The Hepatokine FGF21 Increases the Human Spermatozoa Motility

Adropin may promote insulin stimulated steroidogenesis and spermatogenesis in adult mice testes

Adropin is a versatile peptide which was discovered as a novel metabolic hormone that is involved in the regulation of lipid and glucose homeostasis. However, its possible role in the testicular function is not yet understood. The aim of our study was to explore the distribution pattern of adropin and GPR19 in various cell types and its possible role in testicular functions of adult mice. Immunohistochemical study revealed the intense immunoreactivity of adropin in the Leydig cells, while GPR19 showed intense immunoreactivity in the pachytene spermatocytes and mild immunoreactivity in Leydig cells and primary as well as secondary spermatocytes in mouse testis. Enho mRNA was also found to be expressed in the mouse testis. These findings suggested that adropin-GPR19 signaling may act in autocrine/paracrine manner to modulate testicular functions. Furthermore, to find out the direct role of adropin in the testicular function, in vitro study was performed in which testicular slices were cultured with adropin alone (10 and 100 ng/mL) and in combination with insulin (5 μg/mL). Adropin alone inhibited testicular testosterone synthesis by inhibiting the expression of P450-SCC, 3β-HSD, and 17β-HSD while along with insulin stimulated the testicular testosterone synthesis by increasing the expression of GPR19, IR, StAR, P450-SCC, 3β-HSD, and 17β-HSD. Adropin alone or in combination with insulin promoted germ cell survival and proliferation by upregulating the expression of PCNA, Bcl2, and pERK1/2. Thus, it can be concluded that adropin-GPR19 signaling promotes insulin stimulated steroidogenesis and germ cell survival as well as proliferation in the mice testes in an autocrine/paracrine manner.

PFOS-elicited metabolic perturbation in liver and fatty acid metabolites in testis of adult mice

Introduction

Multiple factors can contribute to sub-fecundity, including genetics, lifestyle, and environmental contaminants. PFASs are characterized as "forever chemicals" due to their ubiquitous contamination and their persistence in the environment, wildlife, and humans. Numerous studies have demonstrated that PFAS exposure adversely affects multiple bodily functions, including liver metabolism and gonadal function. It is unclear, however, how the disruption of hepatic fatty acid metabolism affects testicular function.

Methods

In this study, male mice were administered 0.3 and 3 μg/g body weight of PFOS for 21 days.

Results

Our data showed that PFOS exposure caused hepatic steatosis, as evidenced by significant increases in triglyceride levels, expression of ATP-citrate lyase, and fatty acid synthase, as well as fasting insulin levels. PFOS perturbed the expression levels of hepatokines, of which fibroblast growth factor-21 (Fgf-21), leukocyte cell-derived chemotaxin-2 (Lect-2), and retinol-binding protein-4 (Rbp-4) were significantly reduced, whereas angiopoietin-like 4 (Angptl4) was noticeably increased. While Rbp-4 and Fgf-21 are known to contribute to spermatogenesis and testosterone synthesis. In PFOS-exposed groups, testicular ATP, and testosterone decreased significantly with a significant increase in the expression of peroxisome proliferator-activated receptor-coactivator 1α. Mass spectrophotometry imaging revealed the localization of PFOS in testes, along with significant increases in fatty acid metabolites. These included arachidonic acid, dihomo-α-linolenic acid, dihomo-γ-linolenic acid, oxidized ceramide, diacylglycerol, phosphatidylcholine, and phosphatidylethanolamine, which are associated with inflammation and post-testicular causes of infertility.

Discussion

This study revealed potential links between PFOS-elicited changes in hepatic metabolism and their impacts on testicular biology. This study provides insights into alternative targets elicited by PFOS that can be used to develop diagnostic and therapeutic strategies for improving testicular dysfunction.

Extend the Survival of Human Sperm In Vitro in Non-Freezing Conditions: Damage Mechanisms, Preservation Technologies, and Clinical Applications

Preservation of human spermatozoa in vitro at normothermia or hypothermia maintaining their functions and fertility for several days plays a significant role in reproductive biology and medicine. However, it is well known that human spermatozoa left in vitro deteriorate over time irreversibly as the consequence of various stresses such as the change of osmolarity, energy deficiency, and oxidative damage, leading to substantial limitations including the need for semen examinations, fertility preservation, and assisted reproductive technology. These problems may be addressed with the aid of non-freezing storage techniques. The main and most effective preservation strategies are the partial or total replacement of seminal plasma with culture medium, named as extenders, and temperature-induced metabolic restriction. Semen extenders consist of buffers, osmolytes, and antioxidants, etc. to protect spermatozoa against the above-mentioned adverse factors. Extended preservation of human spermatozoa in vitro has a negative effect on sperm parameters, whereas its effect on ART outcomes remains inconsistent. The storage duration, temperature, and pre-treatment of semen should be determined according to the aims of preservation. Advanced techniques such as nanotechnology and omics have been introduced and show great potential in the lifespan extension of human sperm. It is certain that more patients will benefit from it in the near future. This review provided an overview of the current knowledge and prospects of prolonged non-freezing storage of human sperm in vitro.