Preliminary Study Of Magnetic Resonance Imaging After Transplantation Of Bone Marrow Stromal Cells Via Vena Caudalis In Cerebral Infarction Rat Models

In this study,we made administration of cultivation, differentiation and label of BMSCs by superparamagnetic iron oxide in vitro,and we made use of 1.5 Tesla 47mm inner diameter micro-coil to monitor the transplanted BMSCs via the intravenous route in stroke rats and assess cerebral infarction with Diffusion Weighted Imaging sequence in vivo.The study was divided into two parts.Part OneFeasible Study of Magnetic Resonance Tracking with IntravenousTransplanted BMSCs Labeled with SPIO in Infarcted RatsObjective: To examine the feasibility of MR tracking with intravenous administration of BMSCs labeled by SPIO initially in infracted rat models.Materials and Methods: 24 rats of cerebral infarction were divided into two groupsrintravenous transplanted BMSCs group and intravenous injected PBS group.They were underwent MR scan with TSE-T2WI and FFE-T2WI sequence respectively at 1,3,7 and 14 day afer transplantation,then they were all sacrificed and performed Prussian blue staining to observe the distribution of BMSCs in infarcted rat models.Result: MR low signal was not found in 10 rat brains of transplanted BMSCs,low ring sharped signal ,nevetheless,was found in 2 rats.In general, there were no significante statistical differences in signal intensity of FFE sequence between two groups (Independent-Samples T Test,p<0.05).Prussian blue staining showed that there was the various number of the iron particles in brains of the transplanted BMSCs group.Conclusion: BMSCs labled by SPIO can entered cerebral infarction of rats.1.5T MR scans are not yet display signal changes of T2WI reduced by BMSCs labled by SPIO stablely in rat brains and not adaptable to tracking research via intravenous route.Part Two Preliminary assessment of diffusion function with DWI sequence afterintravenous transplantation of BMSCs in cerebral infarction ratsObjective: To assess the changes of diffusion function in infracted rats with DWI sequence combined with pathologic examination via intravenous transplantation of BMSCs at the different time after infarction.Materials and Methods: 30 SD rats of cerebral infarction were divided into four groups: intravenous transplantation of BMSCs at l(group 1,n=12),3 (group 2,n=12),7(group 3,n=12)days after cerebral infarction and intravenous injection of PBS(group 4,n=9). They were underwent MR scan with DWI sequence respectively in the first,third,seventh and fourteenth day afer transplantation. At the same time,the imagings of every rat were treated in order to measure their average value of rADC .Then they were all sacrificed at fourteenth day and performed immunohistochemistric examination and positive cell count.Result: Average value of rADC of four groups were all increased following to the change of time and there was statistical difference among four groups(one-way ANOVA,p<0.05). Average value of rADC of each observation time point was no statistical difference between transplanted groups of 1^th and 3^th day after transplantation and there was statistical difference between transplanted groups of 3^th and 7^th day (LSD,p<0.05).There were cells of BrdU-labeled within brain with immunohistochemistric method,and there were no statistical differences in the number of BrdU-labeled cells between the transplanted groups at 1 and 3 days after cerebral infarction,and statistical differences existed between 3^th and 7^th day(one-way ANOVA,p<0.05).The number of BrdU-labeled cells in transplanted groups at 1 and 3 days were higher than transplanted groups at 7 day.Conclusion: BMSCs can entered cerebral infarction of rats via intervenous route.DWI can assess diffusion function after transplanted BMSCs and the effectiveness of intravenous transplanted BMSCs at the 1^th and 3^th day after transplantation was better than the 7^th day.