Minocycline alleviates abnormal microglial phagocytosis of synapses in a mouse model of depression.

BACKGROUND: As antidepressants commonly used in the clinic have proved to be problematic, it is urgent to gain an updated understanding of the pathogenesis of depression and find potential therapeutic targets. Since both functional brain imaging studies and autopsy reports indicated that there is indeed a loss of synapses in depressed patients, it is necessary to explore the mechanism of this process. METHODS: We firstly investigated the effect of chronic social defeat stress (CSDS), a mouse model of depression, on behaviors, synapses, microglia, and microglial phagocytosis of synapses in mice. Then, as it is unclear whether microglial phagocytosis leads to synaptic loss, or synaptic loss induces the microglial clearance in CSDS mice, we used minocycline, a microglial activation inhibitor, to inhibit the microglial phagocytosis of synapses and study its effect on synapses and behaviors in CSDS mice. RESULTS: Our results showed that the expression levels of PSD-95 in the hippocampal dentate gyrus (DG) of CSDS mice were significantly reduced, while the microglia were significantly activated and the Iba1+CD68+ cell (phagocytic microglia) density was increased. We co-labeled the synaptic protein PSD-95 with the microglia marker Iba1 and found that the microglia in the hippocampal DG of CSDS mice contained significantly more PSD-95 engulfed puncta, which revealed that microglia in CSDS mice abnormally phagocytized synapses. Moreover, our results indicated that minocycline treatment dampened microglial activation, decreased the phagocytic microglia density, reduced abnormal microglial phagocytosis of synapses, reversed synaptic loss, and alleviated behavioral impairment in CSDS mice. CONCLUSIONS: Under depressive pathological conditions, the activated microglia may abnormally engulf neuronal synapses causing synaptic loss and behavioral impairments. Thus, microglial phagocytosis may be a novel therapeutic target for the treatment of depression.

The Therapeutic Effects of Acupuncture and Electroacupuncture on Cancer-related Symptoms and Side-Effects.

In addition to cancer-related death, malignant progression also leads to a series of symptoms and side-effects, which would detrimentally affect cancer patients' the quality of life, adversely influence their adherence to treatments, and, therefore, negatively affect their long-term survival. Acupuncture and electroacupuncture (EA), as two classic treatment methods in traditional Chinese medicine, have been widely employed to cure various diseases. Recently, the clinical application of acupuncture and EA in cancer patients has received great attention. In this review, we summarized the clinical application of acupuncture and EA in alleviating the cancer symptoms, reducing the cancer treatment-related side-effects, and relieving the cancer pain. The symptoms and side-effects discussed in this review include fatigue, insomnia, chemotherapy-associated dyspepsia syndrome (CADS), pain, xerostomia, and anxiety and depression. The underlying mechanisms of the therapeutic effects of acupuncture and EA might be related to the regulation of the mitochondrial function, coordination of the activity of the nervous system, adjustment of the production of neurotransmitters, and alleviation of the immune responses. In conclusion, acupuncture and EA have been proved to be beneficial for cancer patients. More research, however, is required to clarify the potential mechanisms behind acupuncture and EA for widespread adoption in clinical application.

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.