| Objective:To establish the Echinococcus mutilocularis (Em) infected rat model by injection of prepared Em suspension into the lower right of rats abdomen. BN-to-LEW allograft heart transplantation models were established, observe the influence of the disturbed immune system on the heart graft in Em infected rat. And observe the effects of combined administration of FK506, MMF and L-ABZ on BN-to-LEW rats cardiac graft survival. Methods:1) To establish the Echinococcus mutilocularis (Em) infected rat model by injection of prepared Em suspension into the lower right of rats abdomen.2) To improve the cervical heart transplantation model of rats through Cuff techique. Heart were transplantated from Brown Norway (BN) rats to Lewis (LEW) rats. The aorta and lung atery of donor were anastomosed with the right common carotid artery and right external jugular vein of recipient.3) BN-to-LEW allograft heart transplantation models were established to observe the influence of the disturbed immune system in E.m infected rat on the heart graft. Animals were randomly divided into control group (BN-to-healthy LEW rats, n=12) and Em infection group (BN-to-Em infected LEW rat, n=12). Allograft heart survival time was observed after the heart transplantation. Graft samples were harvested for histopathological examination. Level of IL-4and IFN-y in peripheral blood were assessed. CD4+, CD8+and CD15+infiltration in the graft were detected. Population of CD4+CD25+T regulatory cells in spleen were tested with FACS flow cytometric analysis.4) Experimental rats were randomly divided into6groups and were given agents, all the agents were administrated orally one time per day. Graft samples were harvested for immunohistochemical study. CD15+infiltration in the graft were detected.. Reults:1) Rats received the injection of Em.The success of establishment of the model was monitored by naked eye examination, routine pathological method.2) We operated50+10times. All the transplatated heart recover beat again. The3day survival rate of the cardiac allograft is96.0%. The ischemic time of the donor heart was less than35min. The cardiac allografts were rejected with a mean survival time7.89±1.65days. Pathology examination show that happened typical rejected reaction. The isografts survived more than3months. Pathology examination showed no rejection reaction happened.3) The mean survival time of the grafts in E.m infected rats was16.17±3.19days and7.92±1.93days in no-infected rats respectively with the statistical difference being significant (P≤0.05). Histopathological stage showed no significant difference between infected Em group (average stage at3.38) and control group (average stage at3.79)(P>0.05). On the other hand, level of serum IL-4in infected Em group (152.21±45.62ng/L) was higher than that in control group (50.85±22.15ng/L), but level of serum IFN-y in infected Em group (12.35±1.02ng/L) was lower than that in control group (42.63±4.15ng/L) when rejection occurred in grafts (P≤0.05). FACS flow cytometric analysis results show population of CD4+CD25+Tregulatory T cells in spleen in infected Em group10.8%was higher than that in control group6.1%(P<0.001).4) FK506+MMF can significantly prolong the survival time of graft (vs control,16.11±8.04vs11.6±6.02, P≤0.05). The survival time of the grafts in all other groups were not significantly prolonged. L-ABZ did not affect the survival of graft alone and use of L-ABZ might antagonize the effect of the FK506+MMF. Conclusion:1) Echinococcus mutilocularis (Em) can grow and generate in LEW rat.2) It is a simple and useful technique to establish heart transplantation model in mouse by the cuff-technique. And it has several advantages such as short graft ischemic time, relative small injuries and high achievement ratio and so on.3) The present results demonstrated that echinococcosis multilocularis infection can induce the deviation of the Th2type cytokines, which is beneficial to the survival of the grafts. Echinococcosis multilocularis infection possibly induces immune tolerance after heart allografting in rat, which is mediated by the induction of CD4+CD25+regulatory T cells. This strategy may be attractive for clinical employment to induce transplantation tolerance.4) L-ABZ did not affect the survival of graft alone. and use of L-ABZ might antagonize the effect of the FK506+MMF. |
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