Investigation Of Status Of Infused Mesenchymal Stem Cells In Chronic Kidney Disease Mice

Over the decade,stem cell therapy for kidney diseases has made some progress.Bone marrow mesenchymal stem cells(BMSC)are widely investigated for kidney disease therapy because of their easy acquisition and in vitro culturing and multi-differentiation potentials.At present,the problem of stem cell-based regenerative medicine is to monitor the survival state and differentiation of the infused cells in vivo.Our previous study showed that an aptamer specifically recognizing BMSC was successfully selected by SELEX,and activatable aptamer fluorescent probes(AAP)were constructed based on this aptamer.In vivo imaging results proved that BMSCs migrated to the injured kidney and fluorescence signal in the kidney lasted for about 48 hours,but disappeared subsequently.It is unknown whether the fluorescence probes were metabolized or the status of target cells was changed.In order to figure out the specific reasons for late disappearance of fluorescent signals,we have carried out following experiments:1)Construction of adriamycin-induced renal injury mouse model and treatment with BMSCs.2)AAP monitoring of BMSCs and re-injection of AAPs after fluorescence signal disappearance.3)Construction of GFP reporter vector to trace the transition of BMSCs into podocytes in adriamycin-induced renal injury mice.The experimental results suggest that:1)Adriamycin-induced renal injury model in Balb/c mice was successfully established.2)The fluorescence signal of AAP appeared at 6 h,lasted to about 31 h,and disappeared completely at 48 h.AAP was subsequently re-injected but only weak fluorescent signal was detected at about 1 h.Besides metabolic degradation of AAP, there should be other reasons for the non-recognizating of AAP to BMSCs in vivo.3)The GFP reporter vector driven by the promoter of podocyte specific marker gene Nphs1 was constructed.Through lentivirus packaging infection,two different promoters could work in podocytes.