Hextend Protects Nerve Growth Factor Differentiated PC12 Cells From Oxidative-Radical-Stress-Induced Apoptosis Through its Effect on Phosphoinositide 3-Kinase/Akt and Glycogen Synthase Kinase-3

Abstract

Background & Objectives: The effects of Hextend, a volume expender, on the phosphoinositide 3-kinase (PI3K)/Akt and glycogen synthase kinase-3 (GSK-3) pathway during oxidative-stress induced injury were studied using H2O2 treated PC12 cells which were differentiated by nerve growth factor

Method: To evaluate the toxicity of Hextend itself, nPC12 cells were treated with several concentrations of Hextend, and 3,(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and trypan blue stain were performed. Additionally expression of cytochrome c, caspase-3, poly (ADP-ribose) polymerase (PARP), PI3K/Akt, and GSK-3 was examined using western blot analyses

Results: Following 100 μM H2O2 exposure, the viability of differentiated PC12 cells (Hextend treated vs. not treated) was evaluated the number of viable cell with trypan blue and 3,[4,5-dimethylthiazol-2-yl(MTT). Hextend-treated PC12 cells showed an increase of viability compared to untreated PC12 cells, and treatment of PC12 cells with Hextend induced a dose-dependent inhibition of caspase-3 activation and PARP cleavage. However, inhibition of cytochrome c release was only detected in Hextend treated cells. Upon examination of the PI3K/Akt and GSK-3 upstream pathway, western blots of Hextend treated cells showed increased immunoreactivity (IR) of p85a PI3K, phosphorylated Akt, and phosphorylated GSK-3.

Conclusion: These results show that Hextend affects the PI3K/Akt, GSK-3 pathway as well as downstream signaling, including the cytochrome c and caspase-3 pathways. Therefore, it is suggested that Hextend mediated activation of PI3K/Akt and inhibition of GSK-3 could be a new potential therapeutic strategy or neurodegenerative diseases associated with oxidative injury.