Amelioration of Heavy Metal Mercury-Induced Sleep Disorders Through the Microbiota-Gut-Brain Axis by Plant Polyphenols.

Mercury is a common heavy metal in our lives, which can damage the human nervous system, causing a series of neurological diseases. Mercury damages gut ecology and the intestinal barrier, thus harming the gut microbiota and causing microbial metabolic disorders. Changes in the composition and function of the gut microbiota can affect the synthesis and release of certain inflammatory factors and neurotransmitters. Through the microbiota-gut-brain axis (MGBA), these changes adversely affect nervous system function, ultimately inducing sleep disorders. Plant polyphenols can reduce the damage by mercury to the gut microbiota by repairing the intestinal barrier, regulating immunity and gut microbiota metabolism, alleviating the neurotoxicity of mercury, and improving sleep through the MGBA. This narrative review aims to synthesize current evidence regarding the mechanisms by which mercury disrupts sleep via the MGBA and to critically evaluate the potential utility of plant polyphenols as an indirect intervention strategy targeting this axis. By integrating findings from animal, in vitro, and human studies, this review delineates existing knowledge gaps and proposes future research directions for developing microbiota-centered approaches to mitigate mercury-induced sleep disturbances.