Figure 1.

The cellular viability and the mRNA and protein expressions of GPR4 in MPP⁺- and H₂O₂-treated SH-SY5Y cells. 24 h serum-starved SH-SY5Y cells were treated with different concentrations of MPP⁺ (0.25, 0.5, and 1 mM) and H₂O₂ (50, 75, and 125 µM) for 24 h in serum-free culture media. (A) The cellular viability of the SH-SY5Y cell after treatment with different concentrations of MPP⁺ and H₂O₂ in serum-free media for 24 h. (B) Reverse transcription-polymerase chain reaction (RT-PCR) and immunoblotting demonstrate the mRNA and protein expressions of GPR4 in SH-SY5Y cells at different time points (3, 6, 12, 18, and 24 h) after stimulation with MPP⁺ (1 mM) and H₂O₂ (125 µM) in serum-free media. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and β-actin were utilised as the internal controls. Mean ± standard error of the mean (SEM; n = 3) was employed to express the data. Tukey’s multiple comparison test was performed using a one-way analysis of variance (ANOVA). Each * p < 0.05 refers to the other sample concentrations compared with the control cells.