Impairment of steroidogenesis and follicle development after bisphenol A exposure during pregnancy and lactation in the ovaries of Mongolian gerbils aged females

The ovaries regulate fertility and hormonal control in females, and aging is a crucial factor in this process, when ovarian function is drastically impacted. Exogenous endocrine disruptors may accelerate this process, acting as the main agents in decreased female fertility and hormonal imbalance, since they impact different features related to reproduction. In the present study, we demonstrate the implications of exposure of adult mothers to the endocrine disruptor bisphenol A (BPA) during pregnancy and lactation on their ovarian function during the transition to later in life (aging). The follicle population of BPA exposed ovaries showed impairment in the development of follicles to the mature stages, with growing follicles being halted in the early stages. Atretic and early-atretic follicles were also enhanced. Expression of estrogen and androgen receptors in the follicle population demonstrated impairment in signaling function: ERβ was highly expressed in follicles from BPA exposed females, which also showed a higher incidence of early atresia of developed follicles. ERβ1 wild-type isoform was also enhanced in BPA-exposed ovaries, compared to its variant isoforms. In addition, steroidogenesis was targeted by BPA exposure: aromatase and 17-β-HSD were reduced, whereas 5-α reductase was enhanced. This modulation was reflected in serum levels of estradiol and testosterone, which decreased in BPA-exposed females. Imbalances in steroidogenesis impair the development of follicles and play an important role in follicular atresia. Our study demonstrated that BPA exposure in two windows of susceptibility - gestation and lactation - had implications during aging, enhancing perimenopausal and infertile features.

Differential effects of omega-3 PUFAS on tumor progression at early and advanced stages in TRAMP mice

BACKGROUND

In vitro studies evidenced antitumor effects of omega-3 polyunsaturated fatty acids ([n-3] PUFAs), but their effects on prostate cancer (PCa) remain controversial in epidemiological studies. Here we investigated whether an (n-3) PUFA-enriched diet affects tumor progression in transgenic adenocarcinoma of the mouse prostate (TRAMP), at early (12 weeks age) and advanced stages (20 weeks age).

METHODS

TRAMP mice were fed with standard rodent diet (C12, C20) or (n-3) PUFA-enriched diet containing 10% fish oil (T12, T20). A group of 8 weeks age animals fed standard diet was also used for comparison (C8). The ventral prostate was processed for histopathological and immunohistochemical analyses and serum samples submitted to biochemical assays.

RESULTS

At early stages, (n-3) PUFA increased the frequency of normal epithelium (3.8-fold) and decreased the frequency of high-grade intraepithelial neoplasia (3.3-fold) and in situ carcinoma (1.9-fold) in the gland, maintaining prostate pathological status similar to C8 group. At advanced stages, 50% of the animals developed a large primary tumor in both C20 and T20, and tumor weight did not differ (C20: 2.2 ± 2.4; T20: 2.8 ± 2.9 g). The ventral prostate of T12 and of T20 animals that did not develop primary tumors showed lower cell proliferation, tissue expressions of androgen (AR) and glucocorticoid (GR) receptors, than their respective controls. For these animals, (n-3) PUFA also avoided an increase in the number of T-lymphocytes, collagen fibers, and αSMA immunoreactivity, and preserved stromal gland microenvironment. (n-3) PUFA also lowered serum triglycerides and cholesterol, regulating the lipid metabolism of TRAMP mice.

CONCLUSIONS

(n-3) PUFAs had a protective effect at early stages of PCa, delaying tumor progression in TRAMP mice, in parallel with reductions in cell proliferation, AR, and GR and maintenance of the stromal compartment of the gland. However, (n-3) PUFAs did not prevent the development of primary tumors for the T20 group, reinforcing the need for further investigation at advanced stages of disease.

Low-dose in utero exposure to finasteride promotes developmental changes in both male and female gerbil prostates

The prostate is an accessory reproductive gland that is sensitive to the action of exogenous compounds known as endocrine disrupters that alter normal hormonal function. Finasteride is a widely used chemical that acts to inhibit the conversion of testosterone in its most active form, dihydrotestosterone. It is known that intrauterine exposure to finasteride causes changes in the male prostate even at low dosages; however, it is not known whether these dosages are capable of causing changes in the female prostate, which is present in a large number of mammalian species, including humans. In the present study, histochemistry, immunohistochemistry, immunofluorescence, serological dosages, and three-dimensional reconstruction techniques were employed to evaluate the effects of intrauterine exposure to a low dose of finasteride (100 μg.BW/d) on postnatal prostate development in male and female Mongolian gerbils. The results indicate that the gerbil female prostate also undergoes alterations following intrauterine exposure to finasteride, exhibiting a thickening of periductal smooth muscle and increased stromal proliferation. There are also intersex differences in the impact of exposure on the expression of the androgen receptor, which was increased in males, and of the estrogen-α receptor, which was decreased in the male prostate but unchanged in females. Altogether, this study indicates there are sex differences in the effects of finasteride exposure even at low dosages.