甘草总皂苷及甘草酸对Caco-2细胞P-gp功能和表达的影响

Effect of total saponin from Glycyrrhizae Radix et Rhizoma and glycyrrhizin acid on P-glycoprote function and expression in Caco-2 cells

目的研究甘草总皂苷及其主要成分甘草酸对Caco-2细胞P-糖蛋白(P-gp)功能和表达的影响,进一步探讨甘草配伍解毒可能的作用机制。方法采用流式细胞仪检测罗丹明-123经甘草总皂苷和甘草酸处理后Caco-2细胞对其摄取量的差异评价P-糖蛋白的外排功能;采用western blot检测Caco-2细胞经甘草总皂苷和甘草酸处理后P-糖蛋白表达的差异。结果经过1 h的干预,5、10、50μg/mL的甘草总皂苷和甘草酸使细胞内罗丹明-123的荧光强度较阴性对照组相比显著减少41.4%、37.4%、34.8%;33.3%、29.9%、27.5%,对P-gp功能表现出诱导作用(P<0.05)。高质量浓度的甘草总皂苷(100、200、400μg/mL)和高浓度的甘草酸(100、200、400μmol/L)对细胞内罗丹明-123的荧光强度影响不显著(P<0.05)。经过72 h甘草总皂苷、甘草酸的干预,荧光强度较阴性组相比分别显著增加(P<0.05),呈现剂量依赖性。结论甘草总皂苷、甘草酸在一定剂量范围内既增强Caco-2细胞P-gp的功能,又能上调P-gp的表达。甘草酸可能是甘草总皂苷影响P-gp功能和表达的有效成分。

AIM To study the effects of total saponin from Glycyrrhizae Radix et Rhizoma and glycyrrhizin acid on P-glycoprotein function and expression in Caco-2 cells,and to explore detoxification mechanisms.METHODS Flow cytometry was used to calculate the efflux of rhodamine 123.The western blot was used to detect the expression level of P-glycoprotein in Caco-2 cells. RESULTS After co-incubation with total saponin from Glycyrrhizae Radix et Rhizoma and glycyrrhizin acid at the concentration of 5,10 and 50 μg/mL for 1 h,the efflux of rhodamine 123 significantly decreased by 41.4%,37.4%,34.8%,33.3%,29.9% and 27.5%,respectively.The flurescence intensity of rhodamine 123 was nearly invariable at the high concentration of total saponin from Glycyrrhizae Radix et Rhizoma（100,200,400 μg/mL） and glycyrrhizic acid（100,200,400 μmol/L） after the co-incubation at the concentration（5,10,50,100,200,400 μmol/L） for 72 h.The flurescence intensity was evident to that in negative group with the dose-dependent relationship.CONCLUSION Total saponin from Glycyrrhizae Radix et Rhizoma and glycyrrhizin may induce the function and up-regulate the expression level of P-glycoprotein in Caco-2 cell to a certain concentration range.Glycyrrhizin plays a key role in up-regulatory process.