Physical Exercise Enhances Melatonin Effect in D-Galactose/Aluminum Chloride-Induced Alzheimer's Disease of Ovariectomized Rats: Irisin Induction Associated with Upregulation of PPAR-γ/IGF-1/BDNF and Decreasing TNF-α/p38-MAPK/NLRP3/GFAP Pathway. This evidence concerns the gene BDNF and Alzheimer disease.