Allium cepa Extract and Quercetin Protect Neuronal Cells from Oxidative Stress via PKC-ε Inactivation/ERK1/2 Activation

Figure 3

Role of p38MAPK and ERK1/2 phosphorylation in neuronal cells during oxidative stress. (a) Cortical cells were treated with 10 mM L-buthionine sulfoximine (BSO) for 24 h in the presence or absence of the Allium cepa extract (ACE) (10 mg/mL), quercetin (QCT) (10 μM), SB (10 μM), or U0126 (10 μM). Lactate dehydrogenase (LDH) release was measured after a 24 h BSO treatment. (b) The number of terminal deoxynucleotidyl transferase dUTP nick end labeling- (TUNEL-) positive (%) cells was calculated by dividing the number of TUNEL-stained cells by the total number of cells after a 24 h BSO treatment. (c) Representative immunoblots for p-ERK1/2 and p-p38MAPK loading were normalized versus ERK1/2 and p38MAPK, respectively. Cells were treated with 10 mM BSO for 2 h in the presence or absence (VEH) of ACE (10 mg/mL), QCT (10 μM), or U0126 (10 μM). (d) Reactive oxygen species (ROS) generation was quantified during BSO treatment after cells were pretreated with ACE (10 mg/mL), QCT (10 μM), or U0126 (10 μM) simultaneously with 10 mM BSO for 4 h. All data are mean ± standard error (). versus 0 time; versus VEH; versus ACE or QCT.

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