Cystine Deprivation Induces Oligodendroglial Death: Rescue by Free Radical Scavengers and by a Diffusible Glial Factor
Version of Record online: 23 NOV 2002
Journal of Neurochemistry
Volume 67, Issue 2, pages 566–573, August 1996
How to Cite
Yonezawa, M., Back, S. A., Gan, X., Rosenberg, P. A. and Volpe, J. J. (1996), Cystine Deprivation Induces Oligodendroglial Death: Rescue by Free Radical Scavengers and by a Diffusible Glial Factor. Journal of Neurochemistry, 67: 566–573. doi: 10.1046/j.1471-4159.1996.67020566.x
- Issue online: 23 NOV 2002
- Version of Record online: 23 NOV 2002
- Received January 17, 1996; revised manuscript received March 27, 1996; accepted March 29, 1996.
- Free radicals
Abstract: In this study we examined the effect on oligodendroglial survival of exogenous cystine deprivation. Oligodendroglia isolated from mixed glial primary cultures derived from brains of 1-day-old rats, and then grown for 3 days, were markedly dependent on extracellular cystine for survival. The EC50 values for cystine for a 24-h exposure ranged from 2 to 65 µM. After 6 h of cystine deprivation, the cellular glutathione level decreased to 21 ± 13% of the control. Free radical scavengers (α-tocopherol, ascorbate, idebenone, and N-tert-butyl-α-phenylnitrone) were protective against cystine deprivation but had no effect on the glutathione level. An iron chelator, desferrioxamine mesylate, also was protective. These findings suggest that intracellular hydroxyl radicals are important for this toxicity. In contrast to the observations in 3-day-old cultures, the dependence on exogenous cystine for cell viability was not observed consistently in oligodendroglia cultured for 6 days before the onset of cystine deprivation. Several observations suggested that this loss of cystine dependence was due to a diffusible factor. Sensitivity to the toxicity of cystine deprivation in day 6 cultures increased as the volume of medium was increased from 0.3 to 2 ml. Furthermore, preincubation of cystine-depleted medium with astrocyte cultures eliminated the toxicity of the cystine deprivation. HPLC assay of the conditioned cystine-depleted medium showed no significant change in cystine or cysteine concentration. We conclude that oligodendroglia are highly susceptible to cystine deprivation in day 3 cultures and that this susceptibility is due to the accumulation of intracellular free radicals in the setting of glutathione depletion. The resistance of day 6 oligodendroglial cultures is caused at least in part by a diffusible factor.