El consumo semicrónico moderado de alcohol altera la foliculogénesis y la calidad núcleo-citoplasmática oocitaria, en el ratón / Moderate semi-chronic alcohol consumption alters folliculogenesis and oocyte nuclear-cytoplasmic quality in mice

Resumen El consumo crónico de alcohol es un problema de salud mundial que afecta particularmente a la población femenina. Sin embargo, los efectos de la ingesta semicrónica en cantidades moderadas a bajas en el ovario y el oocito son poco conocidos. En un modelo murino, se administró etanol al 10% en agua de bebida (hembras tratadas) o agua (hembras control) por 15 días, y luego de la superovulación o no (ovulación espontánea), se analizó el ciclo estral y la calidad ovárico-gamética. En las hembras tratadas, la frecuencia y duración del diestro aumentó, y las frecuencias de folículos y cuerpos lúteos disminuyeron vs hembras controles, valores que se restauraron luego de la superovulación. Sin embargo, en las hembras tratadas, la tasa de proliferación celular folicular y el desbalance de la expresión ovárica de VEGF (factor de crecimiento endotelial) persistieron luego de la superovulación. El número de ovocitos ovulados con metafase II anormal, fragmentados y activados partenogenéticamente fue mayor en las hembras tratadas respecto las controles. En conclusión, el consumo semicrónico moderado de alcohol produce anestro, ciclo estral irregular, foliculogénesis deficiente y anomalías núcleo-citoplasmáticas en los oocitos ovulados. Estas alteraciones podrían constituirse en un factor etiológico de pérdida gestacional temprana y desarrollo embrionario anormal luego del consumo de alcohol.

Abstract Chronic alcohol consumption is a global health problem that particularly affects the female population. However, the ef-fects of semi-chronic ethanol intake in low-moderate amounts on the ovary and oocyte are poorly understood. In a mouse model, 10% ethanol was administered in drinking water (treated females) or water (control females) for 15 days, and after superovulation or not (spontaneous ovulation), the estrous cycle and ovarian-gametic quality were analyzed. In treated females, the frequency and duration of the diestrus increased, and the frequencies of follicles and corpus luteum decreased vs control females, values that restored after superovulation. However, in treated females, the follicular cell proliferation rate and the imbalance in ovarian expression of VEGF (endothelial growth factor) persisted after superovulation. The number of ovulated oocytes with abnormal metaphase II, fragmented and parthenogenetically activated was higher in treated females than in control ones. In conclusion, moderate semi-chronic alcohol consumption produces anestrum, irregular estrous cycle, poor folliculogenesis, and nuclear-cytoplasmic abnormalities in ovulated oocytes. These alterations could constitute an etiological factor of early gestational loss and abnormal embryonic development after alcohol consumption.

Experimental study on the effects of melatonin administration on the ovary and the oviduct in the adult mice [with 2 tables and 22 figures]

The aim of the present work is to demonstrate the effect of the melatonin administration for different periods of time on the ovarian follicles and the oviductal epithelium in the adult mice. Also the reversibility of melatonim effect is studied in a trial for assessment of its effect on the fertility in females. In this work, a high dose [8.0 mg/kg] and a low dose [4.0 mg/kg] of melatonin were used. Melatonin was injected to the animals subcutaneously once daily in the late afternoon. A total number of 40 young adult female mice were used. At the beginning of the experiments, they were two months old. Animals were divided into eight groups. Groups I and II composed of three and four months old control animals. Group III received the low dose of melatonin for one month and group IV received the same dose for two months. Group V received the high dose of melatonin for one month and group VI received the same dose for two months. At the end of the experiments, animals received the treatment for one month became three months old and those received the treatment for two months became four months old. Group VII composed of seven months old control animals. Group VIII composed of recovered animals [animals allowed to survive three months without treatment after receiving the high dose for two months]. At the end of the experiment, the recovered animals became seven months old. Animals were sacrificed, their ovaries and the oviducts were removed and processed for histological examination after staining with Haematoxylin and Eosin. Some specimens of the ampulla of the oviduct were processed for ultrastructural study with transmission electron microscope. The numerical density and the diameter of the primary follicles, growing follicles and corpora lutea in the ovaries of all groups of animals were measured and statistically analyzed. The results of the present work demonstrated apparent increase in the size of the ovary in the melatonin treated animals. The numerical density and the diameter of the growing follicles and corpora lutea in all melatonin treated groups showed significant increase in comparison with their corresponding control. The primary follicles showed significant reduction in their numerical density in melatonin treated animals as compared with the control. In the recovered animals, the size and the structure of the ovary appeared nearly similar to the control. Also the numerical density and the diameter of the primary follicles, growing follicles and corpora lutea showed non significant change in comparison with their corresponding control. The oviductal epithelium of the ampulla in the high dose melatonin treated animals showed predominance of the secretory cells. The ultrastructual study of these cells revealed that the apical surface had many microvilli and their cytoplasm contained a lot of secretory granules. This study revealed that nighttime melatonin administration had a stimulatory effect on the ovarian follicular growth. This effect was independent to the dose or the duration of its administration. The oviductal epithelium showed predominance of secretory cells. Its effect on the ovary was reversible. This may provide in the future new insights and directions for the study of its role in the physiology and pharmacology of fertility and contraception in animals and humans

Effect of androgens on oviductal growth in skipper frog Rana cyanophlyctis.

Effects of exogenous androgens (testosterone, testosterone propionate and dihydrotestosterone) and estradiol-17beta on the oviductal growth/hypertrophy were studied in young and bilaterally ovariectomized (BLO) adult frogs (Rana cyanophlyctis) during postbreeding phase of the reproductive cycle. Estradiol-17beta injections induced oviductal hypertrophy to the maximal extent among hormone treated groups. In androgen treated frogs also there was an increase in the oviductal dry weight and protein content both in young and BLO adult frogs, suggesting the role of endogenous androgens in controlling the growth of oviduct in R. cyanophlyctis.

Release of 3h-noradrenaline from the rat oviduct: changes during estrous cycle and by progesterone in vitro

La inervación noradrenérgica del oviducto parece estar bajo la influencia de una modulación hormonal. El nivel de noradrenalina (NA) es específicamente afectado, pero otros procesos como el de liberación del neurotransmisor no han sido estudiados en el oviducto de la rata. En este trabajo se estudió la liberación de 3H-noradrenalina (3H-NA) durante el ciclo estral y en particular su modificación por el efecto de la progesterona "in vitro". La liberación espontánea de 3H-NA no varía durante el ciclo pero sí la inducida por concentraciones depolarizantes de K+, que fue máxima durante el estro. La progesterona inhibió la liberación inducida de 3H-NA (K+ 80 mM) desde bajas concentraciones (5 micronM). A mayores concentraciones (50 micronM), el efecto persistió, pero, además, fue aumentada la liberación de radiactividad basal. Este efecto fue potenciado por RU-486 (antagonista sintético de la hormona). Los resultados sugieren un papel modulador para la progesterona, el cual podría relacionarse con interacciones sobre la membrana de los terminales nerviosos y no con los clásicos receptores nucleares