Intraspinal Transplantation Of Endothelial Progenitor Cells Provides Neuroprotection After Spinal Cord Injury

Objective: To explore whether transplanted EPCs provide neuroprotective effects to rat spinal cord injury.Methods: Endothelial progenitor cells(EPCs)were differentiate from bone marrow mononuclear cells,which obtained from Sprague-Dawley rats' bone marrow.The single cell suspensions of EPCs with a concentration of 1×105 cells/?l for transplantation were labeled by CM-Dil.We constructed the rat SCI model by the modified Allen method and immediately transplanted EPCs into the lesion site,with an EPC culture medium as a control.We examined the BBB score of every rats 1,2,3,4,5,6 weeks post injury.The spinal cord were took out 1 and 2 weeks post injury to look for the CM-Dil labeled cells,examine the expression of VEGF by western blot,detect the CD31 positive cells and the apoptotic cells.6 weeks after surgery,the number of Neu N positive cells and GFAP positive cells were detected.Results:(1)EPCs survived in local injury site and migrated to spinal cord parenchyma after 2 weeks intraspinal transplantation.The expression of VEGF were significantly higher in EPCs transplanted rats than medium transplanted rats after 1and 2 weeks after injury(P<0.05).After 2 weeks,the percentage of CD31 positive endothelial cells in EPCs transplanted rats were 38.32 ± 1.49% and in medium transplanted rats were 19.02±0.47%,the percentage of apoptotic cells were 38.50±5.01%,in EPCs transplanted rats and 18.67±1.86% in medium transplanted rats,the both different was statistically significant.6 weeks after injury,the percentage of number of Neu N(32.04±3.33% vs 19.34±2.70%,P<0.05)in EPCs transplanted rats were significantly more than medium transplanted rats.With the prolongation of the time after injury,the motor function were both improved in experimental group and control group.The BBB score in EPCs treated rats were higher than medium treated rats in every time points,but only in 6 weeks,the different was statistically significant(7.7±1.34 vs 6.1±1.10,P<0.05).Conclusions: EPCs transplantation provide neuroprotective effects for spinal cord injured rats and improve motor function recovery.