Cursio R, Filippa N, Miele C, Van Obberghen E, Gugenheim J
Laboratoire de Recherches Chirurgicales, Faculté de Médecine, Université de Nice, 28 Avenue de Valombrose, 06107 Nice Cedex 2, France.
Br J Surg. 2006 Jun;93(6):752-61. doi: 10.1002/bjs.5329.
This study evaluated the role of protein kinase B (PKB), phosphatidylinositol 3-kinase (PI3-K), Bcl-2-associated death protein (BAD) and mitogen-activated protein kinases (MAPKs) in normothermic ischaemia-reperfusion (IR)-induced apoptosis in rat liver.
Rats were divided into two groups that received either phosphate-buffered saline (control) or the caspase inhibitor Z-Asp-2,6-dichorobenzoyloxymethylketone (Z-Asp-cmk), injected intravenously 2 min before the induction of 120 min of normothermic liver ischaemia. Liver apoptosis was assessed by the terminal deoxyribonucleotidyltransferase-mediated dUTP nick end labelling (TUNEL) method. PI3-K, PKB, BAD and MAPK activities were measured in ischaemic and non-ischaemic lobes at various times after reperfusion.
The number of TUNEL-positive cells was significantly decreased after pretreatment with Z-Asp-cmk. In controls, PI3-K and PKB activities and BAD phosphorylation were inhibited in ischaemic liver lobes. The MAPKs (extracellular signal-regulated kinases, c-Jun N-terminal kinase and p38) showed different patterns of activation during IR. PKB activity was not modified by pretreatment with Z-Asp-cmk.
Induction of apoptosis during IR liver injury might be triggered by inactivation of the antiapoptotic PI3-K-PKB pathway and activation of the proapoptotic MAPKs.
本研究评估了蛋白激酶B（PKB）、磷脂酰肌醇3激酶（PI3-K）、Bcl-2相关死亡蛋白（BAD）和丝裂原活化蛋白激酶（MAPK）在大鼠肝脏常温缺血再灌注（IR）诱导的细胞凋亡中的作用。
将大鼠分为两组，一组接受磷酸盐缓冲盐水（对照组），另一组在诱导120分钟常温肝脏缺血前2分钟静脉注射半胱天冬酶抑制剂Z-Asp-2,6-二氯苯甲酰氧基甲基酮（Z-Asp-cmk）。通过末端脱氧核苷酸转移酶介导的dUTP缺口末端标记（TUNEL）法评估肝脏细胞凋亡。在再灌注后的不同时间测量缺血和非缺血肝叶中的PI3-K、PKB、BAD和MAPK活性。
用Z-Asp-cmk预处理后，TUNEL阳性细胞数量显著减少。在对照组中，缺血肝叶中的PI3-K和PKB活性以及BAD磷酸化受到抑制。MAPK（细胞外信号调节激酶、c-Jun氨基末端激酶和p38）在IR期间表现出不同的激活模式。Z-Asp-cmk预处理未改变PKB活性。
IR肝损伤期间细胞凋亡的诱导可能由抗凋亡PI3-K-PKB途径的失活和促凋亡MAPK的激活触发。
