Effects Of Human Amniotic Mesenchymal Stem Cells Transplantation On The Neurological Function Of Rats With Spinal Cord Injury

Objectives:Human amniotic mesenchymal stem cells(hAMSCs) draw great interest as a source of cells for regeneration medicine because of its phenotypic plasticity.But there are no reports about therapies for neurological disorders by hAMSCs transplantation so far.In this study,we have investigated the effect of hAMSCs transplantation on the neurological function restoration of rats with spinal cord injury in order to evaluate the future application value of hAMSCs in spinal cord injury.Methods:①hAMSCs were isolated from amniotic tissue with trypsin and collagenase two step digestion.The phenotype of the isolated cells was identified by flow cytometry as well as immunofluorescent stain.②Forty adult female SD rats were subjected to spinal cord transsection injury and randomly divided into hAMSCs transplantation group and PBS control group.For transplantation group of 20 rats,a gelfoam absorptted about 2×10~5 hAMSCs was transplanted into the interval of injury ends immediately after spinal cord intersecting in each rat.While hAMSCs were substituted with 10μl PBS fluid in each another 20 model rats as control.③Neurological function was evaluated by Basso Beatlie Bresnahan(BBB) behavioral testing in two groups from 1 to 8 weeks post-transplantation.④Three rats of each group were randomly killed to detect the expression of human cells nuclear antigen and neuroeyte specific proteins of MAP-2,GFAP by immunofluorescent stain at 2 weeks post-transplantation so as to observe the exist and differentiation of transplanted hAMSCs.⑤At 8 weeks post-transplantation,immunohistochemical stain was used to detect the expression of NF-200 in the distal end of injured site.Results:①In primary cultured hAMSCs,the expression level of CD29,CD44 and CD71 were 98.16%,50.96%,and 12.30%respectively,but the hematopoietic cells surface markers such as CD34,CD45,and HLA-DR were absent.Immunofluorescent stain showed that the primary cultured hAMSCs were positive for Vimentin but negative for CK19.②Immunofluorescence staining detected the positive cells of human nuclear antigen in the graft at 2 weeks post-transplantation,but MAP-2 and GFAP expression cells could not be detected.③BBB scores of hAMSCs cell-grafting group increased dramatically form the 2nd week(3.95±0.78) to the 8th(7.67±0.90)week,and their scores were higher than that of PBS control group(P＜0.05).④The expression of NF-200 at the distal end of injured site of spinal cord in the hAMSCs transplantation group was remarkably higher than that of PBS control group.Conclusions:Transplantation of hAMSCs can benefit to improve neurological function restoration of rats with spinal cord injury,and its mechanism might relate to promotion of NF-200 expression in the distal end of injured spinal cord after hAMSCs transplantation.