The effect of Ginkgo biloba extract (EGb 761) on parameters of oxidative stress in different regions of aging rat brains after acute hypoxia.
OBJECTIVE
Neurodegenerative processes of aging seem to be associated with oxidative stress by reactive oxygen species (ROS). This study investigates the influence of age and of acute respiratoric hypoxia on parameters of oxidative stress in different brain regions of Wistar rats and the protective effects of Ginkgo extract (EGb 761) as a radical scavenger.


METHODS
Biopsies of frontal and temporal cortices, the cerebellum, and the brainstem of young and old rats (each group n=6-8: normoxic - hypoxic; unprotected - EGb-protected) were analyzed for malondialdehyde (MDA) levels, superoxide dismutase (SOD) activity, glutathione (GSH) content, and creatine kinase (CK) activity. Experimental hypoxia: downregulation of oxygen partial pressure to 5 vol. % for 20 minutes. EGb administration: daily 100 mg/kg of body weight in drinking water for 3 months.


RESULTS
Effects of age: While most oxidative stress parameters in the temporal cortex, the cerebellum, and the brainstem are increased, this is not the case in the frontal cortex; after additional hypoxia SOD and GSH are diminished in the temporal cortex and the brainstem of old rats. EGb treatment causes contradictory alterations in young, old, and hypoxic brain regions. Minor effects are seen in old hypoxic brains, while there are some protective effects in old normoxic brainstems and cerebellums.


CONCLUSIONS
The old brain appears to adapt appropriately to chronic oxidative stress and to the specific conditions of shortterm hypoxia. EGb's protective effect is especially notable in the brainstem and the cerebellum.
Martin
Rosemarie
R
Institute of Laboratory Medicine, Clinical Chemistry, and Molecular Diagnostics, Department of Medicine, University of Leipzig, Germany.
Mozet
Christian
C
Martin
Hans
H
Welt
Klaus
K
Engel
Christoph
C
Fitzl
Günther
G
D000375:Aging / Q000502:physiology*; D000818:Animals; D001921:Brain / Q000033:anatomy & histology* / Q000187:drug effects* / Q000378:metabolism; D003402:Creatine Kinase / Q000378:metabolism; D020441:Ginkgo biloba / Q000737:chemistry; D005978:Glutathione / Q000378:metabolism; D000860:Hypoxia / Q000378:metabolism*; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects*; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013482:Superoxide Dismutase / Q000378:metabolism; D000096983:Ginkgo Extract
D003402:Creatine Kinase; D005978:Glutathione; D010936:Plant Extracts; D013482:Superoxide Dismutase; C063170:Ginkgo biloba extract; D000096983:Ginkgo Extract