Synergistic effects of follicle-stimulating hormone and epidermal growth factor on in vitro maturation and parthenogenetic development of red-rumped agouti oocytes.

Although oocyte in vitro maturation (IVM) is routinely used for in vitro embryo production in mice and rats, its use in wild rodents remains unexplored. Evidence suggests that hormone and growth factor supplementation influence oocyte meiotic resumption. This study evaluated the synergistic effects of follicle-stimulating hormone (FSH) and epidermal growth factor (EGF) on the IVM and parthenogenetic development of red-rumped agouti oocytes. Initially, we evaluated the IVM rates, mature oocyte quality, oocyte morphometry, and early embryonic development during IVM in the presence of 10, 50, and 75 mIU/mL FSH. No differences among the FSH concentrations were observed for IVM rates, oocyte morphometry, cumulus cell expansion, and viability. Although oocytes matured with 50 mIU/mL FSH showed a higher rate of cumulus expansion index (CEI), only oocytes matured with 10 mIU/mL FSH resulted in morulae after chemical activation (7.9% ± 4.2%). Thus, 10 mIU/mL FSH was used for further experiments. We subsequently evaluated the synergistic effects of 10, 50, and 100 ng/mL EGF and 10 mIU/mL FSH on the same parameters. No differences among the groups were observed in IVM rates, oocyte morphometry, and cumulus viability. Nevertheless, FSH with 10 ng/mL EGF showed a CEI superior to that of the other groups. Furthermore, oocytes matured with FSH alone or with both FSH and 10 or 50 ng/mL EGF developed morulae after activation (5.8%-8.3%). In conclusion, oocytes matured with 10 mIU/mL FSH and 10 ng/mL EGF are recommended for use in red-rumped agouti oocyte IVM, as they positively influence embryonic development.

Comparison of different intracellular cryoprotectants on the solid surface vitrification of red-rumped agouti (Dasyprocta Leporina Lichtenstein, 1823) ovarian tissue.

In contributing to the conservation of wild rodents, the aim of this study was to evaluate the use of distinct cryoprotectants, separately or in combination, for solid surface vitrification (SSV) of red-rumped agouti ovarian tissue. Ovarian cortex from nine females was recovered and fragmented. Fresh fragments (control) were used to analyse the pre-antral follicle (PF) morphology using a histologic procedure, viability using the Trypan blue test, cell proliferation by counting the argyrophilic nucleolar organizing regions (Ag-NORs technique) and DNA integrity using the TUNEL assay. The remaining fragments were vitrified using SSV method with 3 M or 6 M ethylene glycol (EG) or dimethyl sulfoxide (DMSO), or in combination (3 M EG/3 M DMSO), and further evaluated as reported for the fresh samples. All cryoprotectants were effective at preserving PFs morphology compared to the control group (80.7 ± 5.21%), except 6 M EG and 3 M DMSO that provoked a significant (p < .05) decrease on the values of morphologically normal primary (60.0 ± 19.0%) and primordial (44 ± 4.5%) follicles, respectively. Regarding viability, all cryoprotectants provided values similar to that verified for the control group (79.0%), but a significant decrease (p < .05) was observed with EG/DMSO combination (59%). Using Ag-NORs technique, the highest (p < .05) cell proliferative capacity was detected when using EG at each tested concentration. The TUNEL proved the preservation of DNA integrity regardless of the cryoprotectant. In summary, we suggest the use of 3 M EG for the solid surface vitrification of red-rumped agouti ovarian tissue.

Effects of atipamezole and medetomidine administration on seminal variables and functions of erection and ejaculation of the collared peccary (Tayassu tajacu) after electroejaculation.

BACKGROUND: Alpha adrenergic drugs are usually used in the treatment of erectile and ejaculatory dysfunction in humans. The influence of such drugs on the seminal characteristics of wild animals has not been verified; whereas their impact on the seminal characteristics and erectile and ejaculatory functions of collared peccaries (Tayassu tajacu) has already been determined. This study aimed at investigating and comparing the effects of medetomidine and atipamezole on the seminal variables of collared peccaries undergoing electroejaculation as well as at determining whether these drugs affected the erectile and ejaculatory functions of this species. RESULTS: A statistically significant difference in sperm concentration was observed between AP (100.0 ± 26.0 × 106 sperm/ml) and MP (220.2 ± 49.8 × 106 sperm/ml); however, both these treatments did not differ from P treatment (180.0 ± 50.7 × 106 sperm/ml). No statistically significant difference was observed among all treatments with regard to erectile function. With regard to ejaculation time, no significant difference was observed between the MP and AP treatments; however, when compared with the P treatment, AP exhibited a significantly higher difference. CONCLUSIONS: When collared peccaries were anesthetized with propofol, neither medetomidine nor atipamezole significantly affected the characteristics of the semen or the erectile function, despite the fact that the AP treatment increased ejaculation time. Therefore, the data indicate that using propofol alone is an effective anesthetic protocol for collecting semen in collared peccaries. Other non-injectable anesthetic drugs, such as inhaled anesthetics, may be used in future research to collect semen from peccaries.

Morphometric analysis of the placenta in the New World mouse Necromys lasiurus (Rodentia, Cricetidae): a comparison of placental development in cricetids and murids.

BACKGROUND: Stereology is an established method to extrapolate three-dimensional quantities from two-dimensional images. It was applied to placentation in the mouse, but not yet for other rodents. Herein, we provide the first study on quantitative placental development in a sigmodontine rodent species with relatively similar gestational time. Placental structure was also compared to the mouse, in order to evaluate similarities and differences in developmental patterns at the end of gestation. METHODS: Fetal and placental tissues of Necromys lasiurus were collected and weighed at 3 different stages of gestation (early, mid and late gestation) for placental stereology. The total and relative volumes of placenta and of its main layers were investigated. Volume fractions of labyrinth components were quantified by the One Stop method in 31 placentae collected from different individuals, using the Mercator software. Data generated at the end of gestation from N. lasiurus placentae were compared to those of Mus musculus domesticus obtained at the same stage. RESULTS: A significant increase in the total absolute volumes of the placenta and its main layers occurred from early to mid-gestation, followed by a reduction near term, with the labyrinth layer becoming the most prominent area. Moreover, at the end of gestation, the total volume of the mouse placenta was significantly increased compared to that of N. lasiurus although the proportions of the labyrinth layer and junctional zones were similar. Analysis of the volume fractions of the components in the labyrinth indicated a significant increase in fetal vessels and sinusoidal giant cells, a decrease in labyrinthine trophoblast whereas the proportion of maternal blood space remained stable in the course of gestation. On the other hand, in the mouse, volume fractions of fetal vessels and sinusoidal giant cells decreased whereas the volume fraction of labyrinthine trophoblast increased compared to N. lasiurus placenta. CONCLUSIONS: Placental development differed between N. lasiurus and M. musculus domesticus. In particular, the low placental efficiency in N. lasiurus seemed to induce morphological optimization of fetomaternal exchanges. In conclusion, despite similar structural aspects of placentation in these species, the quantitative dynamics showed important differences.

Placentation in Sigmodontinae: a rodent taxon native to South America.

BACKGROUND: Sigmodontinae, known as "New World rats and mice," is a large subfamily of Cricetidae for which we herein provide the first comprehensive investigation of the placenta. METHODS: Placentas of various gestational ages ranging from early pregnancy to near term were obtained for five genera, i.e. Necromys, Euryoryzomys, Cerradomys, Hylaeamys, and Oligoryzomys. They were investigated by means of histology, immunohistochemistry, a proliferation marker, DBA-lectin staining and transmission electron microscopy. RESULTS: The chorioallantoic placenta was organized in a labyrinthine zone, spongy zone and decidua and an inverted yolk sac persisted until term. The chorioallantoic placenta was hemotrichorial. The interhemal barrier comprised fetal capillary endothelium and three layers of trophoblast, an outermost, cellular layer and two syncytial ones, with interspersed trophoblast giant cells (TGC). In addition, accumulations of TGC occurred below Reichert's membrane. The junctional zone contained syncytial trophoblast, proliferative cellular trophoblast, glycogen cells and TGC that were situated near to the maternal blood channels. In three of the genera, TGC were also accumulated in distinct areas at the placental periphery. PAS-positive glycogen cells derived from the junctional zone invaded the decidua. Abundant maternal uNK cells with positive response to PAS, vimentin and DBA-lectin were found in the decidua. The visceral yolk sac was completely inverted and villous. CONCLUSION: The general aspect of the fetal membranes in Sigmodontinae resembled that found in other cricetid rodents. Compared to murid rodents there were larger numbers of giant cells and in some genera these were seen to congregate at the periphery of the placental disk. Glycogen cells were found to invade the decidua but we did not identify trophoblast in the walls of the deeper decidual arteries. In contrast these vessels were surrounded by large numbers of uNK cells. This survey of wild-trapped specimens from five genera is a useful starting point for the study of placentation in an important subfamily of South American rodents. We note, however, that some of these rodents can be captive bred and recommend that future studies focus on the study of time dated pregnancies.

Placentation in the paca (Agouti paca L).

BACKGROUND: The paca is a South American rodent with potential as a commercial food animal. We examined paca placenta as part of a wider effort to understand the reproductive biology of this species. METHODS: Thirteen specimens between midgestation and term of pregnancy were studied by light and transmission electron microscopy. RESULTS: The placenta is divided into several lobes separated by interlobular trophoblast. Maternal arterial channels and fetal veins are found at the centre of each lobe. In the labyrinth, maternal blood flows through trophoblast-lined lacunae in close proximity to the fetal capillaries. The interhaemal barrier is of the haemomonochorial type with a single layer of syncytiotrophoblast. Caveolae occur in the apical membrane of the syncytiotrophoblast and recesses in the basal membrane, but there is no evidence of transtrophoblastic channels. The interlobular areas consist of cords of syncytiotrophoblast defining maternal blood channels that drain the labyrinth. Yolk sac endoderm covers much of the fetal surface of the placenta. The subplacenta comprises cytotrophoblast and syncytiotrophoblast. There are dilated intercellular spaces between the cytotrophoblasts and lacunae lined by syncytiotrophoblast. In the junctional zone between subplacenta and decidua, there are nests of multinucleated giant cells with vacuolated cytoplasm. The entire placenta rests on a pedicle of maternal tissue. An inverted yolk sac placenta is also present. The presence of small vesicles and tubules in the apical membrane of the yolk sac endoderm and larger vesicles in the supranuclear region suggest that the yolk sac placenta participates in maternal-fetal transfer of protein. CONCLUSION: The paca placenta closely resembles that of other hystricomorph rodents. The lobulated structure allows for a larger exchange area and the development of precocial young.