Age-related changes of astorocytes, oligodendrocytes and microglia in the mouse hippocampal CA1 sector

We investigated the age-related alterations of astorocyte, oligodendrocyte and rnicroglia in the mouse hippocampal CA I sector under the same conditions using immunohistochemistry. Glial fibrillary acidic protein (GFAP), 2', 3-cyclic nucleotide 3'-phosphodiesterase (CNPase) and isolectin 134 immunoreactivity was measured in 2-, 8-, 18-, 40-42- and 50-59-week -old mice. Total number of GFAP-positive cells was unchanged in the hippocampal CAI sector up to 40-42 weeks of birth. In 50-59-week-old mice, however, a significant increase in the number of GFAP-positive cells was observed in the hippocampal CA] sector, exhibiting the morphology of reactive astrocytes. In contrast, the fibers of CNPase immunoreactivity were unchanged in the hippocampal CA] sector up to 18 weeks of birth. In 40-42- and 50-59-week-old mice, however, a significant decrease in the densities of CNPase-positive fibers was observed in the hippocampal CAI sector. On the other hand, total number of isolectin B4-positive cells was unchanged in the hippocampal CA] sector up to 40-42 weeks of birth. In 50-59-week-old mice, however, a significant decrease in the number of isolectin B4-POSitive cells was observed in the hippocampal CAI sector. Our results show that astrocytes proliferate and are activated in the hippocampal CAI sector with advancing age. Furthermore, the present study demonstrates that the fibers of oligodendrocytes and total number of microglial cells in the hippocampal CAI sector are decreased during ageing processes. These results suggest that age-related changes of astorocytes, oligodendrocytes and microglia had Occurred in the mouse hippocampal CAI sector. (C) 2007 Elsevier Ireland Ltd. All rights reserved.