Abstract: Objective To evaluate the variance of oxidative tolerance(OT) against hydrogen peroxide (H₂O₂) in differentiated neural stem cells (DNSC).Methods The DNSC of SD rat obtained after 8 days' differentiation, were cultured in media with H₂O₂(0.5 mmol/L) for 2 hours, followed by observation of their variance of oxidative tolerance. The survial was cultured for another 21 days, then observed the capability of proliferation and differentiation. The viability was assessed with fluorescent dye including Hoechst 33342 and PI. The antioxidant stress test included the expression of heat shock proteins (Hsps), catalase(CAT) and superoxide dismutase(SOD). The cellular types were determined by its markers, such as nestin, proliferating cell nuclear antigen(PCNA), MAP-2 and tubulin-β, GFAP, Gal-C. The transmission electron microscope(TEM) was used to study the ultrastructure of DNSC.Results After H₂O₂ attacks, DNSC at the periphery died and fell off from the cover glass, while those located at the central part survived and kept on differentiation and demonstrated positive staining by nestin(PCNA), MAP-2, tubulin-β, GFAP, and Gal-C, with no significant difference from the control group(P>0.05). TEM demonstrated the DNSC at the periphery with a relatively mature organelle and those at the central part with immature characteristics.Conclusion The relatively immature DNSC has a higher resistance against H₂O₂ than those relatively well-differentiated DNSC. DNSC surviving from H₂O₂ attack still keep the capability proliferate and differentiate.

Key words: neural stem cell, oxidative tolerance, preconditioning