| Organ transplantation is now a viable therapeutic option for patients with certain end-stage organ failure. However, episodes of rejection, opportunistic infection, and life-theratening side effects of generalized immunosuperessive remain very real problems for these patients. To ques a new tape immunosuperessive drug and to induced transplantation tolerance have become two question anxious for solving. In fact, any sort of cytostatic drugs also have the function of immnosuppressive action, but they have the defect of non-specific, immnosuppressive activity to be rapidly reversible upon dosage reduction or treatment withdrawal, whereas clonal deletion of alloreactive T cells could have more prolonged effects and contribute to partial peripheral unresponsiveness. The contribution of clonal deletion to peripheral T cell tolerance has been demonstrated in several experimental models. HCPT, an ingredient from Chinese herb drugs have been demonstrated as an inhibitor of DNA topoisomerase I, can inhibt cell proliferation by obstroction DNA duplication, were used treatment neoplasm in clinical. There are paper report that HCPT can induce lymphocyte apoptosis. We discoved that HCPT has the action of immnosuppressive. HCPT , HCPT combined with CsA or HCPT combined with donor specific leukocyte injection after transplantation can induce allogenic kidney transplantation immune tolerance in rats.Meanwhile, we studied the tolerance mechanisms on cellular and molecular level. The whole work consists of three parts as follows:Part One: Immune Tolerance Induced by HCPT and Cyclosporin A in Recipient Rats of Allogenic Kidney Transplantation Induced by HCPTThe inbred DA rats were chosen as kidney donors and Lewis rats as recipients. After transplantation, the recipients were treated with HCPT and/or CsA . Group A received placebo; Group B , HCPTl.Omg kg-'d^LP. ; Group C , HCPT2.0mg kg-'d''L.P. ; Groupe D, CsA lOmg kg-1 d"1 by means of gastric intubation; Group E , HCPTl.Omg kg-1 d"]LP. plus CsA lOmg kg-1 d"1 gastrointubation. Immunosuppression (HCPT and CsA) was withdrawn at 30 days after transplantation. Immune tolerance was verified by challenged with DA and SHR rats skin . Mixed lymphocyte reaction (MLR) and IL2 to the system was investigated in vitro. The levels of cytokine expression were assessed using RT-PCR. The results showed that 4 of 10 group C (HCPT 2.0mg) and 5 of 10 group E (HCPT+CsA) kidney grafts survived longer than 150 days even immunosuppression (HCPT and CsA) was withdrawn at 30 days after transplantation. Immune tolerance was verified by challenged with DA and SHR rats skin . The level of IL2 and EFNr mRNA expression is significantly lower in the grafts of tolerant rats than in the grafts of rejected rats ; the level of IL4 and IL10 mRNA is significantly higer in the grafts of tolerant rats than in the grafts of rejected rats.The level of cytokine mRNAexpression in the grafts is similar to that of spleen of recipients. The lower reaction of MLR to DA lymphocyte could not be reversed by adding IL2 to the system. The study demonstrated that high dosage of HCPT or low dosage of HCPT combined with CsA could induce tolerance in allogenic kidney transplantation in the rats of recipients. Cytokine deviation is one of the mechanisms of allogenic kidney transplantation immune tolerance induced by hydrocamptothecin . The level of cytokine mRNA expression in the grafts is similar to that of spleen of recipients.Part Two: Immune Tolerance Induced by HCPT Combined DonorLeukocyte Injection after Transplantation in Recipient Rats ofAllogenic Kidney TransplantationBased on Part One, we induced DA-Lewis allogenic kidney transplantation immune tolerance by HCPT2.0mg kg'1 d"1 combined donor leukocyte injection after transplantation. Immune tolerance was verified by challenged with DA and SHR rats skin, MLR and DTK. To futher explore tolerance mechanisms, we perform serial kidney transplantation. Grafts and spleens were harvested at definated time for observing the transformation of c...
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