Umbilical Cord Blood-Derived CD34+ Cells Improve Outcomes of Traumatic Brain Injury in Rats by Stimulating Angiogenesis and Neurogenesis

Human umbilical cord blood cells (HUCBCs) have been shown to be beneficial in reducing neurological deficits in rats with brain fluid percussion injury (FPI). This study aimed to assess the basic mechanisms underlying the neuroprotective effects of HUCBC-derived cluster of differentiation 34-positive (CD34+) cells. Rats were divided into three major groups: (i) sham-operated controls; (ii) FPI rats treated with phosphate-buffered saline (PBS); (iii) FPI rats treated with 0.2%, 50%, or 95% CD34+ cells (in 5 × 105 cord blood lymphocytes and monocytes). Intravenous (IV) administration of 0.3 ml of PBS, 0.2% CD34+ cells, 50% CD34+ cells, or 95% CD34+ cells was conducted immediately after FPI. It was found that 4 days post-FPI, CD34+ cells could be detected in the ischemic brain tissues for 50% CD34+ cell- or 95% CD34+ cell-treated FPI rats, but not for the PBS-treated FPI rats or the 0.2% CD34+ cell-treated FPI rats. CD34+ cell (0.2%)-treated FPI rats or PBS-treated FPI rats displayed neurological and motor d...