Impact of BBI on rat cortical neuron cultures. (A) Effect of BBI on LPS/MΦ-mediated neurotoxicity. Supernatant either from LPS- (100 ng/ml) activated macrophage cultures (LPS/MΦ SN) or from BBI- (1-100 μg/ml) treated and LPS-activated macrophage culture (BBI/LPS/MΦ SN) was used to treat rat cortical neurons (1:10). Untreated and unactivated macrophage supernatant was used as a negative control (MΦ SN). Data are expressed as mean ± SD for three independent experiments. (*P < 0.05, **P < 0.01, BBI/LPS/MΦ SN vs LPS/MΦ SN without BBI). (B) Effect of BBI on neuron death for rat cortical neurons. Rat cortical neurons were directly treated with BBI at the indicated concentrations or with supernatant from either unactivated and untreated macrophage culture (MΦ SN) or BBI- (1-100 μg/ml) treated macrophage culture (BBI/MΦ SN) for 24 h. Data are expressed as mean ± SD for three independent experiments. (C) Effect of BBI treatment on neurotoxicity of LPS-activated macrophages. Cortical neuronal cultures were treated with LPS-activated macrophage supernatant in the presence or absence of BBI for 24 h. Data are expressed as mean ± SD for three independent experiments.