卵巢组织冷冻移植在女性生育力保存中的研究进展

医疗技术的发展使得癌症患者的存活率越来越高,但放化疗治疗会导致女性卵巢功能早衰,出现过早绝经甚至丧失生育能力。卵巢组织冷冻保存是保存女性生育力的一种方式,甚至是有些患者唯一的生育力保存的选择。目前在世界范围已有17例婴儿是来自冷冻/解冻-移植后的卵巢组织,这给我们带来了希望,同时也带来了挑战,因为这项技术还存在一定的局限性。目前使用的冷冻方法可以保存卵巢内大量的始基卵泡,但是在移植的初期,因组织缺血缺氧会导致大量的卵泡丢失,影响了移植物的存活,缩减了卵巢组织在体内发挥功能的时间。卵巢组织移植存活程度的影响因素很多,包括移植前个体因素和基础疾病及治疗对卵巢的损伤,冷冻的损伤和移植组织块的大小,移植后血管再生情况等。这篇文章将对卵巢组织冷冻作为女性生育力保存方式的研究进展做一综述。     

Density and distribution of primordial follicles in single pieces of cortex from 21 patients and in individual pieces of cortex from three entire human ovaries

BACKGROUND: At the time of cryopreservation of ovarian tissue for fertility preservation a small biopsy of ovarian cortex is usually taken for histological evaluation of the follicular reserve. The purpose of this study was to evaluate the distribution and density of primordial follicles in single pieces of cortex from individual patients and in pieces of cortex comprising entire ovaries, all prepared for cryopreservation. METHODS: Cortical biopsies from 21 patients and the whole cortex of one ovary were evaluated histologically prior to cryopreservation. In addition, the cortex of two whole ovaries was cryopreserved before histological evaluation. The volume of each cortical fragment was measured, all follicles counted and the follicular density calculated. RESULTS: In individual pieces of cortex follicular density showed a significant inverse linear correlation with age. The follicular density per cortical fragment prepared from each of the three entire ovaries varied from 1.8 to 166, 0.007 to 140 and 0.04 to 4.48 follicles/mm(3) cortical tissue. CONCLUSION: The density of primordial follicles varied more than two orders of magnitude in cortical fragments from each of the three ovaries. Primordial follicles were very unevenly distributed throughout the cortex of these ovaries, although a significant linear correlation between age and follicular density was found.     

Distribution and epidermal growth factor receptor expression of primordial follicles in human ovarian tissue before and after cryopreservation

The freezing of ovarian tissue and the growth of immature oocytes from primordial follicles is an interesting concept in ovarian tissue transplantation and in-vitro fertilization. In this study, the morphology and distribution of primordial follicles were studied in ovarian tissue from 24 women before and after cryopreservation. Cryopreservation did not significantly change either the morphology or number per unit volume of morphologically normal follicles in frozen ovarian tissue. Primordial follicles were predominant, accounting for 78.6% and 82.6% of total follicles in fresh and frozen ovarian tissues respectively. The distribution of follicles was extremely uneven in ovarian tissue. A large variation in follicle numbers was observed in ovarian tissue samples from patient to patient, and even in the same patient, indicating that the number of follicles counted in one sample of ovarian tissue may not represent the number of follicles in other tissue samples. Ovarian tissue could be frozen in the form of strips instead of fragments for fast processing and better viability of ovarian tissue in cryopreservation. The number of follicles in ovarian tissue declined with the increasing age of the patients. An immunohistochemical study showed that immunoreactivity for the epidermal growth factor (EGF) receptor was detected in primordial follicles of adult ovarian tissue. EGF receptor staining was most intense in the oocytes of primordial follicles. Weak staining for EGF receptor was observed in some surrounding pregranulosa cells. Immunohistochemical staining for EGF receptor was also present in the stromal cells of ovarian tissue, but to a much lesser degree. There was no significant difference in the immunohistochemical staining for EGF receptor in ovarian tissue before and after cryopreservation.     

Survival of primordial follicles following prolonged transportation of ovarian tissue prior to cryopreservation

BACKGROUND: Cryopreservation of ovarian tissue for fertility preservation is becoming increasingly common. Treatment of diseases that may deprive the ovaries of follicles is often performed at local hospitals that are without the necessary facilities and expertise to cryopreserve ovarian tissue. The aim of the present study was to evaluate whether primordial follicles of ovarian cortex survive transport for up to 4 h prior to cryopreservation. METHODS: Immediately after recovery of one ovary from each of four patients, the cortex was roughly isolated, placed in IVF culture medium, kept on ice and transported for 3-4 h to the centre where final dissection and cryopreservation took place. Transplantation of pieces of thawed ovarian cortex under the skin of ovariectomized immunodeficient mice for a period of 4 weeks was used to assess the survival of primordial follicles. RESULTS: After transplantation, ovarian tissue from each of the four patients contained surviving follicles. CONCLUSIONS: Transport of roughly isolated ovarian cortex cooled on ice for a period of up to 4 h allows survival of primordial follicles following cryopreservation and transplantation to immunodeficient mice.     

Cryopreservation of oocytes from pre-antral follicles

Cryobiology is a very important tool in reproductive biology. Research in this area focuses on the possibility of restoring fertility in women with reproductive problems or after cancer treatments. Another goal is to establish a genetic resource bank for endangered or commercially important animal species. Cryopreservation of oocytes from pre-antral follicles has been studied during the past decade. Procedures can be divided between the cryopreservation of either ovarian tissue or isolated follicles. Most studies describe a slow freezing/rapid thawing protocol to cryopreserve ovarian fragments. Histology shows that the follicles maintain their morphological integrity, and transplantation of ovarian tissue demonstrates that the follicles can restart their growth and eventually ovulate. Some research groups have obtained offspring using this procedure in mice and sheep. With regard to the cryopreservation of isolated follicles, the few studies reported in this area used the same freezing protocol, and some of them described follicular growth using in-vitro culture. The best result was obtained in mice, with animal birth after follicular cryopreservation and culture. However, additional studies are necessary for a better understanding of the events during follicular cryopreservation and to establish a standard protocol for ovarian transplantation or follicle culture.     

两种冷冻方法冻融人卵巢组织异种移植后血管生成素-2表达变化的比较

目的 通过检测血管生成素-2（Ang-2）的表达,探讨两种冷冻方法对人卵巢组织的冻融及异种移植后的效果。 方法 共收集16例人卵巢组织标本,每例分成2份,其中1份应用程序化冷冻方法进行冷冻,另1份应用玻璃化冷冻方法进行冷冻。解冻后分别移植到去卵巢的雌性裸鼠颈部皮下。32只SCID裸鼠随机分为两组：A组16只,移植以程序化方法冷冻复苏的人卵巢组织;B组16只,移植以玻璃化方法冷冻复苏的人卵巢组织。解冻后及移植6周后观察两组卵巢组织中始基卵泡的存活及颗粒细胞Ang-2的表达情况。 结果 解冻后,A组Ang-2的阳性率明显高于B组（P<0.05）,始基卵泡正常率两组相比差别不明显（P＞0.05）。移植后,始基卵泡正常率及Ang-2的阳性率两组相比均无明显差别（P＞0.05）。解冻后和移植后相比,两组的Ang-2阳性率及A组的始基卵泡正常率差别均不明显（P＞0.05）,B组移植后始基卵泡正常率明显低于解冻后（P<0.05）。 结论 与玻璃化冷冻相比,程序化冷冻对人卵巢组织始基卵泡颗粒细胞Ang-2的表达影响更小。将解冻后的人卵巢组织进行异种移植不影响Ang-2的表达。     

Early massive follicle loss and apoptosis in heterotopically grafted newborn mouse ovaries

BACKGROUND: Ovarian tissue cryopreservation and transplantation can be used to restore fertility to sterile females. A question that warrants further investigation is whether the follicular content is affected by the freeze-thawing and grafting procedure, and if so, to what extent and by what mechanism. METHODS AND RESULTS: Intact newborn mouse ovaries were allografted under the kidney capsule or were cryopreserved by slow freezing with dimethylsulphoxide as the cryoprotectant prior to grafting. Estrogenic activity of ovariectomized recipient mice, as revealed by vaginal cytology, resumed after 11 days of transplantation. At 14 days after transplantation, ovarian grafts were recovered and processed histologically for follicle number counting. The follicular content of grafts of fresh ovaries was 58% of that from ovaries of age-matched 14 day old mice. In frozen-thawed ovarian grafts, the follicular content was only 9% lower than that of fresh grafted ovaries. Apoptosis of follicular cells was investigated by DNA nick end labelling. We observed a marked increase in the staining of fragmentation of DNA shortly after transplantation (2-12 h) of fresh newborn mouse ovaries. CONCLUSIONS: The results of the present study indicate that transplantation rather than cryopreservation accounts for the major and early loss of primordial follicles in grafted newborn mouse ovaries.     

Caspase抑制剂对冻融卵巢组织的影响

目的研究Caspase抑制剂z-DEVD-fmk对冻融小鼠卵巢组织的影响。方法将15只小鼠随机分为3组：A组（新鲜对照组）、B组（添加z-DEVD-fmk组）和C组（未添加z-DEVD-fmk组）,B组和C组的卵巢组织进行玻璃化冷冻,一部分卵巢皮质组织进行组织学分析,另一部分卵巢皮质组织进行自体移植,手术后1个月后测血清雌二醇浓度和移植物增值细胞核抗原（PCNA）表达率。结果光镜观察发现冷冻组的始基卵泡和初级卵泡的形态正常率均明显低于对照组,B组的始基卵泡和初级卵泡的形态正常率与C组比较无明显差异。然而,B组血清雌二醇浓度高于C组,差异有统计学意义。同样,B组移植物卵细胞和间质细胞PCNA蛋白表达率高于C组。结论实验结果提示：Caspase抑制剂z-DEVD-fmk在卵巢组织冻融过程中具有保护作用。     

Two novel techniques to detect follicles in human ovarian cortical tissue

BACKGROUND: Ovarian tissue cryopreservation and transplantation are becoming increasingly important issues for preserving female fertility as shown by recent successes in restoring ovarian activity and even fertility. Primordial follicle content before transplantation is a key issue for success. We investigated two novel methods to detect primordial follicles in human ovarian cortical tissue strips. METHODS: The first method used the fluorescent mitochondrial stain rhodamine 123 in combination with laser scanning confocal microscopy (LSCM). The first method used the fluorescent mitochondrial stain rhodamine 123 (R123) in combination with laser scanning confocal microscopy (LSCM). The second used a simple stereomicroscopic method with glass-bottom dishes for detecting primordial follicles in ovarian cortical tissue strips. Potential toxic effects of R123 and of the exposure to confocal laser were investigated in a mouse ovarian allograft model. RESULTS: Follicles were visible as white spots in thin cortical strips using LSCM in single and fast scanning at low magnification, allowing a fair estimation of the number of primordial follicles present. Using the second method, ovarian follicles were also visible using glass-bottom dishes under the stereomicroscope, although tissue thickness and density were limiting factors of its success. DISCUSSION: Follicles can be visualized in human cortical ovarian strips with R123 in combination with LSCM. Stereomicroscopy using glass-bottom dishes and transmitted illumination is a simple alternative method and has the advantage of allowing further safe clinical use of the analysed tissue.     

Expression of receptors for insulin-like growth factor-I and transforming growth factor-beta in human follicles

The in-vitro growth of immature oocytes in early follicles from cryopreserved human ovarian tissues is a new concept in in-vitro fertilization programmes for the treatment of infertile and cancer patients. To better understand the regulatory mechanism of follicular development, immunohistochemistry was used to study the expression of insulin-like growth factor (IGF) type I receptor (IGF-IR) and transforming growth factor-beta (TGFbeta) type I (TbetaR-I) and type II (TbetaR-II) receptors in fresh and frozen ovarian tissues from 14 women. Immunoreactivities for IGF-IR and TbetaR-I were present simultaneously in the oocytes of primordial, pre-antral and antral follicles. Staining for both IGF-IR and TbetaR-I was also observed in granulosa cells of primordial, pre-antral and antral follicles. IGF-IR and TbetaR-I also stained in thecal cells of pre-antral and antral follicles. Stromal cells in surrounding ovarian tissue expressed IGF-IR and TbetaR-I at various follicular stages. Unlike TbetaR-I, TbetaR-II was expressed only in the oocytes of primordial and primary follicles, and with weak staining intensity in thecal cells. No significant staining for TbetaR-II was found in oocytes and granulosa cells of antral follicles. There was no difference in staining patterns for IGF-IR, TbetaR-I and TbetaR-II between fresh and frozen ovarian tissues, indicating that cryopreservation might not significantly alter the immunoreactivities of these receptors in frozen ovarian tissue. The results suggest that IGF-I and TGFbeta may participate in the regulation of follicular growth by binding to their receptors through an autocrine or paracrine mechanism. IGF-I and TGFbeta may be useful in regulating the in-vitro or in-vivo maturation of oocytes not only in later follicles but also very early follicles, from cryopreserved ovarian tissues for clinical use in the future.     

丹参注射液对冻融小鼠卵巢移植早期光镜结构及超微结构的影响

目的 探讨丹参注射液对冻融小鼠卵巢同种异体移植早期光镜结构及超微结构的影响.方法 收集1日龄小鼠卵巢,慢冻速融后移植至F1代8～12周雄鼠的肾被膜下,分别于移植后第2天(2d)、第7天(7d)和第14天(14d)回收两组卵巢移植物.光镜和电镜技术观察卵巢组织冻融前后和移植前后的组织形态学改变、计数卵泡数量.结果 小鼠卵巢经冻融后原始卵泡的存活率为87.9%.光、电镜观察卵巢组织移植后7d卵泡细胞和颗粒细胞结构欠完整,移植后14d卵泡结构恢复正常.移植后14d丹参组各级卵泡数及卵泡存活率(30.1%)多于生理盐水组(13.2%),差异显著(P＜0.05).结论 结合光镜和电镜观察能更全面地评价冻融过程和移植过程对小鼠卵巢组织的影响,移植早期的缺血缺氧对小鼠卵巢组织造成了远比冻融过程更严重的损伤;丹参注射液可能促进移植后冻融小鼠卵泡发育,减少细胞凋亡.     

Angiogenesis of the Frozen‐Thawed Human Fetal Ovarian Tissue at the Early Stage after Xenotransplantation and the Positive Effect of Salviae miltiorrhizae

Cryopreserving ovarian tissue followed by transplantation has been suggested to preserve fertility for young cancer survivors. However, ischemia in the early stage after transplantation causes massive follicle loss. The aim was to investigate the histological and ultrastructural characteristics of the frozen‐thawed human fetal ovarian tissue after xenotransplantation and the effects of Salviae miltiorrhizae (SM) on the angiogenesis. The human fetal ovarian tissues were frozen‐thawed, xenografted into the immunodeficient nu/nu mice, and then collected 2, 7, and 28 days after transplantation. SM was administered. Compared with that of the frozen‐thawed ovarian tissue, the total follicle number of the grafts was greatly reduced. Nearly half of the primordial follicles were damaged at different levels on day 2. Moreover, edema was prevalent in the stroma during the first week after the graft, especially on day 2. The microvessel density of the grafts was increased on day 2, reached a peak on day 7, and then declined on day 28. Both healthy primordial follicle proportion and the total healthy primordial follicles pool in the SM group were significantly higher than those of the control group (P = 0.003 and P = 0.001). We found a statistically significant difference of microvessel density between the two groups on day 2 (P < 0.001). In the frozen‐thawed fetal ovarian grafts, angiogenesis has been begun on day 2, and the first week is the critical time for the grafts to regain their function, in which SM can facilitate graft vascularization and improve the preservation of primordial follicles. Anat Rec, 2010. © 2010 Wiley‐Liss, Inc.     

Reducing ischaemic damage in rodent ovarian xenografts transplanted into granulation tissue

BACKGROUND: Anti-cancer therapies frequently lead to ovarian damage and impaired fertility. To preserve fertility, cryopreservation and subsequent transplantation of the ovaries have been suggested. One of the challenges in ovarian graft transplantation is overcoming the initial ischaemic damage that depletes a significant fraction of the oocyte pool. METHODS AND RESULTS: Follicular survival in ovarian grafts was examined by magnetic resonance imaging (MRI) and fluorescence microscopy in a model system in which rat ovaries were transplanted into nude mice. Transplantation into angiogenic granulation tissue created during wound healing shortened the ischaemic period by 24 h and significantly increased the pool of healthy primordial follicles and the perfused area of the transplanted grafts. Functional blood vessels were detected within the grafts as early as 2 days after transplantation. Gain of function was demonstrated both by growth of the grafts and by the hormonal influence on the host uteri. CONCLUSION: Implantation of ovarian grafts into an angiogenic granulation tissue improved graft vascularization and follicular survival. This procedure/treatment may be used for reducing the ischaemic damage in ovarian transplants, thus prolonging graft functionality and increasing the yield of oocytes that can be easily recovered for fertilization.     

冻融人胎儿卵巢组织异种移植后早期血管生成的实验观察

目的 石观察冻融人胎儿卵巢组织异种移植后1个月内移植物形态学改变,动态了解微血管情况. 方法 将难免流产胎儿的卵巢组织经过冻融,异种移植至18只裸鼠肾被膜下,分别于移植后2d、7d和28d回收移植物.将新鲜、冻融以及移植后不同时间的卵巢组织进行光镜、电镜观察,RT-PCR检测血管相关基因的表达. 结果 移植后2d卵巢组织的微血管密度显著上升,部分血管处于扩张状态;移植后7d微血管密度达到相对高峰且扩张的血管腔消失,微小血管恢复正常形态;移植后28d微血管密度出现轻微下降.电镜观察发现,移植卵巢内多数原始卵泡结构完整;移植后2d间质水肿,血管内红细胞淤积;移植后7d及28d的间质水肿逐渐消退,大量微小血管生长.移植卵巢的人血管内皮生长因子(VEGF)和血管生成素2(Ang-2)mKNA表达均呈双向改变,即在移植后2d上升到高值.此后表达下降. 结论 冻融人胎儿卵巢组织移植后的血管重建在移植后1个月内基本完成,移植后l周是采取措施提高冻融人胎儿卵巢移植效果的关键时期.     

Alginate: A Versatile Biomaterial to Encapsulate Isolated Ovarian Follicles

In vitro culture of ovarian follicles isolated or enclosed in ovarian tissue fragments and grafting of isolated ovarian follicles represent a potential alternative to restore fertility in cancer patients who cannot undergo cryopreservation of embryos or oocytes or transplantation of frozen-thawed ovarian tissue. In this regard, respecting the three-dimensional (3D) architecture of isolated follicles is crucial to maintaining their proper follicular physiology. To this end, alginate hydrogel has been widely investigated using follicles from numerous animal species, yielding promising results. The goal of this review is therefore to provide an overview of alginate applications utilizing the biomaterial as a scaffold for 3D encapsulation of isolated ovarian follicles. Different methods of isolated follicle encapsulation in alginate are discussed in this review, as its use of 3D alginate culture systems as a tool for in vitro follicle analysis. Possible improvements of this matrix, namely modification with arginine-glycine-aspartic acid peptide or combination with fibrin, are also summarized. Encouraging results have been obtained in different animal models, and particularly with isolated follicles encapsulated in alginate matrices and grafted to mice. This summary is designed to guide the reader towards development of next-generation alginate scaffolds, with enhanced properties for follicle encapsulation.     

Development of antral follicles in human cryopreserved ovarian tissue following xenografting

This study reports the first gross morphological and histological evidence of antral follicle development in human ovarian tissue following cryopreservation. Human ovarian tissue was cryopreserved using propanediol and sucrose and grafted under the renal capsule of bilaterally oophorectomized severe combined immunodeficient (SCID) mice. Follicles at all stages of development were observed in the grafted tissue whereas, prior to grafting, only primary and primordial follicles were present. Antral follicles were rarely observed on grafts examined <20 weeks after grafting either non-frozen tissue (fresh, 1/7) or cryopreserved tissue (0/11). In contrast, development of at least one antral follicle was evident on the majority of sites > or = 20 weeks after grafting (fresh 7/9, cryopreserved 18/24). Antral follicle diameters ranged from 0.1 to 5.0 mm. Histological examination of these antral follicles indicated normal follicular morphology, i.e. antral cavities encapsulated by concentric layers of theca and granulosa cells. Pedicles containing germinal vesicle oocytes were observed protruding from the granulosa cell layers. The development and morphology of the cryopreserved and fresh tissue following grafting was similar.     

Human ovarian tissue cryopreservation: indications and feasibility

BACKGROUND: The cryopreservation of ovarian tissue may enable women exposed to gonadotoxic treatments to have children at a later date. METHODS: Between April 1998 and October 2000, we evaluated the feasibility of long-term ovarian tissue cryopreservation in 51 women who were all at risk of becoming sterile following treatment. RESULTS: Ovarian tissue was not cryopreserved in 20 cases because of the woman's age or premature ovarian failure. In 31 patients, ovarian tissue was frozen by a slow cooling technique using DMSO and sucrose as cryoprotectants. The patients were aged 2.7-34 years and 16 of them were <18 years old. Cryopreservation could be performed in all cases. Ovarian cortex histology was performed for all patients to evaluate the concentration of follicles. The mean number of primordial and primary follicles per mm(2) was 20.36 +/- 19.03 before 10 years of age, 4.13 +/- 2.9 between 10 and 15 years of age and 1.63 +/- 3.35 after 15 years of age. An average mean number of 26 +/- 8.2 ovarian fragments (range 13-50) were cryopreserved per patient for future autografts or for in-vitro growth of follicles. CONCLUSION: Cryopreservation of ovarian tissue may be systematically proposed to young women and girls at risk of becoming sterile as a result of gonadotoxic treatment.     

Anti-Müllerian hormone inhibits initiation of growth of human primordial ovarian follicles in vitro

BACKGROUND: Anti-Müllerian hormone (AMH) inhibits the initiation of the development and early growth of mouse ovarian follicles. Furthermore, the ovarian follicle pool diminishes prematurely in AMH-knockout mice. In this study, we examined whether AMH plays a similar role in humans, controlling ovarian follicle growth. METHODS: Human ovarian cortical tissue biopsy specimens were cut into small pieces and cultured for 7 days in medium containing rat recombinant AMH at 0, 10, 30 or 100 ng/ml. The developmental stages and viability of the follicles were evaluated from histological sections. RESULTS: Similar to previous studies, significant initiation of follicle growth was observed in almost all culture media, as demonstrated by a significantly smaller proportion of primordial follicles (14-26%) compared with non-cultured control tissue (56%). The exception was tissue in medium supplemented with AMH at 100 ng/ml. Here, the proportion of primordial follicles was not significantly different from that in non-cultured tissue; furthermore, it was significantly greater than that in vehicle control cultures and cultures containing AMH at 10 ng/ml, indicating the inhibition of growth initiation. Viability was unaffected by the presence of AMH when compared with tissues in control media. CONCLUSIONS: Recombinant AMH at a concentration of 100 ng/ml has an inhibitory effect on early human ovarian follicular development in vitro, suppressing the initiation of primordial follicle growth.     

Selection of patients before and after anticancer treatment for ovarian cryopreservation

BACKGROUND: Although ovarian cryopreservation in patients with cancer should ideally be performed before the initiation of therapy, cryopreservation from such patients often becomes an option only later. The justification for the procedure needs to be elucidated. METHODS: Eighteen cancer patients before chemotherapy and 23 others after chemotherapy participated in the study. Freshly dissected ovarian samples were prepared for light microscopy to demonstrate follicular numbers and apoptosis, transmission electron microscopy to enhance intracellular changes, and staining with fluorescent markers (calcein AM, rhodamin 123 and ethidium homodimer) to test for viability. RESULTS: High numbers of preantral follicles were detected in ovaries of patients < or =20 years. No antral follicles were detected. All the follicles were viable and not apoptotic. Deterioration in follicular quality was observed after chemotherapy, manifested mainly as an increase in abnormal granulosa cell nuclei (P < 0.05-0.0001) and in oocyte vacuolization (P < 0.0001). CONCLUSIONS: Our study stresses the importance of prechemotherapy ovarian cryopreservation. However, the large number of viable, non-apoptotic follicles in ovaries of younger patients (age < or = 20 years) indicates that ovarian cryopreservation might be considered after treatment in this age group. Further studies of ovarian samples from women aged 20-30 years are needed to determine the exact age margin wherein postchemotherapy ovarian cryopreservation can be suggested.     

The effects of radiotherapy and chemotherapy on female reproduction.

High dose chemotherapy and radiotherapy have radically increased long-term survival of young cancer patients, but major side effects of these treatments are ovarian failure and infertility. Knowledge of the risks and probabilities of ovarian failure caused by treatment is crucial for patients and physicians in order to make informed choices that will best serve patients' interests. This review presents data on ovarian damage and failure following exposure to radiotherapy, chemotherapy and ablative therapy. The risk is evaluated from the published literature according to patient's age, treatment protocol and also according to the diagnosis of some common malignancies. Many of these patients will not be sterilized immediately following treatment, but will suffer from premature menopause. In order to prevent sterilization, ovarian transposition before pelvic irradiation is mandatory. Besides cryopreservation of ovarian tissue and embryos before administration of chemotherapy, the possible protective effect of pituitary-ovarian down-regulation is discussed. The mechanism of primordial follicles damage induced by radio/chemotherapy is presented as well as the role of apoptosis signalling pathways underlying destruction. Increased knowledge of these mechanisms could help to identify potential effective inhibitors that can block the path of primordial follicles destruction and reduce ovarian failure rate.