Deposition of Alpha2-Macroglobulin in Fibrillar Type of Senile Plaques in the Brain of PS/APP-Transgenic Mice

抄録

Alpha2-macroglobulin (A2M), a pan-proteinase inhibitor, accumulates in senile plaques of Alzheimer disease. In this study, we investigated the immunohistochemical localization of A2M in the brain of PS/APP mice. In control mice, A2M immunoreactivity was restricted to the vessels of brain parenchyma. In PS/APP mice, A2M deposition occurred in the brain parenchyma. A2M-positive deposits appeared after three months of age when senile plaque formation began to occur. The number of A2M-positive deposits increased with age. Double-staining for A2M and thioflavin S revealed that A2M accumulated in a subpopulation of thioflavin S-positive fibrillar type of amyloid beta deposits. These results indicate that A2M is implicated in the formation of fibrillar type senile plaques in PS/APP mice.