供肝冷缺血时间延长诱发大鼠原位肝移植术后早期急性排斥反应的研究

目的 研究供肝冷缺血时间延长对大鼠原位肝移植术后早期急性排斥反应的影响.方法 选取30只健康纯系清洁级BN大鼠和30只Lewis大鼠.分别作为纯系移植和同种异体移植的供者,受者均为健康纯系清洁级BN大鼠60只,建立纯系和同种异体原位肝移植模型.根据纯系移植和同种异体移植供肝冷缺血时间的不同,将供、受者分为A、B、C和D组,每组15对.A组:供肝冷缺血1 h后进行纯系移植;B组:供肝冷缺血18 h后进行纯系移植;C组:供肝冷缺血1 h后进行同种异体移植;D组:供肝冷缺血18 h后进行同种异体移植.术后观察受者的2周存活率、移植肝组织病理学及肝功能的改变,检测受者主要组织相容性复合物(MHC)-Ⅱ类分子和核转录因子κB(NF-κB)的表达水平.结果 肝移植术后2周,A、B、C和D组的存活率分别为83.3%、66.7%、16.7%和0%,不管是纯系移植组还是同种异体移植组中供肝的冷保存时间越短,受者的存活率越高,且经肝功能检查发现冷保存时间短的受者移植肝功能恢复较好,移植肝组织病理学损伤和急性排斥反应也明显较轻.B组受者术后移植肝大量表达MHC-Ⅱ类分子,明显高于A组(P＜0.05);两同种异体移植组MHC-Ⅱ类分子的表达量较两纯系移植组增加明显,D组增加最多.A组几乎不表达NF-κB,而B组NF-κB的表达显著增加(P＜0.05);两同种异体移植组受者NF-κB的表达峰值提前.结论 冷缺血时间的延长可以诱导发生和加重大鼠原位肝移植术后早期急性排斥反应,降低术后2周存活率.

Effect of cold ischemia on early acute rejection after orthotopic liver transplantation in rats

Objective To study the mechanism and the impact of prolonged cold ischemia on early acute rejection in rat liver allografts.Methods Thirty cases of isotransplantations from BN to BN rats and 30 cases of allotransplantations from Lewis to BN rats were performed,and donor livers were subjected to 1 or 18 h cold ischemia in 4℃ University of Wisconsin solution before transplantation.Rats were randomly divided into 4 groups (n=15 each):group A:isografts with 1 h cold ischemia transplantation;group B:isografts with 18 h cold isehemia transplantation;group C:allografts with 1 h cold ischemia transplantation;group D:allografts with 18 h cold ischemia transplantation.Recipients were sacrificed at day 2,4 and 6 postoperation (n=3 animals/group/time point for isografts and allografts).Representative specimens were collected for immunohistological assay of MHC-Ⅱand NF-κB or snap frozen in liquid nitrogen for morphological observation.Serum levels of ALT and TBiL were determined.Six recipients of each group were observed for 2-week survival rate postoperatively.Results Immunohistochemical staining of postoperative liver specimens showed stronger MHC-Ⅱ expression on either vascular endothelium or bile duct epithelium in group B than in group A (P＜0.05).In allografts groups,there was a significantly greater expression of MHC-Ⅱ in liver specimens.Prolonged cold ischemia not only up-regulated the expression of NF-κB,but also advanced peak value of the expression of them.There was a significant difference in 2-week survival rate between two allografts groups (P＜0.05).Conclusions Cold ischemia may predispose the liver allograft to the development of acute rejection,in part,not only through the upregulation of the expression of MHC-Ⅱ,but also through the activation of NF-κB.Prolonged cold ischemia can shortern 2-week survival rate postoperatively as well.