Umbilical Cord Mesenchymal Stem Cells(Tianjin Amcellgene Engineering)

The goal of this clinical trial is to learn if drug mesenchymal stem cells (umbilical cord) injection works to treat acute ischemic stroke in adults. It will also learn about the safety and efficacy of drug mesenchymal stem cells (umbilical cord) injection . The main questions it aims to answer are:
Identify the dose-limiting toxicity (DLT) of drug mesenchymal stem cells (umbilical cord) injection in acute ischemic stroke patients.
Dose the drug mesenchymal stem cells (umbilical cord) injection improves the mRS score, NIHSS score, Fugl-Meyer score and and Barthel index of acute ischemic stroke patients? What is the pharmacokinetic characteristics and immunogenic response of mesenchymal stem cells (umbilical cord) injection in the treatment of acute ischemic stroke patients.
What is the the possible molecular mechanisms of mesenchymal stem cells (umbilical cord) injection in the treatment of acute ischemic stroke patients.
Participants will:
Take drug drug mesenchymal stem cells (umbilical cord) injection once or once a week for three consecutive weeks.
After receiving the corresponding dose of mesenchymal stem cells (umbilical cord) injection, the subjects entered a 6-month safety, efficacy observation and further safety evaluation period. Long term efficacy and survival follow-up up to 2 years.