Efecto de la hipercolesterolemia en la via Ras/MAPK durante la capacitación espermática y la reacción acrosomal en conejo new zeland

La hipercolesterolemia es un factor de riesgo para la salud humana. Sin embargo, elcolesterol es un componente de las membranas celulares y caveolina 1 es una proteínaimplicada en su metabolismo. Las caveolinas son una familia de proteínas asociadas avarias funciones de la célula, como transducción de señales, el transporte intracelular, yel control del crecimiento celular y tumoral supresor. Su función depende de suasociación con microdominios de membrana ricos en colesterol proporcionando unvínculo entre la membrana celular y la fisiología espermática. Por lo tanto, el nivelplasmático y celular de este esterol es esencial para la expresión de caveolina 1. En estainvestigación, hemos propuesto que la caveolina 1 posee efecto regulador sobre laseñalización a través de la Ras/MAPK debido a la hipercolesterolemi

Hypercholesterolemia Impaired Sperm Functionality in Rabbits

Hypercholesterolemia represents a high risk factor for frequent diseases and it has also been associated with poor semen quality that may lead to male infertility. The aim of this study was to analyze semen and sperm function in diet-induced hypercholesterolemic rabbits. Twelve adult White New Zealand male rabbits were fed ad libitum a control diet or a diet supplemented with 0.05% cholesterol. Rabbits under cholesterol-enriched diet significantly increased total cholesterol level in the serum. Semen examination revealed a significant reduction in semen volume and sperm motility in hypercholesterolemic rabbits (HCR). Sperm cell morphology was seriously affected, displaying primarily a “folded head”-head fold along the major axe-, and the presence of cytoplasmic droplet on sperm flagellum. Cholesterol was particularly increased in acrosomal region when detected by filipin probe. The rise in cholesterol concentration in sperm cells was determined quantitatively by Gas chromatographic-mass spectrometric analyses. We also found a reduction of protein tyrosine phosphorylation in sperm incubated under capacitating conditions from HCR. Interestingly, the addition of Protein Kinase A pathway activators -dibutyryl-cyclic AMP and iso-butylmethylxanthine- to the medium restored sperm capacitation. Finally, it was also reported a significant decrease in the percentage of reacted sperm in the presence of progesterone. In conclusion, our data showed that diet-induced hypercholesterolemia adversely affects semen quality and sperm motility, capacitation and acrosomal reaction in rabbits; probably due to an increase in cellular cholesterol content that alters membrane related events