Electroacupuncture Rescued the Impairment of Hippocampal Neurons in Perimenopausal Depression Rats via Activating the CREB/BDNF Pathway

Astroglial Connexin 43-Mediated Gap Junctions and Hemichannels: Potential Antidepressant Mechanisms and the Link to Neuroinflammation

Major depression disorder (MDD) is a neuropsychiatric disorder associated with a high suicide rate and a higher disability rate than any other disease. Evidence suggests that the pathological mechanism of MDD is related to astrocyte dysfunction. Depression is mainly associated with the expression of connexin 43 (Cx43) and the function of Cx43-mediated gap junctions and hemichannels in astrocytes. Moreover, neuroinflammation has been a hotspot in research on the pathology of depression, and Cx43-mediated functions are thought to be involved in neuroinflammation-related depression. However, the specific mechanism of Cx43-mediated functions in neuroinflammation-related depression pathology remains unclear. Therefore, this review summarizes and discusses Cx43 expression, the role of gap junction intercellular communication, and its relationship with neuroinflammation in depression. This review also focuses on the effects of antidepressant drugs (e.g., monoamine antidepressants, psychotropic drugs, and N-methyl-D-aspartate receptor antagonists) on Cx43-mediated function and provides evidence for Cx43 as a novel target for the treatment of MDD. The pathogenesis of MDD is related to astrocyte dysfunction, with reduced Cx43 expression, GJ dysfunction, decreased GJIC and reduced BDNF expression in the depressed brain. The effect of Cx43 on neuroinflammation-related depression involving inflammatory cytokines, glutamate excitotoxicity, and HPA axis dysregulation. Antidepressant drugs targeting Cx43 can effectively relieve depressive symptoms.

Electroacupuncture for the treatment of perimenopausal syndrome: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To assess the efficacy, comparative effectiveness and safety of electroacupuncture (EA) in the treatment of perimenopausal syndrome (PMS).

METHODS

Nine databases were searched until June 2019. Only relevant randomized controlled trials (RCTs) of EA for PMS were included.

RESULTS

Twelve trials involving 746 women were included. EA and hormone therapy (HT) did not significantly differ in terms of effective rate (risk ratio (RR) = 0.98, 95% confidence interval (CI) = 0.93 to 1.04), Kupperman index (KI) (mean difference (MD) = -0.25, 95% CI = -0.76 to 0.26) and serum levels of follicle-stimulating hormone (FSH) (MD = -3.80, 95% CI = -11.59 to 3.98) or luteinizing hormone (LH) (MD = -2.51, 95% CI = -10.72 to 5.70). Serum estradiol (E₂) levels were significantly lower in EA versus HT groups (MD = -60.58, 95% CI = -71.93 to -49.23). Compared with sham EA, EA had a significantly greater effect on reductions in KI (MD = -4.71, 95% CI = -6.57 to -2.86) and hot flushes score/24 h (MD = -2.43, 95% CI = -2.93 to -1.93). There were no significant differences between EA and manual acupuncture (MA) in terms of effective rate (RR = 1.14, 95% CI = 0.98 to 1.33) or serum FSH (MD = -2.87, 95% CI = -29.65 to 23.91), LH (MD = 2.73, 95% CI = -9.65 to 15.11) or E₂ (MD = 26.80, 95% CI = -12.06 to 65.65). However, it seemed that EA had a better effect than MA on KI (MD = -2.44, 95% CI = -4.80 to -0.08). Subgroup analyses indicated that EA may have more of a benefit in the pre-menopausal state (hot flushes score/24 h: MD = -1.66, 95% CI = -3.49 to 0.17) compared to post-menopause (p > 0.05).

CONCLUSION

The effect of EA appeared broadly similar to HT and MA in the treatment of PMS, although EA-associated reductions in KI were superior to MA and sham EA, suggesting effects beyond placebo. The evidence base is limited by a small number of eligible studies, risk of bias and clinical/statistical heterogeneity, limiting our ability to draw firm conclusions. As such, additional larger scale, high-quality RCTs are needed.

Antidepressant-like effects of Xiaochaihutang in perimenopausal mice

ETHNOPHARMACOLOGICAL RELEVANCE

Xiaochaihutang (XCHT) is a traditional Chinese medicine prescription for thousand years in China. Our previous researches show that XCHT has antidepressant-like effects in several depression models, but effect and mechanism of XCHT in perimenopausal depression are still vague.

AIM OF THE STUDY

To reveal the antidepressant-like effect and mechanism of XCHT in perimenopausal mice.

MATERIALS AND METHODS

Perimenopausal depression model is executed by ovariectomy combined with chronic unpredictable mild stress (OVX-CUMS). Tail suspension test (TST), forced swim test (FST), elevated plus-maze (EPM), novelty suppressed feeding (NSF) and locomotor activity are used to assess antidepressant-like effects of XCHT. The Level of estradiol (E₂), follicle-stimulating hormone (FSH), gonadotrophin releasing hormone (GnRH), corticosterone (CORT), adrenocorticotrophic hormone (ACTH) and corticotropin releasing hormone (CRH) are evaluated by ELISA. Antidepressant mechanisms of XCHT in OVX-CUMS mice are analyzed by 5-hydroxytryptamine (5-HT), tryptophan hydroxylase 2 (TPH2) and estrogen receptor α and β (ERα/β).

RESULTS

The results show that OVX-CUMS significantly increases the immobility time in TST and FST, increases latency to feed, decreases food consumption in NSF and both the time spend and number of entries in open arms in EPM. While, oral administration of XCHT can significantly normalize above depression-like behaviors in OVX-CUMS mice. Moreover, XCHT also remarkably normalized levels of 5-HT, 5-HIAA, E₂, GnRH, CORT, ACTH and CRH in OVX-CUMS mice. Finally, the expression of ERβ and TPH2 are decreased by OVX-CUMS in prefrontal cortex and hypothalamus, and XCHT can restore these decrease.

CONCLUSION

Current findings suggest XCHT can alleviate perimenopausal depression-like behaviors, restore 5-HT and hormones in OVX-CUMS mice, which may be related to normalizing the functions of HPA/HPO axis and enhancing expression of ERβ and TPH2 in prefrontal cortex and hypothalamus.