The effect of exposure route on the distribution and excretion of hexachloronaphthalene in rats

Abstract

Objectives: Polychlorinated naphthalenes (PCNs), like other persistent organic pollutants (POPs), are widespread, global environmental contaminants. These compounds still represent a great environmental problem, mostly because of the risk of secondary air pollution. They are characterized by long durability and tendency to bioaccumulate, which means that they are practically ubiquitous in all environmental media and ecosystems. The aim of this study was to investigate the distribution and excretion of hexachloronaphthalene (HxCN) in rats following a single intraperitoneal or intragastrical administration. Materials and Methods: Experiments were performed on male outbred Wistar rats with body weight of 220-240 g. They were given [ ]-HxCN in plasma was biphasic and the calculated half-lives for phases I and II were ~6 and 350 h, respectively. Following 120 h after administration, ~51% (intragastrical) and ~34% (intraperitoneal) of the dose were excreted with faeces. Regardless of the administration route, the highest HxCN concentrations were found in liver and adipose tissue, where the compound showed high retention: the highest retention in liver was found 24 h after intragastrical (32%) and intraperitoneal (38%) administration while in adipose tissue ~30% retention was observed 120 h after HxCN administration regardless of its route. Conclusions: Following the calculation of the balance of total [ 14 C]-HxCN excreted and stored, it was found that hexachloronaphthalene belongs to the compounds of a slow turnover rate, and in the case of repeated exposure it may accumulate in the rat body.

The Effect of Prenatal Exposure on Disposition of Hexachloronaphthalene in Female Wistar Rats and Fetal Compartment

“…Our findings indicate that the L/A ratio decreased with time after administration, which is comparable with the results observed by Chen et al [44]. The gradually increasing concentration of HxCN in the adipose tissue after administration was also observed in a previous study on the distribution of this compound in male rats [24]. Our present findings also indicate that HxCN penetrates into the fetus, reaching a level of 0.05% dose/g tissue, which is comparable to the findings obtained by Chen et al [44] following the exposure of the subjects to TCDD (0.053% dose/g tissue).…”

“…In the case of mothers, the greatest retention was observed in the livers, while the opposite was observed in the fetuses; similarly, earlier studies on the distribution of hexachloronaphthalene in male rats also found the highest concentration to be in the liver [24]. This is probably due to the differences present in the fetal liver circulation.…”

“…This prenatal toxicity may be due to the toxic mechanisms or to the transport of the compound through the placenta. Among the all PCNs congeners, hexachloronaphthalene is one of the most bioaccumulative [22][23][24] and toxic [25][26][27]. So far, no research has been carried out that would confirm the penetration of PCNs through the placental barrier.…”

“…The dams received a single oral dose on GD 17, GD 18 or GD 19. The applied dosage was the same as we used in our previous study [24].…”

Burden and Risk of Polychlorinated Naphthalenes in Chinese Human Milk and a Global Comparison of Human Exposure

“…This global concern is attributable to the toxicity, bioaccumulation, and long-range transport of PCNs, which are similar to those of dioxins and dioxin-like chemicals . Studies in laboratory animals − on the toxicity of PCNs reported dermal lesions, oxidative stress, lipid peroxidation, genotoxicity, carcinogenicity, neurotoxicity, and reproductive and developmental toxicity. Known effects of PCNs in humans include chloracne, liver dysfunction, systemic symptoms of digestive problems, anorexia, nausea, vertigo, and even death. − Environmental pollution by PCNs is both historical and ongoing.…”