Pleiotropic actions of melatonin in testicular peritubular myoid cells of immature Syrian hamsters.

BACKGROUND: Peritubular myoid cells are emerging as key regulators of testicular function in adulthood. However, little is known about the role of testicular peritubular myoid cells (TPMCs) in the development of the male gonad. We found that, compared to testes of young adult hamsters, gonads of 21 day-old animals show increased melatonin concentration, seminiferous tubular wall thickening and a heterogeneous packaging of its collagen fibers thus raising the question whether melatonin may be involved in the regulation of TPMCs. METHODS: We established primary cultures of TPMCs from immature hamsters (ihaTPMCs), which we found express melatonergic receptors. RESULTS: Exogeneous melatonin decreased the levels of inflammatory markers (NLRP3 inflammasome, IL1ß) but increased the expression of cyclooxygenase 2 (COX2, key enzyme mediating prostaglandin synthesis) and of the glial cell line-derived neurotrophic factor (GDNF) in ihaTPMCs. Melatonin also stimulated ihaTPMCs proliferation and the expression of extracellular matrix proteins such as collagen type I and IV. Furthermore, collagen gel contraction assays revealed an enhanced ability of ihaTPMCs to contract in the presence of melatonin. CONCLUSION: Melatonin regulates immune and inflammatory functions as well as contractile phenotype of the peritubular wall in the hamster testis. GENERAL SIGNIFICANCE: If transferable to the in vivo situation, melatonin-dependent induction of ihaTPMCs to produce factors known to exert paracrine effects in other somatic cell populations of the gonad suggests that the influence of melatonin may go beyond the peritubular wall and indicates its contribution to testicular development and the establishment of a normal and sustainable spermatogenesis.

Perinatal exposure to Bisphenol A disturbs the early differentiation of male germ cells.

Understanding the effects of Bisphenol A (BPA) on early germ cell differentiation and their consequences in adult life is an area of growing interest in the field of endocrine disruption. Herein, we investigate whether perinatal exposure to BPA affects the differentiation of male germ cells in early life using a transgenic mouse expressing the GFP reporter protein under the Oct4 promoter. In this model, the expression of GFP reflects the expression of the Oct4 gene. This pluripotency gene is required to maintain the spermatogonial stem cells in an undifferentiated stage. Thus, GFP expression was used as a parameter to evaluate the effect of BPA on early germ cell development. Female pregnant transgenic mice were exposed to BPA by oral gavage, from embryonic day 5.5 to postnatal day 7 (PND7). The effects of BPA on male germ cell differentiation were evaluated at PND7, while sperm quality, testicular morphology, and protein expression of androgen receptor and proliferating cell nuclear antigen were studied at PND130. We found that perinatal/lactational exposure to BPA up-regulates the expression of Oct4-driven GFP in testicular cells at PND7. This finding suggests a higher proportion of undifferentiated spermatogonia in BPA-treated animals compared with non-exposed mice. Moreover, in adulthood, the number of spermatozoa per epididymis was reduced in those animals perinatally exposed to BPA. This work shows that developmental exposure to BPA disturbed the normal differentiation of male germ cells early in life, mainly by altering the expression of Oct4 and exerted long-lasting sequelae at the adult stage, affecting sperm count and testis.

Melatonin daily oral supplementation attenuates inflammation and oxidative stress in testes of men with altered spermatogenesis of unknown aetiology.

We have previously shown an inverse correlation between testicular melatonin concentration and inflammation/oxidative stress-related markers levels in infertile men showing unexplained azoospermia. Here, we evaluated the impact of melatonin oral supplementation (daily 3 mg dose used to treat sleep disorders) in the incidence of local inflammation, oxidative stress, and tubular wall fibrosis development in young and middle-aged infertile adult men. Compared with testes without histological alterations, gonads with morphological abnormalities showed lower melatonin concentration along with increased macrophage numbers, TBARS generation, and expression levels of inflammation-related markers and antioxidant enzymes, as well as tubular wall collagen fibers disorganization and thickening. Melatonin oral supplementation not only increased its own testicular levels but also decreased inflammation- and oxidative stress-related markers levels, and improved the tubular wall aspect. Overall, our work provides insights into the potential benefits of melatonin on the inflammatory and oxidative status in testes of patients suffering from unexplained infertility.

Temperature- vs. estrogen-induced sex determination in Caiman latirostris embryos: Both females, but with different expression patterns of key molecules involved in ovarian development.

Caiman latirostris is a species with temperature dependent sex determination (TSD), which implies that the incubation temperature of the eggs is the main factor that determines the sex during a thermo-sensitive period (TSP). However, estrogens play a critical role in this process. The administration of 17ß-estradiol (E2) previous to TSP overrides the effects of male incubation temperature, producing phenotypic females. This effect has been defined as sex reversal or estrogen-induced sex determination (E2SD). The aim of the present study is to describe similarities and differences in the effects of TSD and E2SD treatment conditions on ovary development. Our results show that the two treatment conditions studied are able to produce different ovaries. Treatment with E2 modified the expression pattern of estrogen receptor alpha and progesterone receptor, and expression of the enzyme aromatase. Moreover, in E2SD females, the proliferation/apoptosis dynamic was also altered and high expression of TAp63 was observed suggesting the presence of greater DNA damage in germ cells. To the best of our knowledge, this is the first report that describes the morphology of the female gonad of C. latirostris in three stages of embryonic development and shows the expression of TAp63 during the gonad development of a reptile. It is important to emphasize that the changes demonstrated in E2SD female gonads of embryos show that environmental compounds with proven estrogenic activity alter the follicular dynamics of C. latirostris in neonatal as much as in juvenile animals, endangering their reproductive health and possibly bringing consequences to ecology and evolution.

Morphological characteristics of the interpubic joint (Symphysis pubica) of rats, guinea pigs and mice in different physiological situations. A comparative study.

The pubic joint of male and female rats, guinea pigs and mice was studied using the Picrosirius polarization method which selectively discloses the fibers of the collagenous system. Besides that, considerations were made regarding joint classification. In adult rats (both males and females, including intrapartum specimens), our results confirm those of earlier studies showing that the interpubic joint contains a central core of hyaline cartilage surrounded by fibrocartilaginous areas. Thus, in rats, the pubic joint should more properly be classified as a true synchondrosis. In virgin female guinea pigs and mice, the interpubic joint is formed of fibrocartilage (a true symphysis); whereas at term the bones are joined by a connective ligament, constituting a syndesmosis. Male mice have a similar (fibrocartilaginous) joint structure to virgin female mice, whereas male guinea pigs (like rats) have a hyaline cartilage joint. The foregoing observations indicate that the classification of the pubic joint depends upon the species, age, sex, and physiological reproductive stage studied. Species that are very similar in most other aspects (such as rats and mice) displayed different morphological features of the pubic joint to support the same reproductive processes. Together, the data reported here suggest that interspecies differences are likely to be found in other parameters and should be considered when choosing an appropriate animal model for research or teaching purposes.