Delineation of the molecular mechanisms underlying Colistin-mediated toxicity using metabolomic and transcriptomic analyses.

The mechanisms underlying colistin-induced toxicity are not fully understood. This study used untargeted metabolomics and transcriptomics to elucidate the molecular processes occurring in the liver and kidney of rats after treatment with colistin methanesulfonate (CMS). Rats were treated with 50 mg/kg CMS (high-dose), 25 mg/kg CMS (low-dose), or vehicle control, either as a single dose or once daily for 1 or 4 weeks. We found that metabolic alterations were dose- and treatment duration-dependent in the kidney, whereas mild changes were noted in the liver. Metabolic profiles in the high-dose, low-dose, and control groups of both tissues could be classified using partial least-squares discriminant analysis. Metabolic alterations were associated with the citric acid cycle and related processes, disrupted balance between pro-oxidants and antioxidants, inflammatory responses, and amino acid and nucleic acid metabolism. Gene expression profiles further showed that high-dose treatment was associated with disrupted metabolism, oxidative stress, and proinflammatory signals in the kidney. The expression levels of genes related to the cell cycle, DNA replication, and programmed cell death were also predominantly upregulated. These findings suggested that high-dose treatment was associated with a dramatic increase in cellular kidney injury, while only minor effects were observed in the low-dose group. Almost no significant gene expression was changed in the liver, even with high-dose CMS. In conclusion, untargeted metabolomics and transcriptomics provided better insights into the biological mechanisms underlying colistin-induced nephrotoxicity.