The DHCR7 is the key target of lipotoxic liver injury caused by matrine through abnormal activation of the cholesterol synthesis pathway.

Background: Matrine, the main active ingredient in Sophora flavescens and Sophorae tonkinensis radix et rhizome, is a highly effective insecticide. However, its hepatotoxicity to some extent affects its application value. This study aimed to explore the mechanism underlying matrine-induced liver injury.

Methods: The zebrafish (Danio rerio) and L02 cell model were utilized to investigate the toxic dose of matrine and its effects on liver tissue damage, liver cell morphology and activity, and expression levels of ALT and AST. Zebrafish and L02 cell samples were then collected for transcriptomic testing to further explore the possible mechanism by which matrine induced liver injury. Finally, integrated bioinformatics methods and experiments were used to elucidate the possible mechanisms behind matrine-induced liver injury.

Results: The result presented solid in vivo evidence of matrine-induced hepatotoxicity, supported by abnormal changes of liver morphological, disturbed liver cell structure, obvious apoptosis, as well as elevated levels of ALT and AST in zebrafish. In addition, in vitro L02 cell experiments also showed that matrine can produce significant liver cell damage effects. The integrated bioinformatics analysis results revealed that differentially expressed genes (DEGs) were substantially enriched in multiple pathways related to lipid regulation. Among which, the steroid biosynthesis was the most key signaling pathway, evidenced by the enhanced expression of eight genes, including DHCR7, SQLE, CYP51, CYP24A1, SC5D, LSS, MSMO1 and SOAT1. Furthermore, AY9944, the targeted inhibitor of DHCR7, could offset the toxic effect, as reflected by diminished liver phenotype damage, steatosis, and cholesterol accumulation caused by matrine.

Conclusions: Matrine can upregulate the expression of key genes in steroid biosynthesis pathway, resulting in cholesterol accumulation and then inducing hepatotoxicity. Among them, targeted inhibition of DHCR7 gene expression can alleviate matrine-induced liver injury.