Oral Sodium Hyaluronate Reshapes Gut Microbiota Composition and Suppresses the LPS-TLR4/NF-κB Pathway to Exert Neuroprotection in MPTP-Induced Parkinson's Disease.

Parkinson's disease (PD), a debilitating neurodegenerative disorder, is primarily characterized by motor impairments and concurrent gastrointestinal disturbances. Increasing evidence has highlighted the critical role of the microbiota-gut-brain axis (MGBA) in the pathogenesis of PD. This study investigated the neuroprotective potential of sodium hyaluronate (SH) in a mouse model of PD and its underlying mechanisms via the MGBA. In the oral pre-treatment study, three doses (7.5, 15, and 30 mg/kg/day) were evaluated. The results showed that the high dose (SH-H, 30 mg/kg/day) significantly ameliorated motor disorders and gastrointestinal functional disorders. Therefore, SH-H was selected for subsequent mechanistic investigations. Mechanistically, SH-H restored gut microbiota homeostasis, increased fecal short-chain fatty acid (SCFA) levels, and improved the integrity of the intestinal and blood-brain barrier (BBB). Thus, SH reduced the transfer of lipopolysaccharide (LPS) from the intestine to serum and the substantia nigra (SN), suppressing activation of the LPS-TLR4/MyD88/NF-κB signaling pathway. These effects alleviated neuroinflammation, protected dopaminergic neurons, and reduced the aggregation of α-synuclein (α-syn). In summary, SH attenuated PD-related pathological changes by restoring gut microbiota homeostasis and modulating the MGBA, suggesting that SH may represent a potential therapeutic strategy for PD.