Research Paper Volume 16, Issue 16 pp 11857—11876

Figure 5. Nicotine activates apoptosis through the DLL4/Notch signalling pathway. (A) Volcano map depicting DLL4 expression. (B) Representative qPCR results illustrating the downregulation of DLL4 upon siRNA-mediated DLL4 knockdown. (C) qPCR analysis of the impact of DLL4 knockdown on apoptosis-related genes. (D) WB analysis showing the effects of DLL4 knockdown on apoptosis and Notch signalling pathway-related proteins. (E) Hoechst staining of THP-1 macrophages (bright blue represents the apoptotic cell nucleus) (scale bar: 50 μm). (F) TUNEL assay to assess apoptosis-positive THP-1 macrophages (green fluorescence indicates apoptotic cells) (scale bar: 50 μm). (n = 3. The data are presented as the mean ± SD. ^*P < 0.05, ^**P < 0.01 and ^***P < 0.001 vs. the control group; ^#P < 0.05, ^##P < 0.01 and ^###P < 0.01 vs. the nicotine group).