Jing-Wen Yang

Hippocampal cAMP/PKA/CREB is required for neuroprotective effect of acupuncture.

Acupuncture has beneficial effects in vascular dementia (VaD) patients. The underlying mechanism, however, remains unknown. The present study was designed to investigate whether the cAMP/PKA/CREB cascade is involved in the mechanism of acupuncture in cerebral multi-infarction rats. In this study, cerebral multi-infarction was modeled in adult Wistar rats by homologous blood clot emboli. After a two-week acupuncture treatment at Zusanli (ST36), hippocampal-dependent memory was tested by employing a radial arm maze test. The hippocampus was isolated for analyses of cAMP concentration, phosphodiesterase (PDE) activity and CREB/pCREB and ERK/pERK expressions. The Morris water maze (MWM) task and CREB phosphorylation were evaluated in the presence of PKA-selective peptide inhibitor (H89). The radial arm maze test results demonstrated that acupuncture treatment at ST36 reversed hippocampal-dependent memory in impaired animals. Compared to those of the impaired group, cAMP concentration, PKA activity and pCREB and pERK expressions were increased following acupuncture therapy. Finally, the blockade of PKA reversed the increase in CREB phosphorylation and the improvement in recognitive function induced by acupuncture treatment. These results suggest that acupuncture could improve hippocampus function by modulating the cAMP/PKA/CREB signaling pathway, which represents a molecular mechanism of acupuncture for recognitive function in cerebral multi-infarction rats.

Acupuncture ameliorates cognitive impairment and hippocampus neuronal loss in experimental vascular dementia through Nrf2-mediated antioxidant response.

Emerging evidence suggests acupuncture could exert neuroprotection in the vascular dementia via anti-oxidative effects. However, the involvement of Nrf2, a master regulator of antioxidant defense, in acupuncture-induced neuroprotection in vascular dementia remains undetermined. The goal of our study was to investigate the contribution of Nrf2 in acupuncture and its effects on vascular dementia. Morris water maze and Nissl staining were used to assess the effect of acupuncture on cognitive function and hippocampal neurodegeneration in experimental vascular dementia. The distribution of Nrf2 in neurons in hippocampus, the protein expression of Nrf2 in both cytosol and nucleus, and the protein and mRNA levels of its downstream target genes NQO1 and HO-1 were detected by double immunofluorescent staining, Western blotting and realtime PCR analysis respectively. Cognitive function and microglia activation were measured in both wild-type and Nrf2 gene knockout mice after acupuncture treatment. We found that acupuncture could remarkably reverse the cognitive deficits, neuron cell loss, reactive oxygen species production, and decreased cerebral blood flow. It was notable that acupuncture enhanced nuclear translocation of Nrf2 in neurons and up-regulate the protein and mRNA levels of Nrf2 and its target genes HO-1 and NQO1. Moreover, acupuncture could significantly down-regulated the over-activation of microglia after common carotid artery occlusion surgery. However, the reversed cognitive deficits, neuron cell loss and microglia activation by acupuncture were abolished in Nrf2 gene knockout mice. In conclusion, these findings provide evidence that the neuroprotection of acupuncture in models of vascular dementia was via the Nrf2 activation and Nrf2-dependent microglia activation.

Acupuncture elicits neuroprotective effect by inhibiting NAPDH oxidase-mediated reactive oxygen species production in cerebral ischaemia.

In the current study, we aimed to investigate whether NADPH oxidase, a major ROS-producing enzyme, was involved in the antioxidant effect of acupuncture on cognitive impairment after cerebral ischaemia. The cognitive function, infract size, neuron cell loss, level of superoxide anion and expression of NADPH oxidase subunit in hippocampus of two-vessel occlusion (2VO) rats were determined after 2-week acupuncture. Furthermore, the cognitive function and production of O2− were determined in the presence and absence of NADPH oxidase agonist (TBCA) and antagonist (Apocynin). The effect of acupuncture on cognitive function after cerebral ischaemia in gp91phox-KO mice was evaluated by Morris water maze. Acupuncture reduced infarct size, attenuated overproduction of O2−, and reversed consequential cognitive impairment and neuron cell loss in 2VO rats. The elevations of gp91phox and p47phox after 2VO were significantly decreased after acupuncture treatment. However, no differences of gp91phox mRNA were found among any experimental groups. Furthermore, these beneficial effects were reversed by TBCA, whereas apocynin mimicked the effect of acupuncture by improving cognitive function and decreasing O2− generation. Acupuncture failed to improve the memory impairment in gp91phox KO mice. Full function of the NADPH oxidase enzyme plays an important role in neuroprotective effects against cognitive impairment via inhibition of NAPDH oxidase-mediated oxidative stress.

Acupuncture improves locomotor function by enhancing GABA receptor expression in transient focal cerebral ischemia rats.

Stroke is the major cause of long-term disability among adults. Recent studies have found that GABAergic inhibitory neurotransmission plays a vital role in ameliorate locomotor damage after ischemic injury. Acupuncture has been widely used to improve locomotor function. However, the underlying mechanisms remain unclear. The present study is designed to investigate whether GABA and GABA receptors are involved in the mechanism underlying acupuncture treatment in rats with middle cerebral artery occlusion (MCAO). One week after acupuncture at JiaJi acupoint, the locomotor function and infarct volumes were tested. Then level of GABA and the expressions of GABAAγ2 and GABABR2 were assessed by high-performance liquid chromatography, immunofluorescence and immunohistochemistry, respectively. Compared with normal group, GABAAγ2 and GABABR2 expressions were decreased in striatum and spinal cord of the MCAO group. After acupuncture, the expressions of the two receptors were increased, but levels of GABA and trafficking protein, kinesin binding 1 (TRAK1), which plays a role in the intracellular transport of GABA receptors, were unchanged. The present study suggests that acupuncture could reverse locomotor function by modulating the expressions of GABA receptors in MCAO rats.

Neural mechanisms of acupuncture as revealed by fMRI studies.

As an ancient therapeutic method, acupuncture has been used to treat many diseases as an adjunctive therapy. However, its clinical efficacy remains controversial and the neural mechanisms have not been well understood. Accumulating studies have revealed that fMRI has made it possible to study brain responses to acupuncture. This review aims to provide scientific evidence to support the notion and discuss how these findings contribute to the neural mechanisms of acupuncture.

Acupuncture Attenuated Vascular Dementia–Induced Hippocampal Long-Term Potentiation Impairments via Activation of D1/D5 Receptors

Background and Purpose— Emerging evidence suggests that acupuncture could improve cognitive impairment in vascular dementia by enhancing synaptic plasticity in the hippocampus. The purpose of this study is to investigate whether dopamine, a key mediator of synaptic plasticity, is involved in this cognitive improvement. Methods— Vascular dementia model was established by bilateral common carotid arteries occlusion in male Wistar rats. Three days after the operation, animals received acupuncture treatment for 2 weeks, once daily. The D1/D5 receptors antagonist SCH23390 was administered intraperitoneally 15 minutes before each acupuncture treatment. Morris water maze was examined after acupuncture. Long-term potentiation was studied by an electrophysiological technique. Dopamine and metabolites levels were detected by microdialysis and high-performance liquid chromatography from brain tissue. The expression of D1R and D5R was analyzed by immunofluorescence. Results— Acupuncture remarkably reversed cognitive deficits in 2-vessel occlusion model (2VO) rats, and the acupuncture points Zusanli (ST36) and Baihui (GV20) were confirmed to be the most effective combination. Electrophysiological recording data showed that 2VO-induced impairments of long-term potentiation were prevented by acupuncture. In addition, acupuncture promoted the release of dopamine and its major metabolites in the hippocampus of 2VO rats. The immunofluorescence experiment showed that the decrease of D1R and D5R in hippocampal dentate gyrus region of 2VO rats was reversed by acupuncture. Furthermore, we found that the effects of acupuncture against 2VO-induced impairments in cognition and synaptic plasticity were abolished by SCH23390. Conclusions— Improvement in cognition and hippocampal synaptic plasticity induced by acupuncture was achieved via activation of D1/D5 receptors in 2VO rats.

Mechanisms of acupuncture on vascular dementia—A review of animal studies

ABSTRACT Vascular dementia (VaD) is the second leading type of dementia after Alzheimers disease plaguing the aging population. Acupuncture has served as alternative and complementary medicine in the world for a long time and its use for VaD is based on a large body of preclinical and clinical researches. The mechanisms that underlie the protective effects of acupuncture are slowly beginning to be understood. Acupuncture influences multiple aspects of the pathological process of VaD. It improves cognitive function through protecting cerebral neurons from oxidative stress, apoptosis, and neuroinflammation, regulating glucose metabolism and neurotransmitters. Acupuncture may also improve synaptic plasticity and blood vessel function. It is likely that no single factor can explain the protection provided by acupuncture. This review provides a comprehensive overview of established and recent findings in animal‐based researches aiming to elucidate the complex mechanisms of acupuncture on VaD. HIGHLIGHTSPotential mechanisms of acupuncture on vascular dementia are summarized.Baihui (GV20) and Zusanli (ST36) are the most frequently chosen acupoints in studies for treating VaD.Neuron apoptosis and neuroinflammation are attenuated by acupuncture in VaD animal models.

Acupuncture reversed hippocampal mitochondrial dysfunction in vascular dementia rats

Hippocampal mitochondrial dysfunction due to oxidative stress has been considered to play a major role in the pathogenesis of vascular dementia (VD). Previous studies suggested that acupuncture could improve cerebral hypoperfusion-induced cognitive impairments. However, whether hippocampal mitochondria are associated with this cognitive improvement remains unclear. In this study, an animal model of VD was established via bilateral common carotid arteries occlusion (BCCAO) to investigate the alterations of cognitive ability and hippocampal mitochondrial function. BCCAO rats showed impairments in hippocampal mitochondrial function, overproduction of reactive oxygen species (ROS) and learning and memory deficits. After two-week acupuncture treatment, BCCAO-induced spatial learning and memory impairments as shown in Morris water maze were ameliorated. Hippocampal mitochondrial respiratory complex enzymes (complex I, II, IV) activities and cytochrome c oxidase IV expression significantly increased, which might contribute to the reduction of hippocampal ROS generation. In addition, acupuncture significantly improve mitochondrial bioenergy parameters such as mitochondrial respiratory control rate and membrane potential not PDH A1 expression. Placebo-acupuncture did not produce similar therapeutic effects. These findings suggested that acupuncture reversed BCCAO-induced hippocampal mitochondrial dysfunction, which might contribute to its prevention on cognitive deficits.

Comparison of cognitive performance between two rat models of vascular dementia.

Background and Purpose: An ideal animal model to explore that pathogenesis and prevention of dementia is essential. The present study was designed to compare the difference of behavior and cerebral blood flow of the two vascular dementia rat models at different time intervals. Methods: The rats were randomly allocated to three groups: bilateral common carotid artery occlusion (BCCAO) group, thromboembolism (TE) group and sham-operated (SHAM) group. The performance in the Morris water maze (MWM) was analyzed at 7, 14 and 28 d after operation and cerebral blood flow (CBF) was analyzed at 28 days after operation. Result: The results showed that the two models exhibited longer latency, less times to crossing platform in MWM and lower CBF than the SHAM rats. Compared with the TE rats, the BCCAO rats have a significant prolongation of escape latency at 7 days and 28 days. In the probe trial, the BCCAO rats showed less number of times across the platform. Conclusion: The BCCAO rats maybe provide a more useful model to study the physiopathological mechanisms of cognitive impairment related to chronic cerebral ischemia.

Acupuncture Attenuates Renal Sympathetic Activity and Blood Pressure via Beta-Adrenergic Receptors in Spontaneously Hypertensive Rats

The sympathetic nervous system, via epinephrine and norepinephrine, regulates β-adrenergic receptor (β-AR) expression, and renal sympathetic activation causes sustained increases in blood pressure by enhanced renin release. In this study, we aim to investigate the effect and underlying mechanism of acupuncture at Taichong (LR3) on renal sympathetic activity in spontaneously hypertensive rats. Unanesthetized rats were subject to daily acupuncture for 2 weeks. Mean blood pressure (MBP) and heart rate variability (HRV) were monitored at days 0, 7, and 14 by radiotelemetry. After euthanasia on the 14th day, blood and the kidneys were collected and subject to the following analyses. Epinephrine and norepinephrine were detected by ELISA. The expression of β-ARs was studied by western blotting and PCR. The renin content was analyzed by radioimmunoassay. 14-day acupuncture significantly attenuates the increase of MBP. The HRV indices, the standard deviation of all normal NN intervals (SDNN), and the ratio of the low-frequency component to the high-frequency component (LF/HF) were improved following acupuncture. Renal sympathetic activation induced upregulation of epinephrine, norepinephrine, and renin content were attenuated by acupuncture. In addition, acupuncture decreased β1-AR expression and improved β2-AR expression. These results indicated that acupuncture relieves the increased MBP via the regulation of renal sympathetic activity and β-ARs.