Effects of SAHA on human astrocytic U-373 MG cell viability and their IFN-γ-induced toxicity toward SH-SY5Y human neuronal cells. U-373 MG cells were incubated with or without SAHA at the concentrations indicated for 1 h before stimulation with IFN-γ (50 U/ml). Control U-373 MG cells were incubated with medium only. After 24 h incubation, the cell-free supernatants of U-373 MG cells were collected and the viability of U-373 MG was measured by the MTT assay (A). The collected supernatants were transferred to each well containing SH-SY5Y cells. After 72 h incubation, the SH-SY5Y cell viability was assessed by the MTT (B) and the LDH (C) assays. Data (means ± S.E.M.) are expressed as the percent of live cells, where the 100% value is obtained from either non-stimulated astrocytes in the control group (A) or SH-SY5Y cells incubated with fresh medium only (B), or the percent of lysed cells, where the 100% value is obtained from SH-SY5Y cells lysed by 1% Triton X-100 (C). *Significantly different from IFN-γ stimulation only. n = 6 to 7.