Gypenosides protect primary cultures of rat cortical cells against oxidative neurotoxicity

Linshan Shang, Jincheng Liu, Qingjun Zhu, Ling Zhao, Yuxin Feng, Xuping Wang, Weipeng Cao, Hua Xin

Research output: Contribution to journalArticlepeer-review

55 Scopus citations

Abstract

Gypenosides (GPs) were tested for their ability to protect primary cultures of immature cortical cells against oxidative glutamate toxicity. In immature neural cells, glutamate cytotoxicity is known to be mediated by the inhibition of cystine uptake, leading to depletion of intracellular glutathione (GSH). The depletion of GSH impairs cellular antioxidant defenses resulting in oxidative stress and cell death. We found that pretreatment with GPs (100-400 μg/ml) significantly protected cells from glutamate-induced cell death. It was therefore of interest to investigate whether GPs protect cortical cells against glutamate-induced oxidative injury through preventing GSH depletion. Results show that GPs significantly up-regulated mRNAs encoding γ-glutamylcysteine synthetase (γ-GCS) and glutathione reductase (GR) and enhanced their activities for GSH synthesis as well as recycle. Furthermore, GPs lowered the consumption of GSH through decreased accumulation of intracellular peroxides, leading to an increase in the intracellular GSH content. GPs were also found to prevent lipid peroxidation and reduce the influx of Ca2+ which routinely follows glutamate oxidative challenge. GPs treatment significantly blocked glutamate-induced decrease in levels of Bcl-2 and increase in Bax, leading to a decrease in glutamate-induced apoptosis. Thus, we conclude that GPs protect cortical cells by multiple antioxidative actions via enhancing intracellular GSH, suppressing glutamate-induced cytosolic Ca2+ elevation and blocking glutamate-induced apoptosis. The novel role of GPs implies their remarkable preventative and therapeutic potential in treatment of neurological diseases involving glutamate and oxidative stress.

Original languageEnglish (US)
Pages (from-to)163-174
Number of pages12
JournalBrain Research
Volume1102
Issue number1
DOIs
StatePublished - Aug 2 2006
Externally publishedYes

Keywords

  • Apoptosis
  • Glutathione depletion
  • Gypenoside
  • Neuroprotection
  • Oxidative toxicity

Fingerprint Dive into the research topics of 'Gypenosides protect primary cultures of rat cortical cells against oxidative neurotoxicity'. Together they form a unique fingerprint.

Cite this