Chitooligosaccharides protect cultured hippocampal neurons against glutamate-induced neurotoxicity

Chitooligosaccharides (COSs), the biodegradation product of chitosan, have demonstrated a diverse array of biological activities. Here we report the protective effect of COSs (M.W. 800) against glutamate-induced neurotoxicity in cultured hippocampal neurons. The cell viability assessments, together with Hoechst 33342 staining and flow cytometry for cell apoptosis analysis, indicated that glutamate (125 mu M)-induced cell apoptosis in Cultured hippocampal neurons was attenuated in a concentration-dependent manner by COSs pretreatment. After measurement with Fluo 4-AM, COSs were found to depress glutamate-induced elevation in intracellular calcium concentration ([Ca2+](c)). The enzymatic assay indicated that COSs antagonized glutamate-evoked activation of caspase-3. These results collectively suggest that COSs, prevent cultured hippocampal neurons from glutamate-induced cell damage by interfering with an increase in [Ca2+](c) and inhibiting caspase-3 activity. (C) 2008 Elsevier Ireland Ltd. All rights reserved.