Human umbilical cord mesenchymal stem cells injection
BiologicalPahse 1: Patients will be enrolled into one of three cohorts to receive single injection of human umbilical cord mesenchymal stem cells injection(5×10^5 cells × vascular surface area (cm²), 2.5×10^6 cells × vascular surface area (cm²), 5×10^6 cells × vascular surface area (cm²)).
Phase 2: Based on the data obtained from Phase 1, the investigator will select one dose cohort to conduct study.