ABSTRACT
Per- and poly-fluoroalkyl substances (PFAS) exhibit high persistence in the environment and accumulate within the human body, warranting a thorough assessment of their toxicity. In this study, we exposed mice (male C57BL/6J mice aged 8 weeks) to a composite of nine PFAS, encompassing both long-chain PFAS (e.g., perfluorooctanoic acid and perfluorooctanesulfonic acid) and short-chain PFAS (e.g., perfluorobutanoic acid and perfluorobutanesulfonic acid). The exposure concentrations of PFAS were equivalent to the estimated daily human intake in the composition reported (1 µg/L (sum of the nine compounds), representing the maximum reported exposure concentration). Histological examination revealed hepatocyte vacuolization and irregular hepatocyte cord arrangement, indicating that exposure to low levels of the PFAS mixture causes morphological changes in liver tissues. Transcriptome analysis revealed that PFAS exposure mainly altered a group of genes related to metabolism and chemical carcinogenesis. Machine learning analysis of the liver metabolome showed a typical concentration-independent alteration upon PFAS exposure, with the annotation of substances such as glutathione and 5-aminovaleric acid. This study demonstrates that daily exposure to PFAS leads to morphological changes in liver tissues and alters the expression of metabolism- and cancer-related genes as well as phospholipid metabolism.
ABSTRACT
The Mo contents and the relations between Mo and Cu or Cr contents were investigated in the organs of Japanese wild ducks (spotbill duck, pintail, wigeon, scaup and tufted duck). The highest Mo content in kidney and liver of the dabbling ducks were more than 30 microg g(-1) dry weight (microg g(-1) d. wt.), though that of diving ducks were less than 11 microg g(-1) d. wt. The contents were lower in the ducks migrating within Japan, Eurasia and North America than those in the birds migrating between Japan and Eurasia. The contents of liver in all species were more than 50 and less than 5 microg g(-1) d. wt. for Cu and Cr, respectively. Significant correlations were found between Mo and both elements in pintail and scaup, and Mo and Cr in tufted duck. These results suggest that the contamination of wild ducks reflects the reproductive area, and not the collected area. Mo contents closely correlated with the Cu and/or Cr contaminations.
