MAPT and Alzheimer disease: Recent preclinical research suggests a potential extension of this mechanism to neurodegenerative disease intervention: She Group demonstrated in an AD mouse model that highland barley β-glucan combined with Lactobacillus remodels the gut microbiota, reducing β-amyloid deposition by 39% and P-tau protein expression via the gut-brain axis, while repairing synaptic damage and significantly improving cognitive function (2025) [21].