Effects on the reproductive parameters of two generations ofRattus norvegicusoffspring from dams exposed to heptachlor during gestation and lactation

Abstract

Heptachlor has been targeted for global elimination because of its toxicity and environmental persistence, in accordance with the Stockholm Convention on Persistent Organic Pollutants (POPs). However, there is no regulation of heptachlor use in Mexico, where relatively high levels have been found in maternal breast milk. The aim of this study was to determine the effects of heptachlor on the reproductive system of offspring of two consecutive generations of rats (F1 and F2) from dams orally administered heptachlor during midgestation and lactation. Female offspring were analyzed for different phenotypic, reproductive, and molecular parameters. In the F1 generation, heptachlor treatment induced decreased body weight at weaning, increased female anogenital distance, and delayed vaginal opening. In both generations, serum progesterone levels decreased and estradiol levels remained unchanged, while overexpression of the progesterone receptor was observed in uterine epithelial cells on estrus day. In the F2 generation, expression of the estrogen receptor α increased in the glandular epithelium. Finally, heptachlor treatment did not affect apoptosis in the uterine epithelial cells. Overall, the results indicate that heptachlor induced female reproductive alterations when administered to dams during the perinatal period. Accordingly, exposure to heptachlor may represent a risk for the reproductive health of humans. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 856-868, 2017.

Environment consistently impact on aquaculture: The predominant source of residual pollutants in cultured Chinese mitten crab (Eriocheir sinensis) across China

“…Concentrations of HEPE great as 36.0 μg/kg wm were measured in crab, but this was skewed because a few samples had greater concentrations [ 42 ]. Although the use of HEPE has been strictly restricted in China [ 43 ], some countries have not attached attention to this [ 44 ]. For instance, a large amount of HEPE has been detected in the Three Gorges Reservoir in China (fish and sediments), as well as in the aquatic environment of Côte d’Ivoire [ 5 ], therefore, the possible long-distance transportation way of HEPE residues can via atmosphere [ 19 ].…”

Effects on Puberty of Nutrition-Mediated Endocrine Disruptors Employed in Agriculture

“…The exposure of female rodents to organochlorine insecticides during pre-and either early or later postnatal life has been associated with accelerated puberty. The administration of heptachlor, at a dose of 4.5 mg/kg/day per os to female Wistar rats (F0 generation), from gestation day (GD) 12 to lactation day 21, accelerated vaginal opening and increased the incidence of irregular estrous cycles in the F2 generation, which was indirectly exposed via breastfeeding from the F1 generation [26]. The exposure of pregnant Fischer CDF rats to methoxychlor from GD 11 until birth and, thereafter, the parenteral treatment of the female offspring with methoxychlor until PND 7 resulted in accelerated vaginal opening [27].…”

“…Nevertheless, no difference in the time of puberty onset was observed among animals exposed later in life (from PNDs 35-36 until 55-56) and controls [52]. Male SD rats exposed to the greatest dose of methoxychlor (1200 ppm) in their intrauterine and early postnatal life experienced balanopreputial separation, on average, 2 days later than the controls (PND 43.3 ± 1.6 vs 41.3 ± 1), while, at the same time, they had significantly lower testicular weights on the day of weaning [26]. In another study, methoxychlor was administrated per os to male Long-Evans rats from the day of weaning until PND 80.…”