The Study On The Interactions Between Human Umbilical Cord Mesenchymal Stem Cells And Cyclosporine A

[Objective] Mesenchymal stem cells(MSC) have multilineage differentiationand immunomodulatory capacities and are potentially useful for therapeuticapplications, such as tissue regeneration and allogeneic haematopoietic stem celltransplantation to prevent graft versus host diseases. Cyclosporine A, as the mostusefull immunosuppressive drug, used in kidney transplantation and bone marrowtransplantation to decrease the occurance rate of graft versus host disease, haveprovided great progress in organ transplantation. But cyclosporine A needslong-term use and has numerous adverse effects, including renal dysfunction, liverdysfunction, neurotoxicity. Blood concentration of CsA, which should beexamined frequently, is not only related to its immunosuppressive function, butalso to its toxicity. Thus, CsA combined with other immunosuppressive agents isrecommended. The goal of our study was to investigate the interactions betweenumbilical cord mesenchymal stem cell and cyclosporine A, especially whetherthey had greater immunosuppressive effects on T-lymphocyte proliferation.[Methods] MTT assay was used to examine the antiproliferative effect ofcyclosporine A on umbilical cord MSC; Flow cytometry(FCM) was used toexamine the effects of cyclosporine A on the apoptosis and cell cycle of umbilicalcord MSC; Umbilical cord MSCs were co-cultured with MHC-mismatchedallogeneic human peripheral blood mononuclear cell(PBMC) wthich in response toPHA, and different concentration of cyclosporine A was added in the experimentalgroup, then IFN-γ production of PBMC was detected by ELISA kit to determinethe immunosuppressive action of UC MSC and/or cyclosporine A.[Results] The antiproliferative rate of different concentration of CsAalone(30ng/ml、60ng/ml、120ng/ml、240ng/ml、480ng/ml) on UC-MSC had no significant difference with the control group(P>0.05); FCM results indicated thatthe apoptotic rate of UC-MSC, which was treated with low dose of CsA(30ng/ml、60ng/ml、120ng/ml),was13.26%、14.76%and18.59%respectively, much morehigher than the control group(0.27%), but no no significant difference betweenthem(P>0.05); the apoptotic rate of UC-MSC, which was treated with high dose ofCsA(240ng/ml、480ng/ml),was37.58%and57.14%respectively, much morehigher than the control group and the low dose group; The effect of different doseof CsA on the cell cycle of CsA was that, with the dose of CsA accelerated, thepercentage of G0/G1phase and S phase decreased and increased respectively,which had significant difference with the control group, and the percentage of G2phase had no significant difference. In the co-culture study, the IFN-γ secretedby the experimental group including UC-MSC was much less than the controlgroup which had no UC-MSC, and the result presented MSC dose-dependent;With PBMC response to PHA, the production of IFN-γ in the MSC group、CsAgroup and MSC+CsA group was506.5pg/ml、213pg/ml、150pg/ml respectively,much less than the control group, and there was significant difference betweenthem.[Conclusion]: In our this study, our data demonstrated that IFN-γ secreted by Tlymphocyte which was in response to PHA was effectively inhibited by UC-MSCand the inhibitory action was dependent with the concentration of MSC,indicating UC-MSC had immunosuppressive effect on the activation andproliferation of T lymphocyte, which could possible explain the mechanism ofUC-MSC alleviating GVHD. Besides, UC-MSC combined with CsA had greaterimmunosuppressive effects on T-lymphocyte proliferation and CsA had noantiproliferative effect on UC-MSC, which indicated that CsA possibly had noeffects on the activity and fuction of UC-MSC.