title: Astrocyte activation but not neuronal impairment occurs in the hippocampus of mice after 2 weeks of d-galactose exposure.
abstract: OBJECTIVE
  The objective of this study is to prove that activation of astrocytes precedes neuron cell death in the neurodegenerative process induced by d-galactose (d-gal) exposure.
  
  
  METHODS
  Male adult mice were given intraperitoneal injection of d-gal (200 mg/kg per day) for 2 weeks. The whole brain homogenate and hippocampal sections were then prepared for biochemical analyses, immunohistochemistry and electron microscopy, respectively.
  
  
  RESULTS
  There were no statistically significant differences in brain oxidative and antioxidative parameters between d-gal-treated mice and saline controls. There was also lack of morphological impairment in hippocampal neuronal soma, dendrites and synapses in the model mice. In contrast, hippocampal astrocytes were dramatically activated, and perisynaptic processes of astrocytes were swelling as revealed by ultrastructural analysis. Moreover, d-gal-treated group showed increases in immunostaining levels of glutamate transporter-1 and aquaporin-4 in the hippocampus, which might increase uptake of glutamate from the synaptic cleft into astrocytes.
  
  
  CONCLUSIONS
  These results reveal that astrocytes undergo structural and biochemical changes while no impairment of neuronal elements occurs after 2 weeks of d-gal exposure. Thus, targeting astrocytes may be a promising strategy for the treatment of neurodegenerative diseases at the early stages.
authors.affiliation: Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, 140 Hanzhong Road, Nanjing, Jiangsu Province 210029, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wu
authors.forename: Min
authors.initials: M
authors.lastname: Li
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.forename: Junying
authors.initials: J
authors.lastname: Gao
authors.forename: Hui
authors.initials: H
authors.lastname: Kong
authors.forename: Jiong
authors.initials: J
authors.lastname: Ding
authors.forename: Gang
authors.initials: G
authors.lastname: Hu
authors.forename: Ming
authors.initials: M
authors.lastname: Xiao
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000032:analysis*; D001253:Astrocytes / Q000378:metabolism / Q000648:ultrastructure; D001921:Brain / Q000502:physiology*; D016923:Cell Death; D005690:Galactose / Q000009:adverse effects* / Q000502:physiology*; D018698:Glutamic Acid / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology / Q000473:pathology* / Q000502:physiology; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D019636:Neurodegenerative Diseases / Q000139:chemically induced* / Q000473:pathology; D009474:Neurons / Q000502:physiology*; D018384:Oxidative Stress / Q000502:physiology
chemical_list: D000975:Antioxidants; D018698:Glutamic Acid; D005690:Galactose