Figure 3: Effects of PFOS on the expression of BDNF, TrkB, and CREB in SH-SY5Y cells. Cells were cultured for 48 h with various concentrations of PFOS (10, 50, and 100 μM) or DMSO (control). (a) BDNF mRNA levels in SH-SY5Y cells. (b) BDNF protein levels in the culture supernatant from SH-SY5Y cells. (c) TrkB protein levels in SH-SY5Y cells. (d) CREB mRNA levels in SH-SY5Y cells. (e) CREB and pCREB protein levels and the pCREB/CREB ratio in SH-SY5Y cells; the band intensities of pCREB and CREB were quantified, and the fold increases in the ratio of pCREB/CREB are presented as a bar graph. (f) The protein levels of TrkB, CREB, and pCREB were determined by Western blot analysis using β-Actin as an internal control. Each data point was normalized to the control (DMSO), and the data are presented as mean ± SD from three independent experiments. , experimental values compared with control values.