Alleviation effect of macrophage depletion on hepatotoxicity of triptolide: A new insight based on metabolomics and proteomics.

Ethnopharmacological Relevance: Triptolide (TP) is an abietane-type diterpenoid isolated from the traditional Chinese herb Tripterygium wilfordii Hook. F, which is used to relieve rheumatism, alleviate joint pain and swelling, and promote blood circulation for more than 600 years in China. The most common preparations containing TP from Tripterygium wilfordii Hook F, which are Tripterygium tablets and Tripterygium glycoside tablets, are widely used in clinical for treating rheumatoid arthritis and other autoimmune diseases at present. However, the clinical application is hindered by severe systemic toxicity induced by TP, especially hepatotoxicity. It is crucial to discover potent and specific detoxification strategy for TP.

Aim Of Study: According to our previous study, TP-induced hepatotoxicity is primarily related to macrophages. This study aimed to investigate the alleviation effects of macrophage depletion on the TP-induced liver injury in mice and to explore the related mechanisms by integration of metabolomics and proteomics.

Materials And Methods: Mice were treated with clodronate liposomes to deplete macrophage before administration of triptolide. The alleviation effects were evaluated by biochemical analysis of serum and histopathology observation of the hepatic tissues. Metabolomics and proteomics were carried out to explore the mechanism of macrophage depletion on triptolide-induced liver injury. The levels of mRNA and protein of TLR4- MyD88-NF-κB axis were further detected.

Results: The altered levels of biochemistry indicators, including aminotransferase (ALT) and aspartate aminotransferase (AST), albumin (ALB), and γ-glutamyltranspeptidase (GGT) were significantly recovered, and histopathological liver injury also showed restoring tendency in mice with macrophage depletion compared to mice with TP-treatment. The inflammation indicator interleukin-6 (IL-6) and interleukin-1β (IL-1β) were recovered significantly after depletion of macrophage. Results of metabolomics and proteomics demonstrated that macrophage depletion exerted protective effects on triptolide-induced liver injury by regulating 85 metabolites and 202 proteins. Joint analysis of multi-omics data suggested macrophage depletion could regulate lipid metabolism and maintain inflammatory homeostasis. The increased expression of NF-κB, TLR4, and MyD88 were decreased after depletion of macrophage.

Conclusion: TP-induced hepatotoxicity is mainly associated with dysfunction of macrophages and imbalance of inflammatory homeostasis. The findings of this study may help facilitate the development of novel therapeutic strategies.