By using a different AD rat model, obtained by the administration of Aβ42 peptide into the rodents’ brains, intraperitoneal niacinamide caused the reduction of oxidative stress, apoptosis, and poly(ADP-ribose) polymerase-1 (PARP-1) activity, which are well known to be associated with neuroinflammation and cell death [111]. Here, PARP1 is linked to Alzheimer disease.