Fig. 4

Sinomenine protects hippocampal neuronal cells from indirect toxicity. The C8D1A astrocytic cells were treated with oligomeric amyloid beta (ADDL) in the absence or presence of sinomenine. The conditioned medium was used to treat HT22 cells, and cell death was determined by TUNEL assay. The representative images of DAPI- or TUNEL-stained HT22 cells (a) and quantified summary data (b; n = 4) demonstrate that HT22 cells treated with the conditioned medium from ADDL-treated astrocytic cells showed increased number of TUNEL positive cells. However, sinomenine inhibited the ADDL-induced increase in the number of TUNEL positive cells. The HT22 cells treated with the conditioned medium from astrocytic cells that were treated with sinomenine alone, did not show increased number of TUNEL positive cells. Asterisk indicates significant difference from control (p < 0.05). # indicates significant difference (p < 0.05) between groups as indicated. Scale bar, 50 μm