Interaction between melatonin and follicle-stimulating hormone promotes in vitro development of caprine preantral follicles

The aim of this study was to investigate the effects of melatonin and follicle-stimulating hormone (FSH) on the in vitro culture of goat preantral follicles. Ovarian fragments were cultured for 7 d in α-minimum essential medium (α-MEM(+)) containing melatonin (100, 250, 500, or 1,000 pM), FSH (50 ng/mL), or a combination of the 2 hormones and further analyzed by histology and transmission electron and fluorescent microscopy. The results showed that after 7 d of culture, tissues cultured in α-MEM(+) alone or supplemented with FSH alone, melatonin (500 and 1,000 pM), or the combination of FSH and melatonin (1,000 pM) maintained percentages of normal preantral follicles similar to the fresh control. In contrast to the noncultured tissues, the percentage of developing follicles was increased under all culture conditions after 7 d (P < 0.05). The addition of 1,000 pM melatonin associated with FSH to the culture medium increased follicular and oocyte diameters compared with α-MEM(+) alone after 7 d of culture (P < 0.05). Ultrastructural and fluorescent analyses confirmed the integrity of follicles cultured with 1,000 pM of melatonin plus FSH for 7 d. In conclusion, this study demonstrated that the interaction between melatonin and FSH maintains ultrastructural integrity and stimulates further growth of cultured caprine preantral follicles.

[Comparative morpho-functional characteristics of the organs of the reproductive system of small mammals under conditions of anthropogenic transformation of Southern Ural steppe ecosystems]

The morpho-functional characteristics of reproductive organs of small mammals--striped field mouse (Apodemus agrarius Pallas, 1771), house mouse (Mus musculus Linnaeus, 1758), wood mouse (Sylvaemus uralensis Pallas, 1811), common vole (Microtus arvalis Pallas, 1778), bank vole (Clethrionomys glareolus Schreber, 1780), steppe lemming (Lagurus lagurus Pallas, 1773), little suslik (Spermophilus pygmaeus Pallas, 1778), and red-heeked suslik (Spermophilus major Pallas, 1779)--belonging to the populations inhabiting anthropogenically modified steppe landscapes (zones influenced by the ferrous metallurgy plants and gas processing plant, as well as the territory of the large city) were studied using histological, electron microscopic, immunocytochemical and morphometric methods. In animals studied, inhabiting technologically modified ecosystems, in contrast to those from ecologically safe regions, the testis demonstrated the increased destruction of spermatogenic epithelium. In the ovaries, the accelerated exhaustion of follicular reserve was detected. The increased embryonic death rate was also observed. The portion of the animals participating in reproduction was enlarged, the female fecundity was increased, while the age at puberty was decreased. Among the animal species studied, the variable degree of stability against the effect of the negative factors was demonstrated.

The effect of experimental low zearalenone intoxication on ovarian follicles in pre-pubertal bitches

Companion animals, including bitches, may be exposed to zearalenone (ZEN) toxins that are often present in feed, and ZEN intoxication may lead to ovarian dysfunction. This study involved evaluation of the degree of ZEN-induced hypo stimulation of ovary by determination of proliferative and apoptotic indices and description of the ultra-structural organization of ovarian follicles in pre-pubertal bitches subjected to experimental, long-term exposure to low-dose ZEN mycotoxicosis. The experiment involved 30 clinically healthy, immature Beagle bitches aged approximately 70 days with initial average body weight of 8 kg, randomly divided into three groups of 10 animals each: two experimental groups (EI and EII) and a control group (C). Over a period of 42 days, ZEN was administered per os to EI animals at a dose of 50 microg/kg BW, and to EII bitches at a dose of 75 microg/kg BW. Control group animals were fed placebo containing no ZEN for 42 days. Analytical samples of the mycotoxin were administered daily in gelatin capsules before morning feeding. All the bitches were subjected to ovario-hysterectomy at the end of the experiment. Proliferation index (PCNA method) and apoptotic index (TUNEL test) values were determined by immune-histological analyses. The median for apoptotic index was determined at 13.45 for group EI, 17.84 for group EII, and 8.59 for group C. The median for proliferation index was determined at 35.25 for group EII, 42.44 for group EI, and 70.60 for group C. The results of ultra-structural examinations of the ovaries revealed that experimental, ZEN-induced hyperestrogenism enhanced apoptosis and lowered the proliferative ability of follicular cells what contributed to organelle destruction in pre-pubertal bitches. The changes observed were particularly advanced in EII animals, which were administered a higher dose of ZEN.

[Morphology and cell proliferation evaluation of follicles from cryopreserved human ovarian tissue by vitrification]

OBJECTIVE

To evaluate the morphology and proliferation of follicles from cryopreserved human ovarian tissue by vitrification.

METHODS

Ovarian biopsy specimens were taken from 12 patients. The specimens were randomly distributed into fresh group (Group A) and vitrification group (Group B). Histological examination and ultrastructural observation were performed after cryopreservation. Both were embedded in paraffin block and proliferating cell nuclear antigen (PCNA) was detected by immunohistochemical staining.

RESULTS

The proportions of primordial and primary follicles from Group A and Group B were 86.4%, 13.6% and 84.5%, 15.5%, respectively (P>0.05). There was no significant difference in proportions of morphologically normal primordial follicles between Group A and Group B (P>0.05); but the proportion of morphologically abnormal primary follicles was significantly higher in Group B than that in Group A (P<0.05). The ultrastructural studies showed that in histologically normal primordial follicles, there was no difference between Group A and Group B, while there were a few abnormalities of primary follicles in Group B. Granulosa cells and oocytes of primordial and primary follicles and stromal cells were positive for PCNA staining both in fresh and cryopreserved ovarian tissues; there were no differences between two groups.

CONCLUSION

Vitrification is a favorable method in human ovarian cryopreservation.

The effects of epidermal growth factor (EGF) on the in vitro development of isolated goat secondary follicles and the relative mRNA expression of EGF, EGF-R, FSH-R and P450 aromatase in cultured follicles

The effects of varying concentrations of EGF were evaluated in terms of in vitro follicular development and the mRNA expression levels of EGF, EGF-R, FSH-R and P450 aromatase. After 6 days, the addition of 50 ng/mL of EGF to the culture medium increased the antrum formation rates in comparison to cultured control and after 18 days of culture produced oocytes with higher rates of meiosis resumption when compared to the other treatments (P<0.05). The daily follicular growth rates in presence of EGF (50 or 100) were increased in comparison to the cultured control (P<0.05). Treatment with EGF 50 stimulated the expression of EGF mRNA but reduced EGF-R mRNA expression and estradiol secretion as compared to the cultured control (P<0.05). After 18 days of culture, the mRNA levels for FSH-R and P450 aromatase were greater than those of the non-cultured controls (P<0.05). In conclusion, the effects of EGF treatment on the mRNA levels for EGF, EGF-R, FSH-R, and P450 aromatase varied according to the stage of follicle development.

Participation of Gs-proteins in the action of relaxin-like gonad-stimulating substance (GSS) for 1-methyladenine production in starfish ovarian follicle cells

Gonad-stimulating substance (GSS) in starfish is the only known invertebrate peptide hormone responsible for final gamete maturation, rendering it functionally analogous to gonadotropins in vertebrates. Recently, we purified GSS from radial nerves in the starfish Asterina pectinifera and identified the chemical structure as a heterodimer composed of two different peptides (A- and B-chain) with disulfide cross-linkages. This study examined the hormonal action of GSS on ovarian follicle cells obtained from ovaries in growing (stage IV) and fully grown (stage V) stages, and particularly the mode of signal transduction. The action of GSS on 1-MeAde production by follicle cells in stage V was mediated through the production of cAMP. In contrast, GSS failed to induce 1-MeAde and cAMP production by follicle cells in stage IV. According to competitive experiments using radioiodinated and radioinert GSS, highly specific binding was observed in follicle cells, though their affinities and numbers in stage IV were inferior to those in stage V. Interestingly, Gsα was not detected immunologically in follicle cell membranes of stage IV. Gβ was also faint in stage IV. Although adenylyl cyclase activity in stage V was dose-dependently activated by GSS in the presence of GTP, neither GSS in the presence of GTP nor nonhydrolyzable GTP analogs were effective on the activity in stage IV. These findings strongly suggest that the failure of GSS to produce 1-MeAde is because of a lack of Gs-proteins in follicle cells at stage IV.

[Actin and mRNA export factors distribution in the nucleus of preovulatory mouse oocytes]

Nuclear actin is a part of the chromatin remodeling complex involved in transcriptional and associated with nascent mRNA, providing them an ability to export from the nucleus. It is currently proved that many factors involved in mRNA editing and mRNA export are localized in IGCs. Using confocal laser scanning microscopy and immunogols labeling technique, we identified actin and A1 hnRNP protein in the nuclei of oocytes from mouse preovulatory follicles. We have demonstrated that nuclear actin is detected in association with the chromatin and IGCs. Components of mRNA export complex including proteins A1 and NXF1/TAP are localized in IGCs together with actin. In accordance with the concept suggesting that IGCs participate in RNA retention in the nucleus we discuss that mRNA transcription-export complex including actin, A1 hnRNP protein and NXF1/TAP, along with mRNA and transcription factors is formed in IGCs.

The ovary of Lagostomus maximus (Mammalia, Rodentia): an analysis by confocal microscopy

Lagostomus maximus is a notable mammalian model for reproductive studies. Females have an extremely high ovulation rate, which is due to down-regulation of the follicular apoptosis pathway, which ensures a large pool of developing follicles. This large pool is supported by the convoluted anatomy of the mature ovary, whose germinal tissue is found in irregularly curved ridges throughout the cortex. Medullary tissue is restricted to a minimum. Lyso Tracker Red reconstruction under confocal laser scanning microscopy was used to recognize and measure all follicular stages from primordial to antral. Unlike most mammals in which early primordial follicles are just found in fetal life, the adult ovary shows regions packed with early primordial follicles. Follicle size ranged from 24 to 316 microm. We discuss the relationships of L. maximus follicles size with regard to other species of mammals and propose that the physiology of the adult viscacha ovary obeys to a neoteny process in the evolution of this species.

BMP signaling dynamics in the follicle cells of multiple Drosophila species

The dorsal anterior region of the follicle cells (FCs) in the developing Drosophila egg gives rise to the respiratory eggshell appendages. These tubular structures display a wide range of qualitative and quantitative variations across Drosophila species, providing a remarkable example of a rapidly evolving morphology. In D. melanogaster, the bone morphogenetic protein (BMP) signaling pathway is an important regulator of FCs patterning and dorsal appendages morphology. To explore the mechanisms underlying the diversification of eggshell patterning, we analyzed BMP signaling in the FCs of 16 Drosophila species that span 45 million years of evolution. We found that the spatial patterns of BMP signaling in the FCs are dynamic and exhibit a range of interspecies' variations. In most of the species examined, the dynamics of BMP signaling correlate with the expression of the type I BMP receptor thickveins (tkv). This correlation suggests that interspecies' variations of tkv expression are responsible for the diversification of BMP signaling during oogenesis. This model was supported by genetic manipulations of tkv expression in the FCs of D. melanogaster that successfully recapitulated the signaling diversities found in the other species. Our results suggest that regulation of receptor expression mediates spatial diversification of BMP signaling in Drosophila oogenesis, and they provide insight into a mechanism underlying the evolution of eggshell patterning.

Premature ovarian failure in nobox-deficient mice is caused by defects in somatic cell invasion and germ cell cyst breakdown

PURPOSE

To understand the mechanism of premature ovarian failure (POF).

METHODS

The ultrastructural (electron microscopy) analysis of primordial ovarian follicles in Nobox deficient mice.

RESULTS

We studied, for the first time, the fate of oogonia in embryonic (prenatal) mouse ovaries and showed that the abolishment of the transition from germ cell cysts to primordial follicles in the ovaries of Nobox deficient mice is caused by defects in germ cell cyst breakdown, leading to the formation of syncytial follicles instead of primordial follicles.

CONCLUSIONS

These results indicate that POF syndrome in Nobox deficient mice results from the faulty signaling between somatic and germ line components during embryonic development. In addition, the extremely unusual and abnormal presence of adherens junctions between unseparated oocytes within syncytial follicles indicates that faulty communication between somatic and germ cells is involved in, or leads to, abnormalities in the cell adhesion program.

Ultrastructure of isolated mouse ovarian follicles cultured in vitro

BACKGROUND

In vitro maturation of ovarian follicles, in combination with cryopreservation, might be a valuable method for preserving and/or restoring fertility in mammals with impaired reproductive function. Several culture systems capable of sustaining mammalian follicle growth in vitro have been developed and many studies exist on factors influencing the development of in vitro grown oocytes. However, a very few reports concern the ultrastructural morphology of in vitro grown follicles.

METHODS

The present study was designed to evaluate, by transmission and scanning electron microscopy, the ultrastructural features of isolated mouse preantral follicles cultured in vitro for 6 days in a standard medium containing fetal calf serum (FCS). The culture was supplemented or not with FSH.

RESULTS

The follicles cultured in FCS alone, without FSH supplementation (FCS follicles), did not form the antral cavity. They displayed low differentiation (juxta-nuclear aggregates of organelles in the ooplasm, a variable amount of microvilli on the oolemma, numerous granulosa cell-oolemma contacts, signs of degeneration in granulosa cell compartment). Eighty (80)% of FSH-treated follicles formed the antral cavity (FSH antral follicles). These follicles showed various ultrastructural markers of maturity (spreading of organelles in ooplasm, abundant microvilli on the oolemma, scarce granulosa cell-oolemma contacts, granulosa cell proliferation). Areas of detachment of the innermost granulosa cell layer from the oocyte were also found, along with a diffuse granulosa cell loosening compatible with the antral formation. Theca cells showed an immature morphology for the stage reached. Twenty (20)% of FSH-treated follicles did not develop the antral cavity (FSH non-antral follicles) and displayed morphological differentiation features intermediate between those shown by FCS and FSH antral follicles (spreading of organelles in the ooplasm, variable amount of microvilli, scattered granulosa cell-oolemma contacts, signs of degeneration in granulosa cell compartment).

CONCLUSIONS

It is concluded that FSH supports the in vitro growth of follicles, but the presence of a diffuse structural granulosa cell-oocyte uncoupling and the absence of theca development unveil the incomplete efficiency of the system. The present study contributes to explain, from a morphological point of view, the effects of culture conditions on the development of mouse in vitro grown follicles and to highlight the necessity of maintaining efficient intercellular communications to obtain large numbers of fully-grown mature germ cells.

Studies on cryoprotectant toxicity to zebrafish (Danio rerio) ovarian tissue fragments

Cryopreservation of ovarian tissue is a viable alternative to cryopreservation of oocytes and embryos in many species but it has not been studied in fish. Selection of cryoprotectant is an important step in designing cryopreservation protocols. In order to identify the optimum cryoprotectant (CPA) in a suitable concentration for zebrafish ovarian tissue cryopreservation, studies on toxicities of five commonly used cryoprotectants methanol, ethanol, dimethyl sulfoxide (DMSO), ethylene glycol (EG) and propylene glycol (PG) were carried out. Experiments were conducted on ovarian tissue fragments consisting of stage I and stage II ovarian follicles. Ovarian tissue fragments were incubated in 90% L-15 medium (pH 9) containing 1-4M cryoprotectants for 30min at 22°C. Three different tests were used to assess ovarian tissue fragment viability: trypan blue (TB) staining, fluorescein diacetate (FDA) combined with propidium iodide (PI) staining and adenosine 5´- triphosphate (ATP) assay. Results from these tests showed that ATP assay was more sensitive than FDA+PI or TB staining for assessing cryoprotectant toxicity to follicles in tissue fragments. Methanol and ethanol were the least toxic cryoprotectants tested. Cryoprotectant toxicity increased in the order of methanol/ethanol, DMSO, PG and EG. Ethanol was used for zebrafish ovarian tissue for the first time and the results showed that the effect of methanol and ethanol on ovarian tissue fragments were comparable. As methanol has been shown to be the most effective cryoprotectant for zebrafish ovarian follicles in our laboratory, the use of ethanol will also be considered in assisting future freezing protocol design. The present study also showed that stage II ovarian follicles are more sensitive to cryoprotectant treatment than stage I follicles in tissue fragments. The results obtained in this study provided useful information for ovarian tissue fragment cryopreservation protocol design in the future.

Sheep ovarian tissue vitrification by two different dehydration protocols and needle immersing methods

The present research investigated the effects of two vitrification methods on sheep ovarian tissue. The base medium (BM) of the vitrification solutions contains 60% HEPES tissue culture medium (HTCM), 15% ethylene glycol (EG) and 15% dimethyl sulfoxide (DMSO). Ovarian cortex pieces were dehydrated by two different regimens, the 2-step which consisted of 50% BM and a 90% solution of 0.25 mol/L sucrose in BM for 10 minutes each at 4 degree C and the 4-step method which utilized: a) 25% BM, b) 50% BM, c) 75% BM and d) a 90% solution of 0.25 mol/L sucrose in BM for 5 minutes each at 4 degree C. After warming, the proportion of intact antral follicles in the control (non-vitrified) and 2-step vitrification groups was significantly higher than in the 4-step vitrification group. The number of apoptotic follicles in the ovarian pieces was significantly different between the control and 4-step vitrification groups. These results indicated that sheep ovarian tissue vitrification by the 2-step method was simpler and more effective than the 4-step method.

Fibroblast growth factor-10 maintains the survival and promotes the growth of cultured goat preantral follicles

The aim of the present study was to investigate the effects of fibroblast growth factor-10 (FGF-10) on the survival, activation (transition from primordial to primary follicles), and growth of goat preantral follicles cultured in vitro. Pieces of ovarian cortex were cultured for 1 and 7 d in the absence or presence of FGF-10 (0, 1, 10, 50, 100, and 200 ng/mL). Noncultured and cultured tissues were processed and analyzed by histology, transmission electron microscopy, and viability testing. Results showed that after 7 d, a greater percentage (79.9%) of morphologically normal follicles (containing an oocyte with regular shape and uniform cytoplasm, and organized layers of granulosa cells without a pyknotic nucleus) was observed when cultured with 50 ng/mL of FGF-10 when compared with other concentrations of FGF-10 (0 ng/mL, 67.3%; 1 ng/mL, 68.2%; 10 ng/mL, 63.3%; 100 ng/mL, 64.4%; 200 ng/mL, 52.7%). Ultrastructural analyses and viability testing using fluorescent markers confirmed the follicular integrity of FGF-10 (50 ng/mL)-treated fragments after 7 d of culture. After 7 d, all FGF-10 concentrations reduced the percentage of primordial follicles and increased the percentage of developing follicles. In the presence of 50 ng/mL of FGF-10, follicles increased in diameter after 7 d of culture when compared with other concentrations tested. In conclusion, this study demonstrates that FGF-10 maintains the morphological integrity of goat preantral follicles and stimulates the growth of activated follicles in culture. The culture conditions identified here contribute to the understanding of the factors involved in goat early follicular development.

Solid-surface vitrification is an appropriate and convenient method for cryopreservation of isolated rat follicles

BACKGROUND

Cryopreservation of isolated follicles may be a potential option to restore fertility in young women with cancer, because it can prevent the risks of cancer transmission. Several freezing protocols are available, including slow-rate freezing, open-pulled straws vitrification (OPS) and solid-surface vitrification (SSV, a new freezing technique). The purpose of our study was to investigate the effects of these freezing procedures on viability, ultrastructure and developmental capacity of isolated rat follicles.

METHODS

Isolated follicles from female Sprague-Dawley rats were randomly assigned to SSV, OPS and slow-rate freezing groups for cryopreservation. Follicle viability assessment and ultrastructural examination were performed after thawing. In order to study the developmental capacity of thawed follicles, we performed in vitro culture with a three-dimensional (3D) system by alginate hydrogels.

RESULTS

Our results showed that the totally viable rate of follicles vitrified by SSV (64.76%) was slightly higher than that of the OPS group (62.38%) and significantly higher than that of the slow-rate freezing group (52.65%; P < 0.05). The ultrastructural examination revealed that morphological alterations were relatively low in the SSV group compared to the OPS and slow-rate freezing groups. After in vitro culture within a 3D system using alginate hydrogels, we found the highest increase (28.90 +/- 2.21 microm) in follicle diameter in follicles from the SSV group. The estradiol level in the SSV group was significantly higher than those in the OPS and slow-rate freezing groups at the end of a 72-hr culture period (P < 0.05).

CONCLUSIONS

Our results suggest that the SSV method is an appropriate and convenient method for cryopreservation of isolated rat follicles compared with the conventional slow-rate freezing method and the OPS method.

Morphological expression of angiogenesis in the mammalian ovary as seen by SEM of corrosion casts

In the mammalian ovary, follicular and corpus luteum cycle is associated with intensive microvascular remodelling. The complex angiogenic dynamics are finely tuned by numerous regulatory factors acting as activators (up-regulators) or inhibitors (down-regulators) of angiogenesis. Alterations of such a tight modulation are involved in several pathologies, including infertility, polycystic ovarian syndrome, ovarian hyperstimulation syndrome and ovarian cancer. We have demonstrated in several experimental models that ovarian function is critically and specifically dependent on angiogenesis for follicular development, ovulation, and corpus luteum growth. The aim of this review is to summarize the results we have obtained on the morphodynamic remodelling of ovarian microvascularization, in polyovulatory (rat, rabbit and pig) and monovulatory species (cow), using scanning electron microscopy of vascular corrosion casts. The knowledge of the morphological expression of the up- and down-regulation of angiogenesis occurring in mono and polyovulatory animals might provide useful information to preserve fertility and to increase of the effectiveness of reproductive management in species of domestic interest.

Impact of pituitary FSH purification on in vitro early folliculogenesis in goats

Porcine pituitary follicle stimulating hormone (pFSH) is known to regulate the production of growth factors that have an essential role in early foliculogenesis. However, the effects of different preparations of pFSH on the survival and development of caprine follicles are not yet known. The aim of this study was to evaluate the effects of different pFSH (Stimufol and Folltropin) on the in vitro survival and growth of caprine preantral follicles. Pieces of caprine ovarian tissues were cultured for either one or seven days in a supplemented Minimum Essential Medium, alone or containing either Stimufol (50 ng/mL) or Folltropin (10, 50, 100 and 1000 ng/mL). Fresh control ovarian tissues as well as cultured tissued were processed for histological and ultrastructural studies. The results showed that after seven days, only Stimufol maintained follicular morphology similar to control. Moreover, follicular degeneration was higher in medium alone or with Folltropin at 50, 100 and 1000 ng/mL. However, at day seven, the percentage of growing follicles was higher in 100 ng/mL of Folltropin than Stimufol. In conclusion, FSH preparations affect differently the performance of in vitro culture of caprine preantral follicles. Stimufol was better to preserve follicular morphology while Folltropin was more efficient to promote follicular growth.

Blood vessel remodeling in pig ovarian follicles during the periovulatory period: an immunohistochemistry and SEM-corrosion casting study

BACKGROUND

The present research aims to describe the process of vascular readjustment occurring in pig ovary during the periovulatory phase (from LH surge to ovulation) that drives the transformation of the follicle, a limited blood supplied structure, into the corpus luteum, a highly vascularised endocrine gland required to maintain high levels of progesterone in pregnancy. The swine model was chosen because it is characterized by a long periovulatory window (about 40-44 hrs-similar to human) that permits to recover follicles at a precise endocrinological timing.

METHODS

By validated hormonal protocol (eCG+hCG), able to mimic the physiologic gonadotropin stimulation, preovulatory follicles (PreOFs, 60 h-eCG), follicles in the middle (early periovulatory follicles, EPerOFs, 18 h-hCG) or late (LPerOFs, 36 h-hCG) periovulatory phase were isolated from prepubertal gilts. To understand the angiogenic process, morphological/morphometrical analyses were performed by combining immunohistochemistry (IHC) and SEM of vascular corrosion casts (VCC) techniques.

RESULTS

PreOFs showed a vascular plexus with proliferating endothelial cells (EPI). This plexus was characterized by a dense inner capillary network, with angiogenic figures, connected to the outer network by anastomotic vessels (arterioles and venules of the middle network). EPerOFs decreased their EPI, blood vessel extension in the outer network, and evidenced a reduced compactness of blood vessels. In LPerOFs, a rapid neovascularization was associated to an intensive tissue remodeling: the follicle acquired an undulated aspect presenting arterioles/venules near the basal membrane, increased vascular extension by EPI, sprouting and non-sprouting angiogenesis.The analysis of vascular geometric relations and branching angles evidenced similar values at all stages.

CONCLUSION

These data allow us to hypothesize that EPerOFs are in a quiescent status. LPerOFs represent the "metamorphic" follicles that rapidly turn-on angiogenesis to sustain a successful corpus luteum formation. Particularly, it is interesting to underlie that the non-sprouting angiogenesis, typical of structures in rapid neovascularization, occurred only in the LPerOFs. Moreover, vascular geometric relations showed as blood vessel remodeling occurs with the "maximum output and the minimum energetic expense".This knowledge will allow to better understand the mechanisms regulating the reproductive success and to clarify the complex physiological angiogenic process in adult tissues.

Ultrastructural Preservation of Ovarian Cortical Tissue Cryopreserved in Dimethylsulfoxide for Subsequent Transplantation into Young Female Cancer Patients

Cytotoxic therapy in young women with cancer may cause loss of ovarian function, and ovarian cryopreservation has been proposed as a means of preserving fertility. The objective of this study is to assess ultrastructural preservation of follicles in frozen-thawed ovarian cortical strips, previously cryopreserved using dimethylsulfoxide and a standard slow-cool/rapid-thaw protocol. Ovarian cortical strips (patients, n=7) were thawed and fixed in glutaraldehyde for epoxy resin embedding electron microscopy according to conventional procedures. Oocytes were generally well preserved, on the basis of plasma-membrane integrity, uniformity of chromatin pattern, mitochondrial and rough endoplasmic reticulum (rER) cisternal integrity, and absence of cytoplasmic and intranuclear clear spaces. Frequently, rER cisternae were distended and intramitochondrial matrices lost. Granulosa cells showed somewhat variable preservation. Some were dark-staining; others exhibited washed-out cytoplasm containing damaged or artifactually expanded organelles. The consistently good preservation of oocytes and the good but more variable preservation of granulosa cells provides scientific validation of one component in the overall clinical procedure of attempting to reestablish fertility in young female patients after cytotoxic therapy for cancer.

Healthy Early Preantral Follicle Can Be Obtained in a Culture of Frozen–Thawed Human Ovarian Tissue of 32 Weeks

The objective of this study was to report morphological and functional evidence of a well-preserved preantral follicle recovered from human frozen-thawed ovarian tissue in a long-term culture. The tissue was originally obtained from a 26-year-old woman with breast cancer. The ovarian cortex was collected by laparoscopy and frozen/thawed and cultured for 32 weeks in minimum essential medium alpha-MEM, supplemented with insulin transferrine selenite (ITS), human serum (HS), antibiotics, follicle-stimulating hormone (FSH). and N-acetyl cysteine (NAC). Thawed tissue samples were examined by light microscopy (LM), transmission electron microscopy (TEM), and real-time RT-PCR. LM examination of cortical pieces after 32 weeks of culture showed a healthy early preantral follicle; TEM and real-time PCR confirmed its good state of preservation. The synergy in action of NAC and FSH plays an important role in follicle growth of ovarian tissue cultures. For the first time a well-preserved preantral follicle was found in a culture of frozen-thawed human ovarian tissue.

Combined apoptosis and autophagy, the process that eliminates the oocytes of atretic follicles in immature rats

We studied the alterations of dying oocytes in 1-28 days old rats using TUNEL method, immunolocalizations of active caspase 3, lamp1, localization of acid phosphatase, and DAPI staining. All procedures were performed in adjacent sections of each oocyte. In most dying oocytes exist simultaneously features of apoptosis as active caspase 3 and DNA breaks, and a large increase of lamp1 and acid phosphatase characteristic of autophagy. Large clumps of compact chromatin and membrane blebbing were absent. Electron microscope observations demonstrated the presence of small clear vesicles and autophagolysosomes. All these features indicate that a large number of oocytes are eliminated by a process sharing features of apoptosis and autophagy. In dying oocytes of new born rats the markers of apoptosis predominate over those of autophagy. However, fragmentation and apoptotic bodies were not found. These features suggest that in different cytophysiological conditions the processes of cell death may be differently modulated.

Morphologic, ultrastructural, and biochemical identification of apoptosis in vitrified-warmed mouse ovarian tissue

OBJECTIVE

To evaluate the incidence of apoptosis after vitrification warming of mouse ovaries.

DESIGN

Experimental study.

SETTING

University-based research laboratory.

ANIMAL(S)

Twelve- to 14-day-old National Medical Research Institute female mice.

INTERVENTION(S)

Vitrification of mouse ovaries using ethylene glycol.

MAIN OUTCOME MEASURE(S)

Follicle viability assessment by trypan blue testing, morphologic examination by hematoxylin-eosin staining and transmission electron microscopy, apoptosis assessment using the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling method and DNA laddering technique.

RESULT(S)

No statistically significant difference in follicle viability was observed between vitrified and nonvitrified ovaries. On transmission electron microscopy, vitrified ovaries showed a well-preserved ultrastructure. No sign of apoptosis was observed morphologically or by transferase-mediated deoxyuridine triphosphate nick end-labeling technique in either fresh or vitrified-warmed mouse ovaries. Despite the presence of a laddering pattern of DNA in control induced thymic tissue, no similar pattern was observed in fresh or vitrified-warmed ovaries.

CONCLUSION(S)

The data suggest that the vitrification technique does not induce apoptosis in mouse ovarian tissue investigated just after warming.

Cryopreservation and xenotransplantation of human ovarian tissue: an ultrastructural study

OBJECTIVE

To analyze the ultrastructure of human ovarian follicles after cryopreservation and short-term xenografting.

DESIGN

Prospective experimental study.

SETTING

Academic gynecology and anatomy research units.

PATIENT(S)

Ovarian cortical biopsy specimens were obtained from 13 patients.

INTERVENTION(S)

Each ovarian biopsy specimen was dissected into pieces of 1 mm(3) and divided into three groups: [1] fresh tissue, [2] frozen-thawed tissue, and [3] frozen-thawed tissue xenografted onto the peritoneum of nude mice for 3 weeks.

MAIN OUTCOME MEASURE(S)

Follicular ultrastructure was assessed by light and transmission electron microscopy in [1] fresh, [2] frozen, and [3] frozen-grafted tissue.

RESULT(S)

Thirty-five ovarian follicles were analyzed by light and transmission electron microscopy. Twenty-five primordial and primary ovarian follicles were found. Most of them exhibited ultrastructurally well preserved features (fresh [N = 8/10], frozen [N = 7/10], and frozen-grafted [N = 4/5] tissue). Ten secondary follicles were present in xenografts. By transmission electron microscopy, all the healthy-looking secondary follicles (70%) were shown to contain intact oocytes, with features typical of earlier developmental stages, surrounded by several layers of follicular cells.

CONCLUSION(S)

The present study demonstrates, for the first time, that cryopreservation and xenotransplantation do not appear to greatly affect human primordial/primary follicle ultrastructure. Interestingly, in frozen-thawed xenografts, secondary human ovarian follicles presented a well preserved ultrastructure, but asynchrony between oocyte and granulosa cell development was detected. The possible causes for this asynchrony are discussed.