缺血预处理对大鼠肝移植受体的保护性作用

Experimental research of ischemic preconditioning on the protective effect of the recipient after liver transplantation in rats

目的 :观察缺血预处理对肝移植后早期C X C类趋化因子的表达和中性粒细胞浸润的影响 ,以探讨其保护作用的机制。方法 :建立大鼠肝移植模型 ,供肝于UW液保存 2 4h。实验分大鼠肝移植组 (未处理组 )和缺血预处理组 ,后者于供肝切取前夹闭第一肝门 10min然后开放 10min取肝。于移植后 1h、2h、4h、6h分别测定肝内髓过氧化物酶 (myeloperoxidase ,MPO)活性和血清肝酶学指标、巨噬细胞炎性蛋白 (macrophageinflammatoryprotein ,MIP) 2、肿瘤坏死因子 (tumornecrosisfactor,TNF) α水平。分别取术后 4h肝组织行常规病理切片。结果 :肝酶学指标改变显示缺血预处理组肝功能得到有效改善。缺血预处理组较未处理组肝MPO水平在各时点均有降低 ,并在移植后 4h(0 .4 8± 0 .18U/g组织和 0 .85± 0 .11U/g组织 )和 6h(0 .6 3± 0 .0 4U/g组织和 0 .77± 0 .0 5U/g组织 )出现显著性差异 (P <0 .0 5 )。血清MIP 2水平亦在 4h和 6h显著下降 (2 5 4 6 .5 9± 70 7.78pg/ml和 3488.82± 785 .15pg/ml,10 2 3.72± 6 5 6 .86pg/ml和 185 2 .0 4± 110 8.89pg/ml)。血清TNF α水平仅在 2h变化显著 (370 .77± 14 6 .82pg/ml和 5 17.4 1± 5 7.30pg/ml)。结论 :本研究认为缺血预处理可能通过下调肝细胞对趋化因子的表达 。

Objective:To observe the effect of ischemic preconditioning(IP) on C-X-C chemokine expression and PMNs infiltration in the early stage after liver transplantation to explore the mechanism of protective function.Methods:Male Sprange-Dawley rats were used as donors and recipients of orthotopic liver transplantation(OLT). The donor liver was stored for 24 hours in University of Wisconsin(UW) solution at 4 ℃ before implantation. All rats were randomly divided into two groups:non-IP group and IP group. The portal vein and hepatic artery of the donor liver were clamped for 10 minutes in IP group followed by reperfusion for 10 minutes before liver was cut and taken out. The intrahepatic activity of myeloperoxidase(MPO),serum hepatic enzymology indecis,serum levels of macrophage inflammatory protein-2(MIP) and tumor necrosis factor(TNF)-α were separately assayed after 1 h,2 h,4 h and 6 h after liver transplantation. The hepatic tissues after 4 hours postoperatively were examined routinely.Results:Alterations of the hepatic enzymology indecis suggested that the hepatic function was improved effectively in IP group. Levels of MPO in IP group at each time were lowered than that in non-IP group. And at 4 h(0.48±0.18 U/gm tissue and 0.85±0.11 U/gm tissue) and 6 h(0.63±0.04/gm tissue and 0.77±0.55/gm tissue),the decreases were significant. Similarly,serum MIP-2 was significantly reduced in IP group versus non-IP group(2546.59±707.78 pg/ml and 3488.82±785.15 pg/ml at 4 h,1023.72±656.86 pg/ml and 1852.04±1108.89 pg/ml at 6 h). Changes of serum TNF-α was significant only at 2 h after transplantation(370.77±146.82 pg/ml and 517.41±57.30 pg/ml).Conclusion:This study indicates that IP may protect graft liver from preservation-reperfusion injury after OLT through down-regulation C-X-C chemokine expression of hepatocytes,which alleviates PMNs infiltration after transplantatin.