Objective       To investigate inflammatory cytokines expression and survival of N9 microglia after different stimulations.        Methods       In vitro

cultured N9 microglias were divided into a control group

a LPS+IFN-γ  stimulation group (M1) and an IL-4 stimulation group (M2). Total RNA were extracted and inflammatory cytokine mRNA were detected through Q-RT-PCR and total culture media were collected to detect the concentration of inflammatory cytokines through ELISA

24 h after stimulation. N9 microglias were divided into a control group

a LPS group

an IFN-γ group

a LPS+IFN-γ group

and an IL-4 group to study the effects of the cytokines on N9 microglia survival. The survival rates of each group were detected through Hoechst-PI staining. The expression of caspase-3 was detected by Western blotting.        Results       In the aspect of inflammatory cytokines secretion

the cells in group M1 expressed more pro-inflammatory cytokines than those in the control group and group M2 (P0.01). The cells in group M2 expressed more anti-inflammatory cytokines than those in the other 2 groups (P0.01). In the aspect of cell survival

we found the cells in the IFN-γ and LPS+IFN-γ groups had lower survival rates and higher caspase-3 expression than those in other groups (P0.05，P0.01).        Conclusion       N9 microglia can be polarized like macrophages and express different inflammatory cytokines after different stimulations. IFN-γ may affect the survival of N9 microglia though regulating Caspase-3 expression.