Inibida B e a reserva folicular ovariana / Inhibin B and the ovarian follicular reserve

As inibinas säo glicoproteínas diméricas, constituídas por uma subunidade alfa ligada a uma subunidade ß-A (inibina A) ou a uma subunidade ß-B (inibina B), as quais modulam seletivamente, via circulaçäo sistêmica, a secreçäo hipofisária de FSH. A inibina B tem origem no conjunto de folículos antrais. Com o avanço da idade há declínio gradual do número de folículos ovarianos e consequentemente reduçäo da inibina B, seguido por aumento do FSH que estimula o crescimento dos folículos e mantém a produçäo de estradiol. O aumento dos valores de FSH parece ocorrer tardiamente na seqüência de eventos da falência ovariana. A inibina B, secretada diretamente pelas células da granulosa, é indicador sensível e precoce do declínio da reserva folicular ovariana ao longo dos anos reprodutivos.

The acrosomic reaction in stallion spermatozoa: inductive effect of the mare preovulatory follicular fluid

In the female genital tract, spermatozoa must undergo capacitation and acrosome reaction prior to fertilization. A number of factors may induce physiological acrosome reaction assayed in vitro. The aims of this study are to determine the inductive effect of the preovulatory follicular fluid on the sperm acrosomal status in the equine, once some characteristics of the follicular fluid during folliculogenesis had been evaluated. The spermatozoa were obtained from cauda epididymes of adult stallion. Follicular fluid was taken from mare ovarian follicles classified according to their diameter. In these fluids, total protein, progesterone, estradiol and osmolarity were determined. Afterwards, the effect of preovulatory follicular fluid (50) upon induction of the acrosomic reaction in stallion capacitated spermatozoa was assayed. Results show that during folliculogenesis the ratio progesterone/estrogen is below 1. In large preovulatory follicles, there is a sharp increase of progesterone, reaching a ratio progesterone/estrogen close to 4. Protein concentration and osmolarity increase together with follicular development, being osmolarity very high at the preovulatory stage. Follicular fluid--in vitro--increases the percentage of spermatozoa with acrosome reaction, maintaining high rates of vitality and motility. The characteristics of follicular fluid undergo dynamic changes during the folliculogenesis, such as steroid level, protein concentration and osmolarity. These events may play a role in the reproductive process in vivo, considering that in vitro the follicular fluid is a very effective inductor of the acrosome reaction, with optimum levels of vitality and motility.

Effect of buffalo follicular fluid treatment on follicle population and ovulation rate in guinea pigs.

A number of workers have studied the effect of follicular fluid (FF) on the secretion of follicular stimulating hormone (FSH) but little is known about its potential as a regulator of ovarian activity, including ovulation rate. This paper describes the effect of charcoal treated-buffalo follicular fluid (buFF) treatment on follicular growth and ovulation rate in guinea pigs. Eighteen guinea pigs in three groups of 6 each were given 0.2 ml buFF at 12 hr interval for 3 days at different stages of estrous cycle viz., early-luteal, mid-luteal or follicular phase. One control group received equal volume of saline. Estrus was monitored every morning and evening by inspection of the opening of vaginal membrane and its cytology. All animals were sacrificed at 24 hr after the onset of estrus. Both the ovaries were dissected out, weighed and number of ovulation points recorded. One ovary from each animal was processed for histological examination to determine the population of healthy and atretic follicles. In early-luteal and follicular phase-treated animals the onset of estrus was delayed (P < 0.01) and ovulation rate was not affected. However, estrus occurred at normal when the treatment was initiated at midluteal stage and 50% animals failed to ovulate in this group. The total follicle population at metestrus increased significantly in all treated animals because of increase in number of follicles of size class II (400 to < 600 microns diam.). Atresia was also declined due to treatment. These results demonstrated that the buFF contained some inhibitory substances that delayed the onset of estrus in guinea pigs.

Subpopulations of physiological and ovarian follicular fluid peptide induced apoptotic cells.

Ovarian follicular fluid peptide (OFFP) purified from sheep ovaries enhances apoptotic changes in ovarian granulosa cells of mice. To get an insight into the cell subpopulations responding to OFFP, the heterogeneity of granulosa cells was resolved. Subpopulations of granulosa cells were obtained from ovaries of immature mice treated with PMSG alone and autopsied 48 hr (control) and 72 hr after injection (atretic) and from animals injected OFFP 24 hr after PMSG injection and autopsied 24 hr later (OFFP treated) by separation on discontinuous Percoll gradient. Four fractions were collected and studied for their relative distributions and percent apoptotic cells measured by acridine orange staining. FSH binding to granulosa cell (sedimenting as a major) fraction was studied by radio receptor assay. There is a difference in densities in subpopulations of apoptotic cells induced by OFFP and those generated during the physiological process of atresia. This difference may be a reflection of different granulosa cell subpopulations involved in peptide response or differences in phases as the cells transit from normal to apoptotic phenotype. FSH binding to granulosa cells from OFFP treated animals was significantly less than those from control and atretic group.

Reaçäo acrossômica na exploraçäo de infertilidade masculina em fecundaçäo in vitro / Place of acrosomal reaction in the exploration of male infertility in in vitro fertilization

O acrossoma, vesícula de origem golgiana, tem um papel essencial no desenvolvimento da fecundaçäo, tanto in vivo com in vitro. Neste artigo estudaram diferentes métodos de induçäo da reaçäo cromossômica (RA). Os indutores como o líquido folicular, a progesterona e o cálcio iônico permitem a exploraçäo da dinâmica da RA e a análise dos espermatozóides aptos a realizar esta RA. Este trabalho mostra o interesse destas exploraçöes nos casos de infertilidade masculina em Reproduçäo Assistida.

Participación del líquido folicular en el desarrollo del folículo, la maduración del ovocito y la función espermática / Participation of follicular fluid in follicle development, oocyte maturity and spermatic function

El estudio de la composición del líquido folicular (LF) es de gran importancia en reproducción asistida, por la función que éste desempeña en la maduración del ovocito y en la capacitación espermática. La composición bioquímica del LF está influenciada por el estado de maduración del folículo y recíprocamente dicha composición predice el éxito de la subsecuente maduración folicular y el embarazo. En la mayoría de las especies las concentraciones elevadas de estradiol son comunes de los folículos de madurez intermedia la progesterona de los maduros y los andrógenos de los atrésicos. La concentración del estradiol está asociada con la capacidad fertilizante de los ovocitos y la de sus metabolitos con la estimulación de la producción de progesterona. Además, el IF regula la acción de las gonadotropinas, al favorecer la unión de éstas a su receptor. El LF contribuye regulando la meiosis, ya que contiene factores que estimulan la maduración del ovocito o que bloquean la habilidad de los gránulos corticales para modificar los componentes de la zona pelúcida. Asimismo, la exposición de los espermatozoides a este fluido favorece la reacción acrosomal, su movilidad y la capacidad para penetrar al óvulo

Evidencia de actividad antimicrobiana del líquido folicular: estudio evaluatorio y analítico de muestras obtenidas en un programa de reproducción asistida / Evidence of antimicrobial activity of follicular fluid: evaluatory and analytical study of samples obtained in an assisted reproduction program

Ante la evidente ausencia de infección en pacientes a quienes se les realiza punción ovárica para captura ovular se evaluó la hipótesis de la posible acción antibacteriana que pudiera existir en el líquido folicular. Por lo anterior se tomaron 110 muestras de dicho fluido para análisis antibacteriano de las cuales fueron estudiadas 37, por ser las más claras y no contaminadas. Dichas muestras fueron obtenidas de pacientes hiperestimuladas que estaban a captura ovular a través de vagina por medio de guía ultrasonográfica. Se preparó inóculo bacteriana para evaluar la actividad antimicrobiana del líquido folicular contra cepas de E. coli, P. aeuroginosa, S. agalactie, L. monicitogenesis y C. albicans. Se efectuó recuento de colonias bacterianas a la 2,4,6,12 y 24 horas. El resumen de los resultados informa actividad bacteriostática en todas las cepas estudiadas de la cual E. coli y S. agalactie parecen ser las más sensibles. Seguidos por P. aeuroginosa S. aureus y L. monoatogenes: siendo más evidente, pero aún presente, en C. albicans. Por los resultados obtenidos se concluye que el líquido folicular tiene una acción antibacteriana, probablemente selectiva y que el mantenimiento en ésta línea de investigación corroborará este hallazgo y posiblemente determinará los factores implicados en el mismo