TNF and Alzheimer disease: Concentrations of TNF-α, IL-1, IL-6, and CRP in the hippocampus and cerebral cortex of the AD and Lig+AD groups were significantly higher than those of the control groups, which suggests that injection of Aβ25–35 into the hippocampus may increase the concentrations of these inflammatory cytokines in the hippocampus and cerebral cortex of rats.