[Gut-brain axis and Parkinson's disease: research progress on the gut-brain interaction]

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by motor dysfunction. The main pathological manifestations are abnormal accumulation of α-synuclein (α-Syn) in substantia nigra neurons and loss of dopaminergic neurons (DAn). Gastrointestinal (GI) symptom is one of the common non-motor symptoms in PD. It is known that the brain and gut communicate via the parasympathetic nerves and the enteric nervous system (ENS), forming a bidirectional pathway called the gut-brain axis. Dysbiosis of the gut microbiota may be a key driver in the origin and pathological progression of PD, playing an important role in the spread of pathological α-Syn to the central nervous system (CNS) and thereby promoting the progression of PD. This article reviews the mechanism of gut microbiota dysbiosis in the pathogenesis and progression of PD, including its effects on intestinal barrier integrity, neuroinflammation, and pathological α-Syn transmission, and discusses the diagnosis and therapeutic strategies targeting the gut-brain axis, including microbiota transplantation, vagus nerve stimulation, Toll-like receptor 4 (TLR4) antagonists, exercise training, etc., providing new insights for the diagnosis and treatment of PD.