LC–MS Determination of Trichloroethylene Glutathione Conjugation Metabolites in a Parkinson's Disease Mouse Model

Rational

Investigating TCE glutathione (GSH) conjugation metabolites is essential, as these reactive intermediates play a central role in TCE bioactivation and are implicated in organ-specific toxicities, including nephrotoxicity, hepatotoxicity, and neurotoxicity. Characterizing and quantifying these metabolites enhances our understanding of TCE metabolism, supports biomarker discovery, and helps elucidate mechanisms of TCE-induced toxicity.

Methods

A robust liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was established for the detection and quantification of three major GSH-related TCE metabolites: S-(1,2-dichlorovinyl)-glutathione (DCVG), S-(1,2-dichlorovinyl)-L-cysteine (DCVC), and N-acetyl-S-(1,2-dichlorovinyl)-L-cysteine (NAcDCVC). Serum samples were obtained from male C57BL/6 mice chronically exposed to TCE (100 ppm in drinking water for 15 weeks).

Results

Calibration curves for all three metabolites demonstrated excellent linearity (R² > 0.998). The method achieved limits of detection (LOD) ranging from 0.0057 to 0.0120 nM, limits of quantitation (LOQ) from 0.0189 to 0.0401 nM, recoveries of 75.9%–115.5%, and inter-assay variation of 0.5%–11.5%. PD model mice exhibited elevated serum levels of DCVG and DCVC, while NAcDCVC levels were significantly reduced.

Conclusion

This study presents the first comprehensive LC–MS/MS-based quantification of TCE GSH conjugation metabolites in serum, offering high sensitivity, precision, and reproducibility. The observed elevated serum levels of the toxic metabolites DCVG and DCVC, along with the markedly reduced NAcDCVC concentrations in PD mice, provide a critical foundation for future investigations into the mechanistic links between TCE exposure and PD pathogenesis.