Mizunuma Kazuyuki, Ohdan Hideki, Tashiro Hirotaka, Fudaba Yasuhiro, Ito Hisao, Asahara Toshimasa
Second Department of Surgery, Hiroshima University, Faculty of Medicine, Hiroshima, Japan.
Transplantation. 2003 Mar 15;75(5):579-86. doi: 10.1097/01.TP.0000052593.16876.AF.
We demonstrated that hepatic stellate cells (HSCs) isolated from rat livers exposed to warm ischemia are significantly contractile when compared with HSCs from intact rat livers. This suggests that ischemia-reperfusion (IR)-induced impairment of sinusoidal microcirculation results, at least in part, from contraction of HSCs.
Rho-associated coiled-coil forming protein serine/threonine kinase (ROCK) is one of the key regulators of HSCs motility. Therefore we investigated whether Y-27632, a p160ROCK-specific inhibitor, has beneficial effects on warm IR injury in an in vivo rat partial liver IR model and a rat orthotopic liver transplantation model.
After reperfusion following 90 min of warm ischemia, livers in untreated control rats had persistent congestion and impaired mitochondrial respiration, as demonstrated by increasing deoxy-hemoglobin and reduced cytochrome oxidase contents in the hepatic tissues using in vivo near-infrared spectroscopy. Serum levels of transaminase and endothelin (ET)-1 in these rats were markedly increased 1 hr after reperfusion. In contrast, when Y-27632 (3-30 mg/kg) was administered orally, hepatic tissue contents of deoxy-hemoglobin and cytochrome oxidase rapidly normalized. In such animals, the elevation of serum transaminase levels, but not that of ET-1 levels, was significantly suppressed. This is consistent with in vitro data demonstrating that Y-27632 causes HSCs to undergo relaxation even in the presence of ET-1. Moreover, in a rat orthotopic liver transplantation model, Y-27632 pretreatment dramatically improved the survival of recipients with liver grafts subjected to 45 min of warm ischemia.
Y-27632 attenuates IR-induced hepatic microcirculation disruption by inhibiting contraction of HSCs.
我们证明，与来自完整大鼠肝脏的肝星状细胞（HSCs）相比，从经历热缺血的大鼠肝脏中分离出的肝星状细胞具有显著的收缩性。这表明，缺血再灌注（IR）诱导的肝窦微循环损伤至少部分是由肝星状细胞的收缩所致。
Rho相关卷曲螺旋形成蛋白丝氨酸/苏氨酸激酶（ROCK）是肝星状细胞运动的关键调节因子之一。因此，我们研究了p160ROCK特异性抑制剂Y-27632在大鼠部分肝脏IR体内模型和大鼠原位肝移植模型中对热IR损伤是否具有有益作用。
在90分钟热缺血后的再灌注后，未治疗的对照大鼠肝脏持续充血且线粒体呼吸受损，这通过体内近红外光谱法检测肝组织中脱氧血红蛋白增加和细胞色素氧化酶含量降低得以证明。这些大鼠再灌注1小时后血清转氨酶和内皮素（ET）-1水平显著升高。相比之下，口服Y-27632（3 - 30 mg/kg）时，肝组织中脱氧血红蛋白和细胞色素氧化酶含量迅速恢复正常。在这些动物中，血清转氨酶水平的升高得到显著抑制，但ET-1水平未受抑制。这与体外数据一致，即Y-27632即使在存在ET-1的情况下也能使肝星状细胞松弛。此外，在大鼠原位肝移植模型中，Y-27632预处理显著提高了经历45分钟热缺血的肝移植受体的存活率。
Y-27632通过抑制肝星状细胞的收缩减轻IR诱导的肝微循环破坏。
