The Efficacy Of Human Placenta-derived Mesenchymal Stem Cell Exosomes In The Treatment Of Ischemic Stroke In Rats

Objective:In this study,by using reforming longa method,the rat model of unilateral middle cerebral artery occlusion(MCAO)was established.A certain amount of human placental derived mesenchymal stem cells(HP MSCs)and their exosomes(Exo)were infused through the caudal vein to observe and compare the changes of neural function score,cerebral infarction volume,apoptosis and other related indexes in each group,so as to evaluate whether the exosomes from human placenta mesenchymal stem cells can effectively promote the recovery of neural function in rats.Methods:Selected the healthy SD male rats with a body weight of 250-280 g on the basis of the middle cerebral artery occlusion(MCAO)model by using reforming longa method.The rats were divided into four groups(n = 8),which were sham operation group,MCAO group,MCAO + MSCs group and MCAO + Exo group.In MCAO + MSCs group,3 * 106 stem cells(mixed in 1ml PBS)were injected into caudal vein by syringe 24 hours after ischemia and reperfusion for 90 min.In MCAO + Exo group,the amount of exocrine was 100ug(mixed in 1ml PBS)at the meantime.In sham operation group,the same amount of 1ml PBS was injected into MCAO group.Neurobehavioral scores of each group were observed before and after MCAO on the day of 1,3,7 and 14.After 14 days,all rats were decapitated and their brain tissues were taken to evaluate the volume of cerebral infarction in each group and the apoptosis of cells in ischemic area was detected by TUNEL kit method.Results:1.Identification and detection of human placenta derived mesenchymal stem cells: through flow cytometry,the surface marker molecules CD90 and CD105 of the stem cells were highly expressed,while CD34 and HLA-DR were not expressed,which had typical marker molecules of mesenchymal stem cells.2.Identification and detection of exosomes:(1)The membranous structure of classical exosomes was revealed under the electron microscope;(2)By Western Blot(WB),detected the expression of exosomes specific markers: CD63,Alix and TSG101,which confirmed that the extracted substance was exosomes.3.Compared with the model group,the neurologic function score of the exocrine group was significantly reduced(P < 0.05),the volume of cerebral infarction was significantly reduced(P < 0.05),the number of apoptosis in the ischemic area was significantly reduced(P < 0.05),but there was no significant difference between the stem cell group and the exosome group(P > 0.05).Conclusion:The exosomes derived from human placenta derived mesenchymal stem cells have the effect of stem like cells,which can improve the neural function score of animal model,reduce the volume of cerebral infarction,and reduce the apoptosis of cells in the ischemic area of brain tissue.