The Graafian follicle is a site of L-ascorbate accumulation

Interplay of Oxidants and Antioxidants in Mammalian Embryo Culture System

One principal purpose of assisted reproductive technology (ART) is to produce viable and good quality embryos. However, a variety of environmental factors may induce epigenetic changes in the embryo. Moreover, laboratory conditions including the culture media may also affect embryo development. Therefore, media change is an important factor in maintaining proper oxidant/antioxidant balance during embryo culture. Alterations in the oxidant/antioxidant balance are related to various cellular responses such as an increase in the level of reactive oxygen species (ROS) and consequent lipid peroxidation (LPO), DNA damage, and apoptosis. The current study focuses on the role of external factors on embryo culture and the ability of antioxidants to enhance in vitro fertilization (IVF) outcomes. Indeed, an optimization of media culture by the addition of enzymatic and nonenzymatic antioxidants in animal models and human embryos in ART has been updated in this study, with an emphasis on comparing the available results and their possible reasons.

Ameliorating Effects of Natural Antioxidant Compounds on Female Infertility: a Review

The prevalence of female infertility cases has been increasing at a frightening rate, affecting approximately 48 million women across the world. However, oxidative stress has been recognized as one of the main mediators of female infertility by causing various reproductive pathologies in females such as endometriosis, PCOS, preeclampsia, spontaneous abortion, and unexplained infertility. Nowadays, concerned women prefer dietary supplements with antioxidant properties over synthetic drugs as a natural way to lessen the oxidative stress and enhance their fertility. Therefore, the current review is an attempt to explore the efficacy of various natural antioxidant compounds including vitamins, carotenoids, and plant polyphenols and also of some medicinal plants in improving the fertility status of females. Our summarization of recent findings in the current article would pave the way toward the development of new possible antioxidant therapy to treat infertility in females. Natural antioxidant compounds found in fruits, vegetables, and other dietary sources, alone or in combination with other antioxidants, were found to be effective in ameliorating the oxidative stress-mediated infertility problems in both natural and assisted reproductive settings. Numerous medicinal plants showed promising results in averting the various reproductive disorders associated with female infertility, suggesting a plant-based herbal medicine to treat infertility. Although optimum levels of natural antioxidants have shown favorable results, however, their excessive intake may have adverse health impacts. Therefore, larger well-designed, dose-response studies in humans are further warranted to incorporate natural antioxidant compounds into the clinical management of female infertility.

The effect of adding Rosmarinic and Ascorbic acids to vitrification media on fertilization rate of the mice oocyte: An experimental study

Background

Oocytes vitrification is a pivotal step for the widespread and safekeeping of animal genetic resources. Oocytes endure notable morphological and functional damage during cryopreservation. Oxidative stress is one of the adverse effects that vitrification imparts on oocytes.

Objective

In the present study, we investigated the antioxidant effect of Rosmarinic and Ascorbic acids on the quality and fertilizing ability of frozen-thawed mice oocyte.

Materials and Methods

In this experimental study, germinal vesicle oocytes obtained from two-months-old (30–40gr) NMRI mice were randomly divided into four groups. The basic cryoprotectants were 7.5% (v/v) ethylene glycol+7.5% (v/v) Propanediol as an equilibration media. Vitrification medium contained 15% (v/v) ethylene glycol+15% (v/v) propanediol, and 0.5 M sucrose. In the first group (Control), nothing was added to vitrification mediums, whereas, in the second and third groups, 0.5 mmol/L of Ascorbic acid and 105 µmol/L of Rosmarinic acid were added into vitrification medium, respectively. The cumulative concentration of Rosmarinic and Ascorbic acids were added to group 4. Mouse oocytes were vitrified and preserved for one month. The thawed oocytes were transferred into the α-MEM medium (Alpha Minimum Essential Medium) and maintained in this medium for 24 hr, to be matured and reach the metaphase II stage.

Results

The addition of Rosmarinic and Ascorbic acids to the vitrification solution improved the survival, maturation of Germinal vesicles, fertilization rate, and finally development to 4-cell stage. Maturation rates to 4-cell stage for Ascorbic acid, Rosmarinic acid, and both of them together were 80%, 80.76%, and 86.61%, respectively.

Conclusion

These results indicate that the addition of a cumulative concentration of 0.5 mmol/L Ascorbic acid and 105 µmol/L of Rosmarinic acid to the cryopreservation solution for the mouse immature oocytes would be of significant value (p< 0.01).

Modulatory Effects of Single and Complex Vitamins on the In Vitro Growth of Murine Ovarian Follicles

BACKGROUND

Vitamin is a well-known co-factor for many metabolic processes and its roles in fertility and follicular growth have been studied. Vitamin supplementation is frequently achieved by daily ingestion in the form of a complex capsule. However, the role of single and complex vitamins in in vitro maturation of murine follicles is not fully elucidated.

METHODS

In this study, we evaluated the effects of two forms of vitamins. Pure L-ascorbic acid, and multi-vitamin (vitamin C + vitamin B complex) was treated at two different concentrations (50 and 100 µg/ml), to pre-puberty murine follicles during in vitro maturation. To determine the specific stage of growth that is affected by treatment with vitamins, the vitamins were treated from day 0, 4, 9, and 13. Growth of each follicle was assessed by measuring diameters of whole expanded area and of the granulosa cells. Expression of follicular and oocyte growth-related genes and the effect of vitamin on the viability of follicles was assessed using senescence associated β-galactosidase staining.

RESULTS

Treatment with vitamins promoted the in vitro growth of murine follicles and the upregulated the expression of granulosa cell- and oocyte-specific genes such as BMP15, Fsh receptor, and GDF9. The proliferation of the granulosa cells was enhanced by the treatment of vitamin. Fifty µg/ml concentration vitamin showed greater effects compared to higher concentration. The viability of in vitro grown follicles was also significantly improved in vitamin-treated follicles. The effects of single L-ascorbic acid and complex vitamin were not significantly different to those of day 4 and day 9 follicles. Vitamins promoted murine follicle development in vitro with different effects on specific growth stage.

CONCLUSION

Supplementation of vitamins during in vitro maturation of murine follicles is an efficient strategy for in vitro expansion of follicular cells. These results could be customized to the sophisticated culture of follicles retrieved from aged or cancer-survived female that contain smaller number of follicles with reduced potential to develop into mature follicles.

Influence of ovarian stimulation for IVF/ICSI on the antioxidant defence system and relationship to outcome

Ovarian stimulation is used with IVF/intracytoplasmic sperm injection (ICSI) cycles to obtain multiple oocytes and improve pregnancy rates; however, it also induces perturbation in the oxidant-antioxidant balance leading to oxidation stress. The present study monitored the plasma antioxidant status in women undergoing a long agonist protocol of ovarian stimulation at three different time points: at baseline (T0), after pituitary suppression (T1) and on the day of oocyte retrieval (T2). The antioxidant composition of follicular fluid samples collected on T2 was also evaluated. Significant decreases (P < 0.05) of plasma vitamin C, vitamin E and carotenoids were found between T1 and T2 but not between T0 and T1. At T2, high plasma vitamin E was associated with high numbers of total and mature oocytes retrieved per patient, which, in turn, were favourable for achieving pregnancy. Accordingly, women who became pregnant presented higher vitamin E concentrations both in plasma and FF than those who did not. In conclusion, this study confirmed the occurrence of significant modifications of the plasma antioxidant profile during ovarian stimulation with gonadotrophins; at the same time, it was found that both systemic and follicular antioxidant status may be related to IVF/ICSI outcome.

Elevated blood plasma antioxidant status is favourable for achieving IVF/ICSI pregnancy

The aim of the study was to determine the roles of intrafollicular and systemic oxidative stress and antioxidant response in ovarian stimulation and intracytoplasmic sperm injection (ICSI) outcomes. For this purpose, 102 ICSI patients undergoing controlled ovarian stimulation were enrolled and samples were collected on the day of follicle puncture. Total peroxide (TPX) concentrations and total antioxidant response (TAR) were measured in follicular fluid and blood plasma, and an oxidative stress index (OSI) was calculated based on these two parameters. Urinary concentrations of 8-iso-prostaglandin F2a (F2IsoP) were measured. Elevated intrafollicular oxidative stress was positively correlated with ovarian stimulation outcome: less FSH per retrieved oocyte was used, more oocytes were collected and higher serum oestradiol concentrations were measured in patients with higher follicular OSI. However, high urinary F2IsoP related to lower embryo quality and F2IsoP was also elevated in smoking patients. Patients with endometriosis had lower follicular antioxidant status. Most importantly, higher systemic blood TAR was significantly favourable for achieving clinical pregnancy (P=0.03). In conclusion, the findings suggest clear associations between oxidative stress, antioxidant status and several aspects of ovarian stimulation and IVF/ICSI outcome, including pregnancy rate. Several oxygen-dependent biochemical reactions produce reactive oxygen species as by-products that may eventually lead to oxidative stress, which is detrimental to cells and tissues. Total antioxidant status, on the other hand, comprises several agents that balance the excess of these reactive oxygen species and reduce potential damage to the body. The aim of the current work was to study this balance in 102 patients participating in an ICSI programme and to examine the degree to which total peroxide content and antioxidant status influence infertility and pregnancy outcome. During the study, several tests were performed to characterize oxidative stress levels in ovarian follicular fluid, blood plasma and urine. We found a significantly higher oxidative stress environment in the ovary when compared with blood plasma. This suggests a prominent role of oxidative stress in the ovaries of these patients. The elevated oxidative stress levels were correlated to a higher number of oocytes that could be obtained via the procedure and to a lower amount of FSH needed to mature the oocytes, suggesting that oxidative stress, to some degree, is favourable for hormone stimulation outcome. A high level of lipid peroxidation products in the urine, another marker of oxidative stress, was observed in smokers and this marker was elevated in patients with embryos that had lower developmental potential. A higher overall antioxidant status in blood plasma was advantageous for achieving pregnancy.

Attenuation of Cyclosporine-Induced Sperm Impairment and Embryotoxicity by Crataegus monogyna Fruit Aqueous Extract

OBJECTIVE

Cyclosporine (Cs), a cyclic undecapeptide with potent immuno suppressive activity, causes several adverse effects including reproductive toxicity. This study aims to examine the ability of Crataegus monogyna aqueous fruit extract as an antioxidant to protect against Cs-induced reproductive toxicity.

MATERIALS AND METHODS

In this experimental study, 32 adult male Wistar rats were divided into four groups of eight animals each. Rats in two groups received 40 mg/kg/day Cs for 45 days by oral gavage. In addition, one of the two groups received Crataegus monogyna aqueous extract at a dose of 20 mg/kg/day orally four hours after Cs administration. The remaining two groups consisted of a vehicle treated control (Cont) group and a Crataegus monogyna control (Cr) group. Differences between groups were assessed by analysis of variance (ANOVA) using the SPSS software package for Windows.

RESULTS

Cs treatment caused a signiifcant decrease in sperm count and viability with an increase in DNA damage and protamine deifciency of the sperm cells. We observed signiifcant decreases in fertilization rate and embryonic development, in addition to an increased rate of embryo arrest in Cs-treated rats. Crataegus monogyna co-administration attenuated all Cs-induced negative changes in the above-mentioned parameters.

CONCLUSION

Supplementation with Crataegus monogyna a queous fruit extract could be useful against reproductive toxicity during Cs treatment in a rat model.

Biology and biotechnology of follicle development

Growth and development of ovarian follicles require a series of coordinated events that induce morphological and functional changes within the follicle, leading to cell differentiation and oocyte development. The preantral early antral follicle transition is the stage of follicular development during which gonadotropin dependence is obtained and the progression into growing or atresia of the follicle is made. Follicular growth during this period is tightly regulated by oocyte-granulosatheca cell interactions. A cluster of early expressed genes is required for normal folliculogenesis. Granulosa cell factors stimulate the recruitment of theca cells from cortical stromal cells. Thecal factors promote granulosa cell proliferation and suppress granulosa cell apoptosis. Cell-cell and cell-extracellular matrix interactions influence the production of growth factors in the different follicular compartments (oocyte, granulosa, and theca cells). Several autocrine and paracrine factors are involved in follicular growth and differentiation; their activity is present even at the time of ovulation, decreasing the gap junction communication, and stimulating the theca cell proliferation. In addition, the identification of the factors that promote follicular growth from the preantral stage to the small antral stage may provide important information for the identification for assisted reproduction techniques.

Media composition: antioxidants/chelators and cellular function

Protection of embryos against oxidative insults during culture is necessary to maintain viability. Generation of excessive levels of reactive oxygen species (ROS) is triggered by various components of the in vitro environment, most of which embryos do not normally encounter in vivo. To compensate for these deficiencies in the culture environment, antioxidants and chelators are often used to control or suppress ROS levels as embryos develop. However, there is no consensus regarding dosage, time of exposure, or appropriate combinations of antioxidants and chelators in embryo culture. In order to elucidate this aspect of an embryo's chemical surroundings in vitro, we present the current knowledge on the function and effect of each antioxidant or chelator that is often included in an embryo culture medium.

Age related changes in mitochondrial function and new approaches to study redox regulation in mammalian oocytes in response to age or maturation conditions

Mammalian oocytes are long-lived cells in the human body. They initiate meiosis already in the embryonic ovary, arrest meiotically for long periods in dictyate stage, and resume meiosis only after extensive growth and a surge of luteinizing hormone which mediates signaling events that overcome meiotic arrest. Few mitochondria are initially present in the primordial germ cells while there are mitogenesis and structural and functional differentiation and stage-specific formation of functionally diverse domains of mitochondria during oogenesis. Mitochondria are most prominent cell organelles in oocytes and their activities appear essential for normal spindle formation and chromosome segregation, and they are one of the most important maternal contributions to early embryogenesis. Dysfunctional mitochondria are discussed as major factor in predisposition to chromosomal nondisjunction during first and second meiotic division and mitotic errors in embryos, and in reduced quality and developmental potential of aged oocytes and embryos. Several lines of evidence suggest that damage by oxidative stress/reactive oxygen species in dependence of age, altered antioxidative defence and/or altered environment and bi-directional signaling between oocyte and the somatic cells in the follicle contribute to reduced quality of oocytes and blocked or aberrant development of embryos after fertilization. The review provides an overview of mitogenesis during oogenesis and some recent data on oxidative defence systems in mammalian oocytes, and on age-related changes as well as novel approaches to study redox regulation in mitochondria and ooplasm. The latter may provide new insights into age-, environment- and cryopreservation-induced stress and mitochondrial dysfunction in oocytes and embryos.

Review: role of tubal environment in preimplantation embryogenesis: application to co-culture assays

The culture of early preimplantation stage embryo is still delicate and the metabolic pathways of embryos are not completely understood. Embryo needs are evolutionary during the preimplantation development, consequently it is difficult to meet embryo needs in vitro. Culture conditions have to respect several physical and chemical equilibria: such as redox potential, pH, osmotic pressure, metabolic flux of energetic compounds, endogenous pools of amino acids and transcripts, etc. Embryo culture media are generally supplemented with amino acids, glucose, other energetic metabolites and antioxidant compounds, vitamin, and growth factors etc. Furthermore autocrine and paracrine regulation of embryo development probably exist. In fact embryo culture conditions have to be as non-toxic as possible. Various types of co-culture systems have been devised to overcome these problems. Complex interrelations exist between embryos and co-cultured cells. The beneficial effects of co-cultured cells may be due to continuous modifications of the culture medium, i.e. the elimination of toxic compounds and/or the supply of embryotrophic factors.

Could oxidative stress influence the in-vitro maturation of oocytes?

In the efforts aimed at improving the quality of in-vitro-matured human oocytes, the dynamic balance and roles of pro-/antioxidants merit further consideration. In-vitro maturation (IVM) is emerging as a popular technology at the forefront of fertility treatment and preservation. However, standard in-vitro culture conditions exert oxidative stress or an imbalance between oxidants and antioxidants. Reactive oxygen species (ROS) are oxygen-derived molecules formed as intermediary products of cellular metabolism. By acting as powerful oxidants, ROS can oxidatively modify any molecule, resulting in structural and functional alterations. ROS are neutralized by an elaborate defence system consisting of enzymatic and nonenzymatic antioxidants. This review captures the inherent and external factors that may modulate the oxidative stress status of oocytes. It discusses the suspected impacts of oxidative stress on the gamut of events associated with IVM, including prematuration arrest, meiotic progression, chromosomal segregation, cytoskeletal architecture and gene expression. In-vivo and in-vitro strategies that may overcome the potential influences of oxidative stress on oocyte IVM are presented. Future studies profiling the oxidative stress status of the oocyte may permit not only the formulation of a superior IVM medium that maintains an adequate pro-/antioxidant balance, but also the identification of predictors of oocyte quality.

Reactive oxygen species and oocyte aging: role of superoxide, hydrogen peroxide, and hypochlorous acid

Aging of the unfertilized oocyte inevitably occurs following ovulation, limiting its fertilizable life span. However, the mechanisms that regulate oocyte aging are still unclear. We hypothesize that reactive oxygen species such as superoxide (O2-), hydrogen peroxide (H2O2), and hypochlorous acid (HOCl) are likely candidates that may initiate these changes in the oocyte. In order to test this hypothesis, we investigated direct effects of O2- [hypoxanthine/xanthine oxidase system generating 0.12 (n=42) and 0.25 (n=45) microM O2-/min], H2O2 (20 or 100 microM, n=60), and HOCl, (1, 10, and 100 microM, n=50) on freshly ovulated or relatively old mouse oocytes, while their sibling oocytes were fixed immediately or cultured under physiological conditions (n=96). The aging process was assessed by the zona pellucida dissolution time (ZPDT), ooplasm microtubule dynamics (OMD), and cortical granule (CG) status. The ZPDT increased 2-fold in relatively old, compared to young, untreated oocytes (P<0.0001). Exposure to O2- increased it even further (P<0.0001). Similarly, more O2- exposed oocytes exhibited increased OMD and major CG loss, with fewer having normal OMD and intact CG compared to untreated controls. Interestingly, young oocytes resisted "aging," when exposed to 20 microM H2O2, while the same enhanced the aging phenomena in relatively old oocytes (P<0.05). Exposure to even very low levels of HOCl induced the aging phenomena in young and relatively old oocytes, and higher concentrations of HOCl compromised oocyte viability. Overall, O2-, H2O2, and HOCl each augment oocyte aging, more so in relatively old oocytes, suggesting compromised antioxidant capacity in aging oocytes.

Improvement of transgenic cloning efficiencies by culturing recipient oocytes and donor cells with antioxidant vitamins in cattle

The present study was conducted to investigate effects of antioxidants during maturation culture of recipient oocytes and/or culture of gene-transfected donor cells on the meiotic competence of recipient oocytes, and the developmental competence and quality of the reconstructed embryos after nuclear transfer (NT) in cattle. Gene-transfected donor cells had negative effects on the proportions of blastocyst formation, total cell numbers, and DNA fragmentation indices of reconstructed embryos. Supplementation of either vitamin E (alpha-tocopherol: 100 microM) or vitamin C (ascorbic acid: 100 microM) during maturation culture significantly enhanced the cytoplasmic maturation of oocytes and subsequent development of embryos reconstructed with the oocytes and gene-transfected donor cells, but did not have synergistic effects. The supplementation of vitamin E during maturation culture of recipient oocytes increased the proportions of fusion and blastocyst formation of gene-transfected NT embryos, in which the proportions were similar to those of nontransfected NT embryos. When the gene-transfected donor cells that had been cultured with 0, 50, or 100 microM of vitamin E were transferred into recipient oocytes matured with vitamin E (100 microM), 50 microM of vitamin E increased the proportion of blastocyst formation and reduced the index of DNA fragmentation of blastocysts. In conclusion, gene-transfected donor cells have negatively influenced the NT outcome. Supplementation of vitamin E during both recipient oocyte maturation and donor cell culture enhanced the blastocyst formation and efficiently blocked DNA damage in transgenic NT embryos.

Comparison of reactive oxygen species concentration in seminal plasma and semen parameters in partners of pregnant and non-pregnant patients after IVF/ICSI

The aims of this study were (i) to determine and compare the concentration of reactive oxygen species (ROS) and total antioxidant status (TAS) in seminal plasma and sperm parameters of the male partners of patients undergoing IVF or intracytoplasmic sperm injection (ICSI) treatment and (ii) to establish the relationship between ROS and TAS concentrations and sperm quality and their effect on fertilization and pregnancy rate of patients who achieved a pregnancy and those who were unsuccessful. Twenty-six IVF and 22 ICSI patients were included in this study. The ROS concentration in seminal plasma and sperm concentration, vitality (eosin test), motility, morphology, membrane integrity (HOS test), maturity (chromomycin, CMA3) and DNA fragmentation (TUNEL) results and their relationship to fertilization and pregnancy were analysed. ROS concentrations were similar regarding the seminal plasma of male partners of patients who achieved a pregnancy and those who were unsuccessful. The other semen parameters, concentration, motility, vitality, membrane and DNA integrity, were comparable in both groups. However, both groups demonstrated a negative correlation between ROS concentration and sperm vitality, membrane integrity and morphology. Moreover, an inverse correlation was found between TUNEL, vitality, and membrane integrity. In conclusion, ROS concentration in seminal plasma affects the quality of spermatozoa. A negative correlation between the ROS concentration in seminal plasma and fertilization rate in both IVF/ICSI programmes was shown.

Oxidative stress and its implications in female infertility – a clinician's perspective

Reactive oxygen species (ROS) have a role in the modulation of gamete quality and gamete interaction. Generation of ROS is inherent in spermatozoa and contaminating leukocytes. ROS influence spermatozoa, oocytes, embryos and their environment. Oxidative stress (OS) mediates peroxidative damage to the sperm membrane and induces nuclear DNA damage. ROS can modulate the fertilizing capabilities of the spermatozoa. There is extensive literature on OS and its role in male infertility and sperm DNA damage and its effects on assisted reproductive techniques. Evidence is accumulating on the role of ROS in female reproduction. Many animal and human studies have elucidated a role for ROS in oocyte development, maturation, follicular atresia, corpus luteum function and luteolysis. OS-mediated precipitation of pathologies in the female reproductive tract is similar to those involved in male infertility. OS influences the oocyte and embryo quality and thus the fertilization rates. ROS appears to play a significant role in the modulation of gamete interaction and also for successful fertilization to take place. ROS in culture media may impact post-fertilization development, i.e. cleavage rate, blastocyst yield and quality (indicators of assisted reproduction outcomes). OS is reported to affect both natural and assisted fertility. Antioxidant strategies should be able to intercept both extracellular and intracellular ROS. This review discusses the sources of ROS in media used in IVF-embryo transfer and strategies to overcome OS in oocyte in-vitro maturation, in-vitro culture and sperm preparation techniques.

Role of reactive oxygen species in gynecologic diseases

Free radicals derived from molecular oxygen and nitrogen are highly reactive metabolites called reactive oxygen species (ROS). Cells continuously produce free radicals and ROS as part of the metabolic process. They are involved in the various functions of the reproductive system. Antioxidants are enzymes or compounds that scavenge and reduce the presence of free radicals. Normally, a balance exists between concentrations of reactive oxygen species and antioxidant scavenging systems. The disruption of the delicate balance between pro- and antioxidants results in oxidative stress. Oxidative stress has been implicated in embryo fragmentation, DNA damage, apoptosis and poor pregnancy outcome. It has also been implicated in a large number of gynecologic diseases, such as endometriosis, pre-eclampsia and maternal diabetes. The use of antioxidants may be beneficial in combating the harmful effects of oxidative stress in many of these diseases. The present review outlines the importance of these species in the pathology of various gynecologic diseases. (Reprod Med Biol 2004; 3: 177 - 199).

Drug intervention in early pregnancy after assisted reproductive technology

Implantation in humans is a complex, closely regulated, highly selective and relatively poorly understood process. Humans have the highest rate of miscarriage in mammals and various pharmacological manipulations have been used to minimize pregnancy losses in both spontaneous pregnancies and pregnancies resulting from assisted reproduction technology. The widespread application of protocols using numerous drugs in assisted reproduction treatment has led to an increasing number of pregnancies exposed to these drugs. The vast majority of these protocols have been based on data from a few observational and often retrospective clinical studies. This paper reviews the recent literature on drug interventions in early pregnancy after assisted reproduction treatment. It is concluded that there are still numerous issues about the safety of most drugs for both the women and their fetus. In many cases, the benefits are theoretical and the possible long-term side-effects are untested. There is an urgent need for more epidemiological studies and randomized controlled trials to explore the use, efficacy and side-effects of both old and new drugs in early pregnancy after assisted reproduction treatment.

Oxidative stress indices in follicular fluid as measured by the thermochemiluminescence assay correlate with outcome parameters in in vitro fertilization

OBJECTIVE

To evaluate oxidative stress indices in follicular fluid (FF) by a novel thermochemiluminescence (TCL) assay and investigate the correlation between TCL and i.v.f. cycle parameters.

DESIGN

Prospective, cross-sectional study.

SETTING

I.v.f. Unit of an Obstetrics and Gynecology Department in a university-affiliated hospital.

PATIENT(S)

One hundred eighty-nine women undergoing consecutive i.v.f. treatment cycles during 2001.

INTERVENTION(S)

After oocyte retrieval, pooled FF was centrifuged and the supernatant was tested in the TCL assay.

MAIN OUTCOME MEASURE(S)

Maximal serum E2 levels, number of gonadotropin ampoules, retrieved oocytes, mature oocytes, fertilization and cleavage rates, number of available embryos and cryopreserved embryos, and clinical pregnancy rates and correlation with TCL indices.

RESULT(S)

The TCL curve slope of FF positively correlated with maximal serum E2 levels, number of mature oocytes, and number of cleaved embryos and was inversely correlated with the women's ages and the number of gonadotropin ampoules. Follicular fluid TCL amplitude at 50 seconds ranged from 294 to 711 cps, but all pregnancies (n = 50; 28.1%) occurred within the range of 347-569 cps. With 385 and 569 cps as cutoff levels for the occurrence of pregnancy, the negative predictive value beyond this range was 96% and the positive predictive value within this range was 32%.

CONCLUSION(S)

The TCL results may reflect the age-related increase in free radical activity and is associated with parameters of ovarian responsiveness and IVF outcome. A certain threshold of oxidative stress may be required for the occurrence of conception in i.v.f. TCL is a potential tool to evaluate, treat, and monitor antioxidant therapy in i.v.f. treatments.

Vitamin C and vitamin E supplementation reduce oxidative stress-induced embryo toxicity and improve the blastocyst development rate

To evaluate the adverse effects of exogenously induced reactive oxygen species (ROS) on mouse embryo development by using the 12-phorbol 13-myristate acetate (PMA)-activated leukocyte model as a source of ROS, and to examine the protective effect of antioxidant supplementation (vitamin C and vitamin E). Prospective study. Research laboratory. Effects of ROS on the blastocyst development rate in the presence and absence of antioxidant supplementation. After incubation with the PMA-activated leukocyte supernatant, the median (25th, 75th percentile) rate of blastocyst development significantly decreased from 73% (60%, 80%) after 3 hours to 30% (20%, 40%) after 6 hours compared with control reactions (86% [80%, 100%]). Co-incubating the embryos with vitamin C (50 microM) and the PMA-activated supernatant significantly increased the blastocyst development rate from 73% (60%, 80%) to 90% (80%, 91%) at 3 hours and from 30% (20%, 40%) to 91% (89%, 91%) at 6 hours-a level similar to that of control reactions. The blastocyst development rate increased after vitamin E supplementation (400 microM) at 6 hours, but not significantly and not by as much as after vitamin C supplementation. Exposure of mouse embryos to ROS for extended periods results in embryotoxicity. Vitamin C is more effective than vitamin E in reversing ROS-induced mouse embryo toxicity.

Ascorbic acid supplement during luteal phase in IVF

PURPOSE

To evaluate the impact of ascorbic acid of different doses as additional support during luteal phase in infertility treatment by means of a prospective, randomized, placebo-controlled, group comparative, double-blind study.

METHODS

Voluntary daily oral intake of either ascorbic acid (1, 5, or 10 g/day) or Placebo for 14 days after follicle aspiration for IVF-ET procedure. Data was obtained on 620 cases of women, age <40 years, undergoing first IVF-embryo transfer cycles in two private outpatient infertility clinics. All women were stimulated by the same protocol. The mean age was 31.73 (+/- 4.4 SD) years.

RESULTS

No differences in clinical pregnancy rate and implantation rate were noted in statistical logistic regression analysis between the four intake groups.

CONCLUSIONS

There was no clinical evidence of any beneficial effect, as defined by main outcome measures, of ascorbic acid on IVF-ET. Our data suggest there is no obvious value of high dosed intake of vitamin C during luteal phase in infertility treatment.

Synthesis of ascorbate and urate in the ovary of water buffalo

Blood flow interruption is associated with oxygen depletion and loss of factors for function and survival in downstream tissues or cells. Hypoxia and absence of gonadotropins trigger apoptosis and atresia in the ovary. We studied the antioxidant response of follicular cells to plasma deprivation in ovaries dissected from water buffalo. Aliquots of follicular fluid were aspirated from each antral follicle, before and during incubation of the ovaries at 39 degrees C. Urate, ascorbate, retinol and alpha-tocopherol in the fluid were, titrated by High Performance Liquid Chromatography (HPLC) with spectrophotometric or spectrofluorimetric detection. The total antioxidant capacity of follicular fluid was determined as absorbance decrease, following addition of a source of radical chromophores. The more the incubation progressed, the higher levels of urate, ascorbate and total antioxidant capacity were found. Conversely, changes in concentration of the liposoluble antioxidants were not observed. Ascorbate synthesizing activity in the follicle was demonstrated by detecting the enzyme L-gulono-gamma-lactone oxidase in microsomes prepared from granulosa cells. These cells were also analyzed for the expression of the enzyme CPP32. The enzyme level, measured as DEVD-p-nitroanilide cleaving activity, was found related with the immunoreactivity to anti-CPP32 antibodies. Negative correlation between the enzyme activity (which is known to be induced by peroxynitrite) and the follicular level of urate (which scavenges peroxynitrite) was also observed. The amount of nitrotyrosine, a product of peroxynitrite attack on proteins, was measured in follicular fluids by Enzyme Linked ImmunoSorbent Assay (ELISA). This amount was found positively correlated with the CPP32 activity, and negatively correlated with the urate level in follicular fluid. Alterations in concentrations of ascorbate or urate may be associated with oxidative stress during follicular atresia.