Yamamoto H, Watanabe T, Mizuno H, Endo K, Hosokawa T, Kazusaka A, Gooneratne R, Fujita S
Medicinal Safety Research Laboratories, Sankyo Co., Ltd., Tokyo, Japan.
Free Radic Biol Med. 2001 Mar 1;30(5):547-54. doi: 10.1016/s0891-5849(00)00496-2.
The Long-Evans Cinnamon (LEC) rats accumulate excess copper (Cu) in the liver in a manner similar to patients with Wilson's disease (WD) and spontaneously develop acute hepatitis with severe jaundice. Although hydroxyl radicals (*OH) have been proposed to be a cause of hepatitis by the accumulation of Cu, it is not clear whether or not *OH can be produced in the liver of hepatitic LEC rats in vivo and also can be involved in the onset of hepatitis. In the present study, *OH production in plasma and liver of hepatitic LEC rats was quantified by trapping *OH with salicylic acid (SA) as 2, 3-dihydroxybenzoic acid (2, 3-DHBA). The ratios of 2, 3-DHBA/SA were significantly higher in plasma and liver of hepatitic LEC rats than those of Wistar rats and LEC rats showing no signs of hepatitis. Furthermore, the ratios of 2, 3-DHBA/SA in plasma and liver of hepatitic LEC rats were almost the same as those of Wistar rats treated orally with CuSO(4) (0.5 mmol/kg) 2 h before acetylsalicylic acid (ASA) injection. We also evaluated the protective effects of D-mannitol (a *OH scavenger) treatment against acute hepatitis in LEC rats. D-mannitol (500 mg/kg) was administered intraperitoneally to 10-week-old LEC rats for 3 weeks. D-mannitol treatment suppressed the increases in serum aspartate aminotransferase activity and total bilirubin concentration. In addition, D-mannitol treatment significantly reduced hepatic mitochondrial lipid peroxidation, which is thought to be important in the pathogenesis of Cu-induced hepatotoxicity. These observations suggest that accelerated generation of *OH catalyzed by free Cu in the liver may, at least in part, play a role in the pathogenesis of acute hepatitis in LEC rats.
长-伊文斯肉桂（LEC）大鼠肝脏中会以类似于威尔逊病（WD）患者的方式蓄积过量铜（Cu），并自发发展为伴有严重黄疸的急性肝炎。尽管有人提出羟基自由基（OH）是铜蓄积导致肝炎的一个原因，但尚不清楚OH在体内肝炎状态的LEC大鼠肝脏中是否能够产生，以及是否与肝炎的发病有关。在本研究中，通过用水杨酸（SA）捕获OH生成2,3-二羟基苯甲酸（2,3-DHBA），对肝炎状态的LEC大鼠血浆和肝脏中的OH生成进行了定量。肝炎状态的LEC大鼠血浆和肝脏中2,3-DHBA/SA的比值显著高于Wistar大鼠和无肝炎迹象的LEC大鼠。此外，肝炎状态的LEC大鼠血浆和肝脏中2,3-DHBA/SA的比值与在注射乙酰水杨酸（ASA）前2小时口服硫酸铜（0.5 mmol/kg）的Wistar大鼠几乎相同。我们还评估了D-甘露醇（一种OH清除剂）治疗对LEC大鼠急性肝炎的保护作用。对10周龄的LEC大鼠腹腔注射D-甘露醇（500 mg/kg），持续3周。D-甘露醇治疗抑制了血清天冬氨酸转氨酶活性和总胆红素浓度的升高。此外，D-甘露醇治疗显著降低了肝脏线粒体脂质过氧化，而脂质过氧化被认为在铜诱导的肝毒性发病机制中起重要作用。这些观察结果表明，肝脏中游离铜催化的OH加速生成可能至少在部分程度上参与了LEC大鼠急性肝炎的发病机制。
