Repeated Oral Administration of Oleanolic Acid Produces Cholestatic Liver Injury in Mice

Abstract

Oleanolic acid (OA) is a triterpenoid and a fantastic molecule with many beneficial effects. However, high-doses and long-term use can produce adverse effects. This study aimed to characterize the hepatotoxic potential of OA. Mice were given OA at doses of 100-3,000 µmol/kg (45-1,350 mg/kg), po for 10 days, and the hepatotoxicity was determined by serum biochemistry, histopathology, and toxicity-related gene expression via real-time RT-PCR. Animal body weight loss was evident at OA doses of 1,000 µmol/kg and above. Serum alanine aminotransferase activities were increased in a dose-dependent manner, indicative of hepatotoxicity. Serum total bilirubin concentrations were increased, indicative of cholestasis. OA administration produced dose-dependent pathological lesions to the liver, including inflammation, hepatocellular apoptosis, necrosis, and feathery degeneration indicative of cholestasis. These lesions were evident at OA doses of 500 µmol/kg and above. Real-time RT-PCR revealed that OA produced dose-dependent increases in acute phase proteins (MT-1, Ho-1, Nrf2 and Nqo1), decreases in bile acid synthesis genes (Cyp7a1 and Cyp8b1), and decreases in liver bile acid transporters (Ntcp, Bsep, Oatp1a1, Oatp1b2, and Ostβ). Thus, the clinical use of OA and OA-type triterpenoids should balance the beneficial effects and toxicity potentials.

Low Dose of Oleanolic Acid Protects against Lithocholic Acid–Induced Cholestasis in Mice: Potential Involvement of Nuclear Factor-E2-Related Factor 2-Mediated Upregulation of Multidrug Resistance-Associated Proteins

“…Furthermore, it should be noted that OA is an FXR antagonist as manifested in HepG2 cells (Liu and Wong, 2010). In our study, OA at 20 mg/kg caused no statistical change in FXR target genes such as Bsep; however, OA at doses of 90 mg/kg or above produced a significant Bsep decrease Lu et al, 2013), suggesting FXR antagonism may be one of the mechanisms by which OA produces cholestasis at high doses. In addition, the data from the human PXR reporter assay indicated that OA could cause moderate PXR agonism; however, an in vivo experiment showed no significant induction of PXR target genes Cyp3a11, Sult2a1, and Ugt1a1 by OA, which may be explained by the fact that a species difference exists in PXR agonism by OA, or OA at relatively low doses Oleanolic acid protects against LCA-induced cholestasis 851 at ASPET Journals on May 9, 2018 dmd.aspetjournals.org used in our study may not be sufficient to activate PXR and induce significant target gene expression.…”

“…In C57BL/6 mice, OA produced cholestasis when fed in the diet at a dose of 100 mg/kg/day for 7 days (Sato et al, 2007). Very recently, it was reported that higher doses (90 mg/kg and above) of OA could produce cholestatic liver injury in mice by altering bile acid homeostasis Lu et al, 2013). In the reported study, C57BL/6 mice were given OA at doses of 0, 22.5, 45, 90, and 135 mg/kg, s.c., once daily for 5 days, and liver injury was apparent at doses of 90 mg/kg and above; however, 22.5 mg/kg OA did not cause any liver injury or cholestasis in mice, suggesting quite a narrow margin of safety of OA (the ratio of toxic dose at 90 mg/kg over effective dose at 22.5 mg/kg is about 4).…”

“…; the highest dose (20 mg/kg) is a safe and effective dose, and no liver injury or cholestasis was observed. In addition, we focused on the effect of OA in bile acid output and noted Nrf2-mediated induction of Mrp2, Mrp3, and Mrp4 as the possible mechanism of hepatoprotection of OA, which was not presented in the studies by Liu et al (2013) and Lu et al (2013). Taken together, this suggests that, for the therapy of cholestasis, OA is a double-edged sword; at doses of 90 mg/kg and above, OA can cause apparent liver injury and cholestasis, whereas at doses below 22.5 mg/kg, especially at 20 mg/kg, OA can protect against LCA-induced cholestasis.…”

“…Importantly, OA has been shown to protect against varieties of hepatotoxicants such as acetaminophen, carbon tetrachloride, and cadmium (Liu et al, 1993a,b;Jeong, 1999), and has been used as an over-the-counter Chinese medicine for the treatment of liver diseases such as acute or chronic hepatitis. However, as a note of caution, it was recently reported that high doses (90 mg/kg and above) and longer-term use of OA produces cholestatic liver injury in mice Lu et al, 2013), indicating the hepatotoxic potential of this hepatoprotective compound. Therefore, an important and intriguing question arises concerning whether OA has a hepatoprotective effect on cholestatic liver injury such as LCA-induced cholestasis under normal low hepatoprotective doses.…”

The antibacterial activities of some plant-derived triterpenes

“…In addition, the test lanosteryl triterpenes have previously been reported to have therapeutic potentials such as antihyperlipidemic potential Machaba et al, 2014) and anti-platelet aggregation activity (Mosa et al, 2011). Potential pharmacological importance of oleanolic acid and betulinic acid as anti-inflammatory, antidiabetic, anticancer, immune modulatory, and antioxidant agents have also been reported (Laszczyk 2009;Lu et al, 2013).…”