Objective: To study the effects of peroxynitrite anoin (ONOO-) on the differentiation of hippocampus neural stem cells (NSCs) of primary rat

and the action and potential mechanisms of soy bean isoflavones against oxidative damage produced by ONOO- in brain nerve cells. Method: Hippocampus NSCs of primary rat were prepared according to the methods of trypsin digestion combined with mechanical dissociation

and differentiated nerve cells were identified with the method of immunofluorescence. Dysdifferentiation of hippocampus NSCs were induced by SIN-1(1 mmol ·L-1) as a ONOO- donor

then the cells were treated with HbO2(0.05 mmol ·L-1)

SOD/catalase (50 U ·mL-1)

melatonin (0.5 mmol ·L-1) and isoflavones (0.1 mg ·L-1)

respectively

and the differentiation of NSCs was detected with the method of immunofluorescence. Result: Differentiation of hippocampus NSCs were limited by the SIN-1

the number of nestin-positive (NSE+) cells was significantly decreased and the morphological changes of differentiated neural cells were obvious. The number of NSE+ cells was increased and the morphological changes were alleviated with the treatment of NO- scavenger(HbO2)or O-2·scavenger(SOD/catalase)alonely

but that could be alleviated significantly with the treatment of ONOO- scavenger (melatonin) or soy bean isoflavones and the former was better. Conclusion: The dysfunction in the differentiation of hippocampus NSCs of neonatal rat can be produced by ONOO-

which can be improved moderately by soy isoflavones showing the potential of isoflavones in application to the repair of oxidative damages in brain nerve cells.