A Phase IIa Clinical Trial to Evaluate the Efficacy and Safety of Intravenous Infusion of hUC-MSCs in Patients With AIS

2.0×10\^8 cells per infusion, single administration on D0. Infusion of cell medium placebo on Day 7 (±2 days), and Day 14 (±2 days).

1.0×10\^8 cells per infusion, 3 administrations, on Day 0, Day 7 (±2 days), and Day 14 (±2 days)

Cell medium, 3 administrations, on Day 0, Day 7 (±2 days), and Day 14 (±2 days)