Evaluación de la integridad de membranas plasmáticas en espermatozoides equinos refrigerados

La integridad y correcto funcionamiento de la membrana plasmática es fundamental para el metabolismo espermático y el proceso de fertilización. La capacidad fecundante de los espermatozoides se ve influenciada por el efecto adverso de la criopreservación, este proceso ejerce daños como hinchamiento, ruptura, cambios en la fluidez, alteración del flujo de calcio y cambios en la actividad enzimática en la membrana plasmática; estos eventos pueden inducir una capacitación espermática anticipada y/o reacción acrosomal. En este trabajo se analizó la integridad de la membrana plasmática de los espermatozoides mediante el uso del test hipoosmótico (host). La prueba consiste en colocar los espermatozoides en una solución de citrato de Na. Los espermatozoides cuya integridad de membranas sea normal responderán a dicho cambio mediante la incorporación de agua al medio intracelular y así hincharse (swell) a nivel de la cola para compensar la diferencia de osmolaridad

MiR200 and MiR302: Two big families influencing stem cell behavior

In this review, we described different factors that modulate pluripotency in stem cells, in particular we aimed at following the steps of two large families of miRNAs: the miR-200 family and the miR-302 family. We analyzed some factors tuning stem cells behavior as TGF-\uce\ub2, which plays a pivotal role in pluripotency inhibition together with specific miRNAs, reactive oxygen species (ROS), but also hypoxia, and physical stimuli, such as ad hoc conveyed electromagnetic fields. TGF-\uce\ub2 plays a crucial role in the suppression of pluripotency thus influencing the achievement of a specific phenotype. ROS concentration can modulate TGF-\uce\ub2 activation that in turns down regulates miR-200 and miR-302. These two miRNAs are usually requested to maintain pluripotency, while they are down-regulated during the acquirement of a specific cellular phenotype. Moreover, also physical stimuli, such as extremely-low frequency electromagnetic fields or high-frequency electromagnetic fields conveyed with a radioelectric asymmetric conveyer (REAC), and hypoxia can deeply influence stem cell behavior by inducing the appearance of specific phenotypes, as well as a direct reprogramming of somatic cells. Unraveling the molecular mechanisms underlying the complex interplay between externally applied stimuli and epigenetic events could disclose novel target molecules to commit stem cell fate

Evaluación de semen equino refrigerado con 3 diluyentes alternativos

Las funciones del plasma seminal son mantener la viabilidad espermática, proveer un medio óptimo para el traslado y fecundación de los espermatozoides en el tracto reproductor de la hembra. La refrigeración implica un riesgo en la sobrevida de los espermatozoides; para preservarlos durante períodos prolongados, su actividad metabólica debe ser reducida mediante la dilución en un medio apropiado y la reducción de la temperatura. Los diluyentes utilizados pueden ser de origen comercial o realizados a partir de la fórmula descripta por Kenney en EEUU (1975) a base de leche en polvo. Debida a la amplia gama de aditivos presentes en las leches en polvo de producción nacional es necesario evaluar si éstos pueden tener efectos favorables o no en el proceso de refrigeración de semen equino, para poder ser usadas en su preservación

Mechanical Stimulation of Fibroblasts by Extracorporeal Shock Waves: Modulation of Cell Activation and Proliferation Through a Transient Proinflammatory Milieu

Extracorporeal shock waves (ESWTs) are "mechanical" waves, widely used in regenerative medicine, including soft tissue wound repair. Although already being used in the clinical practice, the mechanism of action underlying their biological activities is still not fully understood. In the present paper we tried to elucidate whether a proinflammatory effect may contribute to the regenerative potential of shock waves treatment. For this purpose, we exposed human foreskin fibroblasts (HFF1 cells) to an ESWT treatment (100 pulses using energy flux densities of 0.19 mJ/mm2 at 3 Hz), followed by cell analyses after 5 min, up to 48 h. We then evaluated cell proliferation, reactive oxygen species generation, ATP release, and cytokine production. Cells cultured in the presence of lipopolysaccharide (LPS), to induce inflammation, were used as a positive control, indicating that LPS-mediated induction of a proinflammatory pattern in HFF1 increased their proliferation. Here, we provide evidence that ESWTs affected fibroblast proliferation through the overexpression of selected cytokines involved in the establishment of a proinflammatory program, superimposable to what was observed in LPS-treated cells. The possibility that inflammatory circuits can be modulated by ESWT mechanotransduction may disclose novel hypothesis on their biological underpinning and expand the fields of their biomedical application

Melatonin and Vitamin D Interfere with the Adipogenic Fate of Adipose-Derived Stem Cells

Adipose-derived stem cells (ADSCs) represent one of the cellular populations resident in adipose tissue. They can be recruited under certain stimuli and committed to become preadipocytes, and then mature adipocytes. Controlling stem cell differentiation towards the adipogenic phenotype could have a great impact on future drug development aimed at counteracting fat depots. Stem cell commitment can be influenced by different molecules, such as melatonin, which we have previously shown to be an osteogenic inducer. Here, we aimed at evaluating the effects elicited by melatonin, even in the presence of vitamin D, on ADSC adipogenesis assessed in a specific medium. The transcription of specific adipogenesis orchestrating genes, such as aP2, peroxisome proliferator-activated receptor \u3b3 (PPAR-\u3b3), and that of adipocyte-specific genes, including lipoprotein lipase (LPL) and acyl-CoA thioesterase 2 (ACOT2), was significantly inhibited in cells that had been treated in the presence of melatonin and vitamin D, alone or in combination. Protein content and lipid accumulation confirmed a reduction in adipogenesis in ADSCs that had been grown in adipogenic conditions, but in the presence of melatonin and/or vitamin D. Our findings indicate the role of melatonin and vitamin D in deciding stem cell fate, and disclose novel therapeutic approaches against fat depots

Melatonin and Vitamin D Orchestrate Adipose Derived Stem Cell Fate by Modulating Epigenetic Regulatory Genes

Melatonin, that regulates many physiological processes including circadian rhythms, is a molecule able to promote osteoblasts maturation in vitro and to prevent bone loss in vivo, while regulating also adipocytes metabolism. In this regard, we have previously shown that melatonin in combination with vitamin D, is able to counteract the appearance of an adipogenic phenotype in adipose derived stem cells (ADSCs), cultured in an adipogenic favoring condition. In the present study, we aimed at evaluating the specific phenotype elicited by melatonin and vitamin D based medium, considering also the involvement of epigenetic regulating genes. ADSCs were cultured in a specific adipogenic conditioned media, in the presence of melatonin alone or with vitamin D. The expression of specific osteogenic related genes was evaluated at different time points, together with the histone deacetylases epigenetic regulators, HDAC1 and Sirtuins (SIRT) 1 and 2. Our results show that melatonin and vitamin D are able to modulate ADSCs commitment towards osteogenic phenotype through the upregulation of HDAC1, SIRT 1 and 2, unfolding an epigenetic regulation in stem cell differentiation and opening novel strategies for future therapeutic balancing of stem cell fate toward adipogenic or osteogenic phenotype

Impact d’anti-androgènes sur la gamétogenèse du rotifère Brachionus calyciflorus

Several studies have shown that pollutants with anti-androgenic activity have an impact on the sexual reproduction of the rotifer Brachionus calyciflorus (Joaquim-Justo et al., submit; Preston et al., 2001). The effects observed are compatible with the phenomenon of endocrine disruption. Fenitrothion, a non-steroidal anti-androgen induces a decrease in fertilization rate following exposure below or equal to 0,5 mg L-1.. The steroidal anti-androgen, cyproterone acetate increases number of cysts in population exposed to concentrations below or equal to 0,5 mg L-1. Cross mating experiments showed that effects of fenitrothion are due to an impact on males exclusively, while effects of cyproterone acetate exposition are due to an impact on females exclusively. In this study, we investigated the impact of fenitrothion on spermatogenesis and observed a decrease in the spermatozoa production and mobility with concentrations down to 0,5 mg L-1. We report a detailed description of the morphology of the male reproductive apparatus in B. calyciflorus based on optic, transmission electron and scanning electron microscopy in controls and exposed individuals

Hydrogen production by ethanol steam reforming: effect of the synthesis parameters on the activity of Ni/TiO2 catalysts

Ethanol steam reforming is an attracting process to produce hydrogen in a sustainable way. In this work the performance of Ni/TiO2 catalysts in ethanol steam reforming was studied. In particular, the effect of the synthesis procedure on the properties of the catalysts and on their activity was deeply investigated. On the basis of the experimental results, it was evidenced that TiO2-supported Ni systems are very sensitive to the synthesis parameters. We found that a proper thermal activation by calcination at 800 degrees C allows to obtain stable catalysts by means of strong interactions between the active phase and the support, preserving the catalyst from sintering phenomena. Nevertheless, the synthesis conditions must be properly tuned in order to prevent Ni incorporation in scarcely reducible structures which would depress catalytic activity. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved

Adsorption of 1,2-dichloroethane on ZSM-5 and desorption dynamics by in situ synchrotron powder X-ray diffraction

The adsorption/desorption behaviour of ZSM-5 loaded with 1,2-dichloroethane was studied using the in situ synchrotron X-ray powder-diffraction technique in the temperature range 30°–600 °C. Rietveld refinements allowed to monitor the DCE decomposition process as well as the structural modifications undergoing on ZSM-5 upon a temperature-programmed thermal treatment. These results clearly demonstrated that regeneration of ZSM-5 is effective when thermally treating the adsorbent at about 300 °C thus minimising the cost of the regeneration step of the adsorption process. Once regenerated and reloaded the Rietveld refinement indicates that both DCE location and content remain substantially unchanged thus confirming ZSM-5 is able to re-adsorb DCE in amounts comparable to that adsorbed in the first cycle, in very good agreement with the chromatographic results. In conclusion, the use of this adsorbent with unchanged adsorption performances after thermal regeneration under mild conditions appears very promising also over several cycles of the adsorption/desorption process