Objective To investigate the effects of cold preservation and reperfusion injury on the regen-eration of donor liver and to study the mechanisms. Methods Male SD rats were divided in to sham group (6 rats), UW 1 h group (48 rats) and UW 12 h group (48 rats). Liver tissue specimens were collected at different time points after orthotopic liver transplantation or sham operation. The morphology of liver tissue was observed via light microscope and transmission electron microscope. Proliferation of hepatocytes and sinusoidal endothelial cells (SECs) were assessed by a double immunostaining technique using antibodies against rat endothelial cell antigen-1 and bromodeoxyuridine (BrdU). Expression of vascular endothelial growth factor (VEGF) and its receptors, fins-like tyrosine kinase-1 (flt-1) and fetal liver kinase-1 (flk-1) was evaluated by immunohistochemistry. The mRNA expression of flt-1 was detected by a RT-PCR method. Mean comparison in groups was conducted by one-way ANOVA or t test. Results BrdU labeling indexes of hepatocytes and SECs in UW 12 h group was significantly higher than those in UW 1 h group (F = 61.45,41.4, P < 0.05). The proliferation of hepatocytes peaked at 48 h after operation in both UW 1 h group and UW 12 h group. However, the proliferation of SECs was fallen behind compared to hepatocytes, with a peak appeared at 72 h in UW 1 h group and at 96 h in UW 12 h group, respec-tively. The expression of VEGF was up-regulated in both UW 1 h group and UW 12 h group compared to sham group. Furthermore, expression of flt-1 and flk-1 was found to be mainly limited in SECs, with a peak in expres-sion occurring between 72 h and 96 h, coinciding with the peak in SECs proliferation in UW 1 h group. Conversely, flt-1 was found to be reduced significantly on mRNA level at any time throughout the experiment in UW 12 h group compared to sham group (F = 141.67, P < 0.05). Conclusion Reduced expression of flt-1 results in a retarded regeneration of SECs, and then the recovery of rat donor liver function is delayed after cold-preserved transplantation.%目的 探讨冷保存再灌注损伤对肝移植大鼠肝脏再生功能的影响及其调节机制.方法 雄性SD大鼠分为假手术组(6只)、UW 1 h肝移植组(48只)、UW 12 h肝移植组(48只).HE染色及透射电镜观察肝组织形态学变化;大鼠内皮细胞抗原和5-溴-2脱氧尿嘧啶核苷(BrdU)双染法检测肝实质细胞及肝窦内皮细胞(SECs)的增殖状况;免疫组织化学法检测VEGF及其受体flt-1、flk-1的表达;RT-PCR法检测flt-1 mRNA的表达.计量资料采用单因素方差分析或t检验.结果 UW 12 h组肝实质细胞和SECs的BrdU标记指数均显著高于UW 1 h组(F=61.45,41.4,P<0.05).UW 1 h组和UW 12 h组大鼠肝实质细胞BrdU标记指数于48 h达高峰,而SECs的BrdU标记指数分别于术后72、96 h达高峰.UW 1 h组和UW12 h组大鼠肝移植术后VEGF表达较假手术组明显增强.UW 1 h组flt-1及flk-1表达较假手术组明显增强,阳性表达主要位于SECs,其表达高峰与SECs增殖高峰一致.UW 12 h组flt-1 mRNA表达较假手术组明显减弱(F=141.67,P<0.05).结论 flt-1表达下调是导致冷保存肝移植大鼠SECs再生高峰延迟,从而减缓移植肝脏功能恢复的重要原因.
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