Serum metabolomics strategy for investigating the hepatotoxicity induced by different exposure times and doses of Gynura segetum (Lour.) Merr. in rats based on GC-MS

Abstract

Gynura segetum (Lour.) Merr. (GS), has been widely used in Chinese folk medicine and can promote circulation, relieve pain and remove stasis. In recent years, the hepatotoxicity caused by GS has been reported, however its mechanism is not fully elucidated. Metabolomic techniques are powerful means to explore the toxicological mechanism and therapeutic effects of traditional Chinese medicine. The purpose of this study was to establish a serum metabolomics method based on Gas Chromatography-Mass Spectrometry (GC-MS) to explore the hepatotoxicity mechanism of different exposure times and doses of GS in rats. Sprague Dawley (SD) rats were administered daily with distilled water, 7.5 g kg⁻¹ GS, or 15 g kg⁻¹ GS by intragastrical gavage for either 10 or 21 days. The methods adopted included enzyme-linked immunosorbent assay (ELISA), Hematoxylin and Eosin (H&E) staining and GC-MS-based serum metabolomics. Serum biochemistry analysis showed that the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglycerides (TG), total bilirubin (TBIL) and total bile acid (TBA) significantly (P < 0.05) increased while the levels of albumin (ALB) and high-density lipoprotein (HDL) significantly (P < 0.05) decreased in GS-treated groups, compared with the control group. Interestingly, the ALT, AST, TG and ALB levels changed in a time- and dose-dependent manner. The results of H&E staining showed the degree of liver damage after administration of GS gradually deepened with the extension of administration time and the increase of the dose. According to the results of metabolomics analysis, 26 differential metabolites were identified, which were involved in 8 metabolic pathways including phenylalanine metabolism, glyoxylic acid and dicarboxylic acid metabolism and so on. Meanwhile, the number of differential metabolites in different GS-treated groups was associated with GS exposure time and dose. Therefore, we concluded that GS might induce hepatotoxicity depending on the exposure time and dose.