Astrocytes are closely associated with Alzheimer\'s disease (AD).However,their precise roles in AD pathogenesis remain controversial.One of the reasons behind the different results reported by different groups might be that astrocytes were targeted at different stages of disease progression.In this study,by crossing hAPP (human amyloid precursor protein)-J20 mice with a line of GFAP-TK mice,we found that astrocytes were activated specifically at an early stage of AD before the occurrence of amyloid plaques,while microglia were not affected by this crossing.Activation of astrocytes at the age of 3-5 months did not affect the proteolytic processing of hAPP and amyloid plaque loads in the brains of hAPP-J20 mice.Our data suggest that early activation of astrocytes does not affect the deposition of amyloid β in an animal model of AD.