Effects of MANF on the viability of MPP+-treated SH-SY5Y cells. A. SH-SY5Y cells were seeded in 96-well plates and exposed to different concentrations of MPP+ for 24 h, and cell viability was assessed by MTT assay. ▲: control group, ▼: treatment with different concentrations of MPP+ for 24 h, SH-SY5Y cells treated with 2 mM MPP+ were used to establish the cytotoxic model of PD. B. Cells were pretreated with different concentrations of MANF (50, 200 and 400 ng/mL) for 2 h before incubation with 2 mM MPP+ for 24 h, and cell viability was assessed by MTT assay or cells were incubated with various concentrations of MANF for 24 h. Data are presented as mean ± S.E.M. *P<0.05, **P<0.01 vs MPP+-treated group. #P<0.05, ##P<0.01 vs control group.