Baiocchi Leonardo, Tisone Giuseppe, Russo Mario Antonio, Longhi Chiara, Palmieri Gianpiero, Volpe Antonio, Almerighi Cristiana, Telesca Claudia, Carbone Marco, Toti Luca, De Leonardis Francesco, Angelico Mario
Hepatology Unit, University of Rome Tor Vergata, Rome, Italy.
Transpl Int. 2008 Aug;21(8):792-800. doi: 10.1111/j.1432-2277.2008.00682.x. Epub 2008 Apr 23.
Cholestasis, induced by liver ischemia-reperfusion injury (IRI), is characterized by dilatation of bile canaliculi and loss of microvilli. Tauroursodeoxycholic acid (TUDCA) is an anti-cholestatic agent, modulating protein kinase C (PKC) alpha pathway. PKC reduces ischemic damage in several organs, its isoform alpha modulates ezrin, a key protein in the maintenance of cell lamellipoidal extensions. We evaluated the effects of TUDCA on cholestasis, canalicular changes and PKCalpha-ezrin expression in a rat model of liver IRI. Livers flushed and stored with Belzer solution or Belzer + 10 mm TUDCA (4 degrees C for 6 h) were reperfused (37 degrees C with O(2)) with Krebs-Ringer bicarbonate + 2.5 micromol/min of Taurocholate or TUDCA. Bile was harvested for bile flow assessment. Liver tissue was employed for Electron Microscopy (EM) and for PKCalpha and ezrin immunoblot and immunofluorescence. The same experiments were conducted with the PKCalpha inhibitor Go-6976. TUDCA-treated livers showed increased bile flow (0.25+/-0.17 vs. 0.042+/-0.02 microl/min/g liver, P<0.05) and better preservation of microvilli and bile canalicular area at EM. These effects were associated with increased PKCalpha and ezrin expression (P=0.03 and P=0.04 vs. control respectively), as also confirmed by immunofluorescence data. PKCalpha inhibition abolished these TUDCA effects. TUDCA administration during IRI reduces cholestasis and canalicular damage in the liver modulating PKCalpha-ezrin pathway.
由肝脏缺血再灌注损伤（IRI）诱导的胆汁淤积，其特征为胆小管扩张和微绒毛丧失。牛磺熊去氧胆酸（TUDCA）是一种抗胆汁淤积剂，可调节蛋白激酶C（PKC）α途径。PKC可减少多个器官的缺血损伤，其α亚型可调节埃兹蛋白，这是维持细胞片状伪足延伸的关键蛋白。我们在大鼠肝脏IRI模型中评估了TUDCA对胆汁淤积、胆小管变化以及PKCα-埃兹蛋白表达的影响。用Belzer溶液或Belzer + 10 mM TUDCA（4℃保存6小时）冲洗并保存的肝脏，在37℃用含2.5 μmol/分钟牛磺胆酸盐或TUDCA的 Krebs-Ringer碳酸氢盐溶液进行再灌注（通O₂）。收集胆汁用于评估胆汁流量。肝脏组织用于电子显微镜（EM）检查以及PKCα和埃兹蛋白的免疫印迹和免疫荧光检测。使用PKCα抑制剂Go-6976进行了相同的实验。TUDCA处理的肝脏胆汁流量增加（0.25±0.17 vs. 0.042±0.02 μl/分钟/克肝脏，P<0.05），并且在EM下微绒毛和胆小管区域保存更好。这些效应与PKCα和埃兹蛋白表达增加相关（分别与对照组相比，P = 0.03和P = 0.04），免疫荧光数据也证实了这一点。PKCα抑制消除了这些TUDCA效应。在IRI期间给予TUDCA可通过调节PKCα-埃兹蛋白途径减轻肝脏胆汁淤积和胆小管损伤。
