MAPT and Alzheimer disease: 5-MTHF treatment was found to decrease memory dysfunction and restrict Aβ1-42 and p-Tau increases in a rat model of AD induced by D-gal and AlCl3 exposure, and the same treatment also ameliorated cholinergic damage and endothelial cell dysfunction, improved the numbers and structures of pyramidal cells in the hippocampal CA1 region and regulated oxidative stress and excitatory amino acid release.