Search

IntroductionAmong substances released into the environment by anthropogenic activities, the heavy metal cadmium (Cd) is known to induce severe testicular injury causing male subfertility/infertility. Zinc (Zn) is another heavy metal that, unlike Cd, is physiologically present in the testis, being essential for spermatogenesis. We aimed to examine the possibility that 50 µM ZnCl2 could counteract the toxic effects induced by Cd in an in vitro model of porcine prepubertal Sertoli cells (SCs) exposed to both subtoxic (5 μM) and toxic (10 μM) concentrations of CdCl2 for 48 h.Materials and MethodsApoptosis, cell cycle, and cell functionality were assessed. The gene expression of Nrf2 and its downstream antioxidant enzymes, ERK1/2, and AKT kinase signaling pathways were evaluated.Materials and ResultsWe found that Zn, in co-treatment with subtoxic and toxic Cd concentration, increased the number of metabolically active SCs compared to Cd exposure alone but restored SC functionality only in co-treatment with subtoxic Cd concentration with respect to subtoxic Cd alone. Exposure of Cd disrupted cell cycle in SCs, and Zn co-treatment was not able to counteract this effect. Cd alone induced SC death through apoptosis and necrosis in a dose-dependent manner, and co-treatment with Zn increased the pro-apoptotic effect of Cd. Subtoxic and toxic Cd exposures activated the Nrf2 signaling pathway by increasing gene expression of Nrf2 and its downstream genes (SOD, HO-1, and GSHPx). Zn co-treatment with subtoxic Cd attenuated upregulation on the Nrf2 system, while with toxic Cd, the effect was more erratic. Studying ERK1/2 and AKT pathways as a target, we found that the phosphorylation ratio of p-ERK1/2 and p-AKT was upregulated by both subtoxic and toxic Cd exposure alone and in co-treatment with Zn.DiscussionOur results suggest that Zn could counteract Cd effects by increasing the number of metabolically active SCs, fully or partially restoring their functionality by modulating Nrf2, ERK1/2, and AKT pathways. Our SC model could be useful to study the effects of early Cd exposure on immature testis, evaluating the possible protective effects of Zn.

Follicle-stimulating hormone (FSH) is the main regulator of spermatogenesis and plays a key role in the development and function of the reproductive system. To assess the effects of different FSH preparations in combination with testosterone on porcine pre-pubertal Sertoli cells, we performed Real Time PCR analysis of AMH, inhibin B and FSH-r, Western blotting analysis of AKT-posphoAKT, ERK1/2-posphoERK1/2, ELISA assay for AMH and inhibin B and a high-throughput proteomic analysis.We observed that all three preparations induced a reduction of AMH in terms of mRNA and secreted protein and, an increase of inhibin B in terms of mRNA in all the formulations while, only α-follitropin induced an increase of inhibin B secreted in the culture medium. Proteomic analysis permitted us to identify 46 secreted proteins.Of those, the SPARC protein was down-regulated after the treatment with testosterone associated with α-follitropin, β-follitropin and urofollitropin (vs group stimulated with T alone). 11 proteins were up-regulated by the different FSH preparations. In detail, Hemoglobin subunit beta, TPA and TPI have been observed to be up-regulated by stimulation with testosterone in addition with α-follitropin or with β-follitropin and or with urofollitropin. All preparations induced an increase in the secreted inhibin beta A chain, but in the medium after stimulation with urofollitropin we observed an higher increase in the levels of this protein. β-follitropin, associated with testosterone, specifically induces an up-regulation of 8 specific secreted proteins.Our study, showing that the three FSH preparations were associated with different effects, could offer the opportunity to shed light inside applications to personalized reproductive medicine.

At present, there is no reliable experimental model “in vitro” to analyze the complex interactions between gonadotropins on the pre-pubertal Sertoli cells (SC) and Leydig cells (LD). Considering that, in the pre-pubertal period, only the anti-mullerian hormone (AMH) is upregulated by FSH and down-regulated by androgens [1-2], AMH could be considered a potential marker of pre-pubertal testis function. The aim of our work was to study the effects of FSH, LH and HCG on an in-vitro model of “mini-testis”. SC and LD, obtained from 15-20 days old neonatal pigs, were isolated and evaluated in terms of purity by AMH (unique pre-pubertal SCs marker), INSL3 (LD marker), ASMI (peritubular cells marker) and PGP9.5 (gonocytes and spermatogonial cells marker). Finally, purified SC and LD were co-cultured to obtain the “mini-testis” and were stimulated with gonadotropins. We have then evaluated: a) AMH, inhibin B and testosterone levels released in the culture medium (by ELISA), both in basal conditions and after stimulations; b) analysis of the follicle-stimulating hormone receptor (FSHR), MAPkinasi (Erk1/2, AKT) by Real Time PCR. We show an increase in inhibin B levels after FSH and FSH/LH stimulation and a selectively increase in testosterone production after LH treatment. AMH secretion was downregulated by FSH treatment. These data seem to preliminarily suggest that ERK1/ ERK2 expression was up-regulated by FSH and FSH/LH stimulation while FSHreceptor expression was down-regulated by FSH and increased by FSH/LH treatment; AKT was up-regulated in all conditions. The proposed model, by creating an artificial mini- testis, could help better understanding the complex and still partially unknown interactions between human gonadotropins, SC and LD possibly creating a novel background to shed light inside a future therapy of male infertility, Italian Journal of Anatomy and Embryology, Vol. 120, No. 1 (Supplement) 2015

Cadmium, an ubiquitous environmental pollutant mainly used for industrial purposes, is highly associated with reproductive toxicity. Sertoli cells (SC), by providing an appropriate microenvironment for the development of germ cells, play a pivotal role on spermatogenesis regulation (Geoffroy-Siraudin et al. 2012). Aim of our investigation was to assess the effects of cadmium on high mammalian SC viability and function. Porcine pre-pubertal SC were isolated, according to previously established methods (Fallarino et al. 2009) and treated with 3 different concentrations (5-10-15 μM) of cadmium chloride. The evaluation of SC function in terms of inhibin B and anti-Müllerian hormone (AMH) secretion showed a significant decrease in all SC treated conditions respect as compared to SC control. On the contrary, evaluation of the FSH-R integrity on SC surface, in terms of 17-b-estradiol production under FSH stimulation, showed no difference between SC control and 5 μM cadmium treated SC monolayers in comparison to 10 and 15μM cadmium treated SC monolayers, where FSH-R was impaired. In addition, the apoptotic test showed a significant increase of early (ANNEXIN V-/Propidium Iodide+) (AV-/PI+) and late apoptotic cells (AV+/ PI+) in all cadmium treated SC conditions in comparison with SC control. In conclusion, our data demonstrate that cadmium, even at low dose, exerts toxic effects on Sertoli cells function possibly adversely affecting the spermatogenesis., Italian Journal of Anatomy and Embryology, Vol 117, No 2 (Supplement) 2012