Figure 2.

Endoplasmic reticulum stress–mediated apoptosis was involved in Mn‐induced cell death. After treatment with Mn and pretreated with 4‐PBA. (A) The CCK‐8 assay was used to measured cell viability by using the microplate reader at 450 nm shown in a bar graph. (B) The LDH release measured using the microplate reader at 490 nm is shown in a bar graph. (C) The percentage of single positive populations (FITC +/PI –) in quadrant Q4 was regarded as the early apoptosis rate. The early apoptosis in neuron cell by flow cytometry (FCM) is shown in a bar graph. (D) (E) The bands of GRP78, phospho‐PERK, phospho‐eIF2α, ATF4, CHOP, Caspase‐12, PARP, GADD34 and β‐actin expression levels measured by Western blotting assay after treatment with Mn for 6, 12 and 24 h. (F) The relative intensity of GRP78, PERK, phospho‐PERK, eIF2α and phospho‐eIF2α and expression of ATF4 after treatment with Mn for 6 h, 12 h and 24 h are shown in a line graph. (G) The protein CHOP, Caspase‐12, PARP and GADD34 expressions after treatment with Mn for 6, 12 and 24 h are shown in a line graph. (H, I) The bands of GRP78, phospho‐PERK, phospho‐eIF2α, ATF4, CHOP, Caspase‐12, PARP, GADD34 and β‐actin expression levels measured by Western blotting assay after treatment with Mn pretreated with high‐dose 4‐PBA. (J) The relative intensity of GRP78, PERK, phospho‐PERK, eIF2α and phospho‐eIF2α and expression of ATF4 are shown in a bar graph after treatment with Mn and pretreated with high‐dose 4‐PBA. (K) The protein CHOP, Caspase‐12, PARP and GADD34 expressions after treatment with Mn and pretreated with high‐dose 4‐PBA are shown in a bar graph. *P < .05, **P < .01, compared to the controls; ^# P < .05, ^## P < .01, compared to the cells treated for 6 h or 100 μmol/L Mn‐treated group; H, high dose, L, low dose