Caldwell-Kenkel J C, Currin R T, Coote A, Thurman R G, Lemasters J J
Department of Cell Biology & Anatomy, University of North Carolina at Chapel Hill 27599-7090, USA.
Transpl Int. 1995;8(2):77-85. doi: 10.1007/BF00344415.
Lethal reperfusion injury to sinusoidal endothelial cells occurs after cold ischemic storage of livers and may be responsible for liver graft failure from storage injury. Here, we evaluated potential mechanisms underlying this reperfusion injury. In rat livers stored in Euro-Collins solution for 24 h and reperfused with Krebs-Henseleit bicarbonate buffer, nonparenchymal cell killing showed periportal predominance as assessed by nuclear staining with trypan blue. In livers reperfused in the retrograde direction, the lobular distribution of cell killing was reversed, indicating that cell killing was more rapid in oxygen-rich upstream regions. However, antioxidants, including allopurinol, desferrioxamine, catalase, superoxide dismutase, superoxide dismutase plus catalase, and U74006F, did not reduce cell killing. Similarly, reperfusion with anoxic buffer did not prevent lethal injury. Antioxidants and anoxic reperfusion also did not improve cell viability in livers stored in UW solution. Nevertheless, superoxide generation, as identified by formazan formation from nitroblue tetrazolium, was increased in Kupffer cells after lives storage and reperfusion as compared to unstored livers. Acidification of the reperfusion buffer from pH 7.4 to pH 7.15 reduced overall nonparenchymal cell killing from about 40% to 10%. Moreover, a pH gradient developed across the liver lobule during reperfusion with the effluent 0.2-0.4 pH units more acidic than the influent. This intralobular pH gradient appears to account for the relative sparing of cells in more acidic downstream regions of the lobule. Lower temperatures of reperfusion also reduced lethal injury. In conclusion, Kupffer cells generated superoxide after perfusion of stored rat livers, but formation of oxygen free radicals did not appear to contribute to lethal reperfusion injury to endothelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)
肝脏冷缺血保存后会发生肝血窦内皮细胞的致死性再灌注损伤，这可能是导致保存损伤引起肝移植失败的原因。在此，我们评估了这种再灌注损伤的潜在机制。将大鼠肝脏置于欧洲柯林斯溶液中保存24小时，然后用 Krebs-Henseleit 碳酸氢盐缓冲液进行再灌注，通过台盼蓝核染色评估发现，非实质细胞死亡呈现门静脉周围优势。在逆行再灌注的肝脏中，细胞死亡的小叶分布发生了逆转，这表明在富氧的上游区域细胞死亡更快。然而，抗氧化剂，包括别嘌呤醇、去铁胺、过氧化氢酶、超氧化物歧化酶、超氧化物歧化酶加过氧化氢酶以及U74006F，均未减少细胞死亡。同样，用缺氧缓冲液进行再灌注并不能预防致死性损伤。抗氧化剂和缺氧再灌注也不能提高置于UW溶液中保存的肝脏的细胞活力。尽管如此，与未保存的肝脏相比，在肝脏保存和再灌注后，通过硝基蓝四氮唑形成甲臜鉴定出枯否细胞中的超氧化物生成增加。将再灌注缓冲液的pH从7.4酸化至7.15可使总体非实质细胞死亡从约40%降至10%。此外，在再灌注过程中，肝脏小叶内形成了pH梯度，流出液的pH比流入液低0.2 - 0.4个单位。这种小叶内pH梯度似乎解释了小叶酸性更强的下游区域细胞相对较少受损的原因。较低的再灌注温度也可减少致死性损伤。总之，保存的大鼠肝脏再灌注后枯否细胞会生成超氧化物，但氧自由基的形成似乎并未导致内皮细胞的致死性再灌注损伤。（摘要截短至250字）
