Responsiveness of hepatic and cerebral cytochrome P450 in rat offspring prenatally and lactationally exposed to a reconstituted PCB mixture.

Perinatal polychlorinated biphenyl (PCB) exposures still remain a serious health concern because offspring receive PCB burden from mother during vulnerable processes of development. Since cytochrome P450 (CYP) represents a toxicological endpoint, in the present study, representing an extended investigation of a previous multitasked one, we explored the long-term responsiveness of CYP1A and CYP2B isoforms by Western blot analysis in liver and whole brain of lactating (PN12), weaning (PN21), and adult offspring (PN60) rats prenatally and lactationally exposed to a reconstituted PCB mixture (RM) of noncoplanar PCB138, 153, 180, and coplanar PCB126 congeners. We chose highly chlorinated PCBs instead of lower chlorinated one, because their recalcitrance to biotransformation makes easy their accumulation/persistence in tissues and breast milk. Dioxin-like congener PCB126 binding aryl hydrocarbon receptor (AHR) is responsible of many toxic effects. Pregnant Sprague-Dawley dams with high affinity AHR received subcutaneous injection of RM (10 mg/kg body weight) daily during gestation (days 15-19) and twice a week during breast-feeding. The results evidenced a transfer of PCBs to neonates through milk and a significant responsiveness of hepatic CYP in both mothers and offspring. In liver of exposed progeny, CYP isoforms exhibited a significant increment at PN12 (70% over control) and at PN21 (270% over control). Contrary to dams, in adult PCB offspring CYP levels showed a decline up to values similar to those of control. This transient developmental responsiveness of CYP isoforms in offspring liver reflects roughly the time course of hepatic PCB levels previously reported. Even if congeners were detected in brain, we failed in evidencing a responsiveness of CYP isoforms probably because of region-specific CYP expression in this organ. In conclusion, induction of offspring hepatic CYP is index of liver PCB burden, and despite the insensitivity of whole brain CYP we cannot exclude brain vulnerability toward PCB. © 2012 Wiley Periodicals, Inc. Environ Toxicol 29: 856-866, 2014.

First evidences of the occurrence of polycyclic synthetic musk fragrances in surface water systems in Italy: spatial and temporal trends in the Molgora River (Lombardia Region, Northern Italy).

The polycyclic synthetic musks (PCMs) such as galaxolide (HHCB), tonalide (AHTN) and celestolide (ABDI) are important ingredients in fragrances for consumer products because of their typical musky scent. In EU, PCMs are classified as HPVC (High Production Volume Chemicals). Furthermore, it has been recognized that these substances are only partially degraded in domestic sewers. For both reasons these chemicals are considered ubiquitous contaminants of aquatic systems. Monitoring data are available for the Northern region of the EU, but it is not known whether they are also representative for the Southern EU countries. The lack of data upon the environmental exposure in Southern EU can be significant, since use patterns and volumes differ from country to country. This is particularly true for Italy that has the largest detergent consumption per capita in EU. Due to this, the objective of the present study was to investigate the occurrence of selected PCMs in the Molgora River (Lombardia region, Italy). To our knowledge it represents the first overview of PCM occurrence in the Italian water bodies. Water samples were collected seasonally in seven sampling stations located before and after the 3 sewage treatment plants present along the river, which serve about 300,000 inhabitants. The spatial and temporal profiles of contamination are described. A comparison of the results with existing monitoring data of other European regions indicated a significant higher level of PCM pollution of the Molgora River and the need to extend the monitoring campaigns to other Italian water bodies, in order to achieve a better knowledge of the levels of PCM contamination in this country.