Effect of α-tocopherol in the vitrification medium on the viability, lipid peroxidation, expression of key developmental, apoptotic and stress-related genes in ovine secondary follicles.

The present study aimed to evaluate the effect of α-tocopherol on viability, lipid peroxidation and the expression of apoptosis, stress and development-related genes in the vitrified sheep secondary follicles. Ovarian secondary follicles (200-300 µm) were isolated and distributed separately to the vitrification treatment and supplemented with 5 mM, 10 mM, 20 mM and 30 mM of α-tocopherol (while the control fresh group was without vitrification and supplementation of α-tocopherol). After a week, the follicles were thawed and evaluated for follicular viability by trypan blue dye exclusion method, lipid peroxidation and gene expression studies. The results showed that the vitrification with 10 and 20 mM of α-tocopherol positively affected (p < .05) the viability of vitrified follicles in comparison with vitrified ones without α-tocopherol but the higher concentration of α-tocopherol, i.e., 30 mM negatively affected the viability (p < .05) in comparison with the 10 and 20 mM of α-tocopherol groups. The malondialdehyde (MDA) levels were significantly (p < .05) higher in the vitrified without α-tocopherol group in comparison to the vitrified with 20 mM of α-tocopherol group. The expression of apoptotic-related gene, BCL2L1 was significantly higher in 10 mM α-tocopherol group compared to the control fresh and CASPASE 3, 9 expressions were significantly higher in the vitrified group when compared to the vitrified with 10 mM α-tocopherol group. Expressions of BAX, BAD, BAK, BMP-15 and GDF-9 showed no significant difference among the groups. The mRNA expression of SOD1 was significantly higher in the vitrified without α-tocopherol group when compared to other groups. We conclude that the supplementation of 10 and 20 mM α-tocopherol in vitrification solution was the efficient vitrification procedure for the vitrification of ovine secondary follicles.

Folliculogenesis-related genes are differently expressed in secondary and tertiary ovarian follicles.

The relative mRNA abundance of 10 genes associated with folliculogenesis was compared between late preantral (secondary) and early antral (tertiary) ovarian follicles in goats. In total, 100 follicles in each category were mechanically isolated. The relative transcript abundance of the mRNAs were determined by qPCR. Data were analyzed using unpaired Student's t-test. Of the 10 tested genes, ABLIM mRNA was not detected in either follicle category, six genes (SLIT3, TYMS, GTPBP1, AKR1C4, PIK3R6, and MAOB) were upregulated in secondary follicles compared with tertiary follicles, and three genes (ARHGEF12, CLEC6A, and CYTL1) showed similar mRNA abundances in both secondary and tertiary follicles. In conclusion, SLIT3, GTPBP1, AKR1C4, and PIK3R6 mRNA abundance was upregulated in secondary follicles (preantral phase) compared with in tertiary follicles (antral phase) in goats.

Effect of Exogenous Melatonin on the Development of Mice Ovarian Follicles and Follicular Angiogenesis.

In mammalian, the periodic growth and development of ovarian follicles constitutes the physiological basis of female estrus and ovulation. Concomitantly, follicular angiogenesis exerts a pivotal role in the growth of ovarian follicles. Melatonin (N-acetyl-5-methoxytryptamine, Mel), exists in follicle fluid, was suggested to affect the development of follicles and angiogenesis. This research was conducted to investigate the effects and mechanisms of Mel on the development of ovarian follicles and its angiogenesis. In total, 40 ICR mice at age of 3 weeks were allocated into four groups at liberty: control, Mel, FSH and FSH + Mel for a 12-day trial. Ovaries were collected at 8:00 a.m. on Day 13 for detecting the development of ovarian follicles and angiogenesis. Results indicated that Mel promoted the development of ovarian follicles of 50-250 µm (secondary follicles) and periphery angiogenesis, while FSH remarkably increased the number of antral follicles and periphery angiogenesis. Mechanically, Mel and FSH may regulate the expression of VEGF and antioxidant enzymes in different follicular stages. In conclusion, Mel primarily acted on the secondary follicles, while FSH mainly promoted the development of antral follicles. They both conduced to related periphery angiogenesis by increasing the expression of VEGF. These findings may provide new targets for the regulating of follicular development.

The optimized research of the in vitro culture of preantral follicles in mice.

OBJECTIVE: Efficiency of preantral follicle culture in vitro is low and is dependent on species, development stage, and follicle-stimulating hormone (FSH) concentration. Here, we optimized the preantral follicle in vitro culture system in mice. METHODS: The primary follicles (PM follicles, 80-100 µm diameter ) and early secondary follicles (ES follicles, 110-130 µm diameter) isolated from 14-day female mice were cultured in mediums containing 10 mIU/mL or 100 mIU/mL r-FSH. The follicle growth and oocyte maturation were observed. Estradiol (E2) was detected by ELISA. FSH receptor (FSHR), Ki-67, 3ß-HSD, CYP17, and CYP19 levels were detected by immunofluorescence and Western blot. RESULTS: The antrum formation and oocyte maturation rates of ES follicles were significantly higher than those of PM follicles (P < .05). They were also significantly higher in ES follicles with 100 mIU/mL r-FSH than with 10 mIU/mL r-FSH (P < .05). A higher FSHR level was found in ES follicles. Meanwhile, with 10 mIU/mL r-FSH, the ES follicles exhibited a pattern of flat growth, whereas a pattern of stereoscopic spatial growth was observed with 100 mIU/mL r-FSH. The 100 mIU/mL r-FSH stimulated granulosa cell proliferation more significantly than 10 mIU/mL r-FSH. Moreover, FSH significantly promoted ES follicle granulosa cell proliferation compared to PM follicular granulosa cells. The secretion of E2 and the expressions of 3ß-HSD, CYP 17, and CYP 19 in ES follicles with 100 mIU/mL r-FSH were significantly higher than those with 10 mIU/mL r-FSH. CONCLUSIONS: The 100 mIU/mL r-FSH ideally promotes the development of ES follicles, whose growth pattern can more reasonably simulate the growth of follicles in vivo.

Supplementation of culture medium with knockout serum replacement improves the survival of bovine secondary follicles when compared with other protein sources during in vitro culture.

The present study evaluated the effect of knockout serum replacement (KSR), fetal bovine serum (FBS) and bovine serum albumin (BSA) on the viability and growth of bovine secondary follicles cultured in vitro for 12 days. To this end, secondary follicles were isolated (185-202 µm) and cultured in vitro in TCM-199+ medium supplemented with KSR (5% and 10%), FBS (5% and 10%) or BSA (3 mg/ml) at 38.5°C with 5% CO2 in air. Follicular diameters were evaluated on days 0, 4, 8 and 12. After 12 days of culture, follicular survival analysis was performing by using calcein-AM and ethidium homodimer. Before and after culture, follicles were fixed in paraformaldehyde for histological evaluation. Follicular diameter at different days of culture were compared using the Kruskal-Wallis test, while the percentages of viable follicles were analyzed by chi-squared test (P < 0.05). Results showed that follicles cultured in the presence of KSR at both concentrations presented higher follicular survival rates than those cultured in control medium alone or supplemented with FBS or BSA. Conversely, the presence of KSR, BSA or FBS did not increase follicular diameter after 12 days of culture. Histology analysis showed that, among the tested treatments, follicles cultured in the presence of KSR had preserved rounded oocytes, juxtaposed granulosa cells and intact basal membrane. In conclusion, supplementation of culture medium with KSR increases the follicular survival of bovine secondary follicles cultured in vitro.

Effects of dexamethasone on growth, viability and ultrastructure of bovine secondary follicles cultured in vitro.

This study aimed to evaluate the effects of dexamethasone on development, viability, antrum formation and ultrastructural integrity of bovine secondary follicles cultured in vitro for 18 days. Bovine ovaries were obtained from slaughterhouses and secondary follicles of ~150-200 µm diameter were isolated and cultured in the laboratory in TCM-199+ alone or supplemented with different concentrations of dexamethasone (1, 10, 100 and 1000 ng/ml). Follicle viability was evaluated after the culture period, using calcein-AM (viable) and ethidium homodimer (nonviable). Follicle diameters and antrum formation were evaluated at days 0, 6, 12 and 18. Before or after in vitro culture, follicles were fixed for histological and ultrastructural analysis. Follicle diameters were evaluated using analysis of variance and Kruskal-Wallis test, while chi-squared test was used to evaluate the percentage of viable follicles and antrum formation (P < 0.05). Follicles cultured for 6 days with all treatments increased their diameters significantly, but there was no significant difference between treatments at the end of the culture period. In vitro cultured follicles showed antral cavity formation at the end of the culture period, but no influence of dexamethasone was seen. Ultrastructural analysis showed that follicles cultured with dexamethasone (1, 10, 100 and 1000 ng/ml) had well preserved granulosa cells. However, oocytes from follicles cultured with 10, 100 or 1000 ng/ml dexamethasone showed signs of degeneration. It can be concluded that follicles cultured in vitro in the presence of dexamethasone demonstrated continuous in vitro growth, but oocytes from follicles cultured with 10, 100 or 1000 ng/ml dexamethasone had poor ultrastructure.

Early ovine preantral follicles have a potential to grow until antral stage in two-step culture system in the presence of aqueous extract of Justicia insularis.

The objective of this study was to determine whether preantral follicles cultured in vitro for 7 days within ovine ovarian cortical strips could be isolated at the secondary follicles (SF) and grown until antral stage during an additional 6 days period of in vitro culture in the presence of aqueous extract of Justicia insularis. Fresh ovarian fragments from 16 adult sheep were fixed for histological analysis (Control 1) or in vitro cultured individually in α-MEM+ supplemented with 0.3 mg/ml J. insularis (Step 1) for 7 days. Part of the fragments then were fixed for histological analysis (in vitro culture group). Remaining fragments were exposed stepwise to increasing trehalose concentrations before immediate isolation of SF and viability assessment (Control 2) or after 6 days of culture in α-MEM++ supplemented with 0.3 mg/ml J. insularis (Step 2). In Step 1, percentage of follicular activation was 80%. In Step 2, a significant increase (p < 0.05) in follicular diameter and antrum formation within 6 days in vitro culture of isolated follicles was achieved. The total antioxidant capacity from both steps significantly increase (p < 0.05) from day 2 to day 6. Confocal analysis of oocytes showed 57.14% oocytes with homogeneous distribution and 42.86% with peri-cortical distribution. In conclusion, SF can be successfully isolated from sheep ovarian cortex after 7 days of culture and are capable of surviving and forming an antral cavity if cultured in vitro for an additional 6 days in the presence of 0.3 mg/ml J. insularis.

Development of macaque secondary follicles exposed to neutral red prior to 3-dimensional culture.

PURPOSE: Neutral red (NR) may assist identification of preantral follicles in pieces of cortical tissue prior to cryopreservation in cancer patients requesting fertility preservation. This study is the first to analyze this effect by follicle growth rate after long-term culture in primates. METHODS: Ovarian cortex was obtained from adult rhesus macaques, was cut into fragments, and was incubated with NR. Secondary follicles were readily visualized following NR staining and then were encapsulated into alginate beads and cultured individually for 4 weeks in αMEM media supplemented with 10 ng/ml FSH at 5% O2. RESULTS: The survival rates of secondary follicles during culture were similar between those derived from control tissue (71 ± 13%) and those treated with NR (68 ± 9%). The proportion of surviving follicles that formed an antrum were also similar in both groups (70 ± 17% control; 48 ± 24% NR-treated). Follicle diameters were not different between control follicles (184 ± 5µm) and those stained with NR (181 ± 7 µm) on the day of isolation. The percentages of surviving follicles within three cohorts based on their diameters at week 4 of culture were similar between the control group and NR-stained tissue group, fast-grow follicles (24 ± 6% vs. 13 ± 10%), slow-grow follicles (66 ± 5% vs. 60 ± 9%), or no-grow (10 ± 9% vs. 27 ± 6%), respectively. There were no differences in follicle diameters between groups during the culture period. Pre-exposure of secondary follicles to NR diminished their capacity to produce both estradiol and androstenedione by week 4 of culture, when follicles are exhibiting an antrum. Inhibitory effects of NR on steroid production by slow-grow follicles was less pronounced. CONCLUSIONS: NR does not affect secondary follicle survival, growth, and antrum formation during long-term culture, but steroid hormone production by fast-grow follicles is compromised. NR can be used as a non-invasive tool for in situ identification of viable secondary follicles in ovarian cortex before tissue cryopreservation without affecting follicle survival and growth in vitro. Whether maturation or developmental competence of oocytes derived from antral follicles in 3D culture that were previously isolated from NR-stained tissue is normal or compromised remains to be determined. Likewise, the functional consequences of pre-exposure to NR prior to ovarian cortical tissue cryopreservation and transplantation are unknown.

Effects of frutalin and doxorubicin on growth, ultrastructure and gene expression in goat secondary follicles cultured in vitro.

This study evaluated the effects of frutalin (0.6, 6.0 or 60.0 µg/mL) and doxorubicin (0.3 µg/mL) on survival, growth and ultrastructure of in-vitro cultured goat secondary follicles. The effects of these substances on the levels of mRNA for Casp3, Casp6, Bax, and Bcl2 were also investigated. Results showed that, after 6 days of culture, frutalin or doxorubicin reduced the percentage of normal follicles (P < 0.05), but doxorubicin had higher toxicity than frutalin. Except for follicles cultured with 0.6 µg/mL frutalin, follicular growth rate was reduced after culture with doxorubicin or frutalin (P < 0.05). The presence doxorubicin or 60.0 µg/mL frutalin increased the levels of mRNA for Casp3, Casp6, Bax, and Bcl2 (P < 0.05). Higher mRNA levels for Casp3, Casp6 and Bax were found in follicles cultured with doxorubicin, but higher levels of Bcl2 mRNA were found in follicles cultured with frutalin (P < 0.05). In conclusion, frutalin has lower toxic effects than doxorubicin on secondary follicles cultured in vitro.

HOXC13 and HSP27 Expression in Skin and the Periodic Growth of Secondary Fiber Follicles from Longdong Cashmere Goats Raised in Different Production Systems.

This experiment was conducted to identify periodic changes in secondary follicles (SFs) over one year of extensive (grazed) and intensive (housed and fed supplement) farming of Longdong cashmere goats. One-year old goats (n = 24, 12 extensively fed and 12 intensively fed) were studied. The diameter, depth, density, activity, and ultra-structural features of SFs were assessed using light microscopy and transmission electron microscopy. HOXC13 and HSP27 expression were studied using immunohistochemistry and immunofluorescence method. The anagen stage in the extensively grazed goats was from April to September, but was longer (April to October) in the housed, supplementary fed group. The depth and activity of the SF in anagen and catagen differed (P < 0.05) between the groups. HSP27 and HOXC13 protein were present in both the epidermis and dermis, with HSP27 immunoreactivity highest in the hair shaft (HS), outer root sheath (ORS) and inner root sheath (IRS). HOXC13 expression was prominent in both the eprdermis and ORS. HSP27 and HOXC13 expression were prominent during anagen, and less so during catagen and telogen. In anagen, HSP27 expression in the HS, IRS, and ORS of the extensively fed group was higher than in the intensively fed group (p < 0.05). In contrast, HOXC13 expression in HS, IRS and ORS of the extensively fed group was lower than in the intensively fed group (P < 0.05). This suggests the growth of cashmere is influenced by nutrition and that housed goats could be used in cashmere production. Anat Rec, 301:742-752, 2018. © 2017 Wiley Periodicals, Inc.

In vitro growth and maturation of isolated caprine preantral follicles: Influence of insulin and FSH concentration, culture dish, coculture, and oocyte size on meiotic resumption.

The aims of this study were: (1) to evaluate the effect of different insulin concentrations, alone or in combination with either a fixed FSH concentration or increasing FSH concentrations on the in vitro culture of isolated caprine preantral follicles and (2) to analyze the efficiency of two IVM media and maturation culture systems (with or without coculture with in vivo grown oocytes) on the meiosis resumption. Secondary follicles were cultured for 18 days in a basic medium supplemented with low- or high-insulin concentration alone or with a fixed FSH concentration or with increasing FSH concentrations. Oocytes grown in vivo or in vitro were matured alone or cocultured. The high-insulin concentration associated with fixed FSH treatment had higher meiotic resumption rate (P < 0.05) and was the only treatment capable of producing oocytes in metaphase II. The rates of germinal vesicle, germinal vesicle breakdown, metaphase I, metaphase II (MII), meiotic resumption, and oocyte diameter were similar between the maturation media. In conclusion, a basic medium supplemented with 10-µg/mL insulin and 100-µg/mL FSH throughout the culture period improved meiotic resumption rate and produced MII oocytes from caprine preantral follicles cultured in vitro. The MII rate was similar between in vivo and in vitro grown oocytes ≥110 µm.

Accelerated follicle growth during the culture of isolated caprine preantral follicles is detrimental to follicular survival and oocyte meiotic resumption.

This study investigated the effect of androstenedione (A4) alone or in association with different concentrations of bovine recombinant FSH on the IVC of isolated goat preantral follicles. Follicles were mechanically isolated from ovarian tissue and cultured for 18 days in α-minimum essential medium supplemented or not with A4 (10 ng/mL) alone or in association with fixed (A4 + FixFSH: 100 ng/mL) or sequential (A4 + SeqFSH: Day 0, 100 ng/mL; Day 6, 500 ng/mL; Day 12, 1000 ng/mL) concentrations of FSH. After 18 days, the oocytes were recovered for IVM and fluorescence analysis. At Day 18 of culture, only A4 + SeqFSH treatment showed a lower (P < 0.05) rate of intact follicles, survival probability, and meiotic resumption, as well as higher (P < 0.05) percentage of degeneration and/or extrusion after antrum formation. Taken together, these results reported a positive correlation between fast-growing follicles and follicles that degenerated and/or extruded after antrum formation. When compared with control, the addition of A4 alone or in association of FSH did not increase (P > 0.05) the estradiol production or androstenedione levels on Day 6. However, on Day 18, the androstenedione levels were significantly lower in A4 + SeqFSH treatment when compared with A4 alone or to A4 + FixFSH treatments, whereas the estradiol production did not differ (P > 0.05). In summary, this study found that accelerated follicle growth negatively impacted the morphology of caprine preantral follicle cultured in vitro. In addition, the association of androstenedione with increasing concentration of FSH was detrimental to follicular survival and oocyte meiotic resumption.