The Neuroprotective Effects of Electroacupuncture on Parkinson's Disease and the Underlying Molecular Mechanisms.

Parkinson's disease (PD) is a chronic neurodegenerative disease whose main pathological features are the degeneration of dopamine neurons and deposition of α-synuclein in neurons. At present, the most important treatment strategy for PD is drugs, and one of the most used drugs is levodopa. However, this therapy shows many problems, such as tolerance and long-term effects, so other treatment strategies need to be explored. As a traditional Chinese medicine treatment method with effective and few side effects, electroacupuncture is considered a non-drug therapy. It serves as a novel, promising therapeutic approach for the treatment of PD. In this review, the application and the effects of electroacupuncture on PD have been described. Besides, the underlying molecular mechanisms of electroacupuncture on PD that contribute to protecting dopaminergic neurons and reducing α-synuclein levels have been illustrated, including ① anti-oxidant stress response, ② anti-neuroinflammatory response, ③ up-regulation of neurotrophic factors and reduction of nerve cell apoptosis, ④ down-regulation of endoplasmic reticulum stress and improvement of mitochondrial function, ⑤ improvement of the function of the ubiquitin-proteasome system, ⑥ anti-excitatory toxicity response, ⑦ activation of autophagy, and ⑧ modulation of gut microbiota. Achieving a better understanding of the neuroprotective effects of electroacupuncture on PD will provide a theoretical basis and facilitate the application of electroacupuncture on PD.

Electroacupuncture may alleviate behavioral defects via modulation of gut microbiota in a mouse model of Parkinson's disease.

OBJECTIVE: Parkinson's disease (PD) is a chronic neurodegenerative disease involving non-motor symptoms, of which gastrointestinal disorders are the most common. In light of recent results, intestinal dysfunction may be involved in the pathogenesis of PD. Electroacupuncture (EA) has shown potential effects, although the underlying mechanism remains mostly unknown. We speculated that EA could relieve the behavioral defects of PD, and that this effect would be associated with modulation of the gut microbiota. METHODS: Mice were randomly divided into three groups: control, PD + MA (manual acupuncture), and PD + EA. MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) was used to establish the mouse model of PD. Rotarod performance tests, open field tests, and pole tests were carried out to assess motor deficiencies. Immunohistochemistry was conducted to examine the survival of dopaminergic neurons. 16S ribosomal RNA (rRNA) gene sequencing was applied to investigate the alterations of the gut microbiome. Quantitative real-time polymerase chain reaction (PCR) was performed to characterize the messenger RNA (mRNA) levels of pro-inflammatory and anti-inflammatory cytokines. RESULTS: We found that EA was able to alleviate the behavioral defects in the rotarod performance test and pole test, and partially rescue the significant loss of dopaminergic neurons in the substantia nigra (SN) chemically induced by MPTP in mice. Moreover, the PD + MA mice showed a tendency toward decreased intestinal microbial alpha diversity, while EA significantly reversed it. The abundance of Erysipelotrichaceae was significantly increased in PD + MA mice, and the alteration was also reversed by EA. In addition, the pro-inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-α were substantially increased in the SN of PD + MA mice, an effect that was reversed by EA. CONCLUSION: These results suggest that EA may alleviate behavioral defects via modulation of gut microbiota and suppression of inflammation in the SN of mice with PD, which provides new insights into the pathogenesis of PD and its treatment.