Figure 1. HOTAIR was up-regulated in MPP⁺-stimulated SK-N-SH cells. (A) After SK-N-SH cells were treated with different concentrations of MPP⁺ (0 mM, 0.25 mM, 0.5 mM and 1 mM) for 24 h, the expression of HOTAIR was detected by qRT-PCR. (B) SK-N-SH cells were stimulated with 1 mM MPP⁺ for 0 h, 12 h, 24 h or 48 h, and qRT-PCR was used to detect HOTAIR expression. *P < 0.05.