Oocyte maturation and expression pattern of follicular genes during in-vitro culture of vitrified mouse pre-antral follicles

In vitro culture of red-rumped agouti preantral follicles enclosed in fresh and vitrified ovarian tissues using TCM199 plus different pFSH concentrations

Considering the relevance of establishing biodiversity conservation tools, the study aimed to investigate the TCM199 supplemented with different follicle-stimulating hormone (FSH) concentrations on survival and development of fresh and vitrified preantral follicles enclosed in red-rumped agouti ovarian tissues cultured in vitro. In the first experiment, six pairs of ovaries were fragmented and cultured for 6 days according to groups: 10 ng/mL pFSH (FSH10 group) and 50 ng/mL (FSH50 group). Non-cultured tissues were considered as a control. In the second experiment, vitrified/warmed fragments of four pairs of ovaries were cultured with the best concentration of FSH established (cryopreserved and cultured group). Non-cryopreserved (fresh control group) and cryopreserved but non-cultured (non-cultured group) tissues were used as controls. For both experiments, preantral follicles were evaluated for survival and development using morphological and viability analysis by trypan blue staining. After culturing fresh samples, FSH50 showed a higher percentage of morphologically normal follicles when compared to FSH10 (P < 0.05). This same response was observed for primordial follicles. Regardless of the concentrations of FSH used during in vitro culture, no difference was observed regarding the percentage of viable follicles and diameters (P > 0.05). Thus, the FSH50 group was used for second experiment, in which 76.2 ± 7.2% normal preantral follicles previously vitrified was found after 6-day culture, also presenting the highest values (P < 0.05) for morphology of primordial follicles (95.2 ± 4.7%). Nevertheless, in vitro culture did not affect the viability and diameter of preantral follicles of cryopreserved tissues (P > 0.05). In conclusion, TCM199 supplemented with 50 ng/mL FSH was efficient in maintaining the in vitro survival of fresh and vitrified red-rumped agouti preantral follicles. This was the first study related to the in vitro culture of ovarian preantral follicles in this species, aiming to contribute to its conservation.

Two-Decade Experience of Royan Institute in Obtaining Mature Oocyte from Cryopreserved Ovarian Tissue: In Vitro and In Vivo Approaches

Ovarian tissue cryopreservation (OTC) holds promise for preservation of fertility among women who have lost their fertility due to diseases such as cancer. OTC has significantly assisted such cases by helping them maintain normal hormonal levels and menstrual cycles. Appropriate strategies to develop and extract mature oocytes from OTC could overcome a range of complications that are associated with ovarian dysfunction, caused by aging, and primary or secondary ovarian insufficiency. Scientists from different departments at The Royan Institute (Tehran, Iran) have been conducting studies to find the best way to extract mature oocytes from animal and human cryopreserved ovarian tissues. The various studies conducted in this area in the past 20 years, by researchers of the Royan Institute, are collated and provided in this review, in order to provide an idea of where we are now in the area of fertility preservation.

The decellularized ovary as a potential scaffold for maturation of preantral ovarian follicles of prepubertal mice

ABBREVIATIONS

GAG: glycosaminoglycan; ECM: extracellular matrix; 2D: two-dimensional; E2: estradiol; P4: progesterone; BMP15: bone morphogenetic protein 15; GDF9: growth differentiation factor 9; ZP2: zona pellucida 2; Gdf9: growth/differentiation factor-9; Bmp6: bone morphogenetic protein 6; Bmp15: bone morphogenetic protein 15.

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, 3β-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 3β-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.

Utilizing Fibrin-Alginate and Matrigel-Alginate for Mouse Follicle Development in Three-Dimensional Culture Systems

In vitro culture of ovarian follicles is a new technique in reproductive technology, which helps in understanding the process of folliculogenesis. The in vitro culture of follicles could be carried out using three-dimensional (3D) natural scaffolds that mimic the ovarian tissue stroma. Selection of the right matrix and culture media in these scaffolds could increase the survival and maturation of the follicles. In this work, the applicability of matrigel-alginate (MA) and fibrin-alginate (FA) 3D scaffolds for folliculogenesis was assessed. The ovaries of 13-day-old Naval Medical Research Institute (NMRI) mice were isolated and distributed into control and vitrification groups. Preantral follicles (mean diameter: 120-140 μm) were mechanically isolated from control and vitrified-warmed ovaries, encapsulated in MA or FA scaffold and cultured for 12 days. Follicle survival, growth, maturation, and quantitative expression of oocyte maturation genes (Gdf9, Bmp15, Fgf8, KitL, Kit, and Amh) and proteins (GDF9 and BMP15) were assessed. Survival rate of culture preantral follicles in control groups was found to be significantly higher than vitrified follicles. Antrum formation was similar in all groups. Follicle diameters were significantly increased in all groups during culture period. A decreasing pattern of gene expression was seen for all genes in all groups. This trend was verified through evaluation of protein expression, during which there was strong staining in antral follicles from all groups in the last day of in vitro culture. The better survival and maturation rate of follicles in the MA compared to FA scaffold indicates that the MA matrix, being rich in extracellular matrix components, could mimic the ovarian condition better and presents a good environment for follicle development.