Anethole supplementation during in vitro maturation increases in vitro goat embryo production in a concentration-dependent manner

During in vitro maturation (IVM) cumulus-oocyte complexes (COCs) are exposed to conditions that can trigger oxidative stress, thus, reducing oocyte maturation and viability. Aiming to mitigate these detrimental conditions, the effects of IVM medium supplementation with anethole have been tested. Anethole, also known as trans-anethole (1-methoxy-4 [1-propenyl]-benzene), is a naturally occurring phenylpropanoid with various pharmacological properties, including antioxidant effects. However, no study has examined anethole effect on goat COCs during IVM. Thus, the aim of this study was to evaluate the effects of different anethole concentrations on oocyte maturation, oxidative stress, and in vitro development of caprine embryos after parthenogenetic activation. Goat COCs were selected and randomly distributed into the following treatments: TCM-199+ medium (control), or TCM-199+ medium supplemented with 30 μg/mL (AN30); 300 μg/mL (AN300) or 2000 μg/mL (AN2000) of anethole. After IVM, part of the COCs was chosen for oocyte viability and chromatin configuration, intracellular reactive oxygen species levels, and mitochondrial membrane potential assessment. Another part of COCs was parthenogenetically activated, and presumptive zygotes were cultured for 7 days. Results demonstrated that anethole at 30 μg/mL increased oocyte maturation and cleavage rates when compared to the other treatments (P < 0.05), as well as oocyte viability and in vitro embryo production when compared to the control treatment (P < 0.05). Additionally, treatment with anethole at 2000 μg/mL decreased oocyte nuclear maturation and cleavage rates when compared to other treatments (P < 0.05) and embryo production if compared to control and AN30 treatments (P < 0.05). Moreover, anethole at 2000 μg/mL increased mitochondrial membrane potential when compared to the other treatments (P < 0.05). In conclusion, anethole exerts a concentration-dependent effect during goat COCs IVM. For a more desirable outcome of oocyte viability and maturation, and in vitro embryo production, the use of anethole at 30 μg/mL is recommended.

Pituitary porcine FSH, and recombinant bovine and human FSH differentially affect growth and relative abundances of mRNA transcripts of preantral and early developing antral follicles in goats

Three different sources of FSH (porcine pituitary, pFSH; recombinant bovine, rbFSH; and recombinant human, rhFSH) were compared during in vitro culture of preantral and early antral follicles of goats for 18 days. Treatments were: base medium supplemented with no FSH (control), 10, 50, or 100 mIU/mL pFSH (pFSH10, pFSH50, and pFSH100, respectively), 100 ng/mL rbFSH (rbFSH), and 50 mIU/mL rhFSH (rhFSH). There were evaluations of follicle morphology, antrum formation, growth rate, estradiol production, oocyte viability and chromatin configuration, and follicle wall relative abundance of mRNA transcript for MMP-9, TIMP-2, CYP17, CYP19A1, FSHR, Insulin-R, and BAX/BCL-2 ratio. Follicle degeneration rates were similar among all treatment groups at the end of culturing. When there were treatments with pFSH, however, there was a lesser (P < 0.05) percentage of intact follicles and estradiol production, and greater (P < 0.05) extrusion rates. Furthermore, with only pFSH10 (antral follicles) and pFSH100 (preantral and antral follicles) treatments, there was a lesser (P < 0.05) follicle growth. For preantral follicles, when there was addition of pFSH10, pFSH100, and rhFSH there was lesser (P < 0.05) oocyte meiotic resumption compared to control and rbFSH treatments. For antral follicles, when there were treatments with rhFSH and pFSH10 there was greater (P = 0.08 - P < 0.05) oocyte maturation. In conclusion, the source of FSH differentially affected gene expression, as indicated by mRNA abundances, and follicular dynamics of preantral and antral follicles in vitro. Addition of FSH during the in vitro culture improved the developmental outcomes only for antral follicles.

Presence of growth hormone receptor (GH-R) mRNA and protein in goat ovarian follicles and improvement of in vitro preantral follicle survival and development with GH

This study aimed to demonstrate the expression of growth hormone receptor (GH-R) mRNA and protein in goat ovarian follicles in order to investigate the effects of GH on the survival and development of preantral follicles. The ovaries were processed for the isolation of follicles to study GH-R mRNA expression or to localization of GH-R by immunohistochemical analysis. Pieces of ovarian cortex were cultured for 7 days in minimum essential medium(+) (MEM(+)) in the presence or absence of GH at different concentrations (1, 10, 50, 100, and 200 ng/mL). High expression levels of GH-R mRNA were observed in granulosa/theca cells from large antral follicles. However, preantral follicles do not express mRNA for GH-R. Immunohistochemistry demonstrated that the GH-R protein was expressed in the oocytes/granulosa cells of antral follicles, but any protein expression was observed in preantral follicles. The highest (P < 0.05) rate of normal follicles and intermediate follicles was observed after 7 days in MEM(+) plus 10 ng/mL GH (70%). In conclusion, GH-R mRNA and protein are expressed in caprine antral follicles, but not in preantral follicles. Moreover, GH maintains the survival of goat preantral follicles and promotes the development of primordial follicles.

Interaction between melatonin and follicle-stimulating hormone promotes in vitro development of caprine preantral follicles

The aim of this study was to investigate the effects of melatonin and follicle-stimulating hormone (FSH) on the in vitro culture of goat preantral follicles. Ovarian fragments were cultured for 7 d in α-minimum essential medium (α-MEM(+)) containing melatonin (100, 250, 500, or 1,000 pM), FSH (50 ng/mL), or a combination of the 2 hormones and further analyzed by histology and transmission electron and fluorescent microscopy. The results showed that after 7 d of culture, tissues cultured in α-MEM(+) alone or supplemented with FSH alone, melatonin (500 and 1,000 pM), or the combination of FSH and melatonin (1,000 pM) maintained percentages of normal preantral follicles similar to the fresh control. In contrast to the noncultured tissues, the percentage of developing follicles was increased under all culture conditions after 7 d (P < 0.05). The addition of 1,000 pM melatonin associated with FSH to the culture medium increased follicular and oocyte diameters compared with α-MEM(+) alone after 7 d of culture (P < 0.05). Ultrastructural and fluorescent analyses confirmed the integrity of follicles cultured with 1,000 pM of melatonin plus FSH for 7 d. In conclusion, this study demonstrated that the interaction between melatonin and FSH maintains ultrastructural integrity and stimulates further growth of cultured caprine preantral follicles.

Presence of c-kit mRNA in goat ovaries and improvement of in vitro preantral follicle survival and development with kit ligand

This study evaluated the levels of c-kit mRNA in goat follicles and the effects of kit ligand (KL) on the in vitro development of cultured preantral follicles. Preantral follicles isolated from goat ovarian cortex were cultured for 18 days in α-MEM(+) supplemented with KL (0, 50 or 100 ng/mL) in the absence or presence of follicle stimulating hormone (FSH). Real-time PCR showed that c-kit mRNA was higher in primordial and primary follicles than in secondary stage. Regarding the culture, KL addition in the absence of FSH improved the follicular survival, antrum formation, oocyte growth and meiotic resumption. KL-positive effects were not observed in the presence of FSH. In conclusion, c-kit mRNAs are detected in all follicular categories. KL promotes the survival and antral cavity formation of caprine preantral follicles after in vitro culture, as well as the growth and meiotic resumption of their oocytes in the absence of FSH.

Steady-state level of bone morphogenetic protein-15 in goat ovaries and its influence on in vitro development and survival of preantral follicles

This study investigates steady-state level of bone morphogenetic protein-15 (BMP-15) mRNA in caprine follicles, and the effects of BMP-15 on in vitro development of preantral follicles. Ovarian fragments were cultured for one or seven days in Minimal Essential Medium (MEM(+)) with BMP-15 (0, 1, 10, 50, 100 or 200 ng/mL), and further analyzed by histology, transmission electron and fluorescent microscopy. BMP-15 mRNA in secondary follicles was higher than in primordial and primary follicles. After seven days, 10, 50 or 100 ng/mL of BMP-15 maintained the percentage of normal follicles similar to the control (non-cultured), and increased the oocyte and follicle diameters when compared to the control and MEM(+). BMP-15 at 100 ng/mL increased the secondary follicles and maintained their ultrastructural integrity. In conclusion, the BMP-15 mRNAs were detected in all follicular categories. BMP-15 (100 ng/mL) maintained the integrity and promoted the growth of caprine preantral follicles cultured for seven days.

Fibroblast growth factor-10 maintains the survival and promotes the growth of cultured goat preantral follicles

The aim of the present study was to investigate the effects of fibroblast growth factor-10 (FGF-10) on the survival, activation (transition from primordial to primary follicles), and growth of goat preantral follicles cultured in vitro. Pieces of ovarian cortex were cultured for 1 and 7 d in the absence or presence of FGF-10 (0, 1, 10, 50, 100, and 200 ng/mL). Noncultured and cultured tissues were processed and analyzed by histology, transmission electron microscopy, and viability testing. Results showed that after 7 d, a greater percentage (79.9%) of morphologically normal follicles (containing an oocyte with regular shape and uniform cytoplasm, and organized layers of granulosa cells without a pyknotic nucleus) was observed when cultured with 50 ng/mL of FGF-10 when compared with other concentrations of FGF-10 (0 ng/mL, 67.3%; 1 ng/mL, 68.2%; 10 ng/mL, 63.3%; 100 ng/mL, 64.4%; 200 ng/mL, 52.7%). Ultrastructural analyses and viability testing using fluorescent markers confirmed the follicular integrity of FGF-10 (50 ng/mL)-treated fragments after 7 d of culture. After 7 d, all FGF-10 concentrations reduced the percentage of primordial follicles and increased the percentage of developing follicles. In the presence of 50 ng/mL of FGF-10, follicles increased in diameter after 7 d of culture when compared with other concentrations tested. In conclusion, this study demonstrates that FGF-10 maintains the morphological integrity of goat preantral follicles and stimulates the growth of activated follicles in culture. The culture conditions identified here contribute to the understanding of the factors involved in goat early follicular development.

Steady-state level of kit ligand mRNA in goat ovaries and the role of kit ligand in preantral follicle survival and growth in vitro

The aims of this study were to investigate steady-state level of Kit Ligand (KL) mRNA and its effects on in vitro survival and growth of caprine preantral follicles. RT-PCR was used to analyze caprine steady-state level of KL mRNA in primordial, primary, and secondary follicles, and in small (1-3 mm) and large (3-6 mm) antral follicles. Furthermore, ovarian fragments were cultured for 1 or 7 days in Minimal Essential Medium (MEM(+)) supplemented with KL (0, 1, 10, 50, 100, or 200 ng/ml). Noncultured (control) and cultured fragments were processed for histology and transmission electron microscopy (TEM). RT-PCR demonstrated an increase in steady-state level of KL mRNA during the transition from primary to secondary follicles. Small antral follicles had higher steady-state levels of KL mRNA in granulosa and theca cells than large follicles. After 7 days, only 50 ng/ml of KL had maintained the percentage of normal follicles similar to control. After 1 day, all KL concentrations reduced the percentage of primordial follicles and increased the percentage of growing follicles. KL at 10, 50, 100, or 200 ng/ml increased primary follicles, compared to MEM(+) after 7 days. An increase in oocyte and follicular diameter was observed at 50 ng/ml of KL. TEM confirmed ultrastructural integrity of follicles after 7 days at 50 ng/ml of KL. In conclusion, the KL mRNAs were detected in all follicular categories. Furthermore, 50 ng/ml of KL maintained the integrity of caprine preantral follicle cultured for 7 days and stimulated primordial follicle activation and follicle growth.

Essential role of follicle stimulating hormone in the maintenance of caprine preantral follicle viability in vitro

The aims of the present study were to investigate the effects of follicle-stimulating hormone (FSH) on survival, activation and growth of caprine primordial follicles using histological and ultrastructural studies. Pieces of caprine ovarian cortex were cultured for 1 or 7 days in minimum essential medium (MEM - control medium) supplemented with different concentrations of FSH (0, 10, 50 or 100 ng/ml). Small fragments from non-cultured ovarian tissue and from those cultured for 1 or 7 days in a specific medium were processed for classical histology and transmission electron microscopy (TEM). Additionally, effects of FSH on oocyte and follicle diameter of cultured follicles were evaluated. The results showed that the lowest percentage of normal follicles was observed after 7 days of culture in control medium. After 1 day of culture, a higher percentage of growing follicles was observed in the medium supplemented with 50 ng/ml of FSH. In the presence of 10 and 50 ng/ml of FSH, an increase in diameter of both oocyte and follicle on day 7 of culture was observed. TEM showed ultrastructural integrity of follicles after 1 day of culture in MEM and after 7 days in MEM plus 50 ng/ml FSH, but did not confirm the integrity of those follicles cultured for 7 days in MEM. In conclusion, this study demonstrated that FSH at concentration of 50 ng/ml not only maintains the morphological integrity of 7 days cultured caprine preantral follicles, but also stimulate the activation of primordial follicles and the growth of activated follicles.

Effect of cryopreservation on viability, activation and growth of in situ and isolated ovine early-stage follicles

Isolated or cortical tissue-enclosed (in situ) sheep early-stage follicles were exposed to 1.5 M dimethyl sulfoxide (DMSO), ethylene glycol (EG) or unexposed, or frozen/thawed in the presence of these cryoprotectants and then cultured for 5 days in enriched minimal essential medium (MEM) or not cultured. Cultured and uncultured follicles were classified as non-viable/viable when they were stained/not stained with trypan blue, respectively. Follicular diameter was measured and the percentages of primordial and developing follicles calculated. Exposure of isolated or in situ follicles to DMSO or EG led to a marked decrease in the percentage of viable follicles. The percentage of viable isolated and in situ follicles further decreased when they were in vitro-cultured for 5 days, EG-exposed follicles generally showing a more damaging effect than DMSO-exposed follicles. Cultured follicles, both isolated and in situ, which were exposed to EG and DMSO, as well as in situ follicles, which had been frozen/thawed in the presence of one of these cryoprotectants, showed similar growth rates as cultured, untreated follicles, while in these groups significantly lower percentages of primordial follicles and higher percentages of more advanced follicular stages were observed. Among the treated groups, the highest percentage (71-75%) of developing follicles was observed after culturing cryoprotectant-exposed isolated follicles. In contrast, when cryopreserved, isolated follicles were cultured, they did not increase in diameter and did not develop into more advanced stages. In conclusion, exposure to or cryopreservation in the presence of EG and DMSO, as well as their further in vitro culture, negatively affected the viability of ovine isolated and in situ early-stage follicles. In vitro growth of early-stage follicles and activation of primordial follicles were better maintained when follicles had been frozen/thawed and cultured in situ.

Morphological and ultrastructural analysis of sheep primordial follicles preserved in 0.9% saline solution and TCM 199

The objective was to determine the morphological and ultrastructural features of sheep primordial follicles preserved in either 0.9% saline solution or TCM 199 at different temperatures. Soon after death, the ovarian pair of each ewe (n = 5) was divided into 25 fragments. One fragment was immediately fixed for morphological evaluation (control). The other 24 fragments were randomly distributed in tubes containing 2 ml of 0.9% saline solution or TCM 199 and maintained at 4, 20 or 39 degrees C for 2, 4, 12, or 24h. Based on histological assessment, storage of ovarian fragments in 0.9% saline solution at 20 degrees C for up to 24h and in both solutions at 39 degrees C for 4, 12 or 24h increased (P < 0.01) the percentage of degenerate primordial follicles compared with controls. In contrast, preservation at 4 degrees C in both solutions, kept the percentage of morphologically normal primordial follicles similar to control values. Although histological integrity of primordial follicles was maintained in fragments stored at 20 degrees C for up to 24h in TCM 199, these results were not confirmed by ultrastructural analysis. Based on transmission electron microscopy, only primordial follicles stored at 4 degrees C for up to 24h, at 20 degrees C for up to 12h and at 39 degrees C for up to 2h in both solutions were ultrastructurally normal. In conclusion, sheep primordial follicles were successfully preserved at 4 degrees C for up to 24h, at 20 degrees C for up to 12h and at 39 degrees C for 2h in 0.9% saline solution or TCM 199.