Prenatal exposure to betamethasone causes intergenerational impairment of epididymal development in the rat

Reproductive outcomes of neonatal exposure to betamethasone in male and female rats

Betamethasone (BM) is the drug of choice for antenatal corticosteroid therapy for women at risk of preterm delivery because it induces fetal lung maturation and enhances survival after birth. However, our group reported evidence of fetal programming and impaired reproductive development and function in rats exposed during the critical window of genital system development. Therefore, we aimed to investigate the effects of BM on the sexual development of rats in the period that corresponds to antenatal corticosteroid therapy in humans. Male and female rats were exposed subcutaneously to BM at 0.1 μg/g of pups' body weight or to a NaCl 0.9% solution (control) on postnatal days 1-3. It was observed that neonatal exposure to BM decreased body weight and weight gain in male and female rats during treatment. The estrous cycle was deregulated and LH level was decreased in female rats. In male rats, the sperm concentration in the caput-corpus of the epididymis was decreased, whereas the sperm transit time and sperm concentration in the cauda of the epididymis were increased. Our results demonstrated that neonatal exposure to BM impaired body growth of male and female rats, deregulated the estrous cycle of female rats, and altered sperm quality of male rats. Therefore, BM exposure from postnatal days 1 to 3 corroborated results previously observed after prenatal exposure to this drug. Despite the recognized importance of human antenatal corticosteroid therapy, the findings of this study should encourage further studies in order to minimize possible adverse postnatal effects.

Emerging organoid models to study the epididymis in male reproductive toxicology

The importance of the epididymis on sperm maturation and consequently male fertility has been well documented. The pseudostratified epithelium of the epididymis is comprised of multiple cell types, including principal cells, which are the most abundant, and basal cells. The role of basal cells has been unclear and has been a source of discussion in the literature. However, the recent demonstration that these cells are multipotent or adult stem cells has opened new areas of research in epididymal biology. One such avenue is to understand the regulation of these stem cells, and to exploit their properties to develop tools for toxicological studies to elucidate the effects of chemicals on cell differentiation and epididymal function in vitro. Studies in both rat and mouse have shown that purified single epididymal basal cells cultured under 3D conditions can proliferate and differentiate to form organoids, or mini organs. Furthermore, these epididymal basal stem cells can self-renew and differentiate into other epididymal cell types. It is known that during epididymal development, basal cells are derived from undifferentiated columnar cells, which have been reported to share common properties to stem cells. Like basal cells, these undifferentiated columnar cells can also form organoids under 3D culture conditions and can differentiate into basal, principal and clear cells. Organoids derived from either basal cells or columnar cells offer unique models for toxicology studies and represent an exciting and emerging approach to understand the epididymis.

Effect of Maternal Water Restriction on Sexual Behavior, Reproductive Performance, and Reproductive Hormones of Male Rat Offspring

The present study aimed to investigate the effect of maternal water restriction on sexual behavior, reproductive performance, and reproductive hormones of male rat offspring. Forty pregnant female rats were divided into two equal groups: Control (C) and water-restricted (WR). Control dams had ad libitum water access throughout pregnancy, while dams in the WR group were subjected to 50% water-restriction from day 10 of pregnancy onwards. The maternal water restriction provoked a significant reduction (p < 0.05) in body weight of dams before delivery and at birth and litter body weights of offspring at birth. Maternal water restriction did not affect relative weights of reproductive and body organs of male rat offspring. All hormonal concentrations, sperm count, and vitality in male rat offspring were not significantly affected by maternal water restriction. Maternal water restriction exposure induced significant (p < 0.05) reduction in intromission latency, intromission frequency, and post-ejaculation interval in male rat offspring while a significant (p < 0.05) increase in the ejaculation latency was detected in maternal WR group. In conclusion, this study suggests that maternal water restriction had a negative impact on some reproductive characteristics but did not severely affect reproductive performance and reproductive hormones of male rat offspring.