五味子醇甲对千里光碱致小鼠肝损伤的改善作用

The protective effect of schisandrol A against senecionine-induced hepatotoxicity in mice

菊三七含千里光碱(senecionine, SEN)等大量吡咯里西啶生物碱(pyrrolizidine alkaloids, PAs),其所导致的肝毒性问题成为最受关注的中药药源性肝损伤之一,但尚无有效的临床治疗药物。本课题组前期研究表明CYP3A4抑制剂利托那韦可有效抑制SEN代谢活化并降低其肝毒性。保肝中药五味子含大量木脂素类活性成分,可通过影响药物代谢酶改善药源性肝损伤。因此,本研究探讨了五味子主要木脂素类化合物五味子醇甲(schisandrol A,SoA)对SEN致小鼠肝损伤的改善作用,并初步探讨其对千里光碱代谢的影响。所有动物实验经上海中医药大学实验动物伦理委员会审查(PZSHUTCM210604002),符合实验动物伦理相关规范。小鼠单次灌胃SEN (150μmol·kg^(-1))造成肝损伤模型,并设SoA (116μmol·kg^(-1))干预组、溶剂对照组和SoA对照组。结果表明, SoA可明显降低SEN致肝损伤小鼠血清转氨酶活性,缓解肝细胞坏死、肝窦淤血等病理状态。进一步测定小鼠血清中SEN代谢产物的含量,结合体外肝微粒体代谢研究,发现SoA可抑制SEN代谢活化关键酶CYP3A4酶活性,降低千里光碱代谢产物的含量。本研究表明, SoA可明显改善SEN致小鼠肝损伤,与抑制SEN代谢活化密切相关。研究结果为基于药物代谢探讨SEN的减毒策略,以及菊三七等含PAs中草药的临床合理应用提供理论依据。

Hepatotoxicity induced by herbal medicines such as Gynura japonica,which contains large amount of pyrrolizidine alkaloids(PAs) such as senecionine(SEN),is among the most serious problems of herbal druginduced liver injury,yet there is no effective treatment in clinic.We have previously reported that ritonavir(the well-known CYP3A4 inhibitor) protected rats against Gynura japonica-induced liver injury in rats,which was closely related to the inhibition of the metabolic activation of PAs.A large number of lignans have been identified in Schisandrae Chinensis Fructis and are reported to attenuate drug-induced liver injuries by modulating the drug metabolism enzymes.Therefore,the present study investigated the protective effect and potential mechanism of schisandrol A(SoA,a representative lignan identified in Schisandrae Chinensis Fructis) against SEN-induced hepatotoxicity in mice.All experiments were approved by the Animal Research Committee of Shanghai University of Traditional Chinese Medicine(PZSHUTCM210604002).Animal welfare and the animal experimental protocols were strictly consistent with related ethics regulations of Shanghai University of Traditional Chinese Medicine.Liver injury was induced by a single gavage of SEN(150 μmol·kg^(-1));mice in the protection group were gavaged with SoA(116 μmol·kg^(-1)) 7 days before SEN treatment.The results show that SoA dramatically alleviated SENinduced liver injury in mice.Mice in the protection group showed decreased serum activities for alanine aminotransferase and aspartate aminotransferase;in addition,the hepatic necrosis and sinusoidal hemorrhage in SENtreated mice were markedly attenuated in the protection group.The serum contents of SEN metabolites in mice were decreased.In vitro studies were performed by using human liver microsomes and proved that SoA inhibits CYP3A4 to decrease the metabolism of SEN.These studies indicate that SoA attenuated SEN-induced liver injury in mice,which was closely related to the inhibition of the metabolic activation of SEN.These results provide a better understanding of the relationship between CYP3A4 and PA-induced toxicity.This work also will be helpful in developing effective treatments for SEN-induced liver injury based on inhibition of its metabolic activation,and in making reasonable evaluations of the safety of herbal medicines containing PAs such as G.japonica.