The effect of Ginkgo biloba extract (EGb 761) on parameters of oxidative stress in different regions of aging rat brains after acute hypoxia
Rosemarie Martin1, Christian Mozet2, Hans Martin1, Klaus Welt3, Christoph Engel4 and Günther Fitzl3
1Institute of Laboratory Medicine, Clinical Chemistry, and Molecular Diagnostics, Department of Medicine, 2Institute of ENT, Department of Medicine, 3Institute of Anatomy, Department of Medicine, 4Institute for Medical Informatics, Statistics and Epidemiology (IMISE), University of Leipzig, Leipzig, Germany.

Abstract

Background and aims: 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 short-term hypoxia. EGb’s protective effect is especially notable in the brainstem and the cerebellum. (Aging Clin Exp Res 2011; 23: 255-263) ©2011, Editrice Kurtis

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