Neuroanatomical, Biochemical, and Functional Modifications in Brain Induced by Treatment with Antidepressants

Research progress on classical traditional chinese medicine formula xiaoyaosan in the treatment of depression

Depression is an emotional disorder that is problematic in psychiatry owing to its unclear etiology and unknown pathogenesis. Traditional Chinese medicine formulations such as Xiaoyaosan have been widely used throughout history to treat depression. In this review, we have focused on recent evidences elucidating the links between Xiaoyaosan and the treatment of depression. Data from animal and clinical studies, focusing on the pharmacological mechanisms, clinical applications, and effective materials that form the basis for the treatment of depression are presented and discussed. We found that the antidepressant effects of Xiaoyaosan are related to the effects of monoamine neurotransmitters, regulation of the hypothalamic-pituitary-adrenal axis, neuroplasticity, synaptic plasticity, inflammatory response, neuroprotection, brain-gut axis, regulation of intestinal microbiota, oxidative stress, and autophagy for reducing neuronal apoptosis. This review highlights the current evidence supporting the use of Xiaoyaosan as an antidepressant and provides an overview of the potential mechanisms involved.

Baicalein Exerts Therapeutic Effects against Endotoxin-Induced Depression-like Behavior in Mice by Decreasing Inflammatory Cytokines and Increasing Brain-Derived Neurotrophic Factor Levels

Inflammation plays an important role in the pathophysiology of depression. This study aims to elucidate the antidepressant effect of baicalein, an anti-inflammatory component of a traditional Chinese herbal medicine (Scutellaria baicalensis), on lipopolysaccharide (LPS)-induced depression-like behavior in mice, and to investigate the underlying mechanisms. In vitro, baicalein exhibited antioxidant activity and protected macrophages from LPS-induced damage. The results of the tail suspension test and forced swimming test (tests for despair potential in mice) showed the antidepressant effect of baicalein on LPS-treated mice. It also substantially decreased the production of pro-inflammatory cytokines, including IL-6, TNF-α, MCP-1, and eotaxin, elicited by LPS in the plasma. Baicalein downregulated NF-κB-p65 and iNOS protein levels in the hippocampus, demonstrated its ability to mitigate neuroinflammation. Additionally, baicalein increased the levels of the mature brain-derived neurotrophic factor (mBDNF) in the hippocampus of LPS-treated mice, and elevated the ratio of mBDNF/proBDNF, which regulates neuronal survival and synaptic plasticity. Baicalein also promoted the expression of CREB, which plays a role in a variety of signaling pathways. In summary, the findings of this study demonstrate that the administration of baicalein can attenuate LPS-induced depression-like behavior by suppressing neuroinflammation and inflammation induced by the peripheral immune response.