Electroacupuncture improves cardiac function and reduces infarct size by modulating cardiac autonomic remodeling in a mouse model of myocardial ischemia

Background: Sympathetic and parasympathetic nerve remodeling play an important role in cardiac function after myocardial ischemia (MI) injury. Increasing evidence indicates that electroacupuncture (EA) can regulate cardiac function by modulating the autonomic nervous system (ANS), but little is known about its effectiveness on neural remodeling post-MI. Objectives: To investigate the role of EA in ANS remodeling post-MI. Methods: Adult male C57/BL6 mice were equally divided into the Control (Ctrl), MI and EA groups after generating the MI model by ligating the left anterior descending (LAD) coronary artery. Echocardiography and 2,3,5-triphenyltetrazolium (TTC) staining were employed to evaluate cardiac function and infarct size after EA treatment for five consecutive days. Serum norepinephrine (NE) levels were measured by ELISA to quantify sympathetic activation. Then, ANS remodeling was detected by immunohistochemistry (IHC), RT-qPCR, and Western blotting. Results: Our preliminary findings showed that EA increased ejection fraction and fractional shortening and reduced infarct area after MI injury. Serum NE levels in the EA group were significantly decreased compared with those in the MI group. IHC staining results demonstrated that the density of growth associated protein (GAP)43 and tyrosine hydroxylase (TH) positive nerve fibers in the EA group were decreased with increased choline acetyltransferase (CHAT) and vesicular acetylcholine transporter (VACHT). Meanwhile, the results verified that mRNA and protein expression of GAP43 and TH were significantly inhibited by EA treatment in the MI mice, accompanied by elevated CHAT and VACHT. Conclusions: EA treatment could improve cardiac function and reduce infarct size by modulating sympathetic and parasympathetic nerve remodeling post-MI, thus helping the cardiac ANS reach a new balance to try to protect the heart from further possible injury.

The Study on Neural Remodeling of Medullary Visceral Zone in Early Sepsis and Interfered by Cholinergic Anti-Inflammatory Pathway ​

BackgroundStudies including our own have shown that the Medullary Visceral Zone (MVZ) can effectively regulate systemic inflammation and immunity through the Cholinergic Anti-inflammatory Pathway (CAP). Sepsis usually causes neuroinflammation in the Central Nervous System (CNS), which will inevitably affect the structure and function in related brain areas such as MVZ, whether the intervention of CAP can affect the structure and function of the MVZ in sepsis needs to be further verified. Methods64 adults, specific pathogens free Sprague-Dawley male rats were used in this study. The septic models were prepared by cecum ligation and puncture (CLP) method, GTS-21 (a selective α7 nicotinic acetylcholine receptor agonist which can mimic CAP’s activation) and MLA (a powerful and selective nicotine acetylcholine receptor antagonist which can mimic CAP’s blocking) were used to interfere CAP. The pathological changes, apoptosis, the expressions of Tyrosine Hydroxylase (TH) and Choline acetyltransferase (CHAT), the expression levels of GAP-43 mRNA, Olig-2 mRNA, VEGF mRNA, GFAP mRNA, MMP-9 mRNA in MVZ were analyzed among different groups. ResultsIn this study, we found that sepsis induced apoptosis and functional suppression of catecholaminergic and cholinergic neurons and gliosis in MVZ, up-regulated key genes’ expressions such as GAP-43 mRNA，GFAP mRNA，VEGF mRNA，MMP-9 mRNA, down-regulated the expression of Olig-2 mRNA. GTS-21, a selective α7 nicotinic acetylcholine receptor agonist, obviously mitigated the above changes; whereas, methyllycaconitine (MLA), a powerful and selective nicotine acetylcholine receptor antagonist, significantly aggravated these changes. ConclusionsOur research shows that activating CAP can effectively mitigate the neural remodeling and neuronal suppression induced by early sepsis in MVZ, the mechanism may involve with its control of systemic and local inflammation. This study reveals that MVZ and CAP may be potential targets to curb the inflammatory storm in early sepsis.

Enhanced atrial internal-external neural remodeling facilitates atrial fibrillation in the chronic obstructive sleep apnea model

Objective Autonomic imbalance plays a crucial role in obstructive sleep apnea (OSA) associated atrial fibrillation (AF). Here, we investigated the potential neural mechanism of AF induced by OSA. Methods Ten dogs were divided into control group (n = 5) and OSA group (n = 5). The chronic OSA model was established by repeat apnea-ventilation cycles for 4 hours a day for 12 weeks. During the process of model establishment, arterial blood gases, atrial effective refractory period (AERP), AF inducibility, normalized low-frequency power (LFnu), normalized high-frequency power (HFnu), and LFnu/ HFnu were evaluated at baseline, 4th week, 8th week, and 12th week. Nerve activities of left stellate ganglion (LSG) and left vagal nerve(LVN) were recorded. Tyrosine hydroxylase(TH), choline acetyltransferase(CHAT), PGP9.5, nerve growth factor(NGF), and c-Fos were detected in the left atrium, LSG, and LVN by immunohistochemistry and western blot. Moreover, high-frequency stimulations of LSG and LVN were conducted to observe the AF inducibility. Results Compared with the control group, the OSA group showed significantly enhanced neural activity of the LSG, increased AF inducibility, and shortened AERP. LFnu and LFnu/HFnu were markedly increased in the OSA group, while no significant difference in HFnu was observed. TH-positive and PGP9.5-positive nerve densities were significantly increased in the LSG and left atrium. Additionally, the protein levels of NGF, c-Fos, and PGP9.5 were upregulated both in the LSG and left atrium. AF inducibility was markedly increased under LSG stimulation without a stimulus threshold change in the OSA group. Conclusions OSA significantly enhanced LSG and left atrial neural remodeling, and hyperactivity of LSG may accelerate left atrial neural remodeling to increase AF inducibility.

Effects and Mechanisms of Cutting Upper Thoracic Sympathetic Trunk on Ventricular Rate in Ambulatory Canines with Persistent Atrial Fibrillation

Objective. The purpose is to observe the effects and neural mechanism of cutting upper thoracic sympathetic trunk (TST) on the ventricular rate (VR) during persistent atrial fibrillation (AF). Methods. Twelve beagle dogs were halving to the control group and experimental group, 6 dogs for each group. Both groups were performed with left atrial rapid pacing (600 beats/min) to induce sustained AF. The experimental group underwent cutting upper TST after a sustained AF model was established, while the control group received thoracotomy without cutting TST. Bilateral stellate ganglion (SG) and left atrial myocardium were harvested for tyrosine-hydroxylase (TH) immunohistochemical staining. Results. After cutting upper TST for 30 minutes, the average VR was 121.5 ± 8.7 bpm (95% CI, 114.8 to 128.0) in the experimental group, which was significantly slower than that of the control group (144.5 ± 4.2 bpm (95% CI, 141.5 to 148.0)) ( P < 0.001 ). After cutting upper TST for 1 month, the average VR of the experimental group (106.5 ± 4.9 bpm (95% CI, 102.0 to 110.0)) was also significantly slower versus that of the control group (139.2 ± 5.6 bpm (95% CI, 135.0 to 143.8)) ( P < 0.001 ). Compared with the control group, both left stellate ganglion (LSG) and right stellate ganglion (RSG) of the experimental group caused neural remodeling characterized by decreased ganglionic cell density and reduced TH staining. TH-positive component was significantly decreased in the left atrium of the experimental group compared with the control group. Conclusions. Cutting upper TST could reduce fast VR during persistent AF. Cutting upper TST induced bilateral SG neural remodeling and reduced sympathetic nerve density in the left atrium, which could contribute to the underlying mechanism of VR control during AF.

Constraint-Induced Movement Therapy Promotes Neural Remodeling and Functional Reorganization by Overcoming Nogo-A/NgR/RhoA/ROCK Signals in Hemiplegic Cerebral Palsy Mice

Background. Little is known about the induction of functional and brain structural reorganization in hemiplegic cerebral palsy (HCP) by constraint-induced movement therapy (CIMT). Objective. We aimed to explore the specific molecular mechanism of functional and structural plasticity related to CIMT in HCP. Methods. The mice were divided into a control group and HCP groups with different interventions (unconstraint-induced movement therapy [UNCIMT], CIMT or siRNA-Nogo-A [SN] treatment): the HCP, HCP+UNCIMT, HCP+CIMT, HCP+SN, and HCP+SN+CIMT groups. Rotarod and front-limb suspension tests, immunohistochemistry, Golgi-Cox staining, transmission electron microscopy, and Western blot analyses were applied to measure motor function, neurons and neurofilament density, dendrites/axon areas, myelin integrity, and Nogo-A/NgR/RhoA/ROCK expression in the motor cortex. Results. The mice in the HCP+CIMT group had better motor function, greater neurons and neurofilament density, dendrites/axon areas, myelin integrity, and lower Nogo-A/NgR/RhoA/ROCK expression in the motor cortex than the HCP and HCP+UNCIMT groups ( P < .05). Moreover, the expression of Nogo-A/NgR/RhoA/ROCK, the improvement of neural remodeling and motor function of mice in the HCP+SN group were similar to those in the HCP+CIMT group ( P > .05). The neural remodeling and motor function of the HCP+SN+CIMT group were significantly greater than those in the HCP+SN and HCP+CIMT groups ( P < .05). Motor function were positively correlated with the density of neurons ( r = 0.450 and 0.309, respectively; P < .05) and neurofilament ( r = 0.717 and 0.567, respectively; P < .05). Conclusions. CIMT might promote the remodeling of neurons, neurofilament, dendrites/axon areas, and myelin in the motor cortex by partially inhibiting the Nogo-A/NgR/RhoA/ROCK pathway, thereby promoting the improvement of motor function in HCP mice.