RESUMO

The gular gland is a skin gland located in the suprasternal region of adult males of some bat families. Knowledge of the morphology and functional aspects of these gland types is often limited. This study aimed to describe the structure and composition of the gular glands of three molossid species (Eumops patagonicus, Molossus fluminensis and Molossus molossus) with respect to their reproductive activity and to define the mechanism involved in secretion release. Different histological, histochemical and immunohistochemical techniques were used to achieve these goals. The results revealed that the size and composition of this gland are variable and are mostly related to the lipid content during the reproductive season. The results also documented, for the first time, the occurrence of mechanoreceptors associated with the surface of the glandular duct by detecting an S100 protein, indicating that an external stimulus activates secretion. Previous studies on other species have classified the gland using obsolete criteria; hence, we adopted a new classification of adenomeres in this study. Moreover, we investigated the gland secretion mechanism previously proposed. This study defines the implications of this gland in the reproduction of this species. Our preliminary interpretation of the function of the gular gland is that it is a cutaneous exocrine gland activated by mechanoreceptors involved in the reproductive behaviour of the Molossidae family.

Assuntos

RESUMO

Plains vizcacha females are able to ovulate up to 800 oocytes per estrus cycle. However, just 10-12 embryos are implanted and only two of them, those located nearest the cervix, are gestated to term. Between 26 and 70 days post-coitum, a constitutive resorption occurs from the embryos located proximal to the ovary, extending progressively toward those distally implanted. Our previous studies on the dynamics of gestation in L. maximus, led us to hypothesize some kind of placental and nutritional insufficiency as the basis for the resorption process. We analyzed histology and arterial architecture of the reproductive tract in pregnant and non-pregnant females. Uterine horns are irrigated through the uterine artery, a branch of the internal iliac artery, in an ascending way from the cervix; segmental arteries irrigating the embryo vesicles become thinner as they approach the ovary. Contrast solution administered during angiographies accumulated in the placenta of embryos closest to cervix. Thus, blood stream favors the embryos nearest the cervix, indicating a gradual nutritional deficiency of those closest to the ovary. Besides, placenta becomes calcified early, at mid-gestation, during the resorption process. Finally, the detection of specialized endothelial venules and inflammatory cells suggest the concurrent participation of immunological processes in embryo vesicles undergoing resorption.

Assuntos

RESUMO

The aim of the present study was to perform a qualitative and quantitative analysis of the effect of different sucrose concentrations combined with ethylene glycol in the preservation of vitrified porcine preantral follicles. Fragments of ovarian cortex were vitrified in cryotubes containing 200 µl of the vitrification solution (30% Ethylene Glycol; 20% Fetal Bovine Serum; 0 M-0.25 M - 0.75 M or 1 M sucrose) and stored in liquid nitrogen for a week. Histological analysis showed that after vitrification the number of normal follicles decreased compared to the fresh tissue (control). The percentage of normal primordial follicles was sucrose dose dependent. The percentage of normal primary follicles was similar in 0 M or 0.25 M sucrose, while higher concentrations (0.75 M and 1 M) increased significantly the percentage of abnormal follicles (p < 0.05). Morphometric analysis showed a statistically significant reduction in the total area of primordial follicles with 0.75 M sucrose and a significant increase in the cytoplasmic area of primordial follicles with 0 M sucrose (p < 0.05). The qualitative and the quantitative analysis appear to be a complementary tool when choosing a vitrification protocol. For our cryopreservation system - vitrification of ovarian cortex slices in cryotubes-the best vitrification medium was TCM 199-Hepes with 30% de ethylene glycol, 20% of Fetal Bovine Serum and 0 or 0.25 M sucrose. The present study shows that the use of high sucrose concentrations in the vitrification solution has a deleterious effect on the preservation of porcine preantral follicles contained in ovarian tissue. Consequently, its use at 0.75 M or 1 M wouldn't be recommended.

Assuntos

RESUMO

Nothura maculosa is a South American Tinamidae with a marked seasonal reproductive pattern. This work describes ovarian seasonal changes in this species related to gonadotrope (GTHs) population. Ovary and pituitary samples were collected monthly from adult birds during four annual periods. They were fixed in Bouin's solution and processed for light microscopy. The data of post-fixation gonadal weight were analysed using STATISTIX 4.0. Histological sections of the ovaries were stained with H/E, PAS and Goldner-Masson trichrome. Single and double immunostaining were applied on pituitary sections with anti-chicken-FSH and anti-chicken-LH antibodies. The samples were analysed in quarterly periods of the year, Pl: March-May (resting stage); P2: June-August (developing stage); P3: September-November (reproductive stage); P4: December-February (involutive stage). Ovary weight (ow) significantly varied among periods (p<0.001). During Pl, only primordial and previtellogenic follicles were observed, ow 0.09±0.01 g (n=25); during P2, developing follicles with signs of vitellogenesis were detected, ow 0.13+0.01 g (n=14); during P3, maximum follicular development was found, ow 0.9 +/- 0.15 g (n=39); P4 exhibited great variability in follicular stages, ow 0.18+0.18 g (n=19). Involutive atresia was observed in all the periods, while bursting atresia and post-ovulatory follicles were only characterized at P3 and P4. The GTHs containing few LH and FSH immunoreactive (ir) granules were predominant during P1-P2. The GTHs with LH ir granules were abundant in intermediate zone and caudal lobe in P3 and P4 while few cells contained both types of granules. The number of FSH cells was increased during P3 and P4. The histological ovarían changes were narrowly correlated with the variations in the gonadotrope population.

Nothura maculosa es un tinámido sudamericano que presenta marcada estacionalidad reproductiva. Este trabajo describe los cambios estacionales del ovario de esta especie, en relación con la población de gonadotropas (GTHs). Muestras de ovarios y pituitarias de ejemplares adultos fueron colectadas mensualmente durante cuatro años; se fijaron en solución de Bouin y procesadas para M.O. Los datos del peso gonadal posfijación fueron analizados usando STATISTIX 4.0. Los cortes de ovarios fueron coloreados con H/E, P.A.S. y Tricrómico de Goldner-Masson. En cortes de adenohipófisis se aplicó inmunocitoquímica simple y doble (sistema ABC, Vector Lab.), empleando anticuerpos anti-pollo FSH y anti-pollo LH. Las muestras se analizaron en períodos trimestrales de cada año (P): Pl: Marzo-Abril-Mayo (etapa de reposo), P2: Junio-Julio-Agosto (etapa de desarrollo), P3: Septiembre-Octubre-Noviembre (etapa reproductiva), P4: Diciembre-Enero-Febrero (etapa involutiva). El peso de los ovarios (PO) varió significativamente entre los periodos (p< 0.001). Durante Pl, sólo se observaron folículos primordiales y pre-vitelogénicos, PO 0.09 +/- 0.01 g (n=25); durante P2, se detectaron folículos en desarrollo con signos de vitelogénesis, PO 0.13+0.01 g (n=14); durante P3, se encontró máximo desarrollo folicular, PO 0.90+0.15 g (n=39); P4 exhibió gran variabilidad folicular, PO 0.18+0.18 g (n=19). La atresia involutiva se observó en todos los períodos, mientras que la atresia explosiva y los folículos postovulatorios caracterizaron a P3 y P4. Las GTHs conteniendo escasos granulos LH y FSH inmunoreactivos (ir) predominaron durante Pl y P2. Las GTHs con granulos LH¡> eran abundantes en la zona intermedia y en el lóbulo caudal en P3 y P4 mientras que escasas células contenían ambos tipos de granulos. El número de células FSH¡> se incrementó durante P3 y P4. Los cambios histológicos del ovario se correlacionaron estrechamente con las variaciones en la población de gonadotropas.

Assuntos