Apoptosis and the ovary: a fashionable trend or food for thought?

Changes in the localization of ovarian visfatin protein and its possible role during estrous cycle of mice

Visfatin is a crucial adipokine, which also regulates ovarian functions in many animals. Mice estrous cycle is characterized by a dynamic complex physiological process in the reproductive system. Expression of various factors changes during the estrous cycle in the ovary. To the best of our knowledge, no previous study has been conducted on the expression of visfatin in mice ovaries during the estrous cycle. Therefore, we investigated the localization and expression of visfatin protein in the ovary of mice during the estrous cycle. Western blot analysis showed the elevated expression of visfatin in proestrus and lowest in diestrus. Immunohistochemical localization of visfatin showed intense staining in the corpus luteum of proestrus and diestrus ovaries. Thecal cells, granulosa cells, and oocytes also showed the presence of visfatin. Expression of ovarian visfatin was correlated to BCL2 and active caspase3 expression and exhibited a significant positive correlation. Furthermore, in vivo inhibition of visfatin by FK866 in the proestrus ovary down-regulated active caspase3 and PCNA expression, and up-regulated the BCL2 expression. These results suggest the role of visfatin in the proliferation and apoptosis of the follicles and specific localization of visfatin in the corpus luteum also indicate its role in corpus luteum function, which may be in progesterone biosynthesis and regression of old corpus luteum. However, further study is required to support these findings. In conclusion, visfatin may also be regulating follicular growth during the estrous cycle by regulating proliferation and apoptosis.

Impact of obesity on 7,12-dimethylbenz[a]anthracene-induced altered ovarian connexin gap junction proteins in female mice

The ovarian gap junction proteins alpha 4 (GJA4 or connexin 37; CX37), alpha 1 (GJA1 or connexin 43; CX43) and gamma 1 (GJC1 or connexin 45; CX45) are involved in cell communication and folliculogenesis. 7,12-dimethylbenz[a]anthracene (DMBA) alters Cx37 and Cx43 expression in cultured neonatal rat ovaries. Additionally, obesity has an additive effect on DMBA-induced ovarian cell death and follicle depletion, thus, we investigated in vivo impacts of obesity and DMBA on CX protein levels. Ovaries were collected from lean and obese mice aged 6, 12, 18, or 24 wks. A subset of 18 wk old mice (lean and obese) were dosed with sesame oil or DMBA (1mg/kg; ip) for 14days and ovaries collected 3days thereafter. Cx43 and Cx45 mRNA and protein levels decreased (P<0.05) after 18 wks while Cx37 mRNA and protein levels decreased (P<0.05) after 24 wks in obese ovaries. Cx37 mRNA and antral follicle protein staining intensity were reduced (P<0.05) by obesity while total CX37 protein was reduced (P<0.05) in DMBA exposed obese ovaries. Cx43 mRNA and total protein levels were decreased (P<0.05) by DMBA in both lean and obese ovaries while basal protein staining intensity was reduced (P<0.05) in obese controls. Cx45 mRNA, total protein and protein staining intensity level were decreased (P<0.05) by obesity. These data support that obesity temporally alters gap junction protein expression and that DMBA-induced ovotoxicity may involve reduced gap junction protein function.

The expression patterns of pro-apoptotic and anti-apoptotic factors in human fetal and adult ovary

The influence of pro-apoptotic Bax and anti-apoptotic Bcl-2 proteins on the cell death (caspase-3, TUNEL) of different ovarian cell lineages was immunohistochemically analyzed in six fetal and five adult human ovaries in order to disclose possible mechanisms of cell number control. Mild to moderate expression of Bcl-2 characterized ovarian surface epithelium, follicular cells and oocytes of 15 and 22 week human ovaries, while expression of Bax and caspase-3 gradually increased in all ovarian cell populations, except caspase-3 in the ovarian surface epithelium. Different levels of Bax and Bcl-2 proteins co-expression characterized fetal ovarian cells, while TUNEL and caspase-3 co-expression was found only in some of them. In adult ovaries, Bcl-2 was moderately and Bax strongly expressed in the surface ovarian epithelium and stroma. Bcl-2 and Bax expression in granulosa and theca interna cells varied depending on the stage of follicular atresia. Caspase-3 apoptotic cells characterized granulosa cells of adult atretic follicles. Our results indicate that intracellular levels of Bcl-2 and Bax protein might regulate the final destiny of developing germ cells. Caspase-3 dependent apoptosis seems to be the most important, but not the only cell death pathway in ovaries. In adult ovaries, caspase-dependent cell death characterized granulosa cells, but not the germ cells.

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.

Apoptosis and ultrastructural assessment after cryopreservation of whole human ovaries with their vascular pedicle

OBJECTIVE

To investigate possible damage caused by freeze-thawing whole human ovaries.

DESIGN

Prospective experimental study.

SETTING

Academic gynecology research unit in a university hospital.

PATIENT(S)

Ovaries were obtained from three women (aged 29-36 years).

INTERVENTION(S)

Ovaries were perfused and bathed in cryoprotective solution, and slow freezing was performed. Rapid thawing was achieved by perfusion and bathing with a decreased sucrose gradient.

MAIN OUTCOME MEASURE(S)

Apoptosis was assessed by the terminal deoxynucleotidyl transferase-mediated biotinylated deoxyuridine triphosphates nick end-labeling (TUNEL) method and by immunohistochemistry for active caspase-3 in fresh ovaries, after cryoprotectant exposure, and after thawing. Morphometric analysis of TUNEL-positive surface area was performed. Ultrastructure was assessed by transmission electron microscopy (TEM) in the thawed tissue.

RESULT(S)

No primordial or primary follicles were found to be positive for either TUNEL or active caspase-3. No statistically significant difference in mean TUNEL-positive surface area values was found between the three groups: fresh, 0.05% +/- 0.03%, with 134 high-power fields (HPFs); cryoperfused, 0.02% +/- 0.01%, with 130 HPFs; and thawed, 0.09% +/- 0.03%, with 622 HPFs. By means of TEM, follicles and vessels showed a well-preserved ultrastructure, with 96.7% (29/30) healthy-looking primordial and primary follicles, and 96.3% (180/187) healthy-looking endothelial cells.

CONCLUSION(S)

Cryopreservation of intact human ovary with its vascular pedicle, according to the freeze-thawing protocol described here, is not associated with any signs of apoptosis or ultrastructural alterations in any cell types. Whole-organ vascular transplantation may thus be a viable option in the future.

L'apoptose des cellules de la granulosa peut-elle être considérée comme un marqueur prédictif du succès de la fécondation in vitro ?

During in vitro fertilization (IVF) morphological criteria are the only means usable today to select embryos before their uterine transfer in order to obtain pregnancy with the best chances of success. Since several years many attempts have been made to find more functional means. Quantification of apoptosis of granulosa cells has been proposed for this purpose. The aim of this review is to take stock of our knowledge on apoptosis and its mechanisms in granulosa cells and to analyse how quantification of these apoptotic cells could be a reliable and predictive marker of success for an attempt of an IVF in terms of pregnancy.

Fine structural and cytochemical analysis of the processes of cell death of oocytes in atretic follicles in new born and prepubertal rats

The process of cell death of oocytes was studied in atretic ovarian follicles of rats aged from 1 to 28 days using light and electron microscope and cytochemical methods. These methods were TUNEL procedure for DNA breaks, active caspase-3 and lysosome-associated membrane protein 1 (LAMP-1) immunolocalizations. The structural features of the process of oocyte death are mainly characterized by the presence of abundant clear vacuoles and autophagosomes, as well as by the absence of large clumps of compact chromatin associated to the nuclear envelope and apoptotic bodies. These features are common to oocytes in all types of follicles studied. Cytochemical features consisting in positive reactions to TUNEL method, active caspase-3 and LAMP-1 immunolocalizations, are common to the cell death of oocytes in all types of follicles. Particular features of the process of cell death of oocytes are found in different types of follicles. Two morphological patterns of cell death occur in pre-follicular oocytes of the new born and in primordial follicles in 1 to 5 days old rats. One is distinguished by clear nucleoli and moderate compaction of chromatin in clumps frequently resembling meiotic bivalents. The second pattern is characterized by nucleolar condensation and by the absence of compact chromatin. The process of cell death of oocytes in antral follicles is characterized by ribonucleoprotein ribbon-like cytoplasmic structures, pseudo-segmentation, and loss of contact with granulosa cells.

Predictive value of cumulus cell apoptosis with regard to blastocyst development of corresponding gametes

OBJECTIVE

To test if a high degree of apoptosis in cumulus cells could indicate diminished oocyte quality and developmental competence.

DESIGN

Prospective analysis.

SETTING

Public hospital and university.

PATIENT(S)

Thirty seven women who gave written consent to participate in this study.

INTERVENTION(S)

Cumulus-oocyte complexes were denuded separately and the resulting cumulus cell suspensions were analyzed for presence of apoptosis using a terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP nick-end labeling (TUNEL) assay detection kit.

MAIN OUTCOME MEASURE(S)

Percentage of apoptotic cumulus cells and blastocyst formation rate.

RESULT(S)

Younger patients (< or = 35 years) showed significantly fewer apoptotic cumulus cells than older ones. In all patients gamete maturity was shown to be highly correlated to the rate of apoptosis in cumulus cells. At zygote and cleavage stages (days 1 to 4) no morphologic features were related to the degree of programmed cell death. However, blastocyst development was predictable taking into account the percentage of apoptosis in associated somatic cells. In addition, there was a trend toward better quality blastocysts from follicles with a lower rate of apoptotic cells. No influence on pregnancy and implantation rate was observed.

CONCLUSION(S)

Apoptotic processes within follicles seem to impair oocyte maturation. Though not manifested in the morphologic appearance, gametes and embryos derived from cumulus complexes with no or minor apoptosis have an increased chance of giving rise to optimal blastocysts.

Apoptosis in the ovary: molecular mechanisms

Cell death was first described in rabbit ovaries (Graaffian follicles), the phenomenon being called 'chromatolysis' rather than apoptosis. In humans, the ovarian endowment of primordial follicles is established during fetal life. Apoptotic cell death depletes this endowment by at least two-thirds before birth, executed with the help of several players and pathways conserved from worms to humans. To date, apoptosis has been reported to be involved in oogenesis, folliculogenesis, oocyte loss/selection and atresia. Several pro-survival and pro-apoptotic molecules are involved in ovarian apoptosis with the delicate balance between them being the determinant for the final destiny of the follicular cells. This review critically analyses the current knowledge about the biological roles of these molecules and their relevance to the dynamics of follicle development. It also presents the existing literature and assesses the gaps in our knowledge.

Cryopreservation of pig granulosa cells: effect of FSH addition to freezing medium

We cryopreserved swine granulosa cells by a slow cooling rate system; FSH was added to the freezing medium to test its effectiveness in protecting the cells. After thawing, proliferative activity, viability, steroidogenesis and apoptosis were tested; moreover, we determined heat shock protein (HSP70) production, to investigate the recovery from stress and superoxide dismutase (SOD) and catalase activity to evaluate a possible impairment of the antioxidant pathway. E2 production was enhanced by cryopreservation in particular with FSH; on the contrary, P4 production was inhibited by the freezing process in particular without FSH. Only the higher FSH concentration (10 ng/ml) stimulated steroid secretion in freshly collected cells; P4 production by cells cryopreserved in the presence and in absence of FSH was increased by both 5 and 10 ng/ml while the lowest concentration was effective in stimulating E2 production only when FSH was added to freezing medium. Freezing did not modify proliferative activity, while apoptosis was higher in frozen than in fresh cells. HSP70 production was lower in cells cryopreserved in presence of FSH, whose antioxidant metabolism was also conserved: SOD and catalase activities were similar to control. In conclusion, cryopreservation does not seem to markedly affect granulosa cells, in particular if they are frozen in presence of FSH; the gonadotrophin somehow improves their performances after thawing, probably stimulating E2 production and the antioxidant metabolism.

Gap junctional communication and connexin43 expression in relation to apoptotic cell death and survival of granulosa cells

Ovarian follicular atresia in all vertebrates is mediated via apoptosis that is initiated in the granulosa cell layer. Here we investigated the relation between connexin expression, cell coupling, and apoptosis in avian granulosa cells. Results from qualitative and quantitative immunocytochemical analysis and Western blotting of connexin43 (Cx43) and electron microscopic observations of gap junctions were compared with functional data on gap junctional coupling obtained by fluorescence recovery after photobleaching in four experimental groups: a control group of freshly isolated granulosa cells, 24-hr serum-free cultures as the apoptosis-inducing condition, and two other groups in which apoptosis was inhibited by either hormone substitution or exposure to elevated extracellular calcium. Our work shows that apoptosis induction in granulosa cells is accompanied by an increased level of cell coupling and that decreasing cell coupling with the gap junction blocker alpha-glycyrrhetinic acid dose-dependently inhibits apoptosis. The level of Cx43 expression was inversely related to the apoptotic index, suggesting that Cx43 expression plays a role in granulosa cell survival. Our study supports the hypothesis that gap junctional coupling plays a role in propagating a cell death message and suggests a role for Cx43 expression per se in granulosa cell survival.

Expression of bcl(xs) and c-myc in atretic follicles of mouse ovary

At birth, in the human female, one million follicles are present, out of which only 450 ovulate during the reproductive lifespan while the remainder of the 99.9% follicles degenerate. It is therefore important to understand the regulation of follicular atresia. Immature mice injected with pregnant mare serum gonadotrophin (PMSG) were used as a model for follicular atresia. In this model, we demonstrated by various methods, including the TdT-mediated dUTP nick end labelling (TUNEL) technique, that granulosa cells in atretic follicles undergo apoptosis. In eukaryotic cells, apoptosis is regulated by genes such as bcl(2) and c-myc. Regulation of apoptosis in the ovary by these proteins/genes was studied using the mouse model. bcl(2) is anti-apoptotic; however, bcl(xs), a member of the bcl(2) family, is apoptotic. Immunohistochemical localization of bcl(xs) in the granulosa cells of atretic follicles suggested its role in follicular atresia. Expression of c-myc was studied by in-situ hybridization in the mouse follicular atresia model. In the atretic follicles, expression of c-myc in granulosa cells was observed. Thus our studies indicate that bcl(xs) regulates granulosa cell apoptosis, while c-myc may also play a role in cell death during follicular atresia.

Cumulus cells apoptosis as an indicator to predict the quality of oocytes and the outcome of IVF-ET

PURPOSE

Our purpose was to establish an evaluation system for oocyte quality based on the incidence of cumulus cells apoptosis and to examine the effect of coculture, using autologous cumulus cells, on the outcome of IVF-ET according to proliferative activities of helper cells and the incidence of cumulus cells apoptosis.

METHODS

Cumulus cell masses were collected from 91 mature oocytes among 330 oocytes retrieved from a total of 34 IVF-ET cycles with tubal infertility and unexplained infertility. The incidence of apoptosis in cumulus cells was assessed by apoptosis detection kit fluorescein. On ovum pick up, 2nd day embryos were cocultured with autologous cumulus cells. Prior to coculture, in vitro proliferative activity of cumulus cells was evaluated.

RESULTS

Cumulus cells from patient groups over 40 years old had a significantly increased apoptosis incidence, a lower fertilization rate, and the decreased number of oocytes retrieved compared to the other age groups (P < .05). The incidence of cumulus cells apoptosis was significantly lower when the number of oocytes retrieved was 5 or less (P < .05). Cumulus cells from fertilized oocytes (0.43 +/- 0.07%) and those from patients who became pregnant (0.44 +/- 0.11%) following IVF-ET showed a significantly lower incidence of apoptosis compared to those of unfertilized oocytes (1.80 +/- 0.35%; P < .001) and the nonpregnant group (0.81 +/- 0.10%; P < .05). Embryo quality also had a negative correlation with the incidence of cumulus cells apoptosis. Coculture of fertilized oocytes with cumulus cells with high proliferative activity resulted in improved rates of implantation and pregnancy compared to that with poor active cumulus cells. No significant difference was found between the in vitro proliferative activity of cumulus cells and the incidence of cumulus cells apoptosis (P < .063).

CONCLUSIONS

The age of women might influence the incidence of apoptosis in cumulus cells, and the increased incidence of apoptosis is associated with the number of oocytes retrieved, the fertilization rate, and the pregnancy outcome following IVF-ET. These results suggest that the incidence of cumulus cells apoptosis can be used in predicting oocyte quality, outcome of IVF-ET, and age-related decline in fertility.

First and second messenger role of calcium. Survival versus apoptosis in serum-free cultured granulosa explants

In order to elucidate the causal relationship between increased intracellular free calcium ([Ca2+]i) and induction of apoptosis, serum-free cultured granulosa cell (GC) explants were subjected to various experimental protocols interfering with normal Ca2+ homeostasis. Modulation of apoptotic indices was calculated on DAPI-stained GC explants. In some experiments [Ca2+]i was measured with the Ca2+ probe fura-2 in combination with epifluorescence microscopy. Buffering of [Ca2+]i with BAPTA-AM resulted in inhibition of apoptosis, while increasing extracellular Ca2+ (otherwise called [Ca2+]e load) resulted in a biphasic response characterized by an initial inhibitory effect on apoptosis followed by a delayed phase of increased apoptosis that became apparent at 4 h after withdrawal of the [Ca2+]e load. The initial inhibitory effect of the [Ca2+]e load on apoptosis was dependent on the concentration of the load (range 2-50 mM), was augmented when the [Ca2+]e load was applied in the presence of the Ca2+ channel blocker methoxyverapamil, and was mimicked by applying Mg2+ and Gd3+, two Ca(2+)-receptor agonists. These observations point towards the involvement of an extracellular Ca(2+)-sensing receptor (CaR). Measurements of [Ca2+]i showed that the ion was increased just after [Ca2+]e load, followed by recovery that was complete at 2 h after the load. Collectively these data suggest that a [Ca2+]e load initiates apoptosis, becoming manifest 4 h later, by the provoked [Ca2+]i increase, and this effect is preceded by an apoptosis-inhibiting phase presumably involving CaR activation. We conclude that Ca2+ may act as a first (extracellular) messenger promoting cell survival and as a second (intracellular) messenger activating the cell death pathway.

Oocyte attrition

During oogenesis, germ cell numbers sharply decrease when meiosis is initiated. There is solid evidence (DNA ladders, in situ detection) that this loss is through apoptosis. Oocyte apoptosis appears to hit mitotic primordial germ cells (PGC), pachytene oocytes and early primordial follicles. The control of oocyte apoptosis is not fully understood, although survival factors (LIF, kit ligand and FGF), as well as death inducing factors (fas ligand, TGFbeta), have been identified. Fas ligand binding on oocytic fas may result in caspase 8 activation. Two pathways inducing oocyte apoptosis may then be operating. In the first one, activated caspase 8 will induce activation of executioner caspases. In the second one, activated caspase 8 will trigger the cleavage of the bcl(2) family member Bid, which will act on mitochondria, resulting in cytochrome c release, caspase 9 activation and finally, activation of all executioner caspases. As a consequence of caspase activation, alterations in the cell nucleus (DNAse activation, PARP fragmentation), in the cell cytoskeleton (lamin) and cell metabolism will occur, producing cell death. During folliculogenesis, germ cell loss, owing to oocyte apoptosis, has been postulated within primordial and preantral follicles. Its regulatory mechanisms may be even more complex than those operating in foetal oocytes since additional control factors include EGF/TGFalpha and bcl(2) (survival) and activin (death inducer). In contrast, oocytes from antral follicles appear to be very unsensitive to death inducing stimuli.

Mechanisms controlling the function and life span of the corpus luteum

The primary function of the corpus luteum is secretion of the hormone progesterone, which is required for maintenance of normal pregnancy in mammals. The corpus luteum develops from residual follicular granulosal and thecal cells after ovulation. Luteinizing hormone (LH) from the anterior pituitary is important for normal development and function of the corpus luteum in most mammals, although growth hormone, prolactin, and estradiol also play a role in several species. The mature corpus luteum is composed of at least two steroidogenic cell types based on morphological and biochemical criteria and on the follicular source of origin. Small luteal cells appear to be of thecal cell origin and respond to LH with increased secretion of progesterone. LH directly stimulates the secretion of progesterone from small luteal cells via activation of the protein kinase A second messenger pathway. Large luteal cells are of granulosal cell origin and contain receptors for PGF(2alpha) and appear to mediate the luteolytic actions of this hormone. If pregnancy does not occur, the corpus luteum must regress to allow follicular growth and ovulation and the reproductive cycle begins again. Luteal regression is initiated by PGF(2alpha) of uterine origin in most subprimate species. The role played by PGF(2alpha) in primates remains controversial. In primates, if PGF(2alpha) plays a role in luteolysis, it appears to be of ovarian origin. The antisteroidogenic effects of PGF(2alpha) appear to be mediated by the protein kinase C second messenger pathway, whereas loss of luteal cells appears to follow an influx of calcium, activation of endonucleases, and an apoptotic form of cell death. If the female becomes pregnant, continued secretion of progesterone from the corpus luteum is required to provide an appropriate uterine environment for maintenance of pregnancy. The mechanisms whereby the pregnant uterus signals the corpus luteum that a conceptus is present varies from secretion of a chorionic gonadotropin (primates and equids), to secretion of an antiluteolytic factor (domestic ruminants), and to a neuroendocrine reflex arc that modifies the secretory patterns of hormones from the anterior pituitary (most rodents).

Superoxide dismutase activity in human follicular fluid after controlled ovarian hyperstimulation in women undergoing in vitro fertilization

OBJECTIVE

To determine the activity of superoxide dismutase (SOD) and the total protein concentration in human preovulatory ovarian follicular fluid (FF) in relation to corresponding serum levels and the fertilization capacity of oocytes.

DESIGN

Prospective, observational study.

SETTING

Academic-based center for reproductive medicine.

PATIENT(S)

Twenty-eight female partners of infertile couples, 13 of whom were smokers, undergoing controlled ovarian hyperstimulation for IVF.

INTERVENTION(S)

Blood and follicular fluid samples were collected 34-36 hours after hCG administration.

MAIN OUTCOME MEASURE(S)

Levels of SOD activity and total protein concentrations.

RESULT(S)

Superoxide dismutase activity was present in all the FF studied and mean levels were statistically significantly higher than in serum. Total protein concentrations in serum were statistically significantly correlated with corresponding concentrations in FF. There was no difference in SOD activity between smokers and nonsmokers. Total protein concentrations in FF were marginally and statistically significantly lower in nonsmokers. Follicular fluid from patients whose oocytes did not become fertilized had a statistically significantly higher level of SOD activity than that from patients whose oocytes did become fertilized.

CONCLUSION(S)

Superoxide dismutase activity is present in FF and is higher than in serum. The degree of SOD activity is variable and seems to be inversely related to the fertilization of oocytes.

Evidence for alternative pathways of granulosa cell death in healthy and slightly atretic bovine antral follicles

Granulosa cell death is an early feature of atresia; however, there are many apparent contradictions in the literature concerning the mode of granulosa cell death. We have therefore examined this process in bovine healthy and atretic antral follicles, using a variety of established techniques. Light and electron microscopic observations indicated the presence of pyknotic or shrunken nuclei in both the membrana granulosa and the antrum. In the membrana granulosa, these nuclei were frequently crescent shaped and uniformly electron dense and were approximately the same size as healthy nuclei, all of which are typical of early apoptosis. However, these nuclei were within the membranes of a healthy granulosa cell, suggesting that phagocytosis by a neighboring granulosa cell is an unusually early event in the apoptotic pathway of granulosa cells. In the membrana granulosa, pyknotic nuclei stained intensely with hematoxylin but weakly with the DNA-intercalating stain propidium iodide. A percentage of these pyknotic nuclei stained by TUNEL (terminal deoxy-UTP nick end-labeling). However, in the antrum, the pyknotic nuclei and larger globules of DNA stained intensely with both hematoxylin and propidium iodide, but were not TUNEL positive. The comet assay of cell death produced a streak tail of randomly nicked DNA, rather than the plume of low mol wt apoptotic DNA. Globules collected from fresh follicular fluid stained intensely with propidium iodide and were shown by PAGE to contain DNA, the majority of which was high mol wt. In conclusion, granulosa cells within the membrana granulosa die by apoptosis, with phagocytosis by a neighboring cell preceding any potential budding of the nucleus or cell itself. Granulosa cells near the antrum are sloughed off into the antrum, and their death has features more consistent with that of other cell types that undergo death as a result of terminal differentiation.

The incidence of apoptotic bodies in membrana granulosa can predict prognosis of ova from patients participating in in vitro fertilization programs

OBJECTIVE

To investigate the relationship between the incidence of apoptotic bodies in membrana granulosa and follicular steroid concentrations in human follicles.

DESIGN

Case-controlled prospective study for 132 individual follicles.

SETTING

Procedures were performed in Yamagata University Hospital.

PATIENT(S)

Thirty-six normo-ovulatory women with tubal infertility underwent ovulation induction for IVF-ET with a conventional hyperstimulation method.

INTERVENTION(S)

Patients underwent follicle aspiration after the administration of hCG.

MAIN OUTCOME MEASURE(S)

The nuclei of recovered granulosa cells were examined by fluorescence microscopy, and the incidence of apoptotic bodies was tabulated. Intrafollicular steroids were evaluated mainly by RIA. These data were analyzed with respect to oocyte-retrieval, oocyte maturity, fertilization, and embryo quality.

RESULT(S)

Membrana granulosa cells in the follicles from which oocytes were subsequently fertilized showed a significantly lower incidence of apoptotic bodies than those in follicles from which the oocytes did not fertilize. Membrana granulosa cells in the follicles from which oocytes were developed into good quality showed a significantly lower incidence of apoptotic bodies than those in the follicles from which oocytes developed into fair and poor quality. The incidence of apoptotic bodies was significantly higher in the mural granulosa cell region than in the cumulus cell region in most cases. Intrafollicular E2, P, and free T levels were not different between the oocyte groups.

CONCLUSION(S)

These results indicate that lower incidence of apoptotic bodies in individual follicles is associated with better outcomes for oocytes. Also, mural granulosa cells and cumulus cell in each follicle may show differentiation during follicular maturation.