CCL2 and Parkinson disease: As shown in Fig. 5, compared with PD + PBS group, the transplantation of MenSCs significantly down-regulated the amount of pro-inflammatory factors IL-1β (Fig. 5C, #p < 0.05), MCP-1 (Fig. 5E, ###p < 0.001), and TNF-α (Fig. 5F, ##p < 0.01) in the cerebrospinal fluid (CSF).