Effects of umbilical cord blood monocytes transplantation on EPO protein and oligodendrocyte progenitors in neonatal rats with hypoxic-ischemic brain damage

Objective: To study the effects of umbilical cord blood monocytes (UCBMC) transplantation on erythropoietin (EPO) protein and oligodendrocyte progenitor cells in hypoxia-ischemia (HI) neonatal rats. Methods: Forty seven-day-old Sprague-Dawley rats were randomly divided into normal control (N), HI, UCBMC and HI+UCBMC groups (n=10 each). Hypoxic-ischemic brain damage (HIBD) model was prepared according to the Rice method. Twenty-four hours after hypoxia, the N and HI groups were injected with 2 μL phosphate buffered saline (PBS), and the UCBMC and HI+UCBMC groups were injected with 3×10⁶ UCBMC via the lateral ventricle. EPO protein and oligodendrocyte progenitor cells in the subventricular zone of the injured brain were observed by EPO/DAPI and NG2/DAPI immunofluorescence double staining, and their correlation was analyzed. Results: Seven days after transplantation, there were more NG2 ⁺DAPI⁺ and EPO⁺DAPI⁺ cells in the HI+UCBMC group than in the UCBMC (P<0.05), N and HI groups (P< 0.01). More NG2⁺DAPI⁺ and EPO⁺DAPI⁺ cells were observed in the UCBMC group compared with the N and HI groups (P<0.01). There were more NG2⁺DAPI⁺ cells in the N group than in the HI group (P<0.01). The number of NG2⁺DAPI⁺ cells was correlated with the number of EPO⁺DAPI⁺ cells in the HI+UCBMC group (r=0.898, β=1.4604, P<0.01). Conclusions: UCBMC can promote expression of oligodendrocyte progenitor cells, which is correlated with an increase in EPO protein and thus repairs brain white matter damage in neonatal rats with HIBD.