ABSTRACT
Pregnane X receptor (PXR), a member of nuclear receptor superfamily, plays an important role in xenobiotic and endogenous metabolism, endocrine balance, and cell proliferation, etc. Previous study has shown that pregnenolone 16α-carbonitrile (PCN), a mouse PXR agonist, could induce liver enlargement. And we found that the change in hepatocytes exhibits regional distribution characteristics: hepatocyte enlargement occurs around the central vein (CV) area, while hepatocyte proliferation occurs around the portal vein (PV) area. In this study, the dynamic changes of hepatocytes during PXR-induced liver enlargement were determined. Serum and liver samples from male C57BL/6 mice were collected for biochemical and pathological analysis after PCN treatment for 1, 2, 3, 5 days, respectively. The animal experiment was approved by the Animal Ethics Committee of Sun Yat-Sen University. The results showed that with the increase in the PCN treatment days, the feature of this regional change of hepatocyte around the CV and PV areas became more and more obvious. At the same time, the factors related to hepatocyte enlargement, such as the expression of PXR downstream genes and the hepatic content of triglyceride (TG), has gradually increased. The upregulation of proliferation-related proteins and downregulation of cyclin-dependent kinases inhibitor proteins were observed in the early stage of PCN treatment, suggesting that hepatocyte proliferation occurs earlier than hepatocyte enlargement during PXR-induced liver enlargement. This study reveals the dynamic change of hepatocytes during PXR-induced liver enlargement and provides a new insight in liver enlargement promoted via PXR activation.
ABSTRACT
Schisandrol B (SolB) is one of the active constituents from a traditional Chinese medicine Schisandra chinensis or Schisandra sphenanthera. Our previous studies found that SolB exerts hepatoprotective effects against drug-induced liver injury and promotes liver regeneration. We further found that SolB significantly induces liver enlargement but the mechanisms remain unclear. The purpose of this study was to investigate the change of lipidome in liver tissues during SolB-induced hepatomegaly. The animal experiment protocol was approved by the Institutional Animal Care and Use Committee at Sun Yat-sen University. Serum and liver samples of male C57BL/6 mice were collected after intraperitoneal injection of SolB (100 mg·kg-1·d-1) for 5 days. Lipidomics analysis was performed using Q Exactive UHPLC-MS/MS system. The results showed that SolB significantly promoted liver enlargement in mice without liver injury and inflammation. Lipid accumulation was observed in the liver tissues after SolB treatment. Thirty-five lipids were identified with significant change and triglycerides (TG) were found to have the most significant increase in SolB-treated group, indicating the increase of energy production during SolB-induced hepatomegaly. This study reveals the impact of SolB on lipid metabolism and provides a potential explanation for liver enlargement induced by SolB.