Objective   To determine changes of IFNand iNOS genes expressions, and the effect of cy closporine A (CsA)on regulating the tr anscription of IFNand iNOSgenes.

  Methods   By using orthotopic liver tr ansplantation rat model and semi quantitative RTPCR, IFNmRNA and iNOSmRNA levels in the liver tissues of the rats in Wistar Wistar liver transplantation group, SDW istar liver transplantation group and SDW istar liver transplantation plus CsAtreatment group 3.0 mg/(kg·d), im on the 1st, 3rd, 5th, 7th and 12 th day after transplantat ion.

  Results   In the different periods after the or thotopic liver transplantation, all the IFNmRNA and iNOSmRNA levels of the liver tissues in Wistar Wistar liver transplantation group were relative low.In the liver tissues of rats in SDW istar liver transplantation group, all the IFNmRNA and iNOSmRN Alev els were remarkably increased(P < 0.05).In comparison with the detection results from SDW istar liver transplantation group, the transcription of IFN and iNOS genes in the liver tissues of rats in SDW istar liver transplantation plus CsAtreatment group were obviously inhibited(P < 0.05).The changes between IFNmRNA and iNOSmRNA levels mentioned above showed fine correlation(r=0.765, P < 0.05).

  Conclusion   The IFNmRNA and iNOSmRNA levels are closely associated with the reject reaction after or thotopic liver transplantat ion.The mechanism of CsAa gainst graft rejection may be relative to its down regulation of IFNand iNOSgene transcriptions.