Effect and molecular mechanism research of Astragalus membranaceus on inhibiting intestinal absorption of six alkaloids of Aconitum carmichaelii in spleen deficiency rats / 中草药·英文版

Objective: To investigate the effect and the mechanism of Astragalus membranaceus (Huangqi in Chinese, HQ) extract on the intestinal absorption of six alkaloids of Aconitum carmichaelii (Fuzi in Chinese, FZ) in rats with spleen deficiency and provide novel insights into the application of HQ on modulating intestinal barrier. Methods: Four-week-old male Sprague-Dawley rats were fed with Xiaochengqi Decoction to induce the spleen deficiency model for 40 d. Single-pass intestinal perfusion model were used to study the effects of HQ extract on the absorption of alkaloids. Protein expression and mRNA levels of MRP2 and BCRP and tight junction proteins (TJ, including Claudin-1, Occludin and ZO-1) were measured using Western blot and real-time PCR, respectively. The location and expression of TJ protein was also investigated by the immunofluorescence method. Results: Compared with the normal group, the protein expression of MRP2, BCRP and TJ proteins in the model group were significantly down-regulated. After oral administration of HQ, the alkaloid absorption in intestinal villi was inhibited, MRP2, BCRP and TJ proteins were up-regulated, the green fluorescence staining of Claudin-1, Occludin, and ZO-1 was enhanced, and a thick layer of mucus was deposited on the surface of the epithelium of the intestinal cavity. Conclusion: HQ as an intestinal barrier modulator improves the physiological changes of the intestinal environment of spleen deficiency to reduce the absorption of toxic components, leading to a decrease in the absorption of drug-like molecules.

Research on Therapeutic Mechanism of Canhuang Tablets on Jaundiced Rats Induced by ANIT / 中国实验方剂学杂志

Objective:To explore the therapeutic mechanism of Canhuang tablets on the mRNA and protein expression of farnesoid X receptor (FXR), uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) and multidrug resistance associated protein 2 (MRP2) in the liver of jaundiced rats induced by α-naphthalene isothiocyanate (ANIT). Method:The rats were divided into normal group, model group, Canhuang tablets (CHP) group and ursodeoxycholic acid tablets (UDCA) group. The jaundice model was reproduced by ANIT. After the intervention of the corresponding drugs, the contents of total bilirubin (TBIL), total bile acid (TBA), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) in serum and the liver histopathology were examined to evaluate the therapeutic effect of CHP. The relative mRNA and protein expressions of FXR, UGT1A1 and MRP2 in rat liver tissues were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. Result:CHP can significantly reduce the increase of TBIL, TBA, ALT, AST and ALP caused by ANIT in rat serum, and inhibit the liver pathological changes, which showed that the removing jaundice effect of CHP was better than UDCA. Compared with the normal group, ANIT significantly inhibited the mRNA levels of FXR, UGT1A1 and MRP2 in rat liver tissues after modeling (P<0.01). Compared with the model group, CHP and UDCA significantly increased the mRNA levels of target genes of each protein after intervention (P<0.01), and CHP was superior to UDCA in improving the mRNA level of bilirubin metabolizing enzyme UGT1A1 (P<0.01). In the aspect of affecting protein expression, compared with the normal group, ANIT modeling significantly increased the expression of FXR in rats (P<0.05). CHP intervention showed a tendency to promote the expression of FXR, while UDCA did not, but there was no significant difference between them. In the aspects of promoting bilirubin metabolism and bile excretion, the expressions of UGT1A1 and MRP2 were significantly decreased by ANIT modeling (P<0.01), while the expressions of UGT1A1 and MRP2 proteins were significantly increased after treatment of CHP (P<0.01). CHP was superior to UDCA in increasing the expression of bilirubin and bile acid efflux protein MRP2 (P<0.01). Conclusion:The jaundice abating mechanism of CHP is related to activating FXR mRNA expression in liver, promoting the mRNA and protein expression of bilirubin metabolizing enzyme UGT1A1 and bile acid transporter MRP2, improving liver metabolism of free bilirubin and promoting bile acid excretion from the liver, and alleviating cholestatic liver injury.

Potential mechanism of cholagogic effect about Gardenia Jasminoides Ellis (Zhizi)-mediated increase of bile acids urinary excretion in normal rats / 中草药·英文版

Objectives: Gardenia Jasminoides Ellis (Zhizi), belonging to Rubiaceae family, has been traditionally used for treatment cholestasis and jaundice for centuries in Asian countries. In the theory of Traditional Chinese Medicines, Zhizi could dispel dampness and heat via the urine to execute its choleretic effects. However, the potential molecular mechanism has been still poorly clarified. Here, we investigated the effect of different dose of Zhizi aqueous extract powder (0.3 g/kg/d and 0.9 g/kg/d) on urinary excretion of bile acids (BAs), and defined the potential mechanism via renal BAs efflux transporters Mrp2 and Mrp4 in normal rats. Methods: Male Wistar rats were orally administrated with 0.3 or 0.9 g/kg/d dose of Zhizi aqueous extract powder for 2 weeks, then body weight, serum aminotransferase, total BAs concentrations in liver, bile, serum, kidney and urine, 1 h bile flow, 12-h urinary volume, biliary and urinary excretion amount of total BAs as well as protein expression of major renal BAs efflux transporter Mrp2 and Mrp4, were all evaluated. Results: Zhizi especially the high dose of Zhizi aqueous extract powder could reduce hepatic total BAs concentration. Additionally, bile flow and biliary excretion had no significant difference, but the remarkable increasing urinary excretion of BAs and 2 to 3 folds up-regulated renal Mrp2 expression were observed after administrated with Zhizi as compared with the control group. Conclusion: The findings indicate that Zhizi reduces hepatic total BAs level by increasing urinary excretion rather than the biliary excretion of BAs, which, in turn ascribed to elevated protein expression of Mrp2 at apical membrane of renal tubular epithelial cells.

A novel chemo-resistant gene MSX2 discovered by establishment of two pancreatic cancer drug resistant cell lines JF305/CDDP and PANC-1/GEM / 中华肿瘤杂志

Objective@#To explore new multidrug resistant genes of pancreatic cancer by establishment and characterization of chemo-resistant cell lines.@*Methods@#The cisplatin-resistant cell line JF305/CDDP and the gemcitabine-resistant cell line PANC-1/GEM were induced by high-dose intermittent treatment. CCK-8 assay was used to detect the 50% inhibiting concentration (IC50), drug resistance index (R), cross-resistance, and growth difference of different cells. The changes of cell cycle and migration ability of drug-resistant cells were determined by flow cytometry and transwell assay, respectively. And then real-time fluorescence quantitative PCR was used to detect the expression of multidrug resistance-related genes.@*Results@#The drug resistance indexes of JF305/CDDP and PANC-1/GEM were 15.3 and 27.31, respectively, and there was cross-resistance. Compared with the parental cells, the proliferation rate of JF305/CDDP was decreased by 40% on the fourth day (P<0.05); the proportion of S phase was decreased from (45±2)% to (30±2)% (P<0.05), and the migration ability was enhanced from (32 ±1) cells per field to (158±5) cells per field (P<0.01). The expression of multidrug resistance-related genes MRP2, MDR1, LRP and MSX2 was increased in JF305/CDDP cells (P<0.05). Knockdown of MSX2 in JF305 cells reduced the expression of MRP2, whereas overexpression of MSX2 in PANC-1 cells upregulated MRP2 level (P<0.05).@*Conclusions@#Two stable multidrug resistant cell lines of pancreatic cancer, JF305/CDDP and PANC-1/GEM, were successfully established. MSX2 might be a new drug resistance related gene in pancreatic cancer cells by up-regulation of MRP2 expression.

Effect of arecoline hydrobromide on mRNA expression of hepatic and renal transporters in vivo / 中草药

Objective: To explore the effect of arecoline hydrobromide (AH) on the expression of rat hepatic and renal transporters. Methods: The effect of AH on the mRNA expression of 13 hepatic and renal transporters was studied after orally giver AH (0.8, 4, and 20 mg/kg/d) to rats for 21 d. Results: The results from the real-time PCR indicated that, AH treatment at low dose significantly decreased the mRNA levels of hepatic MRP2 and MDR1A, while significantly increased renal MRP5 mRNA level. On the other hand, AH treatment at high dose significantly inhibited the mRNA expression of hepatic OCT2, OAT2, OCTN2, OATP1A1, OATP1A4, OATP2B1, MRP2, and MDR1A, as well as renal MRP2, BCRP, and MDR1A. However, the mRNA expression of renal OCTN2, OATP1A1, OATP1A4, and MRP5 were significantly up-regulated following the treatment of high dose of AH. And the AH-induced effect on the above transporters was dose dependent in some extent. Conclusion: Due to the drug interaction caused by the alteration in expression and function of hepatic and renal transporters, it is suggested that the betel nut addicts should be paid more attention in case of adverse drug interactions.

Effects of magnesium isoglycyrrhizinate on the expressions of UGT1A, MRP2 protein and mRNA in L-02 cells damaged by triptolide / 天津医药

Objective To observe the effect of magnesium isoglycyrrhizinate on the expressions of UGT1A, MRP2 protein and mRNA of L-02 cells damaged by triptolide, and to investigate hepatoprotective mechanism of magnesium isoglycyrrhizinate in terms of drug metabolism. Methods L-02 cells were divided into 4 groups:normal group, triptolide group, magnesium isoglycyrrhizinate group and rifampicin group. Magnesium isoglycyrrhizinate group and rifampicin group were pretreated by magnesium isoglycyrrhizinate and rifampicin for 24 h and the remaining two groups added medium. Triptolide were added for 18 h except normal group. Cell survival rate was tested by MTT. The expression levels of UGT1A, MRP2 protein and mRNA were detected by Western blot assay and RT-PCR. Results Compared with triptolide group, cell survival rate was significantly higher in magnesium isoglycyrrhizinate group (P<0.05). Meanwhile, the expression levels of UGT1A, MRP2 protein and mRNA were significantly lower in triptolide group compared with those of control group (P<0.05). The expression levels of UGT1A, MRP2 protein and mRNA were significantly up-regulated in magnesium isoglycyrrhizinate pretreatment group than those of triptolide group (P<0.05). The UGT1A protein and mRNA expressions were significantly decreased in rifampicin pretreatment group than those of magnesium isoglycyrrhizinate group ( P<0.05), but there were no significant differences in MRP2 protein and mRNA expressions between the two groups. Conclusion Magnesium isoglycyrrhizinate shows protective effects on triptolide induced L-02 cell injury, which may be involved with the activation of UGT1A and MRP2.

Psoralen induced bile acid accumulation and cytotoxicity by inhibiting MRP2 and MRP3 in HepG2 cells / 中国药理学通报

Aim To investigate the toxicity of isopsor-alen in HepG2 cells and its effects on bile acid, bile acid synthesis and transport. Methods Cell viability was evaluated by MTT assay and bile acid was deter-mined inside HepG2 cells, with exposure to various isopsoralen for 24h. The mRNA transcription of BSEP, MRP2, MRP3, NTCP, OATP2, OSTα, CYP7A1, CYP27 A1 , FXR and PXR were assessed by real-time PCR. Results The cell viability was decreased dose-dependently with isopsoralen in HepG2 cells, and IC50 was 118. 1μmol·L-1 exposure to isopsoralen for 24h. Bile acid inside cells significantly increased with 100 and 400 μmol · L-1 isopsoralen. Isopsoralen caused the down-regulation of MRP2 , MRP3 , CYP7 A1 mRNA at 25 μmol · L-1 . Beside these, the up-regulation of OATP2,OSTα,CYP27A1,FXR,PXR with 100 μmol· L-1 isopsoralen, but there was no significant change of BSEP and NTCP. Conclusion The results show that isopsoralen induces bile acid accumulation and cytotox-icity which may be associated with the down-regulation of MRP2, MRP3 in HepG2 cells.

Genetic Variations of ABCC2 Gene Associated with Adverse Drug Reactions to Valproic Acid in Korean Epileptic Patients

The multidrug resistance protein 2 (MRP2, ABCC2) gene may determine individual susceptibility to adverse drug reactions (ADRs) in the central nervous system (CNS) by limiting brain access of antiepileptic drugs, especially valproic acid (VPA). Our objective was to investigate the effect of ABCC2 polymorphisms on ADRs caused by VPA in Korean epileptic patients. We examined the association of ABCC2 single-nucleotide polymorphisms and haplotype frequencies with VPA related to adverse reactions. In addition, the association of the polymorphisms with the risk of VPA related to adverse reactions was estimated by logistic regression analysis. A total of 41 (24.4%) patients had shown VPA-related adverse reactions in CNS, and the most frequent symptom was tremor (78.0%). The patients with CNS ADRs were more likely to have the G allele (79.3% vs. 62.7%, p = 0.0057) and the GG genotype (61.0% vs. 39.7%, p = 0.019) at the g.-1774delG locus. The frequency of the haplotype containing g.-1774Gdel was significantly lower in the patients with CNS ADRs than without CNS ADRs (15.8% vs. 32.3%, p = 0.0039). Lastly, in the multivariate logistic regression analysis, the presence of the GG genotype at the g.-1774delG locus was identified as a stronger risk factor for VPA related to ADRs (odds ratio, 8.53; 95% confidence interval, 1.04 to 70.17). We demonstrated that ABCC2 polymorphisms may influence VPA-related ADRs. The results above suggest the possible usefulness of ABCC2 gene polymorphisms as a marker for predicting response to VPA-related ADRs.

Stereoselective bile excretion of ibuprofen glucuronide and the transport mechanism in the biliary efflux / 中国临床药理学与治疗学

AIM: To illustrate the effects of drug transporters on the bile efflux of ibuprofen glucuronide(IBG), the difference of bile excretion and plasma concentration of ibuprofen(IB) and its glucuronides was studied in EHBR and normal SD rat(SDR). METHODS: After 20 mg/kg of IB enantiomers administrated intravenously, the bile and blood were collected from the rats and the concentration of IB and their glucuronide were measured by HPLC methods. RESULTS: The bile excretion of IBG was obviously (but no totally) suppressed in EHBR (1.7%±1.0%, 0.6%±0.9% of the dose respectively for S-IBG and R-IBG) compared with that in SDR (18.4%±4.0% and 3.0%±2.4% of the dose respectively for S-IBG and R-IBG), for both kinds of rats, there are more S-IBG excreted than that of R-IBG. As the result of reduction of IBG excreted in bile, the concentration of IBG was higher in blood in EHBRs. CONCLUSION: The results suggest that Mrp2 is the most important transporter for IBG, and other transporter(s) may participate in the process.

Expression of bilirubin transporter Mrp2 in liver of obstructive jaundice rats and the significance / 第三军医大学学报

Objective To study the changes of transport protein Mrp2 excreting bilirubin across the canalicular membrane in obstructive jaundice rats. Methods The Mrp2 transcription and protein levels of hepatocytes was measured by RT PCR and immunofluorescence microscopy in obstructive jaundice rats. A correlation analysis of the transcription and protein levels with TNF ? and serum bilirubin was conducted. Results The Mrp2 transcription and protein levels were significantly lower in hepatocytes following bile duct obstruction and negatively correlated with TNF ? and bilirubin in rat serum. Conclusion Overexpression of inflammatory factor TNF ? may cause downregulation of transcription and protein levels of Mrp2 gene in obstructive jaundice rats. Bilirubin secretion across canalicular membrane can be inhibited. These may lead to or exaggerate hyperbilirubinemia.