| Objective To build the animal model of murine ventral heterotopic cardiac transplantation and explore the improved technique.Methods All abdominal heterotopic heart transplantation models were divided into tow groups as follows, allograft group and isograft group. The donor heart aorta and the recipient ventral aorta, as well as the donor pulmonary artery and the recipient inferior caval vein, were anastomosed by using the end-to-side suture technique respectively. In each group, mean survival times (MST) of transplanted hearts and their pathologic histological changes at respective rejection point or observation termination were analyzed.Results The succeeding rate was 91%(91/100). All heart allografts in isograft group survive more than 40d, except for 2 cases (7d), significantly longer than group A, in which the MST of allograft group is (7.7±0.8)d, P<0.05. At postoperative 7th day, the lymphocyte significantly increased in allograft group, with obvious necrosis changes, and the pathologic histological change was Grade 3R. At postoperative 28th day, transplanted hearts in isograft group were hardly damaged with a Grade OR pathologic histological change, and there was no lymphocytes infiltrated.Conclusions The method to build the murine ventral heterotopic cardiac transplantation model is stable and reliable, so it can be used for the study of transplantation immunity.Objective To explore the role of the activity, purity and the alloreactivity of the CD4+ memory T isolated from skin grafts.Methods With use of the mouse skin transplantation model, the CD4+Tm were isolated by magnetic activated cell sorting (MACS). The activity, purity and the alloreactivity of the CD4+Tm cells were detected.Results The activity of the CD4+Tm cells was (98.9±0.3)%, and the proportion of CD4+CD44+CD62L-CCR7- lymphocytes was approximately 95%. The IFN-γsecreted by CD4+Tm cells was detected by ELISPOT, and its function was donor specific.Conclusions Magnetic activated cell sorting isolation kit could used to isolate CD4+Tm lymphocytes from skin allografts effectively. The CD4+Tm was detected with good activity and high purity, as well as the alloreactivity. The isolate CD4+Tm lymphocytes could used to do other research in transplantation immunity. Objective To explore the role of alloreactive CD4+memory T cells in survival of allografts and the mechanisms of survival prolongation of FTY720 in the CD4+memory T cells mediated allograft rejection.Methods With use of the mouse skin transplantation model, the CD4+Tm were isolated by magnetic activated cell sorting (MACS) from recipients. And then these cells were transferred into RAG-/-recipients to explore that how CD4+Tm influenced the survival of allografts and the role of FTY720 on CD4+Tm in allografts.Results The fluorescence intensity of alloreactive CD4+Tm cells labeled with CFSE fell off gradually after transferred into recipents via tail vein injection 1 day before operation. The mean survival time (MST) of allografts in Tm group was shorter than negative group (no transferred Tm) and FTY720 treatment group (a dose of 0.3 mg/kg/d was started on day 4 before surgery and administered throughout the duration of the experiment). There were more CD4+lymphocytes and FasL+lymphocytes infiltrating into the allografts in Tm group compared with negative group and FTY720 treatment group. And the CD4+were mainly in the middle layer especially, the FasL+infiltrated near epicardium, endocardium and around the vessels. The expression level of granzyme B in allografts was much lower in Tm group than positive group. And the secretion of Th1 and Th2 cytokines was down regulated in FTY720 treatment group than Tm group.Conclusions The alloreactive CD4+Tm from skin allograft could mediate allograft rejection and shorten the survival time of allografts, the main mechanism of which might contain the FasL-Fas non-secreting pathway. And the transplantation rejection could be suppressed by use of low-dose FTY720.
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