The Interstitial Gland as a Source of Pro- or Anti-Senescent Cells during Chinchilla Rabbit Ovarian Aging.

The aging ovary in mammals leads to the reduced production of sex hormones and a deterioration in follicle quality. The interstitial gland originates from the hypertrophy of the theca cells of atretic follicles and represents an accumulative structure of the ovary that may contribute to its aging. Here, reproductive and mature rabbit ovaries are used to determine whether the interstitial gland plays a crucial role in ovarian aging.

Gene expression dynamics during temperature-dependent sex determination in a sea turtle.

Fifty years ago, researchers discovered a link between ambient temperature and the sex of turtle embryos. More recently, significant progress has been made in understanding the influence of temperature on freshwater turtles. However, our understanding of the key genetic factors in other turtle groups, such as sea turtles, remains limited.

Light and focused ion beam microscopy workflow for resin-embedded tissues.

Although the automated image acquisition with the focused ion beam scanning electron microscope (FIB-SEM) provides volume reconstructions, volume analysis of large samples remains challenging. Here, we present a workflow that combines a modified sample protocol of the classical transmission electron microscope with FIB-SEM volume imaging. The proposed workflow enables efficient 3D structural surveys of rabbit ovaries collected at consecutive developmental stages.

A High-Fat and High-Carbohydrate Diet Promotes Reminiscent Hallmarks of an Aging Ovary in the Rabbit Model.

The primary definition of ovarian aging refers to the loss of follicles. Moreover, the aging of the microenvironment in ovaries, specifically affecting the follicles, may reveal deterioration with advancing age. Besides aging, metabolic disorders associated with hypercaloric diets may affect ovarian health and manifest characteristics associated with premature aging.

Spatiotemporal Expression of Foxl2 and Dmrt1 before, during, and after Sex Determination in the Sea Turtle Lepidochelys olivacea.

The sex of sea turtles is determined by temperature during egg incubation. Thus, climate change affects the sex ratio, exacerbating their vulnerability to extinction. Understanding spatiotemporal effects of temperature on sex determination at the gonadal level may facilitate the design of strategies to mitigate the effects of global warming.

17β-Estradiol modulates cell proliferation of medullary cords during ovarian differentiation of the Lepidochelys olivacea sea turtle.

In turtles undergoing temperature sex determination (TSD), bipotential gonads express Sox9 in medullary cords at both female- (FPT) and male-producing temperatures (MPT). Subsequently, when the sex fate of medullary cords becomes dimorphic, at FPT, Sox9 is downregulated, whereas at MPT, its expression is maintained. Medullary cords in the ovary turn into ovarian lacuna, whereas in the testis they differentiate as seminiferous cords.

Dimorphic DNA methylation during temperature-dependent sex determination in the sea turtle Lepidochelys olivacea.

Sex determination in vertebrates depends on the expression of a conserved network of genes. Sea turtles such as Lepidochelys olivacea have temperature-dependent sex determination. The present work analyses some of the epigenetic processes involved in this.

Exogenous estradiol alters gonadal growth and timing of temperature sex determination in gonads of sea turtle.

Temperature sex determining species offer a model for investigating how environmental cues become integrated to the regulation of patterning genes and growth, among bipotential gonads. Manipulation of steroid hormones has revealed the important role of aromatase in the regulation of the estrogen levels involved in temperature-dependent sex determination. Estradiol treatment counteracts the effect of male-promoting temperature, but the resulting ovarian developmental pattern differs from that manifested with the female-promoting temperature.

Formation of the genital ridges is preceded by a domain of ectopic Sox9-expressing cells in Lepidochelys olivacea.

Bipotential gonads represent the structural framework from which alternative molecular sex determination networks have evolved. Maintenance of Sox9 expression in Sertoli cells is required for the structural and functional integrity of male gonads in mammals and probably in most amniote vertebrates. However, spatial and temporal patterns of Sox9 expression have diversified along evolution.