蓑衣莲酮的保肝作用及其作用机制研究

With the wide use of drugs alone and in combination, drug-induced liver injury (DILI) has become the fifth cause of death. Development of safer and more effective drugs for the prevention and treatment of DILI is very urgent. Despite its effectiveness, the most widely used antipyretic analgesics acetaminophen has become also the most common drugs causing acute liver failure. In our previous study, auriculatone has been obtained as a trace component from the acid hydrolysate of Hemsleya amabilis. Initial pharmacological evaluations showed that, auriculatone at 0.125 μM still protected normal hepatocytes from acetaminophen injury by 100%, much better than the acetaminophen specific antidote N-acetylcysteine. Meanwhile, auriculatone is not only non-toxic within 1000 μM, but obviously promotes the proliferation of normal hepatocytes at 500-1000 μM. The prominent hepatoprotective effect and wide safety window indicated that auriculatone might be a very safe and effective hepatoprotective agent. The project aims to give an extensive evaluation of auriculatone as a hepatoprotective agent by the hepatocytes and animal models of chemical-induced liver injury and to understand the mechanisms of action of its hepatoprotective effects.

随着药物的广泛应用及联合用药的增多，药物性肝损害已成为全球第五大死亡原因，开发更加安全、有效的预防和治疗药物性肝损伤的药物非常紧迫。解热镇痛药对乙酰氨基酚虽然疗效比较确切、应用广泛，但不合理使用已使其成为引起急性肝衰竭最为常见的药物。在前期研究中，我们从中药雪胆酸水解液中获得了齐墩果酸相关制剂中的微量成分蓑衣莲酮。药理实验证实，蓑衣莲酮具有比临床用药对乙酰氨基酚特异解毒剂N-乙酰半胱氨酸更低的保肝有效浓度，在0.125 μM时仍然100%保护正常肝细胞免受对乙酰氨基酚的损害，在1000 μM以内对肝细胞无毒，在500-1000 μM时可明显促进正常肝细胞的增殖。突出的保肝作用和良好的安全性表明，蓑衣莲酮可能是一种非常安全、有效的保肝药物。本课题拟在前期研究的基础上，开展蓑衣莲酮的安全性以及在肝损伤细胞和动物模型上的保肝作用和作用机制研究，期望为蓑衣莲酮作为保肝药物的开发提供实验依据。

解热镇痛药对乙酰氨基酚虽然疗效比较确切、应用广泛，但不合理使用已使其成为引起急性肝衰竭最为常见的药物。本课题研究发现，蓑衣莲酮在1000 μM 以内对肝细胞无毒，在 500-1000 μM 时可明显促进正常肝细胞的增殖。体外预给药实验表明，蓑衣莲酮具有突出的保肝活性，在10 μmol/L时与阳性药N-乙酰半胱氨酸相当。同时发现，蓑衣莲酮后给药能显著改善肝细胞损伤，且在低浓度下（0.3125-5 μmol/L）蓑衣莲酮衍生物能显著提升肝细胞的存活率，其中蓑衣莲酮活性最为显著，且在0.3125-5 μmol/L浓度范围内保肝效果较阳性药NAC活性更为明显。其前药蓑衣莲酮硫酸酯在体内无论是腹腔注射预给药50g/kg还是损伤后静脉注射给药25g/kg均表现出几乎完全抑制对乙酰氨基酚毒性的作用，血清中ALT和AST的水平显著降低(p＜0.001)，肝脏指数显著提高(P＜0.001)至正常值水平，抗氧化酶SOD和CAT的活力、GSH和MDA的水平几乎使肝脏保持在正常水平上，肝组织结构正常，肝小叶清晰，肝细胞液化性坏死伴淋巴细胞浸润显著降低，炎细胞浸润浸润基本消失。这些结果均优于或相当于阳性药NAC。机制研究表明，其突出的作用可能与抑制CYP450酶CYP2E1、CYP3A11、CYP1A2的活性，使APAP毒性中间产物NAPQI生成减少，肝内GSH的消耗减少，GSH含量增加，氧化应激减弱；同时显著增加小鼠线粒体中Na+K+-ATPase酶、Ca2+Mg2+-ATPase酶的活力及线粒体蛋白含量，使线粒体蛋白浓度升高，进而抑制肝坏死，增加小鼠肝指数，最终达到保护肝脏的作用。蓑衣莲酮硫酸酯是一个极有开发价值的保肝药物。