Male animal sterilization: history, current practices, and potential methods for replacing castration.

Sterilization and castration have been synonyms for thousands of years. Making an animal sterile meant to render them incapable of producing offspring. Castration or the physical removal of the testes was discovered to be the most simple but reliable method for managing reproduction and sexual behavior in the male.

Cryptorchidism and testicular cancer in the dog: unresolved questions and challenges in translating insights from human studies†.

Cryptorchidism, the failure of one or both testes to descend into the scrotum, and testicular cancer show a strong correlation in both dogs and humans. Yet, long-standing medical debates persist about whether the location of undescended testes directly causes testicular cancer in humans or if both conditions stem from a common origin. Although testicular cancer is a prevalent disease in dogs, even less is known about its cause and correlation with testicular descent in this species.

Prenatal exposure to Di(2-ethylhexyl) phthalate and high-fat diet synergistically disrupts gonadal function in male mice†.

Prenatal exposure to Di (2-ethylhexyl) phthalate (DEHP) impairs the reproductive system and causes fertility defects in male offspring. Additionally, high-fat (HF) diet is a risk factor for reproductive disorders in males. In this study, we tested the hypothesis that prenatal exposure to a physiologically relevant dose of DEHP in conjunction with HF diet synergistically impacts reproductive function and fertility in male offspring.

Single neonatal estrogen implant sterilizes female animals by decreasing hypothalamic KISS1 expression.

Reproductive sterilization by surgical gonadectomy is strongly advocated to help manage animal populations, especially domesticated pets, and to prevent reproductive behaviors and diseases. This study explored the use of a single-injection method to induce sterility in female animals as an alternative to surgical ovariohysterectomy. The idea was based on our recent finding that repetitive daily injection of estrogen into neonatal rats disrupted hypothalamic expression of Kisspeptin (KISS1), the neuropeptide that triggers and regulates pulsatile secretion of GnRH.

Estrogen receptor alpha signaling in dendritic cells modulates autoimmune disease phenotype in mice.

Estrogen is a disease-modifying factor in multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE) via estrogen receptor alpha (ERα). However, the mechanisms by which ERα signaling contributes to changes in disease pathogenesis have not been completely elucidated. Here, we demonstrate that ERα deletion in dendritic cells (DCs) of mice induces severe neurodegeneration in the central nervous system in a mouse EAE model and resistance to interferon beta (IFNβ), a first-line MS treatment.

Endothelin 2: a key player in ovulation and fertility.

Ovulation is the fundamental biological process during which an oocyte is expelled from the ovary, and it is an essential step toward establishing a pregnancy. Understanding regulatory mechanisms governing the ovulation process is essential for diagnosing and treating causes of infertility, identifying contraceptive targets, and developing novel contraception methods. Endothelin-2 (EDN2) is a 21 amino acid-long peptide that is transiently synthesized by granulosa cells of the ovulatory follicle prior to ovulation and plays an essential role in ovulation via promoting contraction in the myofibroblast cells of the theca layer of the follicle.

Protective Effects of Endothelin-2 Expressed in Epithelial Cells on Bleomycin-Induced Pulmonary Fibrosis in Mice.

Initially, endothelin (ET)-2 was described as an endothelium-derived vasoconstrictor. However, accumulating evidence suggests the involvement of ET-2 in non-cardiovascular physiology and disease pathophysiology. The deficiency of ET-2 in mice can be lethal, and such mice exhibit a distinct developmental abnormality in the lungs.

Early postnatal exposure to di(2-ethylhexyl) phthalate causes sex-specific disruption of gonadal development in pigs.

Di(2-ethylhexyl) phthalate (DEHP) is a chemical commonly used as a plasticizer to render polyvinyl chloride products more durable and flexible. Although exposure to DEHP has raised many health concerns due to the identification of DEHP as an endocrine disruptor, it is still used in consumer products, including polyvinyl chloride plastics, medical tubing, car interiors, and children's toys. To investigate the impact of early life exposure to DEHP on the ovary and testes, newborn piglets were orally dosed with DEHP (20 or 200 mg/kg/day) or vehicle control (tocopherol-stripped corn oil) for 21 days.

Progesterone Receptor Serves the Ovary as a Trigger of Ovulation and a Terminator of Inflammation.

Ovulation is triggered by the gonadotropin surge that induces the expression of two key genes, progesterone receptor (Pgr) and prostaglandin-endoperoxide synthase 2 (Ptgs2), in the granulosa cells of preovulatory follicles. Their gene products PGR and PTGS2 activate two separate pathways that are both essential for successful ovulation. Here, we show that the PGR plays an additional essential role: it attenuates ovulatory inflammation by diminishing the gonadotropin surge-induced Ptgs2 expression.

Germline-dependent transmission of male reproductive traits induced by an endocrine disruptor, di-2-ethylhexyl phthalate, in future generations.

In males, defective reproductive traits induced by an exposure to an endocrine disruptor are transmitted to future generations via epigenetic modification of the germ cells. Interestingly, the impacted future generations display a wide range of heterogeneity in their reproductive traits. In this study, the role that the Y chromosome plays in creating such heterogeneity is explored by testing the hypothesis that the Y chromosome serves as a carrier of the exposure impact to future generations.

Prenatal exposure to an environmentally relevant phthalate mixture disrupts testicular steroidogenesis in adult male mice.

Endocrine disrupting chemicals (EDCs) in the environment are considered to be a contributing factor to the decline in the sperm quality. With growing evidence of the harmful effects of EDCs on the male reproductive system, we tested the hypothesis that prenatal exposure to an environmentally relevant phthalate mixture adversely affects reproductive outcomes and androgen synthesis. In this study, an environmentally relevant composition of phthalates (15% DiNP, 21% DEHP, 36% DEP, 15% DBP, 8% DiBP, and 5% BBzP) that were detected in urine samples of pregnant women in Illinois, United States, was used.

Sanitary pads and diapers contain higher phthalate contents than those in common commercial plastic products.

Sanitary pads and diapers are made of synthetic plastic materials that can potentially be released while being used. This study measured the amounts of volatile organic compounds (VOCs) (methylene chloride, toluene, and xylene) and phthalates (DBP, DEHP, DEP, and BBP) contained in sanitary pads and diapers. In sanitary pads, 5,900- and 130-fold differences of VOC and phthalate concentrations were seen among the brands.

Porcine intestinal lymphoid tissues synthesize estradiol.

Estradiol (17β-estradiol) is synthesized primarily in the gonads of both sexes and regulates the development and function of reproductive organs. Recently, we reported that intestinal lymphocyte homeostasis is regulated by estradiol synthesized in the endothelial cells of the high endothelial venules (HEVs) of mesenteric lymph nodes and Peyer's patches in mice. This observation prompted us to hypothesize that HEVs of intestinal lymphoid tissues are sites of estradiol synthesis across species.

Birth of clones of the world's first cloned dog.

Animal cloning has gained popularity as a method to produce genetically identical animals or superior animals for research or industrial uses. However, the long-standing question of whether a cloned animal undergoes an accelerated aging process is yet to be answered. As a step towards answering this question, we compared longevity and health of Snuppy, the world's first cloned dog, and its somatic cell donor, Tai, a male Afghan hound.

Generation and characterization of an estrogen receptor alpha-iCre knock-in mouse.

Two estrogen receptors, ESR1 and ESR2, are responsible for the classical actions of estrogens in mammalian species. They display different spatiotemporal expression patterns and nonoverlapping functions in various tissues and physiological conditions. In this study, a novel knock-in mouse line that expresses codon-improved Cre recombinase (iCre) under regulation of the natural Esr1 promoter (Esr1-iCre) was developed.

Label-free, multi-scale imaging of ex-vivo mouse brain using spatial light interference microscopy.

Brain connectivity spans over broad spatial scales, from nanometers to centimeters. In order to understand the brain at multi-scale, the neural network in wide-field has been visualized in detail by taking advantage of light microscopy. However, the process of staining or addition of fluorescent tags is commonly required, and the image contrast is insufficient for delineation of cytoarchitecture.

Extra-gonadal sites of estrogen biosynthesis and function.

Estrogens are the key hormones regulating the development and function of reproductive organs in all vertebrates. Recent evidence indicates that estrogens play important roles in the immune system, cancer development, and other critical biological processes related to human well-being. Obviously, the gonads (ovary and testis) are the primary sites of estrogen synthesis, but estrogens synthesized in extra- gonadal sites play an equally important role in controlling biological activities.