Objective To study the effects of hypoxic preconditioning on the Fos and Jun expression and apoptosis in cultured rat hippocampal neurons after anoxia\|reoxygenation. Methods The hippocampal neurons cultured for 12d from control and hypoxic\|preconditioning groups were exposed to anoxia environment (0\^90?l/L N\-2+0\^10?l/L CO\-2) for 4h and than reoxygenated for 24h and 72h.The expression of Fos and Jun were revealed immunocytochemically using the antiserum against Fos and Jun.The apoptosis was examied using the terminal deoxynucleotidyl transferese\|mediated biotinylated deoxyuridine triphosphate nickel and labeling(TUNEL) method and flow cytometric analysis. Results The increased of percentage of Fos and Jun positive neurons and apoptosis neurons in cultured hippocampal neurons after anoxia\|reoxygenation than those in befor anoxia.The precentage of Fos and Jun positive neurons and apoptosis neurons were less in the hypoxic\|preconditioning group than that in control aftre anoxia\|reoxygenation.Conclusion\ Hypoxic\|preconditioning increases tolerance of hippocampal neurons to anoxia and decreases the precentage in Fos and Jun expressing neurons and apoptosis neurons in hippocampus aftre anoxia\|reoxygenation in vitro. \;[