Aging in a dish: Age-dependent changes of neuronal survival, protein oxidation, and creatine kinase BB expression in long-term hippocampal cell culture

Results from different experimental systems demonstrate that increased oxid ative damage plays a role in normal aging and age-associated pathology. In the current study, long-term cultures of hippocampal neurons were examined as a model system. It was established that neuronal survival in long-term c ulture decreases according to the Gompertz law and that neuronal "aging in the dish" is associated with increased oxidative damage of cell proteins. T he increase of protein carbonyl formation in aged neurons was demonstrated both by Western blot analysis for oxidized proteins and by in situ immunocy tochemical method, which was developed to analyze protein oxidation in fixe d cells. In aging neuronal cultures, a gradual increase in creatine kinase (CK) content but decreased activity of enzyme per immunoreactive protein wa s found, suggesting the accumulation of inactive CK molecules, The increase in CK content was not a result of generalized protein elevation, since ana lysis of beta-actin content showed a time-dependent loss, probably reflecti ng decreased number of cellular processes with aging. These findings, showi ng "aging in a dish," consistent with the notion that aging is associated w ith increased protein oxidation, provide a system for study of age-related neurodegenerative disorders associated with oxidative stress. (C) 1999 Wile y-Liss, Inc.