| Objective: (1)In order to study on immunity of renal transplantation,a model of renal allograft in rat was established.(2)Monitoring the kinetic levels of Th1/Th2 cytokine in serum and their mRNA expression in renal allograft,the value of predicting rejection or tolerance in renal transplantation by them was researched .(3) Monitoring the kinetic level of CD4+CD25+ regulatory T cells in peripheral blood of renal allograft in rat,the value of predicting rejection or tolerance in renal transplantation by it was researched.(4)Cyclosporin A(CsA) was the common immune suppressive drug,it was combined with donor bone marrow cells (DBMC) transfusion to induce immune tolerance of renal allograft in rat.The mechanism of inducing immune tolerance was exploited in order to provide experimental evidence for clinic renal transplantation.Methods:(1) Wistar rats were served as donors and SD rats were served as recipients. Rat renal transplantations were performed with end-side anastomosis of the donor left renal artery valve and recipient abdominal aorta, end-side anastomosis of the donor left supra-renal inferior vena cava and the recipient sub-renal inferior vena cava .To connect the donor ureter with ureterocystic flap to the recipient's bladder.(2)The cytokines of IL-2,IFN-γ,IL-4,IL-10 in serum was assayed by ELISA and their mRNA expression in renal allograft was monitored by real-time quantitative RT-PCR.(3) Monitoring the kinetic level of CD4+CD25+ regulatory T cells in peripheral blood of renal allograft in rat was by FCM(flow cytometry).(4) CsA combined with donor bone marrow cells (DBMC) transfusion induce immune tolerance of renal allograft in rat.The survival time was observed.The kinetic level of creatinine in serum was assayed by all automatic biochemical analyzing instrument. The cytokines of IL-2,IFN-γ,IL-4,IL-10 in serum were assayed by ELISA and their mRNA expression in renal allograft was monitored by real-time quantitative RT-PCR on 7 day after operation. Monitoring the kinetic level of CD4+CD25+ regulatory T cells in peripheral blood of renal allograft in rat was by FCM.To prove the specificity of immune tolerance,the MLR(mixed lymphocyte reaction) test was performed.To know the severity of rejection,pathological examination of renal allograft was executed.Results:(1) The stable and practical model of renal transplantation was successfully achieved.The time of vein and artery anastomosis was (18±1.5)min and (15±1.0)min respectively on average.All time of the operation was (135±22)min on average.Warm-ischemic time was shorter than 5s,cold-ischemic time was from 40 to 45 min.The level of Th1 cytokines(IL-2,IFN-γ) in serum or their mRNA expression in renal allograft was significantly higher than that in the syngraft control group.On the contrary, the level of Th2 cytokines(IL-4,IL-10)was significantly reduced.(3)During the process of acute rejection, the level of CD4+CD25+ regulatory T cells in peripheral blood of renal allograft in rat was significantly reduced than that in the syngraft control group.In CsA group, the level of CD4+CD25+ regulatory T cells was significantly higher than that in the syngraft control group.(4)CsA combined with donor bone marrow cells (DBMC) transfusion could induce immune tolerance of renal allograft in rat successfully.The survival time in CsA combined with DBMC transfusion group was significantly longer than that in CsA group. The level of Th1 cytokines(IL-2,IFN-γ) in serum or their mRNA expression in renal allograft was significantly lower than that in CsA group and the level of Th2 cytokines(IL-4,IL-10)was significantly higher.That was to say that the cytokines were deviated from Th1 to Th2. The percentage of CD4+CD25+ regulatory T cells in peripheral blood was higher than that in CsA group.The results of MLR showed that the immune reaction of recipient against donor was specific,but the immune reaction of recipient against the third donor was non-specific in CsA combined with DBMC transfusion group as compared with CsA group.The examination of renal allograft in pathology showed that the severity of rejection was reduced in CsA combined with DBMC transfusion group as compared with CsA group.Conclusions: (1) The improved renal allograft model in rats had a high successful rate and its operation was easily mastered.(2) Monitoring the kinetic level of Th1/Th2 cytokine in serum and their mRNA expression in renal allograft could predict or diagnose rejection occurring.The rising of Th1 cytokines level showed that hyperresponsive immune status existed in recipient against renal allograft and there was the possibility of acute rejection occurring. The rising of Th2 cytokines level showed that hyporesponsive immune status or tolerance existed in recipient against renal allograft.(3) CD4+CD25+ regulatory T cells played an important role in suppressing rejection of renal transplantation. Monitoring the kinetic level of CD4+CD25+ regulatory T cells in peripheral blood of renal allograft could predict or diagnose rejection occurring and recognize immune reaction or tolerance status existing in recipient against renal allograft.(4) CsA combined with DBMC transfusion could induce immune tolerance of renal allograft in rat successfully.The mechanism of tolerance was associated with deviation of cytokines from Th1 to Th2 and the rising of CD4+CD25+ regulatory T cells percentage in recipient.
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