Effects of HFPO-DA (GenX) exposure on placental glycolysis and metabolic microenvironment in pregnant rats.

Hexafluoropropylene oxide dimer acid (HFPO-DA; GenX) is an environmentally persistent per- and polyfluoroalkyl substance (PFAS) alternative whose placental toxicity remains poorly understood. Pregnant Sprague-Dawley rats (n = 20, 5 dams/group) received oral HFPO-DA at 0, 1, 10, or 100 mg/kg·day from gestational day (GD) 0-19. Placental tissues collected on GD20 were analysed by targeted metabolomics, lipidomics, histopathology, immunohistochemistry (IHC), and immunofluorescence (IF). After false discovery rate (FDR) correction, three energy metabolites were significantly altered (q < 0.05): oxaloacetate and glutamate were downregulated, while pyruvate was dose-dependently upregulated, consistent with restricted TCA cycle entry. Lipidomics identified 148 nominally significant lipid species, with elevated ceramides and long-chain fatty acids alongside reduced triglycerides, a pattern suggestive of impaired mitochondrial β-oxidation capacity. Histopathology revealed dose-dependent villous hyperplasia, trophoblast disorganization, and vascular lesions at the high dose. Protein analysis showed decreased SDHB, increased HIF-1α and PDK1, and a non-significant rise in PDHA1, collectively consistent with a shift toward Warburg-like metabolic reprogramming. These findings suggest that gestational HFPO-DA exposure may disrupt placental energy and lipid homeostasis at supra-environmental doses, identifying placental metabolism as a potentially sensitive target of next-generation PFAS.