Gene expression profiling and pathway analysis of hepatotoxicity induced by triptolide in Wistar rats

- Female Wistar rats were exposed to triptolide and microarrays were performed.
- Triptolide altered insulin signaling pathway and glucose metabolism.
- Triptolide altered cell cycle, increased oxidative stress and apoptosis.
- Triptolide-induced hepatotoxicity in female rats involved glucocorticoid and IGF-1.

Triptolide (TP), a major component of TWHF, is widely used to treat rheumatoid arthritis, systemic lupus erythematosus, nephritis and leprosy. However, its clinical use is limited by hepatotoxicity. To further elucidate the underlying mechanism of its hepatotoxic effects, hepatic gene expression profiles were analyzed. TP (1000 and 300 μg/kg) was orally administered to Wistar rats for 14 days. Current study indicated that female rats were more sensitive to TP-induced hepatotoxicity than males. Genome-wide microarray analyses identified 3329 differentially expressed genes in liver of female rats. Analyses of these genes identified over-represented functions associated with insulin signaling pathway, glucose metabolism, cell cycle, oxidative stress and apoptosis, which were consistent with the results of significant increase of Caspase-3 activity and reduction of serum glucose, GSH/GSSG ratio, glucose-6-phosphatase and phosphoenolpyruvate carboxykinase activities, liver glycogen. In addition, it was observed for the first time that glucocorticoids and IGF1 might get involved in TP-induced hepatotoxicity. These data suggest that TP treatment could alter the hepatic redox status, reduce serum glucose and induce hepatocyte apoptosis, consistent with the differential expression of genes involved in insulin signaling pathway, glucose metabolism pathway and cell stress pathway, all of which might contribute to the overall TP-induced hepatotoxicity.