Protective Effect of Ultra Low Molecular Weight Heparin on Glutamate-Induced Apoptosis in Cortical Cells.

Purpose: To investigate the effect of ultra low molecular weight heparin (ULMWH) on glutamate induced apoptosis in rat cortical cells and to explore the possible mechanisms. Materials and Methods: Cell viability was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Apoptosis was first analyzed with Hoechst 33258 and then confirmed by DNA fragmentation. The concentration of free intracellular calcium ([Ca²⁺]_i) was determined with fura-2/AM fluorometry. The expression of Bcl-2 family protein and caspase-3 were evaluated with Western blot. Results: Typical apoptotic morphological change in rat cortical cells treated with 100 µmol/L glutamate for 24 h was detected by Hoechst 33258 staining, which was then confirmed by the DNA ladder of agarose gel electrophoresis. The apoptotic rate of the glutamate treated cells was up to 33.21%, and 24 h of treatment with glutamate increased [Ca²⁺]_i, down-regulated Bcl-2 expression, up-regulated Bax expression, and increased caspase-3 activation in rat cortical cells. Our research demonstrated that ULMWH pretreatment can prevent the glutamate- induced apoptosis, attenuate the increase of [Ca²⁺]i not only in medium containing Ca²⁺ but also in Ca²⁺-free medium, up-regulate the expression of Bcl-2, down-regulate the expression of Bax, and decrease caspase-3 activation. Conclusion: ULMWH has neuroprotective capacity to antagonize glutamate-induced apoptosis in cortical cells, through decrease of Ca²⁺ release and modulation of apoptotic processes. [ABSTRACT FROM AUTHOR]