The Experimental Study Of Treatment To Cerebral Ischemic Rats With Bone Marrow Mesenchymal Stem Cells

Backround and ObjectiveCerebravascular disease (CVD) is one of clinical common diseases, which rank tothe 3rd leading cause of death to human being and the 1st cause of death lead by allvascular diseases. More than 300 millions people died in CVD every year in China andthe mobility is 200 millions. Occurrence of disability after cerebral ischemia iscommon, which seriously undermines the quality of the patients' lives.and also leadeconomic burdem to their families and the society. 70% of cerebravascular diseases areischemic and even up to 85% in USA and Eeurop country. Up to now, there is no bettermethod to treat such patients except thrombolytic therapy in the acute period. BMSCshave newly developed to be a promising method on the treatment of ischemic cerebralstroke. Resent publications showed that human BMSCs transplantation can improvethe functional restore of the cerebral ischemic rats after MCAO.Bone marrow mesenchymal stem cells (BMSCs) are multipotent and representone group of non-hematopoietic stem cells in the marrow, which can differentiate intomultiple lineages. BMSCs had the ability to help the structural and functionalreconstruction of injured or senile organs and become one of the most promising stemcells in the field of regenerative medicine for their advantage of easy accessibility andlower immogenecity.Whether BMSCs can benefite to ischemic brain? How long can the stem cellssurvive and what is the exacte machenism of the treatment? Is there a certaininformation transform connection? There are no consensuses about all these questions.There still exist a lot of controversial issues about BMSCs therapy for stroke in thepre-clinical research. In present study we designed a series experiments to explore theeffects and the machenism of BMSCs transplantation to cerebral ischemia in order tosupply the experimental data for clinical application. MethodsBased on rats MCAO model, we have studied dynamicly the relative aspects ofBMSCs transplantation by brain stereotaxtic technique. The study includes three parts:1. We cultivated the BMSCs come from Wistar rats marrow and transplanted thecells into the rats brain. Before transplantation and after that we monitored theelectroencephalogram (EEG) of the rats dynamicly and performed stastatic analysis tothe data.2. Study the survival time, migration and differentiation of BMSCs in vivo.Accsess the rats's behaviors depend on series behavioral tests. Analyze the secretinglevel ofneurotrophic factors in the rats's brain at different time points.3. BMSCs labeled with Feridex were injected into the cortex of cerebral ischemicrats and traced the cells in vivo by Magnetic resonance imaging aim to study thesurvival and migration of BMSCs, even the influence to infracted volume of brainischemic rats. We performed at 1d after MCAO, 1d and 14 days after transplantation.In brievely, to study the machenism and relevant evidence of BMSCstransplantation based on the electrophysiology, morphology, functionology andimageology.Results1. We found that not only the quick waves of EEG were re-established and theproportion of slow waves decreased, but also the mean wave amplitude of BMSCstreated group were increased at the same time points compared to the control.2. So many hBMSCs survived after 2 weeks of transplantation. However, thenumber of hBMSC decreased at the 3rd week after transplantation and few cells couldbe detected at 1 month. No definite evidence supported the differentiation of neural cellderived from hBMSC during the whole process. Our result also showed the hBMSCscan migrate to the border of ischemia during the first 2 weeks.3. The mRNA level of neurotrophic factors increased more significantly inhBMSCs treanted group than control group at certain time points, nevertheless, all the cytokines decreased at the 4th week and no statistical difference between two groups.4. The neurological function of rats treated with hBMSCs recovered from 10dafter transplantation, which includes motor function, sensory function and learningcapacity.5. The traceing of BMSCs labeled with Feridex by MR imagine showed thatBMSCs can migrate to the ischemic hemisphere along the corpus callosum and to theborder of the infarction. There was no significant difference in infarct volume changesamong the three groups.ConclusionOur results showed BMSCs infused into brain cortex can improve neurofunctionalrecovery after cerebral ischemia. At the same time, BMSCs transplantation canimprove the brain electrophysiological excitation of the rats. The transplanted stemcells can survive and migrate towards the lesion during certain period, but no definiteevidence support that hBMSCs can differentiate into nerve cells in viovo. The secretinglevel of neurotrophic factors in rats's brain can increased during certain period, whichprotect the ischemic brain and improve neurofuctional recovery. In vivo tracking ofbone marrow mesenchymal stem cells labeled with Feridex by magnetic resonanceimaging is feasible and convenient to study the survival and migration of BMSCs,which is the development trend of molecular imaging.