Department of General and Transplantation Surgery, Ruprecht-Karls University, Heidelberg, Germany.
Mol Nutr Food Res. 2011 Jun;55(6):855-63. doi: 10.1002/mnfr.201000643. Epub 2011 May 19.
Polyphenolic constituents of green tea (Camellia sinensis) have been shown to be potent scavengers of reactive oxygen species (ROS). Thus, this study was designed to assess its effects after liver ischemia-reperfusion.
Fasted Sprague-Dawley rats were gavaged with different concentrations of green tea extract (GTE) 2 h before 90 min of warm ischemia of the left lateral liver lobe (30% of liver). Controls were given the same volume of Ringer's solution. A preparation of pentobarbital sodium (intraperitoneal) and ketamine (intramuscular) was used for anesthesia. After reperfusion, transaminases, liver histology, hepatic microcirculation, and both phagocytosis of latex bead particles as well as the expression of tumor necrosis alpha (TNF-α) to index cellular activation were investigated. Furthermore, the expression of superoxide dismutase (Mn-SOD) was assessed. After 90 min of warm ischemia aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) increased dramatically to 1946 ± 272/3244 ± 757 U/L, 1680 ± 134/2080 ± 379 U/L, and 7857 ± 1851/2036 ± 1193 U/L at 2/6 h, respectively. GTE (200 mg/kgbody weight) significantly prevented this increase in a dose-dependent manner by 21-51% at 2 h and 29-34% at 6 h, respectively. Histology confirmed the protective effects while both TNF-α expression and phagocytosis of latex beads by Kupffer cells (KCs) were significantly reduced. GTE intake significantly increased the expression of manganese superoxide dismutase. In vivo microscopy revealed improved acinar and sinusoidal perfusion after GTE.
Preconditioning with a single oral dose of GTE ameliorates ischemia-reperfusion injury in liver. Decreased cellular activation and improved microcirculation are the proposed mechanisms.
绿茶（Camellia sinensis）中的多酚成分已被证明是活性氧（ROS）的有效清除剂。因此，本研究旨在评估其在肝缺血再灌注后的作用。
禁食的 Sprague-Dawley 大鼠在 90 分钟的左侧外侧肝叶（肝脏的 30%）温热缺血前 2 小时给予不同浓度的绿茶提取物（GTE）灌胃。对照组给予相同体积的林格氏液。戊巴比妥钠（腹腔内）和氯胺酮（肌肉内）用于麻醉。再灌注后，研究了转氨酶、肝组织学、肝微循环以及乳胶珠的吞噬作用和细胞活化的肿瘤坏死因子-α（TNF-α）的表达。此外，还评估了超氧化物歧化酶（Mn-SOD）的表达。在 90 分钟的温热缺血后，天冬氨酸转氨酶（AST）、丙氨酸转氨酶（ALT）和乳酸脱氢酶（LDH）分别急剧增加到 1946±272/3244±757 U/L、1680±134/2080±379 U/L 和 7857±1851/2036±1193 U/L，在 2 小时和 6 小时时，GTE（200mg/kg 体重）以剂量依赖性方式分别显著降低了 21-51%和 29-34%。组织学证实了保护作用，同时 KCs 中 TNF-α的表达和乳胶珠的吞噬作用均显著降低。GTE 的摄入显著增加了锰超氧化物歧化酶的表达。体内显微镜显示，GTE 后腺泡和窦状灌注得到改善。
单次口服 GTE 预处理可改善肝脏的缺血再灌注损伤。减少细胞激活和改善微循环是提出的机制。
