Follicle development in cryopreserved bitch ovarian tissue grafted to immunodeficient mouse

Local delivery of platelet-derived factors mitigates ischemia and preserves ovarian function through angiogenic modulation: A personalized regenerative strategy for fertility preservation

As the most prominent and ideal modality in female fertility preservation, ovarian tissue cryopreservation, and transplantation often confront the challenge of ischemic damage and follicular loss from avascular transplantation. To surmount this impediment, we engineered a novel platelet-derived factors-encapsulated fibrin hydrogel (PFH), a paradigmatic biomaterial. PFH encapsulates autologous platelet-derived factors, utilizing the physiological blood coagulation cascade for precise local delivery of bioactive molecules. In our study, PFH markedly bolstered the success of avascular ovarian tissue transplantation. Notably, the quantity and quality of follicles were preserved with improved neovascularization, accompanied by decreased DNA damage, increased ovulation, and superior embryonic development rates under a Low-concentration Platelet-rich plasma-derived factors encapsulated fibrin hydrogel (L-PFH) regimen. At a stabilized point of tissue engraftment, gene expression analysis mirrored normal ovarian tissue profiles, underscoring the effectiveness of L-PFH in mitigating the initial ischemic insult. This autologous blood-derived biomaterial, inspired by nature, capitalizes on the blood coagulation cascade, and combines biodegradability, biocompatibility, safety, and cost-effectiveness. The adjustable properties of this biomaterial, even in injectable form, extend its potential applications into the broader realm of personalized regenerative medicine. PFH emerges as a promising strategy to counter ischemic damage in tissue transplantation, signifying a broader therapeutic prospect. (197 words).

Prospective solutions to ovarian reserve damage during the ovarian tissue cryopreservation and transplantation procedure

Birth rates continue to decline as more women experience fertility issues. Assisted reproductive technologies are available for patients seeking fertility treatment, including cryopreservation techniques. Cryopreservation can be performed on gametes, embryos, or gonadal tissue and can be used for patients who desire to delay in vitro fertilization treatment. This review focuses on ovarian tissue cryopreservation, the freezing of ovarian cortex containing immature follicles. Ovarian tissue cryopreservation is the only available treatment for the restoration of ovarian function in patients who undergo gonadotoxic treatments, and its wide adoption has led to its recent designation as "no longer experimental" by the American Society for Reproductive Medicine. Ovarian tissue cryopreservation and subsequent transplantation can restore native endocrine function and can support the possibility of pregnancy and live birth for the patient. Importantly, there are multiple steps in the procedure that put the ovarian reserve at risk of damage. The graft is highly susceptible to ischemic reperfusion injury and mass primordial follicle growth activation, resulting in a "burnout" phenomenon. In this review, we summarize current efforts to combat the loss of primordial follicles in grafts through improvements in freeze and thaw protocols, transplantation techniques, and pharmacologic adjuvant treatments. We conducted a review of the literature, with emphasis on emergent research in the last 5 years. Regarding freeze and thaw protocols, we discuss the widely accepted slow freezing approach and newer vitrification protocols. Discussion of improved transplantation techniques includes consideration of the transplantation location of the ovarian tissue and the importance of graft sites in promoting neovascularization. Finally, we discuss pharmacologic treatments being studied to improve tissue performance postgraft. Of note, there is significant research into the efficacy of adjuvants used to reduce ischemic injury, improve neovascularization, and inhibit hyperactivation of primordial follicle growth activations. Although the "experimental" label has been removed from ovarian tissue cryopreservation and subsequent transplantation, there is a significant need for further research to better understand sources of ovarian reserve damage to improve outcomes. Future research directions are provided as we consider how to reach the most hopeful results for women globally.

The effect of vitamin C on the recovery of activity and survival of autografted ovaries through inhibition of oxidation and inflammation

Ovarian tissue autografting is a valuable clinical option to help restore fertility in women with cancer. However, many follicles are lost due to ischemia-reperfusion (IR) injury, which depletes follicles after grafting. We aimed to investigate the effect of vitamin C, an antioxidant with anti-apoptotic and anti-inflammatory properties, on improving the structure and function of autografted ovaries in mice. Thirty-six female NMRI mice (4-5 weeks old) were divided into three groups of 12: control (no grafting), autograft + vitamin C (50 mg/kg/day intraperitoneally), and autograft + saline (100 µl/day/animal, intraperitoneally). After the ovarian autografting and before the start of the experiment, each group was further divided into 7-day and 28-day subgroups. Seven days after ovary autografting, serum levels of malondialdehyde (MDA), total antioxidant capacity (TAC), and inflammatory factors were measured. On day 28, ovarian histology, DNA fragmentation, and estradiol and progesterone levels were assessed. Results were analyzed using one-way ANOVA and Tukey's test, with significance set at p<0.05. In the autograft + vitamin C group, there were significant increases in the mean total volume of the ovary, cortex (p<0.05), medulla, number of follicles, and levels of IL-10, progesterone, estradiol, and TAC (p<0.001), compared to the autograft group. Conversely, the rate of apoptosis and serum levels of MDA, IL-6, and TNF-α were notably reduced in the autograft + vitamin C group (p<0.001). These results suggest that vitamin C can significantly enhance the recovery of autografted ovaries through its antioxidant, anti-inflammatory, and anti-apoptotic effects.

Cryopreservation of canine ovarian tissue by slow freezing and vitrification: Evaluation of follicular morphology and apoptosis rate

In this study, we aimed to evaluate the efficacy of cryopreserving canine ovarian tissue using vitrification and slow freezing methods while investigating potential differences in cryotolerance based on follicular type and cryopreservation technique. Twenty-eight ovaries were collected from 14 anoestrus bitches of various breeds, aged between 2 and 5 years, and undergoing elective ovariohysterectomy. The ovaries were sectioned into small fragments and randomly assigned to three groups: vitrification, slow freezing, and a control group (fresh tissue). Vitrification was performed using cryotubes containing DAP 213 solution (2M DMSO, 1M acetamide, 3M propylene glycol) in two stages, while slow freezing involved cryotubes with 1.5M DMSO solution inserted into a programmable machine. The effects of cryopreservation were evaluated by histology and immunohistochemistry (cleaved caspase-3), to determine the percentage of cells undergoing apoptosis. Histological examination revealed that the slow freezing group exhibited a significantly higher percentage of intact follicles (45.75 %) compared to those subjected to vitrification (38.17 %; P = 0.01). Immunohistochemical evaluation further indicated that 84.21 % of the follicles in the slow freezing group did not express caspase-3, suggesting the absence of apoptosis. Conversely, vitrified samples exhibited significantly more apoptotic cells compared to other groups (P < 0.001). Furthermore, early antral follicles displayed a higher susceptibility to degeneration regardless of the cryopreservation method employed. Nevertheless, when comparing the cryopreserved groups, early antral follicles showed greater degeneration in slow freezing group, while preantral follicles were the most affected in the vitrification group. In conclusion, slow freezing demonstrated superior preservation of viable follicles compared to vitrification and emerged as the preferred technique for cryopreserving canine ovarian tissue. These findings contribute valuable insights into optimizing cryopreservation methods for canine ovarian tissue, potentially benefiting reproductive technologies and fertility preservation in canines.

Erythropoietin effects on cryopreserved/transplanted cat ovarian tissue: A comparison of two incubation methods

Many feline species are currently threatened with extinction. Therefore, germplasm bank establishment has become imperative. However, cryoinjury and ischemia-reperfusion injury pose significant obstacles to both cryopreservation and xenotransplantation. In this regard, erythropoietin (Epo) represents a potential alternative strategy due to its properties. This study aimed to assess the incubation of domestic cat ovarian tissue in Epo, both before and after cryopreservation, and investigate its effectiveness in promoting revascularization following xenotransplantation. Sixteen ovaries from 8 healthy cats were sliced following elective bilateral ovariohysterectomy (OHE). Subsequently, 8 fragments measuring 3 mm³ each were obtained from the cortical region of each ovary. The fragments were allocated into 3 treatment groups: Cryo group, fragments were cryopreserved, thawed and immediately transplanted; Cryo + Epo group, fragments were first cryopreserved in nitrogen, thawed, incubated in Epo (100 IU) for 2h and transplanted; and the Epo + Cryo group, in which fragments were first incubated in Epo (100 IU) for 2h, cryopreserved, thawed and immediately transplanted. The fragments were then xenotransplanted into the dorsal subcutaneous region of ovariectomized female nude mice and retrieved at 7, 14, 21, and 28 days post-transplantation. The results indicated that Epo effectively enhanced follicular survival, preservation of viability, and tissue revascularization. The Epo + Cryo group displayed better revascularization rates on D14 and D21 post-transplantation and an increase in primordial and growing follicles on D28, the Cryo + Epo group exhibited significantly more follicles on D14 and D21, with fewer degenerated follicles.

Research progress on mechanism of follicle injury after ovarian tissue transplantation and protective strategies

Ovarian tissue cryopreservation and transplantation is the only way to preserve fertility for female cancer patients in prepubertal ages and those who cannot delay radiotherapy or chemotherapy. However, the success rate of cryopreservation and transplantation of ovarian tissue is still low at present due to the risk of ischemia and hypoxia of the grafted tissues. Abnormal activation of primordial follicles and ischemia-reperfusion injury after blood supply recovery also cause massive loss of follicles in grafted ovarian tissues. Various studies have explored the use of different drugs to reduce the damage of follicles during freezing and transplantation as well as to extend the duration of endocrine and reproductive function in patients with ovarian transplantation. For example, melatonin, N-acetylcysteine, erythropoietin or other antioxidants have been used to reduce oxidative stress; mesenchymal stem cells derived from different tissues, basic fibroblast growth factor, vascular endothelial growth factor, angiopoietin 2 and gonadotropin have been used to promote revascularization; anti-Müllerian hormone and rapamycin have been used to reduce abnormal activation of primordial follicles. This article reviews the research progress on the main mechanisms of follicle loss after ovarian tissue transplantation, including hypoxia, ischemia-reperfusion injury and associated cell death, and abnormal activation of follicles. The methods for reducing follicle loss in grafted ovarian tissues are further explored to provide a reference for improving the efficiency of ovarian tissue cryopreservation and transplantation.

Ethanol, Carnoy, and paraformaldehyde as fixative solutions for histological evaluation of preantral follicles in equine ovarian tissue

The most adequate fixative solution for equine ovarian tissue is still to be determined as a tool to evaluate the improvement of methodological studies in assisted reproductive techniques and fertility preservation. This study aimed to evaluate a short-time ethanol 70% (ST-EtOH, 45 min) exposure as an alternative fixative compared with two classically fixatives [Carnoy's (CAR) solution and paraformaldehyde 4% (PFA)] at different fixation times (6 h, 12 h). The end points evaluated were morphology and classes of preantral follicles, follicular and stromal cell densities, and follicular and oocyte nuclear diameters in equine ovarian tissue. Ovaries (n = 6) from ovariectomized young mares were fragmented (3 × 3 × 1 mm; 20 fragments/ovary) and fixed in the tested treatments. Overall, a total of 11,661 preantral follicles were evaluated in 1444 histological slides. The ST-EtOH similarly preserved the preantral follicle morphometry and stromal cell density compared to the PFA fixative, regardless of the exposure time. Nonetheless, the CAR fixative solution had the greatest percentage of normal preantral follicles and the highest stromal cell density among all treatments. In conclusion, Carnoy's solution must be preferred compared with ST-EtOH and PFA fixatives for studies concerning the cellular morphology of equine ovarian tissue. Moreover, ST-EtOH fixative is a good alternative for equine ovarian tissue when a quick histological evaluation is required instead of more time-consuming and expensive techniques. Additional studies concerning the impact of different fixatives on the ultrastructure of cellular populations and their compatibility with IHC and molecular techniques in equine ovarian tissue are warranted.

Effects of erythropoietin on ischaemia-reperfusion when administered before and after ovarian tissue transplantation in mice

RESEARCH QUESTION

Is the optimal timing for administering erythropoietin to minimize ischaemic injury in ovarian tissue transplantation before ovary removal for cryopreservation and subsequent transplantation or after transplantation?

DESIGN

Thirty Swiss mice (nu/nu) were divided into three groups: treatment control group (n = 10); erythropoietin before harvesting group (EPO-BH) (n = 10) and erythropoietin after transplantation group (EPO-AT) (n = 10). Animals underwent bilateral ovariohysterectomy and their hemiovaries were cryopreserved by slow freezing. At the same time, previously cryopreserved hemiovaries were transplanted subcutaneously in the dorsal region. Erythropoietin (250 IU/kg) and sterile 0.9% saline solution were administered every 12/12 h over 5 consecutive days in the EPO-AT and EPO-BH groups, respectively.

RESULTS

Administration of erythropoietin in the EPO-AT group improved the viability of ovarian follicles, reducing degeneration and increasing the number of morphologically normal growing follicles at 14 days after transplantation compared with the EPO-BH group (P = 0.002). This group also showed higher percentages of proliferative follicles at 7 days after transplantation (P ≤ 0.03), increased blood vessel count (P ≤ 0.03) and greater tissue area occupied by blood vessels at days 7 and 14 after transplantation (P ≤ 0.03), compared with hormone administration before cryopreservation (EPO-BH group) and the treatment control group. Additionally, treatment with erythropoietin before or after transplantation reduced fibrotic areas at 7 days after transplantation (P = 0.004).

CONCLUSION

Erythropoietin treatment after transplantation reduced ischaemic damage in transplanted ovarian tissue, increased angiogenesis, maintenance of ovarian follicle proliferation and reduced fibrosis areas in the grafted tissue.

Ovarian tissue cryopreservation and transplantation: a review on reactive oxygen species generation and antioxidant therapy

Cancer is the leading cause of death worldwide. Fortunately, the survival rate of cancer continues to rise, owing to advances in cancer treatments. However, these treatments are gonadotoxic and cause infertility. Ovarian tissue cryopreservation and transplantation (OTCT) is the most flexible option to preserve fertility in women and children with cancer. However, OTCT is associated with significant follicle loss and an accompanying short lifespan of the grafts. There has been a decade of research in cryopreservation-induced oxidative stress in single cells with significant successes in mitigating this major source of loss of viability. However, despite its success elsewhere and beyond a few promising experiments, little attention has been paid to this key aspect of OTCT-induced damage. As more and more clinical practices adopt OTCT for fertility preservation, it is a critical time to review oxidative stress as a cause of damage and to outline potential ameliorative interventions. Here we give an overview of the application of OTCT for female fertility preservation and existing challenges; clarify the potential contribution of oxidative stress in ovarian follicle loss; and highlight potential ability of antioxidant treatments to mitigate the OTCT-induced injuries that might be of interest to cryobiologists and reproductive clinicians.

The effect of platelet lysate on mouse ovarian structure, function and epigenetic modifications after autotransplantation

RESEARCH QUESTION

What are the effects of platelet lysate on structure, function and epigenetic modifications of heterotopically transplanted mouse ovarian tissues?

DESIGN

Mice were divided into three groups (n = 17 per group): control (mice with no ovariectomy, grafting or treatment), autograft and autograft plus platelet lysate (3 ml/kg at the graft sites). Inflammatory markers, serum malondialdehyde (MDA) concentration and total antioxidant capacity were assessed on day 7 after transplantation. Twenty-eight days after transplantation, stereological and hormonal analyses were conducted. Chromatin immunoprecipitation and quantitative real-time polymerase chain reaction were also used to quantify the epigenetic modifications of maturation genes, parallel to their expression.

RESULTS

The total volume of the ovary, cortex and medulla, and the number of different types of follicles, the concentration of interleukin (IL)-10, progesterone and oestradiol and total antioxidant capacity significantly decreased in the autograft group compared with the control group (P < 0.001); these parameters significantly increased in the autograft plus platelet lysate group compared with the autograft group (P < 0.001). The concentrations of tumour necrosis factor alpha, IL-6 and MDA increased significantly in the autograft group compared with the control group (P < 0.001); in the autograft plus platelet lysate group, these parameters significantly decreased compared with the autograft group (P < 0.001). In the autograft plus platelet lysate group, the expression levels of Gdf-9 (P < 0.0021), Igf-1 (P < 0.0048) and Igf-2 (P < 0.0063) genes also increased along with a lower incorporation of MeCP2 in the promoter regions (P < 0.001) compared with the autograft group.

CONCLUSIONS

Platelet lysate can contribute to follicular survival by improving folliculogenesis and increasing the expression of oocyte maturation genes.

L-Carnitine improves follicular survival and function in ovarian grafts in the mouse

CONTEXT

Ovarian tissue transplantation is performed to preserve fertility in patients undergoing chemotherapy and radiotherapy. However, the ischemia-reperfusion injury which occurs after the ovarian tissue transplantation causes follicular depletion and apoptosis. l -Carnitine has antioxidant and anti-inflammation properties.

AIMS

Therefore, we aimed to investigate the beneficial effect of l -carnitine on mouse ovaries following heterotopic autotransplantation.

METHODS

Mice were randomly divided into three groups (six mice per group): control, autografted and autografted+l -carnitine (200mg/kg daily intraperitoneal injections). Seven days after ovary autografting, the serum levels of malondialdehyde (MDA), total antioxidant capacity, tumor necrosis factor alpha (TNF-α), interleukin (IL)-6 and IL-10 were measured. Ovary histology, serum concentrations of progesterone and estradiol were also measured 28days after autotransplantation. Data were analysed using one-way analysis of variance (ANOVA) and Tukey test, and the means were considered significantly different at P Key results: In the autografted+l -carnitine group, the total volume of the ovary, the volume of the cortex, the number of follicles, the serum concentrations of IL-10, estradiol and progesterone significantly increased compared to the autografted group. In the autografted+l -carnitine group, serum concentrations of IL-6, TNF-α and MDA were significantly decreased compared to the autografted group.

CONCLUSIONS

Our results indicated that l -carnitine can ameliorate the consequences of ischemia-reperfusion on the mice ovarian tissue following autotransplantation.

IMPLICATIONS

l -carnitine improves the structure and function of transplanted ovaries.

Assisted reproductive techniques for canines: preservation of genetic material in domestic dogs

Assisted reproductive techniques (ARTs), such as artificial insemination, in vitro fertilization, and cryopreservation of gametes/zygotes, have been developed to improve breeding and reproduction of livestock and for the treatment of human infertility. Their widespread use has contributed to improvements in human health and welfare. However, in dogs, only artificial insemination using frozen semen is readily available as an ART to improve breeding and control genetic diversity. A recent priority in sperm cryopreservation is the development of alternatives to egg yolk, which is widely used as a component of the sperm extender. Egg yolk can vary in composition among batches and is prone to contamination by animal pathogens. The latter can be a problem for international exchange of cryopreserved semen. Low-density lipoprotein and skim milk are promising candidates for use as extenders, to ensure fertility after artificial insemination. Although not tested for its effects on fertility following artificial insemination, polyvinyl alcohol may also be a useful alternative to egg yolk as an extender. The development of cryopreservation techniques for canine embryos lags behind that for other mammals, including humans. However, given the success of non-surgical embryo transfer in 2011, studies have sought to refine this approach for practical use. Research on sperm cryopreservation has yielded satisfactory results. However, investigation of other approaches, such as cryopreservation of oocytes and gonadal tissues, remains insufficient. Techniques for the efficient induction of estrus may aid in the development of successful canine ARTs.

Metabolic activity in cryopreserved and grafted ovarian tissue using high-resolution respirometry

Cryopreservation of ovarian tissue followed by transplantation represents a strategy to restore ovarian function and fertility. Stress from cryopreservation-thawing processes can lead to alterations and/or damage to mitochondrial structure and functionality. High resolution respirometry and histological analysis were used to evaluate the effect of cryopreservation and transplantation on ovarian tissue. Four different conditions were performed: Fresh non-transplanted tissue, Fresh transplanted tissue, Cryopreserved non-transplanted tissue and Cryopreserved transplanted tissue. All groups were able to respond to the substrates-uncoupler-inhibitor protocol. We found a dramatic decrease in general oxygen consumption in hemi-ovaries submitted to cryopreservation and/or transplantation. The effect of cryopreservation on mitochondrial metabolism was less intense than effect of transplantation, since the transplantation affected all of the mitochondrial states. A total of 2644 follicles were analyzed. Of these, 2198 were classified as morphologically normal. The percentage of morphologically normal follicles was significantly lower in the Cryopreserved transplanted group when compared to the Cryopreserved non-transplanted group and the Fresh transplanted group (p-value < 0.05). Despite decreased follicular viability and mitochondrial activity, the cryopreservation followed by transplantation of ovarian tissue proved feasible for attempts to restore ovarian function.

Effect of Lysophosphatidic Acid on the Vascular Endothelial Growth Factor Expression in Autotransplanted Mouse Ovaries Encapsulated in Sodium Alginate

Objective: The aim of this study was to evaluate the effect of lysophosphatidic acid (LPA) supplementation during in vitro culture and transplantation of mouse ovaries on the follicular development and expression of vascular endothelial growth factor (VEGF) as an angiogenesis factor at the mRNA and protein levels. Materials and methods: Three weeks old mice ovaries were cultured in the presence and absence of LPA for 24 hours, then they were capsulated in sodium alginate in the presence and absence of LPA as four experimental groups. After transplantation the vaginal smears were performed daily to evaluate the initiation of the estrous cycle. The morphology and follicular distribution were analyzed at the first and fourth estrous cycles using hematoxylin and eosin staining. Then in the groups that showed higher and lower follicular development the immunohistochemistry assay was conducted to identify VEGF protein expression, and the real time RT-PCR was done to analyze the expression of Vegf gene at the first estrus cycle. Results: The large size follicles and also the corpus luteum were prominent in all transplanted groups at fourth estrus cycle in comparison with intact control groups. The statistically lowest percentage of small size follicles and the highest percentages of large size follicles were seen in LPA⁺/LPA^- group (p<0.05). The expression ratio of Vegf to β-actin was significantly higher in this group in comparison with non-LPA treated and intact control groups (p <0.05). Conclusion: LPA as an angiogenesis factor increases the follicular development in transplanted ovaries but it causes early discharge of ovarian reserve.

Ovarian tissue damage after grafting: systematic review of strategies to improve follicle outcomes

Frozen-thawed human ovarian tissue endures large-scale follicle loss in the early post-grafting period, characterized by hypoxia lasting around 7 days. Tissue revascularization occurs progressively through new vessel invasion from the host and neoangiogenesis from the graft. Such reoxygenation kinetics lead to further potential damage caused by oxidative stress. The aim of the present manuscript is to provide a systematic review of proangiogenic growth factors, hormones and various antioxidants administered in the event of ovarian tissue transplantation to protect the follicle pool from depletion by boosting revascularization or decreasing oxidative stress. Although almost all investigated studies revealed an advantage in terms of revascularization and reduction in oxidative stress, far fewer demonstrated a positive impact on follicle survival. As the cascade of events driven by ischaemia after transplantation is a complex process involving numerous players, it appears that acting on specific molecular mechanisms, such as concentrations of proangiogenic growth factors, is not enough to significantly mitigate tissue damage. Strategies exploiting the activated tissue response to ischaemia for tissue healing and remodelling purposes, such as the use of antiapoptotic drugs and adult stem cells, are also discussed in the present review, since they yielded promising results in terms of follicle pool protection.

Taurine improves follicular survival and function of mice ovarian grafts through increasing CD31 and GDF9 expression and reducing oxidative stress and apoptosis

Ischemia-reperfusion (IR) injury is a major limitation of ovarian transplantation which threatens the follicular and graft survival. Taurine as a potent anti-oxidant, anti-apoptotic and anti-inflammatory agent, can prevent graft damages due to IR. We aimed to investigate the effect of taurine on the follicular survival and function of autotransplanted mouse ovaries. Female mice (4-5 weeks old) were divided into: control, autograft and autograft + taurine (200 mg/kg/day). The level of CD31 expression was evaluated two days (48 h) post transplantation. In addition, on day 7 post transplantation the serum levels of malondialdehyde (MDA) and the total antioxidant capacity (TAC) were assessed. Also, 28 days post transplantation; ovaries were studied stereologically and the percentage of apoptotic follicles, level of GDF9 expression and the serum concentrations of progesterone and estradiol were measured. Data were analyzed using one-way ANOVA and Tukey's test and the means were considered significantly different at P < 0.05. The total volume of the ovary (P < 0.01), volume of the cortex (P < 0.01) and medulla (P < 0.04), total number of different types of follicles, expression of GDF9 and CD31 and also the levels of progesterone, estradiol and TAC increased significantly in the autograft + taurine group compared to the autograft group (P < 0.001). The MDA level and apoptosis rate decreased significantly in the autograft + taurine group compared to the autograft group (P < 0.001). Taurine could significantly improve follicular survival and the function of grafted ovaries by accelerating the angiogenesis and reducing oxidative stress and apoptosis.

Fertility Preservation: The Challenge of Freezing and Transplanting Ovarian Tissue

Cancer treatments are increasingly effective, but can result in iatrogenic premature ovarian insufficiency. Ovarian tissue cryopreservation is the only option available to preserve fertility in prepubertal girls and young women who require immediate chemotherapy. Ovarian tissue transplantation has been shown to restore hormonal cycles and fertility, but a large proportion of the follicle reserve is lost as a consequence of exposure to hypoxia. Another crucial concern is the risk of reimplanting malignant cells together with the grafted tissue. In this review, the authors advance some challenging propositions, from prevention of chemotherapy-related gonadotoxicity to ovarian tissue cryopreservation and transplantation, including the artificial ovary approach.

Heterotopic autotransplantation of ovarian tissue in a large animal model: Effects of cooling and VEGF

Heterotopic and orthotopic ovarian tissue autotransplantation techniques, currently used in humans, will become promising alternative methods for fertility preservation in domestic and wild animals. Thus, this study describes for the first time the efficiency of a heterotopic ovarian tissue autotransplantation technique in a large livestock species (i.e., horses) after ovarian fragments were exposed or not to a cooling process (4°C/24 h) and/or VEGF before grafting. Ovarian fragments were collected in vivo via an ultrasound-guided biopsy pick-up method and surgically autografted in a subcutaneous site in both sides of the neck in each mare. The blood flow perfusion at the transplantation site was monitored at days 2, 4, 6, and 7 post-grafting using color-Doppler ultrasonography. Ovarian grafts were recovered 7 days post-transplantation and subjected to histological analyses. The exposure of the ovarian fragments to VEGF before grafting was not beneficial to the quality of the tissue; however, the cooling process of the fragments reduced the acute hyperemia post-grafting. Cooled grafts compared with non-cooled grafts contained similar values for normal and developing preantral follicles, vessel density, and stromal cell apoptosis; lower collagen type III fibers and follicular density; and higher stromal cell density, AgNOR, and collagen type I fibers. In conclusion, VEGF exposure before autotransplantation did not improve the quality of grafted tissues. However, cooling ovarian tissue for at least 24 h before grafting can be beneficial because satisfactory rates of follicle survival and development, stromal cell survival and proliferation, as well as vessel density, were obtained.

Supportive techniques to investigate in vitro culture and cryopreservation efficiencies of equine ovarian tissue: A review

During the reproductive lifespan of a female, only a limited quantity of oocytes are naturally ovulated; therefore, the mammalian ovary possesses a substantial population of preantral follicles available to be handled and explored in vitro. Hence, the manipulation of preantral follicles enclosed in ovarian tissue aims to recover a considerable population of oocytes of high-value animals for potential application in profitable assisted reproductive technologies (ARTs). For this purpose, the technique of preantral follicle in vitro culture (IVC) has been the most common research tool, achieving extraordinary results with offspring production in the mouse model. Although promising outcomes have been generated in livestock animals after IVC of preantral follicles, the quantity and quality of embryo production with those oocytes are still poor. In recent years, the mare has become an additional model for IVC studies due to remarkable similarities with women and livestock animals regarding in vivo and in vitro ovarian folliculogenesis. For a successful IVC system, several factors should be carefully considered to provide an optimum culture environment able to support the viability and growth of preantral follicles enclosed in ovarian tissue. The cryopreservation of the ovarian tissue is another important in vitro manipulation technique that has been used to preserve the reproductive potential in humans and, in the future, may be used in highly valuable domestic animals or endangered species. Several improvements in cryopreservation protocols are necessary to support the utilization of ovarian tissue of different species in follow-up ARTs (e.g., ovarian fragment transplantation). This review aims to provide an update on the most current advances regarding supportive in vitro techniques used in equids to evaluate and manipulate preantral follicles and ovarian tissue, as well as methodological approaches used during IVC and cryopreservation techniques.

Rescue of caprine fetal ovaries, vitrification and follicular development after xenotransplantation in two immunodeficient mice models

Domestic and wild goats are very susceptible animals to predation, specially when pregnancy occurs. This study aimed to evaluate the use of goat fetal ovarian tissue for vitrification followed by xenotransplantation and fresh xenotransplantation in two immunosuppressed mice models (C57BL/6 SCID and Balb-C NUDE). Goat fetus ovaries were collected in slaughterhouses, divided into small cortical pieces and were destined for fresh xenotransplantation (FX) and cryopreservation followed by xenotransplantation (CX). Five recipients from each lineage were used for FX and 10 animals from each lineage for CX. The mice were euthanized after 65 postoperative days, and the transplants were collected for microscopic assessment. The blood plasma was collected for estradiol measurement. Independently of mice strain, all recipients presented complete estrus cycle in FX and 80% after CX groups. Follicles were observed at all development stages without morphological changes. The volume density and total vessel surface observed in the transplants were different (p <0.01) between groups. The estradiol levels in the recipients did not differ (p <0.05) among the treatments. Thus, it is possible to activate the preantral follicles in the ovaries of fetuses by optimizing germplasm utilization and conservation of domestic and endangered wild goats that are in predatory situations, undesirable drowning or accidental death, since provided conditions for xenotransplantation are performed.

Cold case: Small animal gametes cryobanking

Germplasm preservation of animals, whether they are valuable domestic breeds or rare species, is the main goal of gamete cryobanking. Dogs and cats act as models for this purpose thanks to the wide availability of biological material which can be employed to experiment protocols that can then be applied to wild animals. This review is focused on spermatozoa, oocytes and gonadal tissues cryobanking in small domestic animals, which is still an unsolved case. Like in a courtroom, evidences of cryoinjuries affecting cellular structures will be presented, penalties as loss of functionality due to cellular alterations will be described, and appeal as strategies to protect gametes from damages or rescue their functionality will be discussed. Differences and similarities between single cell or tissue cryopreservation will be highlighted, together with the rationale for the choice of one type of preservation or another and the fundamental principles which they are based on. The deep analysis of different aspects that still hamper the success of cryopreservation in small animals can help clarify where research is most needed. Therefore, as in a cold case, investigation should remain open in order to hopefully find the solution and make these procedures more and more efficient in the future.

Utilizing platelet-rich fibrin bioscaffold at the graft site improves the structure and function of mice ovarian grafts

Aim: The effect of platelet-rich fibrin (PRF) bioscaffold on the structure and function of mice-autotransplanted ovaries was investigated. Materials & methods: Mice were divided into three groups: control, autografted and autografted + PRF bioscaffold. Angiogenesis, ovary histology and serum biochemical factors were assessed. Results: The total volume of the ovary, the number of follicles and the level of superoxide dismutase activity, total antioxidant capacity, IL-10, progesterone and estradiol were significantly higher in the autografted + PRF bioscaffold group compared with the autografted group. In the autografted + PRF bioscaffold group, angiogenesis was accelerated and apoptosis rate, IL-6, TNF-α, malondialdehyde concentrations were significantly lower compared with the autografted group. Conclusion: PRF bioscaffold improves the structure and function of mice-autografted ovary.

Vitrification of canine ovarian tissues with polyvinylpyrrolidone preserves the survival and developmental capacity of primordial follicles

Ovarian tissue cryopreservation combined with immature follicle development can preserve female fertility in wildlife, regardless of age or reproductive timing. To investigate the effects of different cryopreservation methods and cryoprotectants on follicular survival and developmental capacity, ovarian cortical pieces from 15 dogs were cryopreserved by slow freezing or vitrification with different additional cryoprotectants as follows: dimethyl sulfoxide (DMSO), polyvinylpyrrolidone (PVP), combined DMSO and PVP (each at half the concentration of when used independently), or none (control). Cryopreserved ovarian tissues were evaluated by neutral red staining, histology, and xenotransplantation assays. Among cryopreservation conditions tested, vitrification with combined DMSO and PVP significantly improved the maintenance of follicular morphology compared to that in control. Furthermore, ovarian tissues vitrified using this condition maintained follicle morphology and developmental capacity 9 weeks after grafting, as shown by an increased percentage of primary and secondary follicles and a significant decrease in the transition stage from primordial to primary stage follicles 5 and 9 weeks after grafting. In contrast, slow freezing and control groups lost intact follicles by 5 weeks after grafting. The described cryopreservation techniques, which preserve canine follicle development, will build the foundation of ovarian tissue cryopreservation to preserve female fertility in wild canids.

Evaluation of Z-VAD-FMK as an anti-apoptotic drug to prevent granulosa cell apoptosis and follicular death after human ovarian tissue transplantation

PURPOSE

To evaluate the efficiency of ovarian tissue treatment with Z-VAD-FMK, a broad-spectrum caspase inhibitor, to prevent follicle loss induced by ischemia/reperfusion injury after transplantation.

METHODS

In vitro, granulosa cells were exposed to hypoxic conditions, reproducing early ischemia after ovarian tissue transplantation, and treated with Z-VAD-FMK (50 μM). In vivo, cryopreserved human ovarian fragments (n = 39) were embedded in a collagen matrix containing or not Z-VAD-FMK (50 μM) and xenotransplanted on SCID mice ovaries for 3 days or 3 weeks.

RESULTS

In vitro, Z-VAD-FMK maintained the metabolic activity of granulosa cells, reduced HGL5 cell death, and decreased PARP cleavage. In vivo, no improvement of follicular pool and global tissue preservation was observed with Z-VAD-FMK in ovarian tissue recovered 3-days post-grafting. Conversely, after 3 weeks of transplantation, the primary follicular density was higher in fragments treated with Z-VAD-FMK. This improvement was associated with a decreased percentage of apoptosis in the tissue.

CONCLUSIONS

In situ administration of Z-VAD-FMK slightly improves primary follicular preservation and reduces global apoptosis after 3 weeks of transplantation. Data presented herein will help to guide further researches towards a combined approach targeting multiple cell death pathways, angiogenesis stimulation, and follicular recruitment inhibition.

Laparoscopic ovarian biopsy pick-up method for goats

Biopsy pick-up (BPU) has been considered a safe method to harvest ovarian fragments from live animals. However, no studies have been reported on the use of BPU to collect in vivo ovarian tissue in goats. The goals of this study were: (i) to test different biopsy needle sizes to collect ovarian tissue in situ using the BPU method (Experiment 1), and (ii) to study ovarian tissue features such as preantral follicle density, morphology, class distribution, and stromal cell density in ovarian fragments obtained in vivo through a laparoscopic BPU method (Experiment 2). In Experiment 1, goat ovaries (n = 20) were collected in a slaughterhouse and subjected to in situ BPU. Three needles (16, 18, and 20G) were tested. In Experiment 2, the most efficient biopsy needle from Experiment 1 was used to perform laparoscopic BPU in goats (n = 8). In Experiment 1, the recovery rate was greater (P < 0.05; range 50-62%) with 16G and 18G needles than the 20G (17%) needle. The mean weight of ovarian fragments collected by the 16G needle was greater (P < 0.05) than the 18G and the 20G needle. In Experiment 2, 62 biopsy attempts were performed and 52 ovarian fragments were collected (90% success rate). Overall, 2054 preantral follicles were recorded in 5882 histological sections analyzed. Mean preantral follicular density was 28.4 ± 1.3 follicles per cm². The follicular density differed (P < 0.05) among animals and ovarian fragments within the same animal. The mean stromal cell density in the ovarian fragments was 37.1 ± 0.5 cells per 2500 μm², and differed (P < 0.05) among animals. Moreover, preantral follicle density and stromal cell density were associated (P < 0.001). The percentage of morphologically normal follicles was 70.1 ± 1.2, and differed (P < 0.05) among animals. The majority (79%) of the morphologically normal follicles was classified as primordial follicles, and differed (P < 0.05) among animals and between ovaries. In summary, a laparoscopic BPU method has been developed to harvest ovarian tissue in vivo with a satisfactory success rate in goats. Furthermore, this study described for the first time that goat ovarian biopsy fragments have a high heterogeneity in follicular density, morphology, class distribution, and stromal cell density.

Expectations and limitations of ovarian tissue transplantation

Constant progress in the diagnosis and treatment of cancer disease has increased the number and prognosis of cancer survivors. However, the toxic effects of chemotherapy and radiotherapy on ovarian function have resulted in premature ovarian failure. Patients are, therefore, still expecting methods to be developed to preserve their fertility successfully. Several potential options are available to preserve fertility in patients who face premature ovarian failure, including immature or mature oocyte and embryo cryopreservation. However, for children or prepubertal women needing immediate chemotherapy, cryopreservation of ovarian tissue is the only alternative. The ultimate aim of this strategy is to implant ovarian tissue into the pelvic cavity (orthotopic site) or in a heterotopic site once oncological treatment is completed and the patient is disease free. Transplantation of ovarian tissue with sufficiently large numbers of follicles could potentially restore endocrine function and allow multiple cycles for conception. However, the success of ovarian tissue transplantation still has multiple challenges, such as the low number of follicles in the graft that may affect their longevity as well as the survival of the tissue during ex vivo processing and subsequent transplantation. Therefore, this review aims to summarize the achievements of ovary grafting and the potential techniques that have been developed to improve ovarian graft survival.

The Effect of Erythropoietin in Preventing Ischemia-Reperfusion Injury in Ovarian Tissue Transplantation

Condensation Erythropoietin improved the survival of follicles in ovarian grafts most likely by reducing ischemic injury, by improving neoangiogenesis, and by its antioxidant effects.

OBJECTIVE

Ovarian tissue cryopreservation and transplantation are the only options accepted for prepubertal girls and women requiring immediate chemotherapy. Ischemia-reperfusion injury is the main obstacle for ovarian tissue transplantation. In the present study, we aimed to evaluate the effects of recombinant human erythropoietin (EPO) on tissue viability in autotransplanted rat ovaries.

STUDY DESIGN

Seventeen female rats were randomized into 3 groups as sham control group (n = 5), EPO-treated group (n = 6), and EPO-untreated group (n = 6). Both ovaries were excised and transplanted into a subcutaneous pouch formed at the anterior abdominal wall in the EPO-treated and untreated groups. In the EPO group, 5000 U/kg EPO was applied as local injection to the site that ovarian tissue was placed and the dose was repeated with the same route at the end of the fourth week. After 2 months, ovaries were removed and blood samples were obtained. Levels of estradiol (E₂), vascular endothelial growth factor (VEGF), VEGF-C, and lipid hydroperoxidase (LPO) and the activity of glutathione peroxidase (GPX), superoxide dismutase (SOD), and catalase (CAT) were measured both in blood and tissue samples. Histopathological and morphometric analyses were also performed on tissue samples.

RESULTS

Considering serum levels, mean CAT was significantly higher ( P = .003) and mean SOD ( P = .033), LPO ( P = .050), VEGF ( P = .001), and VEGF-C ( P = .024) were significantly lower in the EPO-treated group than in the untreated group. Mean serum GPX levels were similar. Significantly higher levels of E₂ were determined in the EPO group than in the untreated group. Highest serum E₂ levels were found in the sham group ( P = .001). Tissue levels of GPX (1.23) and CAT (53.17) were significantly higher in the EPO group ( P = .002 and P = .001, respectively). However, tissue levels of SOD and LPO, VEGF, and VEGF-C levels were significantly lower in the EPO group than those in the untreated group ( P = .033, P = .050, P = .002, and P = .003, respectively). In tissue examination, the highest values of x, y axis and epithelial height were in the sham group. Mean value of the EPO group was found statistically significantly higher than that of the untreated group ( P ≤ .05). In terms of antral follicle count, ordering was found as sham > EPO-treated > EPO-untreated group. Follicle counts in the EPO group were significantly higher than those in the untreated group ( P ≤ 0.05).

CONCLUSION

Erythropoietin improved the survival of follicles in ovarian grafts most likely by reducing ischemic injury, by improving neoangiogenesis, and by its antioxidant effects.

Ovarian features in white-tailed deer (Odocoileus virginianus) fawns and does

The knowledge about ovarian reserve is essential to determine the reproductive potential and to improve the methods of fertility control for overpopulated species, such as white-tailed deer (Odocoileus virginianus). The goal of this study was to evaluate the effect of age on the female reproductive tract of white-tailed deer, focusing on ovarian features. Genital tracts from 8 prepubertal and 10 pubertal females were used to characterize the preantral follicle population and density, morphology, distribution of follicular classes; stromal cell density; and apoptosis in the ovary. In addition, uterus and ovary weights and dimensions were recorded; and the number and the size of antral follicles and corpus luteum in the ovary were quantified. Overall, fawns had a greater (P < 0.05) preantral follicle population, percentage of normal follicles, and preantral follicle density than does. The mean stromal cell density in ovaries of fawns and does differed among animals but not between age groups. The apoptotic signaling did not differ (P > 0.05) between the ovaries of fawns and does. However, apoptotic ovarian cells negatively (P < 0.001) affected the preantral follicle morphology and density, and conversely, a positive correlation was observed with stromal cell density. As expected, the uteri and ovaries were larger (P < 0.002) and heavier (P < 0.001) in does than in fawns. In conclusion, this study has shown, for the first time, the preantral follicle population and distribution of classes, rate of morphologically normal follicles, and density of preantral follicles and stromal cells in white- tailed deer. Therefore, the findings herein described lead to a better understanding of the white-tailed deer ovarian biology, facilitating the development of new methods of fertility control.

New Insights into the Role of Autophagy in Ovarian Cryopreservation by Vitrification

Ovarian cryopreservation by vitrification is a highly useful method for preserving female fertility during radiotherapy and chemotherapy. However, cryoinjury, osmotic stress during vitrification, and ischemia/reperfusion during transplantation lead to loss of ovarian follicles. Ovarian follicle loss may be partially reduced by several methods; however, studies regarding the mechanism of ovarian follicle loss have only investigated cell apoptosis, which consists of type I programmed cell death. Autophagy is type II programmed cell death, and cell homeostasis is maintained by autophagy during conditions of stress. The role of autophagy during cryopreservation by vitrification has rarely been reported. The potential role of autophagy during ovarian cryopreservation by vitrification is reviewed in this article.

The Mare Model to Study the Effects of Ovarian Dynamics on Preantral Follicle Features

Ovarian tissue collected by biopsy procedures allows the performance of many studies with clinical applications in the field of female fertility preservation. The aim of the present study was to investigate the influence of reproductive phase (anestrous vs. diestrous) and ovarian structures (antral follicles and corpus luteum) on the quality, class distribution, number, and density of preantral follicles, and stromal cell density. Ovarian fragments were harvested by biopsy pick-up procedures from mares and submitted to histological analysis. The mean preantral follicle and ovarian stromal cell densities were greater in the diestrous phase and a positive correlation of stromal cell density with the number and density of preantral follicles was observed. The mean area (mm²) of ovarian structures increased in the diestrous phase and had positive correlations with number of preantral follicles, follicle density, and stromal cell density. Biopsy fragments collected from ovaries containing an active corpus luteum had a higher follicle density, stromal cell density, and proportion of normal preantral follicles. In conclusion, our results showed: (1) the diestrous phase influenced positively the preantral follicle quality, class distribution, and follicle and stromal cell densities; (2) the area of ovarian structures was positively correlated with the follicle and stromal cell densities; and (3) the presence of an active corpus luteum had a positive effect on the quality of preantral follicles, and follicle and stromal densities. Therefore, herein we demonstrate that the presence of key ovarian structures favors the harvest of ovarian fragments containing an appropriate number of healthy preantral follicles.

Effects of L-carnitine on follicular survival and graft function following autotransplantation of cryopreserved-thawed ovarian tissues

The aim of this study was to investigate the effects of L-carnitine (LC) on follicular survival and ovarian function following cryopreservation-thawing and autotransplantation of ovarian tissues. ICR mice were divided into three groups: control; saline group (cryopreservation+autograft+saline); and LC group (cryopreservation+autograft+L-carnitine). The ovarian tissues from control group, saline group, and LC group were histological assessed. There were no significant differences in the percentage of morphologically normal primordial follicles between the LC group and the saline group. After 28 days of autotransplantation, apoptosis rates, plasma malondialdehyde (MDA), progesterone (P4) and estradiol (E2) concentrations, and follicular densities of grafts were evaluated. Apoptosis rate and the concentration of MDA in the LC group were significantly lower than those in the saline group. The concentration of E2 and follicular densities of grafts in LC group were significantly higher than that in saline group. LC inhibits follicle apoptosis and increases follicular survival and function of ovarian graft.

Influence of mouse strain on ovarian tissue recovery after engraftment with angiogenic factor

Background

For women facing gonadotoxic treatment, cryopreservation of ovarian tissue with subsequent retransplantation during remission is a promising technique for fertility preservation. However, follicle loss within grafted ovarian tissue can be caused by ischemia and progressive revascularization. Several xenograft models using different immunodeficient rodent lines are suitable for studying ovarian tissue survival and follicular viability after frozen-thawed ovarian cortex transplantation. SCID mice, which are deficient for functional B and T cells, are the most commonly used mice for ovarian xenograft studies. However, due to incomplete immunosuppression, NOD-SCID mice displaying low NK cell function and an absence of circulating complement might be more appropriate. The present study aims to define the most appropriate immunodeficient mouse strain for ovarian tissue xenotransplantation by comparing ovarian graft recovery in SCID and NOD-SCID mice following engraftment in the presence of isoform 111 of vascular endothelial growth factor.

Methods

Sheep ovarian cortex fragments were embedded in a collagen matrix, with or without VEGF₁₁₁, before being stitched onto the ovaries of SCID and NOD-SCID mice. Transplants were recovered after 3 days to study early revascularization or after 3 weeks to evaluate follicle preservation and tissue fibrosis through histological analyses.

Results

At day 3, vessels were largely reorganized in the ovarian grafts of both mouse strains. After 3 weeks, the cortical tissue was clearly identifiable in SCID mice but not in NOD-SCID mice. Upon VEGF₁₁₁ treatment, vascularization was significantly improved 3 days after transplantation in SCID mice. This increase in vessel density was correlated with better follicular preservation in SCID mice 3 weeks after transplantation. Fibrosis was not decreased by VEGF treatment in either mouse strain.

Conclusions

Tissue architecture and follicular morphology were better preserved in ovarian tissues grafted in SCID mice in comparison with NOD-SCID mice. Moreover, tissue revascularization was improved in SCID mice by VEGF₁₁₁ graft treatment. Thus, we consider SCID mice to be the best murine model for studying ovarian tissue xenografts.

Isoform 165 of vascular endothelial growth factor in collagen matrix improves ovine cryopreserved ovarian tissue revascularisation after xenotransplantation in mice

BACKGROUND

Aggressive anti-cancer treatments can result in ovarian failure. Ovarian cryopreservation has been developed to preserve the fertility of young women, but early graft revascularisation still requires improvement.

METHODS

Frozen/thawed sheep ovarian cortical biopsies were embedded in collagen matrix with or without isoform 165 of vascular endothelial growth factor (VEGF165) and transplanted into ovaries of immunodeficient mice. Ovaries were chosen as transplantation sites to more closely resemble clinical conditions in which orthotopic transplantation has previously allowed several spontaneous pregnancies.

RESULTS

We found that VEGF165 significantly increased the number of Dextran-FITC positive functional vessels 3 days after grafting. Dextran- fluorescein isothiocyanate (FITC) positive vessels were detectable in 53% and 29% of the mice in the VEGF-treated and control groups, respectively. Among these positive fragments, 50% in the treated group displayed mature smooth-muscle-actin-alpha (alpha-SMA) positive functional vessels compared with 0% in the control group. CD31 positive murine blood vessels were observed in 40% of the VEGF165 transplants compared with 21% of the controls. After 3 weeks, the density of murine vessels was significantly higher in the VEGF165 group.

CONCLUSION

The encapsulation of ovarian tissue in collagen matrix in the presence of VEGF165 before grafting has a positive effect on functional blood vessel recruitment. It can be considered as a useful technique to be improved and further developed before human clinical applications in female cancer patients in the context of fertility preservation.

Effects of erythropoietin on ischemia, follicular survival, and ovarian function in ovarian grafts

Ovarian tissue transplantation is performed to preserve fertility in patients undergoing chemotherapy and radiotherapy. However, ischemia/reperfusion (IR) injury and free radical production occurring during the revascularization of the transplanted tissue are the major limitations of this procedure. The aim of this study was to investigate the effect of erythropoietin (EPO) as an antioxidant on oxidative stress and ovary survival following transplantation. The Naval Medical Research Institute (NMRI) mice (4–5 weeks old) were divided into three groups (six mice per group): control; autograft+saline, and autograft+EPO (500 IU/kg i.p.). After 28 days, ovary compartments were estimated stereologically. DNA fragmentation and plasma malondialdehyde (MDA), progesterone, and estradiol (E2) concentrations were also evaluated. The results were analyzed using one-way ANOVA and Tukey's test, and the means were significantly different at P<0.05. The mean total volume of ovary, cortex, and medulla and the number of follicles increased significantly in the autograft+EPO group (P<0.01). Apoptosis rate in the autograft+EPO group was lower than that in the autograft+saline group. The concentration of MDA decreased significantly in the autografted EPO-treated group than in the autografted saline-treated group (P<0.01). The concentration of E2 increased significantly in the autograft+EPO group than in the autograft+saline group (P<0.01). EPO reduced IR injury, increasing follicle survival and function in grafted ovaries.

Free Persian abstract

A Persian (Farsi) translation of the abstract is freely available online at http://www.reproduction-online.org/content/147/5/733/suppl/DC1

Autologous and allogeneic ovarian orthotopic transplantation: morphologic, endocrinologic and natural pregnancy assessment

PURPOSE

To assess pregnancy of rabbits submitted to bilateral ovariectomy and orthotopic allogeneic or autologous intact and sliced ovarian transplantation without a vascular pedicle and to determine the morphofunctional aspects of the transplanted ovaries.

METHODS

Fifty-six female rabbits were studied. The ovaries were removed and orthotopically transplanted or replaced without vascular anastomoses: Group 1 (n=8), only laparotomy and laparorrhaphy, Group 2A (n=8) intact ovaries were transplanted on both sides, Group 2B (n=8) both ovaries were sliced and orthotopically transplanted, Group 2C (n=8), an intact ovary was transplanted on one side and a sliced ovary on the other side. In Group 3 the ovaries were reimplanted according to the procedure and subgroups described for Group 2. Three months later, the animals were paired with males for copulation. Estradiol, progesterone, FSH and LH hormone levels were assessed. A histologic study was carried out, and the number of pregnancies and litters were also determined. Chi-square test compared the number of pregnancies and litters. One-way ANOVA and the Tukey-Kramer tests compared the hormonal dosages.

RESULTS

Pregnancies occurred in seven (87.5%) rabbits of Group 1, in three rabbits (37.5%) of Groups 2A and 3A, in four rabbits (50%) of groups 2B, 3B and 3C, and in five (62.5%) of group 2C. Normal hormone serum levels and histology confirmed the vitality of all ovaries.

CONCLUSION

Orthotopic allogeneic and autologous ovarian transplantation without a vascular pedicle is viable in rabbits, and preserves their hormonal levels and fertile functions.