Hepatoprotective effect and metabonomics studies of radix gentianae in rats with acute liver injury

Abstract

Context: As a well-known traditional Chinese medicine for protecting the liver, the mechanism of Radix Gentianae (RG) remains unclear.

Objective: The hepatoprotective effect and metabonomics of RG were studied to explore the molecular and metabolic mechanisms of RG protecting the liver.

Materials and methods: Sprague-Dawley rats were divided into control and model group (n = 10, orally given distilled water), intervention group (4 subgroups, n = 10, prophylactically and orally given 0.63, 2.5 and 5.6 g/kg RG and 0.2 g/kg bifendatatum for 7 d). On day 7 of the intervention, all rats except the control were injected intraperitoneally with 2.5% carbon tetrachloride vegetable oil solution (1.5 mL/kg) to induce liver injury. After 24 h of carbon tetrachloride injection, rat serum and liver tissue were collected for determining AST, ALT, TNF-α, MCP-1, IL-6, SOD, MDA, GSH, and GSH-PX. Rat serum was used for analysing endogenous metabolism by UPLC-Q-TOF-MS.

Results: Different doses of RG can significantly decrease the levels of AST, ALT, TNF-α, MCP-1, IL-6 and MDA, and increase the levels of SOD, GSH, and GSH-PX in rats with liver injury (p < 0.05; TNF-α, and IL-6, p < 0.05 only at 5.6 g/kg dose). Eight biomarkers of liver injury were obtained in serum metabonomics, involving five significant metabolic pathways. RG can improve steroid biosynthesis, linoleic acid metabolism, porphyrin and chlorophyll metabolism, and fatty acid biosynthesis.

Conclusion: RG demonstrated a good ability to protect the liver and improving endogenous metabolism in rats with liver injury. This can help us understand the mechanism of RG and more clinical verifications were inspired.

Keywords: Gentiana; metabolic mechanism; molecular mechanism; pharmacodynamics.

Figure 1.

The pathological sections of liver tissue of rats among diverse groups (×200): (A) the control group (CG); (B) the model group (MG); (C) the Bifendatatum positive control group (PCG); (D) the low dose group of RG (LRGG); (E) the medium-dose group of RG (MRGG); (F) the high dose group of RG (HRGG). (1. The size and morphology of hepatocytes were abnormal; 2. There were lots of vacuoles; 3. The shape of the liver cord was changed; 4. The hepatic sinusoid was fuzzy).

Figure 2.

The contents of biochemical indexes in serum and liver of rats among diverse groups (n = 10): (A) Aspartate aminotransferase (AST) level; (B) alanine aminotransferase (ALT) level; (C) tumour necrosis factor-α (TNF-α) level; (D) monocyte chemoattractant protein-1 (MCP-1) level; (E) interleukin-6 (IL-6) level; (F) superoxide dismutase (SOD) level; (G) malondialdehyde (MDA) level; (H) glutathione (GSH) level; (I) glutathione peroxidase (GSH-PX) level. ^△p < 0.05 when compared with the CG group; *p < 0.05 when compared with the MG group.

Figure 3.

The scores of principal component analysis: (A) Positive ion mode; (B) Negative ion mode (model parameters-A: R²X = 0.696, Q² = 0.525; B: R²X = 0.724, Q² = 0.643).

Figure 4.

The scores of orthogonal partial least squares discriminant analysis and their 200 times permutation tests: (A1) CG vs. MG score under positive ion mode; (A2) All groups score under positive ion mode; (B1) CG vs. MG score under negative ion mode; (B2) All groups score under negative ion mode (model parameters-A1: R²Y = 0.794, Q² = 0.728; A2: R²Y = 0.978, Q² = 0.876; B1: R²Y = 0.994, Q² = 0.968; B2: R²Y = 0.973, Q² = 0.894).

Figure 5.

The result of metabolic pathway analysis of potential biomarkers of liver injury: (a) Steroid biosynthesis; (b) Linoleic acid metabolism; (c) Porphyrin and chlorophyll metabolism; (d) Arachidonic acid metabolism; (e) Fatty acid biosynthesis.

Figure 6.

The relative content of biomarkers of liver injury of rats among diverse groups (n = 10): (A) Lathosterol level; (B) Oleic acid level; (C) Bilirubin level; (D) Linoleic acid level; (E) Cholic acid level; (F) Arachidonic acid level; (G) Chenodeoxycholic acid level; (H) Palmitic acid level. The relative content of metabolites was characterised by the peak area of each sample. ^#p < 0.05 when compared with the MG group.