Chronic systemic D-galactose exposure induces memory loss, neurodegeneration, and oxidative damage in mice: protective effects of R-alpha-lipoic acid.
Chronic systemic exposure of D-galactose to mice, rats, and Drosophila causes the acceleration of senescence and has been used as an aging model. However, the underlying mechanism is as yet unclear. To investigate the mechanisms of neurodegeneration in this model, we studied cognitive function, hippocampal neuronal apoptosis and neurogenesis, and peripheral oxidative stress biomarkers and also the protective effects of the antioxidant R-alpha-lipoic acid. Chronic systemic exposure of mice to D-galactose (100 mg/kg, s.c., 7 weeks) induced a spatial memory deficit, an increase in cell karyopyknosis, apoptosis, and caspase-3 protein levels in hippocampal neurons, a decrease in the number of new neurons in the subgranular zone in the dentate gyrus, a reduction of migration of neural progenitor cells, and an increase in death of newly formed neurons in the granular cell layer. The D-galactose exposure also induced an increase in peripheral oxidative stress, including an increase in malondialdehyde and decreases in total antioxidative capabilities (T-AOC), total superoxide dismutase (T-SOD), and glutathione peroxidase (GSH-Px) activities. A concomitant treatment with lipoic acid ameliorated cognitive dysfunction and neurodegeneration in the hippocampus and also reduced peripheral oxidative damage by decreasing malondialdehyde and increasing T-AOC and T-SOD, without an effect on GSH-Px. These findings suggest that chronic D-galactose exposure induces neurodegeneration by enhancing caspase-mediated apoptosis and inhibiting neurogenesis and neuron migration, as well as increasing oxidative damage. In addition, D-galactose-induced toxicity in mice is a useful model for studying the mechanisms of neurodegeneration and neuroprotective drugs and agents.
Institute of Gerontology and Geriatrics, Chinese PLA General Hospital, Beijing, People's Republic of China.
Xu
X
Cui
Pingping
P
Zuo
Qing
Q
Zhang
Xuekun
X
Li
Yazhuo
Y
Hu
Jiangang
J
Long
Lester
L
Packer
Jiankang
J
Liu
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D053148:Caspase 3; D020169:Caspases / Q000187:drug effects / Q000378:metabolism; D003704:Dementia / Q000188:drug therapy / Q000503:physiopathology / Q000517:prevention & control; D004195:Disease Models, Animal; D005690:Galactose / Q000037:antagonists & inhibitors* / Q000633:toxicity; D005979:Glutathione Peroxidase / Q000378:metabolism; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology; D008569:Memory Disorders / Q000139:chemically induced / Q000188:drug therapy* / Q000503:physiopathology; D051379:Mice; D008810:Mice, Inbred C57BL; D019636:Neurodegenerative Diseases / Q000139:chemically induced / Q000188:drug therapy* / Q000503:physiopathology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D018696:Neuroprotective Agents / Q000494:pharmacology / Q000627:therapeutic use; D009498:Neurotoxins / Q000037:antagonists & inhibitors / Q000633:toxicity; D018384:Oxidative Stress / Q000187:drug effects* / Q000502:physiology; D013482:Superoxide Dismutase / Q000378:metabolism; D008063:Thioctic Acid / Q000494:pharmacology* / Q000627:therapeutic use
D000975:Antioxidants; D018696:Neuroprotective Agents; D009498:Neurotoxins; D008315:Malondialdehyde; D008063:Thioctic Acid; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases; D005690:Galactose