Background: Manganese-dependent superoxide dismutase (MnSOD) is a majordefense mechanism against potential cellular damage by reactive oxygen species (ROS). We have reportedincreased lipid peroxidation and decreased Cu/Zn SOD enzymatic activity in the temporal cortex of Alzheimer'sdiseased (AD) brains. Material/Methods: We now report the expression of MnSOD in the hippocampus of AD(n=8) and non-AD patients (n=7) via immunohistochemical methods, in both neuronal and non neuronal cells.We tested the hypothesis that there is differential expression of MnSOD in the CA1, CA2/3, and CA4 regionof the hippocampus which may account for the neuronal loss seen in Alzheimer's disease. For neuronalcells, profile counts were made and expressed as positive neuronal profiles (MnSOD-IR) per mm(2) withinhippocampal regions CA1, CA2/3, and CA4. Results: The AD MnSOD-IR counts were over 9-fold higher in theCA2/3 region (p

Keywords: Aged, 80 and over, Alzheimer Disease - enzymology, Free Radicals - metabolism, Hippocampus - enzymology, Neurons - enzymology, Regression Analysis, Superoxide Dismutase - metabolism