Transcriptome comparisons detect new genes associated with apoptosis of cattle and buffaloes preantral follicles

Background To develop new breeding technology to improve the breeding ability of bovine, it is the development trend to find the main reason for the occurrence of atresia in these organisms. Transcriptomes of small (100–120 μm) and large (200–220 μm) preantral follicles from cattle and buffalo ovaries were evaluated in vivo and in vitro to understand the transcriptional modulation in preantral follicles that leads to the phenomenon of atresia. Methods The preantral follicles were checked as dead, damage, or live follicles in vivo and in vitro by using trypan blue then bisbenzimide and propidium iodine. Transcriptomes of small (100–120 μm) and large (200–220 μm) preantral follicles of cattle and buffalo were evaluated in vivo and in vitro by microarray and RT-PCR. Healthy preantral follicles were selected based on staining results, and then RNA was extracted from them. Results The viability percentage of preantral follicles in cattle was higher (26.7% and 20%) than buffalo (10%) in vivo and in vitro, respectively. According to the microarray data analysis for cattle preantral follicles, only eleven genes were detected corresponding to five upregulated and six downregulated in large size (200–220 μm) compared to small (100–120 μm) size preantral follicles, while in buffalo, 171 genes were detected (92 upregulated and 79 downregulated) in large size compared to small preantral follicle size. The results of RT-PCR of the selected genes (FASTKD1, BAG2, RHOB, AGTR2, MEF2C, BCL10, G2E3, TM2D1, IGF-I, IGFBP3, PRDX3, and TRIAP1) validated the microarray results. In conclusion, the data of gene expression showed significant differences between small and large sizes in both buffalo and cattle preantral follicles. Conclusion Apoptotic genes were upregulated in the large preantral follicle compared with the small preantral follicles. Moreover, the expression level of these apoptotic genes was significantly upregulated in buffalo than in the cattle. Most of these genes were significantly upregulated in the large buffalo preantral follicle compared with the small size. However, anti-apoptotic genes were upregulated in large cattle preantral follicle and downregulated in large buffalo preantral follicle.

Effect of Ethylene Glycol on Structural Integrity at Each Stage of Preantral Follicle Development Post Vitrification of Rat Ovary-Histological Analysis

The structure of follicular tissue affects the ability to maintain the structural integrity of follicles against cryoinjury post-vitrification. Histological analysis was conducted on the structural integrity of each stage of preantral follicles post-vitrification using 7.5% and 15.0% doses of ethylene glycol (EG), and ovarian sections with HE staining were observed using an Olympus CX21 microscope connected to Optilab 3.0 lens and Image Raster software. Analysis was conducted on the ovarian cortex in the tracing line area using polygon measure tools to obtain follicle density (follicles/mm2) and follicle index (%) data. The result showed that the EG group 7.5% (KP1) increased follicle density compared to the vitrified group (KKV) in primordial (15.83±1.77) and primary (22.94±8.51) stages. Meanwhile, KP2 (EG 15%) was in primordial (41.92±6.45), primary (11.69±1.95), secondary (33.48±3.63), and tertiary (5.93±0.69) stages. KP1 increased grade 3 follicle index compared to KKV in primary (27.66±2.34), secondary (32.41±6.99), and tertiary (25.00±5.00) stages. Meanwhile, KP2 was in primary (26.87±6.68) and tertiary (25.00±5.00) stages. Both doses of 7.5% and 15.0% EG were able to maintain structural integrity at certain stages of preantral follicles. Secondary and tertiary follicles are the best stages in maintaining grade 3 follicular integrity with the addition of 7.5% EG.

Single-cell transcriptome and cell-specific network analysis reveal the reparative effect of neurotrophin-4 in preantral follicles grown in vitro

Background In-vitro-grow (IVG) of preantral follicles is essential for female fertility preservation, while practical approach for improvement is far from being explored. Studies have indicated that neurotrophin-4 (NT-4) is preferentially expressed in human preantral follicles and may be crucial to preantral follicle growth. Methods We observed the location and expression of Tropomyosin-related kinase B (TRKB) in human and mouse ovaries with immunofluorescence and Western blot, and the relation between oocyte maturation and NT-4 level in follicular fluid (FF). Mice model was applied to investigate the effect of NT-4 on preantral follicle IVG. Single-cell RNA sequencing of oocyte combined with cell-specific network analysis was conducted to uncover the underlying mechanism of effect. Results We reported the dynamic location of TRKB in human and mouse ovaries, and a positive relationship between human oocyte maturation and NT-4 level in FF. Improving effect of NT-4 was observed on mice preantral follicle IVG, including follicle development and oocyte maturation. Transcriptome analysis showed that the reparative effect of NT-4 on oocyte maturation might be mediated by regulation of PI3K-Akt signaling and subsequent organization of F-actin. Suppression of advanced stimulated complement system in granulosa cells might contribute to the improvement. Cell-specific network analysis revealed NT-4 may recover the inflammation damage induced by abnormal lipid metabolism in IVG. Conclusions Our data suggest that NT-4 is involved in ovarian physiology and may improve the efficiency of preantral follicle IVG for fertility preservation.

Evaluation of protective effects of mirtazapine and mesna on cisplatin-induced ovarian damage in rats

To evaluate whether mirtazapine and mesna have protective effects on cisplatin-induced ovarian injury. A total of 32 female Wistar Albino rats were divided into 4 groups (8 rats per group) and included in the study. No medication was administered to the first group; only intervention was that their ovaries were removed and anti-mullerian hormone (AMH) values were measured. The second group received intramuscular cisplatin at a single dose of 7.5 mg/kg. The third group received a single dose of 200 mg/kg mesna intraperitoneally, and 30 minutes later, a single dose of 7.5 mg/kg intramuscular cisplatin was administered. The fourth group received oral 30 mg/kg mirtazapine, and 60 minutes later, a single dose of 7.5 mg/kg intramuscular cisplatin was administered. Oral 30 mg/kg mirtazapine was continued for ten days. Ovaries and AMH values of all groups were evaluated at the end of tenth day. In the cisplatin group when compared to normal ovarian tissue total histopathological damage score increased (p=0.037), preantral follicle count decreased (p=0.003) and AMH levels decreased (p<0.001). In the cisplatin + mesna group total ovarian damage score was also increased (p=0.005), preantral and antral follicles decreased (p<0.001 and p=0.001, respectively), and AMH levels decreased (p<0.001). In the cisplatin + mirtazapine group, total ovarian damage score (p<0.001), preantral follicle count (p=0.002) and AMH values were decreased (p<0.001). It was concluded that mesna and mirtazapine were not effective in preventing ovarian damage due to cisplatin.

Insulin-like growth factor 2 is produced by antral follicles and promotes preantral follicle development in macaques

Insulin-like growth factors (IGFs) are known for their involvement in endocrine and paracrine regulation of ovarian function. While IGF2 is the predominant circulating and intra-ovarian form of IGFs in primate species, the stage-specific follicular expression, action and regulation of IGF2 are not well defined. Therefore, experiments were conducted to investigate the follicular IGF production in response to steroid hormone regulation and the direct IGF actions on follicular development and function in vitro. Preantral follicles were isolated from rhesus macaque ovaries and cultured to the antral stage in media supplemented with follicle-stimulating hormone and insulin. Follicles were randomly assigned to treatment groups: (a) control, (b) trilostane (a steroid synthesis inhibitor), (c) trilostane + estradiol, (d) trilostane + progesterone, and (e) trilostane + dihydrotestosterone. Media was analyzed for IGF concentrations, which were correlated to follicle growth. Follicles produced IGF2, but not IGF1, at the antral stage. Steroid depletion decreased, while steroid replacement increased, IGF2 production by antral follicles. Media IGF2 levels correlated positively with antral follicle diameters. Macaque preantral follicles and granulosa cells were subsequently cultured without (control) and with recombinant human IGF2 supplementation. Follicle survival, growth and paracrine factor production, as well as granulosa cell proliferation and gonadotropin receptor gene expression, were assessed. IGF2 addition increased follicle survival rates, diameters and inhibin B production, as well as granulosa cell proliferation. These data demonstrate that IGF2 produced by antral follicles, in response to steroid hormone regulation, could act as a paracrine factor that positively impacts preantral follicle development and function in primates.

Impact of imatinib or dasatinib coadministration on in vitro preantral follicle development and oocyte acquisition in cyclophosphamide-treated mice

Objective: We investigated the impact of tyrosine kinase inhibitor (imatinib or dasatinib) coadministration with cyclophosphamide (Cp) on preantral follicle development in an in vitro mouse model.Methods: Seventy-three female BDF1 mice were allocated into 4 experimental groups: group A, saline; group B, Cp (25 mg/kg); group C, Cp (25 mg/kg) and imatinib (7.5 mg/kg); and group D, Cp (25 mg/kg) and dasatinib (7.5 mg/kg). Preantral follicles were isolated and cultured in vitro up to 12 days. Final oocyte acquisition and spindle integrity of metaphase II (MII) oocytes were assessed. Levels of 17β-estradiol and anti-Müllerian hormone (AMH) in the final spent media were measured by enzyme-linked immunosorbent assays, and the mRNA levels of Star, Sod1, Mapk3, and Casp3 in the final follicular cells were quantified by real-time polymerase chain reaction.Results: The percentage of MII oocytes per initiated follicle, the proportion of MII oocytes with normal spindles, and the 17β-estradiol level were similar in all four groups. The median AMH level in group B (7.74 ng/mL) was significantly lower than that in group A (10.84 ng/mL). However, the median AMH levels in group C (9.96 ng/mL) and group D (9.71 ng/mL) were similar to that in group A. The mRNA expression levels of Star, Sod1, Mapk3, and Casp3 were similar in all four groups.Conclusion: Coadministration of imatinib or dasatinib with Cp could preserve AMH production capacity in this in vitro mice preantral follicle culture model, and it did not affect MII oocyte acquisition.

Antral follicular count and its relationship with ovarian volume, preantral follicle population and survival, oocyte meiotic progression and ultrastructure of in vitro matured bovine cumulus–oocyte complexes

SummaryThis study aimed to evaluate the relationship between antral follicular count (AFC) and ovarian volume (OV), preantral follicular population and survival, meiotic progression and ultrastructure of cumulus–oocyte complexes (COCs) after in vitro maturation. In experiment 1, the relationship between AFC and preantral follicle population and survival was evaluated by classical histology. In experiment 2, the relationship among AFC, OV, ability of oocytes to resume meiosis and ultrastructure of in vitro matured bovine COCs was studied. A positive correlation (P < 0.05) between AFC and the numbers of healthy primordial, degenerate and total follicles was observed, as well as with healthy secondary follicles and total follicles. The numbers of grades I and II oocytes in ovaries of high AFC class were higher compared with those with intermediate or lower AFC. After in vitro maturation, COCs from ovaries of high AFC had a higher percentage of oocytes in metaphase II compared with those of intermediate and low AFC (P < 0.0001). Ovaries of intermediate AFC had a higher percentage of oocytes in metaphase II compared with ovaries with low AFC (P < 0.0001). The proportion of oocytes in metaphase I, telophase I and anaphase I in COCs from ovaries of intermediate AFC (26.04%) was higher (P < 0.05) compared with that seen in COCs of ovaries with high (8.55%) and low (14.15%) AFC. No differences in the ultrastructure of oocytes were seen. In conclusion, after in vitro maturation, cow ovaries with high AFC have higher numbers of oocytes that reach in metaphase II (MII), but they also have higher numbers of degenerated primordial and primary follicles.

Fibrin Scaffold Incorporating Platelet Lysate Enhance Follicle Survival and Angiogenesis in Cryopreserved Preantral Follicle Transplantation

Background: Transplantation of cryopreserved follicles can be regarded as a promising strategy for preserving fertility in cancer patients under chemotherapy and radiotherapy by reducing the risk of cancer recurrence. The present study aimed to evaluate whether fibrin hydrogel supplemented with platelet lysate (PL) could be applied to enhance follicular survival, growth, and angiogenesis in cryopreserved preantral follicle grafts. Materials and Methods: Preantral follicles were extracted from 15 four-week-old NMRI mice, cryopreserved by cryotop method, and encapsulated in fibrin-platelet lysate for subsequent heterotopic (subcutaneous) auto-transplantation into the neck. Transplants were assessed in three groups including fresh follicles in fibrin-15%PL, cryopreserved follicles in fibrin-15%PL, and cryopreserved follicles in fibrin-0% PL. Two weeks after transplantation, histological, and immunohistochemistry (CD31) analysis were applied to evaluate follicle morphology, survival rate, and vascular formation, respectively. Results: Based on the results, fibrin-15% PL significantly increased neovascularization and survival rate (SR) both in cryopreserved (SR=66.96%) and fresh follicle (SR=90.8%) grafts, compared to PL-less fibrin cryopreserved transplants (SR=28.46%). The grafts supplemented with PL included a significantly higher percentage of preantral and antral follicles. Also, no significant difference was observed in the percentage of preantral follicles between cryopreserved and fresh grafts of fibrin-15% PL. However, a significantly lower (P=0.03) percentage of follicles (23.37%) increased to the antral stage in cryopreserved grafts of fibrin-15%PL, compared to fresh grafts (35.01%). Conclusion: The findings demonstrated that fibrin-PL matrix could be a promising strategy to improve cryopreserved follicle transplantation and preserve fertility in cancer patients at the risk of ovarian failure. [GMJ.2020;9:e1558]