Ovarian Grafts 10 Days after Xenotransplantation: Folliculogenesis and Recovery of Viable Oocytes

Effects of different subcutaneous sites on heterotopic autotransplantation of canine ovarian tissue

Ovarian tissue transplantation makes it possible to restore fertility; however, the success of this technique depends on the transplant region used. Therefore, this study aimed to evaluate the effect of two subcutaneous regions on canine ovarian transplantation, pinna (Pi) and neck (Ne), for 7 and 15 days. Ovaries collected by ovariosalpingohysterectomy were fragmented using a punch device. Fresh fragments were fixed, and the others were immediately grafted onto the animal itself in the Pi and Ne regions for 7 and 15 days. Recovered fragments were evaluated for histology (morphology, development and stromal density), picrosirius (collagen fibers), and immunohistochemistry (fibrosis and cell proliferation). The results showed that follicular normality rates were lower in Pi-7 (78%) vs. control (90%) and Pi-15 (86%), similar in Ne-7 (92%) and superior in Ne-15 (97%) compared to the control, with the effect of the region Ne (94%) superior (P < 0.05) to Pi (82%). Stromal density reduced in both regions vs. control but was similar within 15 days. Fragments from both regions showed higher fibronectin labeling and deposition of type I and lower type III collagen fibers (P < 0.05) vs. control. Proliferation rates in Ne-7 were higher (P < 0.05) than in control, and Pi-15 was higher (P < 0.05) than Ne-15. In conclusion, the pinna may be a region with greater potential than the neck after a 15-day autotransplantation of canine ovarian tissue.

Production of marmoset eggs and embryos from xenotransplanted ovary tissues

The common marmoset (Callithrix jacchus) has attracted attention as a valuable primate model for the analysis of human diseases. Despite the potential for primate genetic modification, however, its widespread lab usage has been limited due to the requirement for a large number of eggs. To make up for traditional oocyte retrieval methods such as hormone administration and surgical techniques, we carried out an alternative approach by utilizing ovarian tissue from deceased marmosets that had been disposed of. This ovarian tissue contains oocytes and can be used as a valuable source of follicles and oocytes. In this approach, the ovarian tissue sections were transplanted under the renal capsules of immunodeficient mice first. Subsequent steps consist of development of follicles by hormone administrations, induction of oocyte maturation and fertilization, and culture of the embryo. This method was first established with rat ovaries, then applied to marmoset ovaries, ultimately resulting in the successful acquisition of the late-stage marmoset embryos. This approach has the potential to contribute to advancements in genetic modification research and disease modeling through the use of primate models, promoting biotechnology with non-human primates and the 3Rs principle in animal experimentation.

Drastic Loss of Antral Follicles Due to Gene Expression Dysregulation Occurs on the First Day After Subcutaneous Ovarian Transplantation

Ovarian cryopreservation is an alternative for the preservation of fertility, and the subcutaneous transplantation site is considered one of the most promising. Studies evaluating the follicular growth and its relationship with gene expression and vascular perfusion are essential for improving this technique and its clinical application. Thus, the aim of this study was to evaluate the effect of subcutaneous autotransplantation and vitrification on follicular growth and atresia and their relationship with vascular perfusion and gene expression. Therefore, female mice were ovariectomized, and the ovaries were divided in two experimental groups (1) vitrified (treatment, n = 97) and (2) not vitrified (control, n = 97) and subsequently were transplanted. Then grafts, from both groups, were recovered after 1, 12, or 23 days (D1, D12, D23) and subjected to follicular quantification, morphometry, and qPCR. Non-transplanted ovaries (D0) were also used. The estrous cycle and vascular perfusion were monitored throughout the experiment. On D9, 100% of the animals had reestablished their estrous cycles (p > 0.05). Blood perfusion at the transplant site was similar for both treatments (p > 0.05), with greater perfusion at the site of vitrified transplants only on D1 (p < 0.05). A drastic reduction in the number of antral follicles and an increased number of atretic follicles were observed on D1 (p < 0.0001), associated with upregulation of Casp3, Fshr, and Igf1r; and downregulation of Bax, Acvr1, Egfr, and Lhcgr (p < 0.05). Our findings indicate that the first day after subcutaneous transplantation is a critical period for follicular survival, with intense follicular atresia independent of Bax upregulation.

Ectopic autologous transplantation of ovarian tissue as a feasible technique to assess ovarian morphophysiology

The cryopreservation of murine ovarian tissue and its transplantation can be a promising technique for the preservation of fertility and an alternative for the future reconstitution of scientific valuable strains of mice. Accordingly, the aim of this study was to describe the entire surgical procedure for ovariectomy and dorsal subcutaneous autotransplantation in mice, and also some data about the efficiency of this procedure. Female C57Bl/6J mice (n = 18) were anaesthetised and bilaterally ovariectomized. After surgery, ovaries were autotransplanted in small subcutaneous pouches in the dorsal region of the forelimbs. The animals were inspected daily and, 23 days after transplantation, euthanasia and recovery of ovarian tissues were performed. Postoperative recovery, oestrous cyclicity, and folliculogenesis progression were evaluated. At 23 days after transplantation, the recovery of the ovaries was feasible, all classes (primordial to antral) of follicles were observed. Additionally, satisfactory efficiency rates were obtained, with 100% of anaesthesia survival rate, survival, graft recovery, folliculogenesis progression and oestrous cyclicity. In general, this short article describes ovarian ectopic autologous transplantation as an effective technique for maintaining rodent oogenesis and endocrine ovarian function. Even more broadly, we can still assume that the application of this technique may reduce the number of breeding matrices and experimental animals in the near future.

Molecular Mechanism and Prevention Strategy of Chemotherapy- and Radiotherapy-Induced Ovarian Damage

Fertility preservation is an emerging discipline, which is of substantial clinical value in the care of young patients with cancer. Chemotherapy and radiation may induce ovarian damage in prepubertal girls and young women. Although many studies have explored the mechanisms implicated in ovarian toxicity during cancer treatment, its molecular pathophysiology is not fully understood. Chemotherapy may accelerate follicular apoptosis and follicle reservoir utilization and damage the ovarian stroma via multiple molecular reactions. Oxidative stress and the radiosensitivity of oocytes are the main causes of gonadal damage after radiation treatment. Fertility preservation options can be differentiated by patient age, desire for conception, treatment regimen, socioeconomic status, and treatment duration. This review will help highlight the importance of multidisciplinary oncofertility strategies for providing high-quality care to young female cancer patients.

Hormonal Stimulation of Human Ovarian Xenografts in Mice: Studying Folliculogenesis, Activation, and Oocyte Maturation

Ovarian tissue cryopreservation and banking provides a fertility preservation option for patients who cannot undergo oocyte retrieval; it is quickly becoming a critical component of assisted reproductive technology programs across the world. While the transplantation of cryopreserved ovarian tissue has resulted in over 130 live births, the field has ample room for technological improvements. Specifically, the functional timeline of grafted tissue and each patient's probability of achieving pregnancy is largely unpredictable due to patient-to-patient variability in ovarian reserve, lack of a reliable method for quantifying follicle numbers within tissue fragments, potential risk of reintroduction of cancer cells harbored in ovarian tissues, and an inability to control follicle activation rates. This review focuses on one of the most common physiological techniques used to study human ovarian tissue transplantation, xenotransplantation of human ovarian tissue to mice and endeavors to inform future studies by discussing the elements of the xenotransplantation model, challenges unique to the use of human ovarian tissue, and novel tissue engineering techniques currently under investigation.

The CC-chemokine receptor 2 is involved in the control of ovarian folliculogenesis and fertility lifespan in mice

The chemokine receptor 2 (CCR2) was first described as a chemotactic factor involved in immune responses, but it also plays an essential function in several biological processes. The chemokine (C-C motif) ligand 2 (CCL2) binds to CCR2 triggering G protein-coupled receptor (GPCR) signaling in leukocytes, including activation of PI3K/Akt/mTOR, a key pathway that is also related to follicular activation and survival. However, the potential role of CCR2 in ovarian follicular physiology remain unexplored. Thus, we investigated the role of CCR2 on follicular growth during adult life and aging. Ovaries and oocytes were collected from wild type (WT) mice at 1.5 months old (mo), and CCR2 expression was observed predominantly in oocytes included in growing follicles, as well as after ovulation. Follicle populations were assessed in WT and CCR2-/- mice at 1.5 mo, and CCR2-/- mice had more primordial and less primary and secondary follicles, while there were no differences in antral follicle numbers. Pro-apoptotic genes Bax and Casp3 were downregulated, while anti-apoptotic Bcl2 was upregulated in CCR2-/- mice. To further characterize the role of CCR2 in ovarian aging, follicle populations were assessed in WT and CCR2-/- mice at 1.5, 2.5, 6, 10, and 12 mo. A larger ovarian follicular reserve at 1.5-6 mo was observed in CCR2-/- mice. Finally, CCR2-/- aged mice (6-12 mo) ovulated more oocytes than WT mice. Altogether, these data suggest that CCR2 plays an important role in the regulation of murine folliculogenesis, potentially affecting the reproductive lifespan.

Vitrification leads to transcriptomic modifications of mice ovaries that do not affect folliculogenesis progression

Ovarian tissue cryopreservation is emerging as a promising alternative for fertility preservation of cancer survivors. To date, more than a hundred couples have successfully had babies using this procedure, although it is still considered experimental and demands further investigation. In this work, we evaluated the effects of vitrification, warming and autotransplantation procedures on the morphology and gene expression of murine ovaries. Ovaries were removed from adult female C57BL6 mice (n = 15), vitrified, warmed and autotransplanted (vitrified group), additionally, ovaries were autotransplanted without vitrification (control group, n = 15). After twenty days, grafted ovaries were harvested and used for histological and ultrastructural analysis, germinal vesicle (GV) oocyte collection, RNA sequencing, and Transmission Electron Microscopy (TEM). All classes of follicles and GV were observed in both control and vitrified/warmed transplanted ovaries, and the numbers of primordial, antral and atretic follicles were not different (p > 0.05). Using RNA-seq, we detected 16,602 vs 13,527 expressed genes in vitrified and control ovaries, respectively; and 623 significantly dysregulated genes (fold change >1.5; 332 up-regulated and 291 down-regulated). Cellular membranes, cytoskeletons, and extracellular matrices were found as the main functions of the differentially expressed genes. Moreover, vitrified samples also presented ultrastructural alterations in the cytoskeleton, cell junctions, and endoplasmic reticulum. Taken together, this work showed for the first time that ovarian cells might trigger a compensatory gene regulation mechanism to maintain cellular structure and folliculogenesis progression after vitrification and autotransplantation.

Influence of graft size, histocompatibility,and cryopreservation on reproductive outcome following ovary transplantation in mice

Purpose

Transplantation of ovarian tissue is a valuable method to rescue mouse strains with fertility problems and to revitalize archived strains. The purpose of this study was to investigate the effect of (i) different sizes of transplanted ovary pieces on reproductive outcome, (ii) use of immunodeficient recipients to overcome the limitation of histocompatibility, and (iii) to compare different protocols for cryopreservation of ovarian tissue.

Methods

Halves, quarters, and eights of mouse ovaries were transplanted. Half ovaries from B6 donors were transferred into immunodeficient mice. Halves of ovaries were frozen according to four different protocols, thawed and transferred.

Results

Pregnancy rate after transplantation of ovarian tissue was high (90–100%) independent of the transplant size. Although, the average litter size was significantly lower for recipients of quarters and eights (4.4 and 4.6 vs. 6.5), the total number of offspring produced per donor ovary was higher compared with recipients of halves. Pregnancy rate of immunodeficient recipients was 40% (mean 4.7 offspring per litter). All four cryopreservation protocols used were able to preserve functionality of the ovarian tissue.

Conclusions

Transplantation of ovarian tissue smaller than halves resulted in reduced litter sizes. The distribution of ovarian tissue of one donor female to 4 or 8 recipients will therefore yield in a higher total number of offspring in a certain time period. The use of immunodeficient recipients is an option for non-histocompatible donors. Cryopreservation of ovarian tissue is generally feasible but the function of frozen-thawed ovary halves after transplantation differs depending on the freezing protocol used.

Protective effects of resveratrol on random-pattern skin flap survival: an experimental study

Random-pattern skin flap transplantation is a common procedure in plastic surgery, but its distal area usually incurs ischemia and necrosis. Resveratrol (Rev), a natural polyphenol primarily found in peanuts, grapes, and red wine, which exerts multi-bioactivity. In this study, forty-eight rats with the modified "McFarlane flap" model were divided into Control and Rev groups, which were treated with vehicle Control and Rev, respectively. After 7 days of continuous treatment and observation, ischemic flap tissues were harvested to evaluate angiogenesis, apoptosis, oxidative stress, and autophagy. It was observed a greater survival area of flaps, accompanied with reduced water content and stronger blood supply, in the Rev group than in the Control group. In addition, Rev upregulated the expression of MMP9, VEGF, and Cadherin5, indicating that Rev promotes angiogenesis in ischemic flaps. Moreover, Rev decreased the levels of Bax, CYC, and Caspase3, suggesting that it inhibits apoptosis. Besides, Rev increased the expression of SOD1, eNOS, HO1, the activities of SOD and GSH, and reduced the levels of MDA, which uncovers that it depresses oxidative stress in ischemic flaps. Finally, it increased the expression of Beclin1, LC3II, VPS34, and CTSD, and decreased SQSTM1/p62 levels, which reveals that it activates autophagy in the flaps. These results suggest that Rev promotes random skin flap survival through proangiogenic, antiapoptotic, and antioxidative effects; moreover, autophagy is activated in the process, which might be another underlying mechanism for the flap survival.