APP and brain ischemia: A similar protective role of microglia was also apparent in the progression of neurodegeneration in APP-PS1 transgenic mice [35], the extent of excitotoxic injury in a model of brain injury induced by cerebral ischemia [36], and the dopaminergic neurotoxicity of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyrine (MPTP) [37].