: Major depressive disorder (MDD) is a common neuropsychiatric challenge that primarily targets young females. MDD as a global disorder has a multifactorial etiology related to the environment and genetic background. A balanced gut microbiota is one of the most important environmental factors involved in human physiological health. The interaction of gut microbiota components and metabolic products with the hypothalamic-pituitary-adrenal system and immune mediators can reverse depression phenotypes in vulnerable individuals. Therefore, abnormalities in the quantitative and qualitative structure of the gut microbiota may lead to the progression of MDD. In this review, we have presented an overview of the bidirectional relationship between gut microbiota and MDD, and the effect of pre-treatments and microbiomebased approaches, such as probiotics, prebiotics, synbiotics, fecal microbiota transplantation, and a new generation of microbial alternatives, on the improvement of unstable clinical conditions caused by MDD.

中文翻译：

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肠道微生物群和重度抑郁症：当前的理解和新的治疗策略

：重度抑郁症 (MDD) 是一种常见的神经精神疾病，主要针对年轻女性。 MDD 作为一种全球性疾病，具有与环境和遗传背景相关的多因素病因。平衡的肠道微生物群是影响人类生理健康的最重要的环境因素之一。肠道微生物群成分和代谢产物与下丘脑-垂体-肾上腺系统和免疫介质的相互作用可以逆转易感个体的抑郁表型。因此，肠道菌群数量和质量结构的异常可能导致MDD的进展。在这篇综述中，我们概述了肠道微生物群与MDD之间的双向关系，以及预处理和基于微生物组的方法的效果，例如益生菌、益生元、合生元、粪便微生物群移植和新一代微生物替代品，改善MDD引起的不稳定临床状况。