular fractional shortening. Serum interleukin-1β (IL-1β), cardiac troponin (cTn), and N-terminal brain natriuretic peptide precursor levels were measured using ELISA. Histopathological changes in rat myocardium were observed through HE staining, while collagen deposition in rat myocardial tissue was assessed using the Masson staining method. Picro sirius red staining, immunohistochemical staining, and RT-qPCR were utilized to distinguish between the various types of collagen deposition. The expression level of TGF-β1 and SMAD2/3/4/7 mRNA in rat myocardial tissues was determined using RT-qPCR. Additionally, western blot analysis was conducted to assess the protein expression levels of TGF-β1, SMAD3/7, and p-SMAD3 in rat myocardial tissues. Results: Compared with the Sham group, the left ventricular ejection fraction and left ventricular fractional shortening values of the Model group were significantly decreased (P < 0.01);the left ventricular end-diastolic volume and left ventricular end-systolic volume values were remarkably increased (P < 0.01);serum N-terminal brain natriuretic peptide precursor content was increased (P < 0.01);serum IL-1β and cTn levels were increased (P < 0.01);myocardial collagen volume fraction were increased (P < 0.01);and those of the expression of TGF-β1 and SMAD2/3/4 mRNA was increased (P < 0.01);the expression of SMAD7 mRNA was decreased (P < 0.01);the protein expression levels of TGF-β1, SMAD3, and p-Smad3 were increased (P < 0.01);the protein expression level of SMAD7 was decreased (P < 0.01) in the Model group. Compared to the Model group, the expression levels of the proteins TGF-β1, SMAD3, and p-Smad3 in myocardial tissue were found to be decreased (P < 0.01), and the expression level of the protein SMAD7 was found to be increased (P < 0.01) in the Model + EA group;the collagen volume fraction and deposition of type Ⅰ /Ⅲ collagen were decreased (P < 0.01) in the Model + EA group. Conclusion: Electroacupuncture alleviates myocardial fibrosis in rats with heart failure, and this effect is likely due to attributed to the modulation of the TGF-β1/Smads signaling pathway, which helps reduce collagen deposition in the extracellular matrix.

Electroacupuncture modulates the activity of the hippocampus-nucleus tractus solitarius-vagus nerve pathway to reduce myocardial ischemic injury

The hippocampus is involved in the regulation of the autonomic nervous system,together with the hypothalamus and brainstem nuclei,such as the paraventricular nucleus and nucleus tractus solitarius.The vagus nerve-nucleus tractus solitarius pathway has an important role in cardiovascular reflex regulation.Myocardial ischemia has been shown to cause changes in the autonomic nervous system,affecting the dynamic equilibrium of the sympathetic and vagal nerves.However,it remains poorly understood how the hippocampus communicates with brainstem nuclei to regulate the autonomic nervous system and alleviate myocardial ischemic tissue damage.A rat model of acute myocardial ischemia（AMI） was made by ligating the left anterior descending branch of the coronary artery.Three days before ischemia,the hippocampal CA1 region was damaged.Then,3 days after ischemia,electroacupuncture（EA） at Shenmen（HT7）-Tongli（HT5） was performed（continuous wave,1 m A,2 Hz,duration of 30 minutes）.Cluster analysis of firing patterns showed that one type of neuron was found in rats in the sham and AMI groups.Three types of neurons were observed in the AMI ＋ EA group.Six types of neurons were found in the AMI ＋ EA ＋ Lesion group.Correlation analysis showed that the frequency of vagus nerve discharge in each group was negatively correlated with heart rate（HR）（P 〈 0.05,r =-0.424）,and positively correlated with mean arterial pressure（MAP）（P 〈 0.05,r = 0.40987） and the rate-pressure product（RPP）（P 〈 0.05,r = 0.4252）.The total frequency of the nucleus tractus solitarius discharge in each group was positively correlated with vagus nerve discharge（P 〈 0.01,r = 0.7021）,but not with hemodynamic index（HR： P 〉 0.05,r =-0.03263; MAP： P 〉 0.05,r =-0.08993; RPP： P 〉 0.05,r =-0.03263）.Some neurons（Neuron C） were negatively correlated with vagus nerve discharge,HR,MAP and RPP in the AMI ＋ EA group（vagus nerve discharge： P 〈 0.05,r =-0.87749; HR： P 〈 0.01,r =-0.91902; MAP： P 〈 0.05,r =-0.85691; RPP： P 〈 0.01,r =-0.91902）.Some neurons（Neurons C,D and E） were positively correlated with vagus nerve discharge,HR,MAP and RPP in the AMI ＋ EA ＋ Lesion group（vagus nerve discharge： P 〈 0.01,r = 0.8905,P 〈 0.01,r = 0.9725,P 〈 0.01,r = 0.9054; HR： P 〈 0.01,r = 0.9347,P 〈 0.01,r = 0.9089,P 〈 0.05,r = 0.8247; MAP： P 〈 0.05,r = 0.8474,P 〈 0.01,r = 0.9691,P 〈 0.01,r = 0.9027; RPP： P 〈 0.05,r = 0.8637,P 〈 0.01,r = 0.9407,P 〈 0.01,r = 0.9027）.These findings show that the hippocampus-nucleus tractus solitarius-vagus nerve pathway is involved in the cardioprotective effect of EA at the heart meridian.Some interneurons in the nucleus tractus solitarius may play a particularly important role in the cardiomodulatory process.

Effect of electroacupuncture on the expression of CGRP and 5-HT in the serum and colon of IBS-C rats

Objective:To investigate the effects of electricity on the expression of procalcitonin(CGRP)and serotonin(5-HT)in serum and colon in rats with constipation-type irritable bowel syndrome(IBS-C).Methods:50 rats were randomly divided into three groups:normal control group,model group,electroacupuncture group with four single points(tianshu electroacupuncture group,Colonic acupuncture group,Quchi electroacupuncture group,Shangjuxu acupoint group,and bilateral acupoint alternating between left and right),and non-meridian non-acupoint group(non-meridian non-acupoint group on both hip of electroacupuncture rats).The IBS-C model was replicated in the other three groups,except the normal control group,using the cold-fear-starvation synthesis method.After successful replication of the model,the four electroacupuncture single-point group and the non-acupoint group began electroacupuncture treatment once a day for 3 consecutive days.The visceral sensitivity and the expression of CGRP and 5-HT in serum and colon were observed.Results:Compared with the normal control group,the minimum volume threshold of abdominal retractile reflex(AWR)in the model group decreased(P<0.05),and the expressions of 5-HT and CGRP in serum and colon increased(P<0.05).Compared with the model group,AWR minimum volume threshold was increased in the electroacupuncture group with four single acupuncture points(P<0.05),the expression of 5-ht and CGRP in serum and colon was significantly decreased(P<0.05),and there was no significant change in each indicator in the non-acupuncture point group(P>0.05).Conclusion:Electroacupuncture combined with four single points can effectively improve the visceral sensitivity of IBS-C rats and regulate the levels of 5-HT and CGRP in serum and colon of rats,thus providing experimental basis for the clinical treatment of IBS-C.

Mechanism of acupuncture on anti-neuronal apoptosis and the regulation of PI3K/AKT signaling pathway in heroin relapse rats

Objective:To explore the mechanism of acupuncture intervention on anti-neuronal apoptosis in heroindependent rats based on the PI3K/AKT signaling pathway.Methods:A total of 30 SD rats were randomly divided into a normal group,a model group and an acupuncture group,10 rats in each one.In the model group and the acupuncture group,the heroin relapse rat model was established by intramuscular incremental injection of heroin.In the model group,no any intervention was applied.In the acupuncture group,after modeling,acupuncture was applied at"Bǎihuì(百会GV20)"and"Dàzhuī(大椎GV14)".Transmission electron microscope(TEM)was adopted to observe neuronal apoptosis in the rats.The effect of acupuncture on anti-neuronal apoptosis was compared.Using reverse transcription-polymerase chain reaction(RT-PCR)and western blot methods,the mRNA and protein expressions of PI3 K and AKT were detected in ventral tegmental area(VTA).Results:It was found that edema was presented in VTA neuronal cytoplasm and organelles basically disappeared in the heroin relapse rats,nuclear chromatin aggregation,condensation and increased neuronal apoptosis were presented as well.After acupuncture at"Bǎihuì(百会GV20)"and"Dàzhuī(大椎GV14)",a small amount of mitochondria,rough endoiplasmic reticulum and glycogen granules were visible in the cytoplasm of VTA neurons.The nuclear membrane structure was clear and the chromatin in the nucleus was basically normal.The fluorescence quantitative polymerase chain reaction(PCR)and western blot methods were adopted to detect mRNA and protein expressions of PI3K and AKT.It was found that the mRNA and protein expressions of PI3K and AKT in the brain of the rats in the model group were lower than those in the normal group(all P<0.05).Compared with the model group,the mRNA and protein expressions of PI3K and AKT in the acupuncture group were increased(all P<0.05),tending to the levels as the normal group.Conclusion:The effect of acupuncture on anti-brain cell apoptosis in heroin relapse rats may be related to the inhibition of PI3K/AKT signaling pathway.