Expression Profile of Fas-Fas Ligand in Spiral Ganglion Cells During Apoptosis

OBJECTIVES: To examine the expression profile of Fas-Fas ligand (FasL) during glutamate (Glu)-induced spiral ganglion cell (SGC) apoptosis. METHODS: Cultured SGCs were treated with 10-mM, 25-mM, and 50-mM concentrations of Glu and incubated for 24 or 48 hours. The expression intensity of FasL, Fas, caspase 3, and morphology of single SGC were evaluated using immunofluorescence staining. RESULTS: In semiquantitative analysis of the Glu-treated SGC, FasL, and caspase 3 expression intensity were increased with concentration- and time-dependent manner. Fas expression intensity did not change with different concentration at 48 hours. In morphologic analysis of the Glu-treated SGC, number of apoptotic cells were increased with concentration- and time-dependent manner. CONCLUSION: FasL was expressed in apoptotic SGCs, suggesting that the Fas-FasL signaling pathway may be involved in the Glu-induced apoptosis of dissociated SGCs.