Tripterygium wilfordii multiglycoside-induced hepatotoxicity via inflammation and apoptosis in zebrafish / 中国天然药物

Tripterygium wilfordii multiglycoside (GTW) is a commonly used compound for the treatment of rheumatoid arthritis (RA) and immune diseases in clinical practice. However, it can induce liver injury and the mechanism of hepatotoxicity is still not clear. This study was designed to investigate GTW-induced hepatotoxicity in zebrafish larvae and explore the mechanism involved. The 72 hpf (hours post fertilization) zebrafish larvae were administered with different concentrations of GTW for three days and their mortality, malformation rate, morphological changes in the liver, transaminase levels, and histopathological changes in the liver of zebrafish larvae were detected. The reverse transcription-polymerase chain reaction (RT-PCR) was used to examine the levels of microRNA-122 (miR-122) and genes related to inflammation, apoptosis, cell proliferation and liver function. The results showed that GTW increased the mortality of zebrafish larvae, while significant malformations and liver damage occurred. The main manifestations were elevated levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), significant liver atrophy, vacuoles in liver tissue, sparse cytoplasm, and unclear hepatocyte contours. RT-PCR results showed that the expression of miR-122 significantly decreased by GTW; the mRNA levels of inflammation-related genes il1β, il6, tnfα, il10, cox2 and ptges significantly increased; the mRNA level of tgfβ significantly decreased; the mRNA levels of apoptosis-related genes, caspase-8 and caspase-9, significantly increased; the mRNA level of bcl2 significantly decreased; the mRNA levels of cell proliferation-related genes, top2α and uhrf1, significantly reduced; the mRNA levels of liver function-related genes, alr and cyp3c1, significantly increased; and the mRNA level of cyp3a65 significantly decreased. In zebrafish, GTW can cause increased inflammation, enhanced apoptosis, decreased cell proliferation, and abnormal expression of liver function-related genes, leading to abnormal liver structure and function and resulting in hepatotoxicity.

Study on difference of liver toxicity and its molecular mechanisms caused by Tripterygium wilfordii multiglycoside and equivalent amount of triptolid in rats / 中国中药杂志

Tripterygium wilfordii multiglycoside( GTW),an extract derived from T. wilfordii,has been used for rheumatoid arthritis and other immune diseases in China. However its potential hepatotoxicity has not been investigated completely. Firstly,the content of triptolid( TP) in GTW was 0. 008% confirmed by a LC method. Then after oral administration of GTW( 100,150 mg·kg-1) and TP( 12 μg·kg-1) in female Wistar rats for 24 h,it was found that 150 mg·kg-1 GTW showed more serious acute liver injury than 12 μg·kg-1 TP,with the significantly increased lever of serum ALT,AST,TBA,TBi L,TG and bile duct hyperplasia even hepatocyte apoptosis. The expression of mRNA and proteins of liver bile acid transporters such as BSEP,MRP2,NTCP and OATP were down-regulated significantly by GTW to inhibit bile acid excretion and absorption,resulting in cholestatic liver injury. Moreover,GTW was considered to be involved in hepatic oxidative stress injury,although it down-regulated SOD1 and GPX-1 mRNA expression without significant difference in MDA and GSH levels. In vitro,we found that TP was the main toxic component in GTW,which could inhibit cell viability up to 80% in Hep G2 and LO2 cells at the dose of 0. 1 μmol·L-1. Next a LC-MS/MS method was used to detect the concentration of triptolid in plasma from rats,interestingly,we found that the content of TP in GTW was always higher than in the same amount of TP,suggesting the other components in GTW may affect the TP metabolism. Finally,we screened the substrate of p-glycoprotein( p-gp) in Caco-2 cells treated with components except TP extrated from GTW,finding that wilforgine,wilforine and wilfordine was the substrate of p-gp. Thus,we speculated that wilforgine,wilforine and wilfordine may competitively inhibit the excretion of TP to bile through p-gp,leading to the enhanced hepatotoxity caused by GTW than the same amount of TP.