Antioxidant properties of coenzyme Q10-pretreated mouse pre-antral follicles derived from vitrified ovaries.

AIM: This study evaluated the antioxidant status of pre-antral follicles derived from vitrified ovaries pretreated with coenzyme Q10 (CoQ10). METHODS: Mouse pre-antral follicles derived from fresh and vitrified warmed ovarian tissue were cultured with or without CoQ10 (50 µmol/L). Follicular growth, total antioxidant capacity (TAC), malondialdehyde (MDA) level, and superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT) activity during cultivation were assessed. RESULTS: The growth rate of the fresh pre-antral follicles was higher compared with the vitrified groups, especially in the CoQ10-treated than non-treated groups. MDA increased while TAC decreased at 96 h of the cultivation period. TAC was higher while MDA was lower in the fresh pre-antral follicles than in the vitrified groups. These rates were higher in the CoQ10-treated than non-treated groups. The vitrified and fresh CoQ10-pretreated groups had significantly higher SOD, GPX, and CAT activity compared with the CoQ10 non-treated groups. CONCLUSION: CoQ10-supplemented maturation medium can increase antioxidant enzyme activity and decrease lipid peroxidation in cultured pre-antral follicles derived from fresh and vitrified mouse ovaries.

Augmenting effect of vitrification on lipid peroxidation in mouse preantral follicle during cultivation: Modulation by coenzyme Q10.

Cryopreservation-induced oxidative stress (OS) may lead to lipid peroxidation, which may be responsible for decreased cell survival rate. Coenzyme Q10 (CoQ10) as a potent antioxidant may improve cell viability by neutralizing OS. In this study, oxidative lipid injury following the vitrification of preantral follicles was investigated. The effects of CoQ10 treatment on the malondialdehyde (MDA) levels, lipid peroxidation products, and activities of enzymatic and nonenzymatic antioxidants of vitrified preantral follicles were also studied. Preantral follicles were isolated from immature mouse ovaries and were vitrified. After warming, these follicles were cultured with or without CoQ10 for four days. The levels of total antioxidant capacity (TAC) and MDA, as well as the activities of superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT), were assessed at 0, 24, 48, 72, and 96 hours of culture period. The MDA level in the vitrified preantral follicles was higher than that in the fresh groups. By contrast, the MDA level was significantly lower in the groups with CoQ10 treatment than in those without this treatment during cultivation. The TAC level was higher in the fresh preantral follicles than in the vitrified groups. The rates were also higher in the CoQ10-treated groups than in those without this treatment. The activities of SOD, GPX, and CAT were also significantly higher in the fresh groups than in the vitrified groups, especially in the groups with CoQ10 treatment than in those without this treatment. Lowering the vitrification-induced lipid peroxidation of preantral follicles by CoQ10-supplemented maturation medium may be mediated by increasing SOD, GPX, and CAT activities and TAC level during cultivation.

Effects of the phytoestrogen, genistein, and protein tyrosine kinase inhibitor-dependent mechanisms on steroidogenesis and estrogen receptor expression in porcine granulosa cells of medium follicles.

The use of soy-based products in pig diets had raised concerns regarding the reproductive toxicity of genistein, the predominant isoflavone in soybeans. Genistein was reported to exhibit weak estrogenic activity but its mechanism of action is not fully recognized. The aim of the study was to examine the in vitro effects of genistein on (1) progesterone (P(4)) and estradiol (E(2)) secretion by porcine granulosa cells harvested from medium follicles, (2) the viability of cultured granulosa cells, and (3) the mRNA and protein expression of estrogen receptors α and ß (ERα and ERß) in these cells. In addition, to verify the role of protein tyrosine kinase (PTK)-dependent mechanisms possibly involved in genistein biological action, we tested the effects of lavendustin C, the nonsteroidal PTK inhibitor, on granulosa cell steroidogenesis. We found that genistein inhibited (P < 0.05) basal P(4) secretion by granulosa cells harvested from medium follicles of pigs. In contrast, lavendustin C did not affect basal P(4) secretion by the cells. Moreover, genistein increased (P < 0.05) basal granulosal secretion of E(2). In contrast, lavendustin C did not alter basal E(2) secretion by porcine granulosa cells. In addition, we demonstrated that genistein increased mRNA and protein expression of ERß (P < 0.05) in the examined cells. The expression of ERα mRNA was not affected by genistein and ERα protein was not detected in the cultured granulosa cells of pigs. In summary, the genistein action on follicular steroidogenesis in pigs involved changes in the granulosal expression of ERß. However, the genistein action on P(4) and E(2) production by granulosa cells harvested from medium follicles did not seem to be associated with PTK.

Catalase prevents lipid peroxidation and enhances survival of caprine preantral follicles cryopreserved in a 1,2-propanediol-freezing medium.

The objectives of this study were to determine: 1) the optimal concentration (1.0 or 1.5 M) and duration of exposure (5, 10, or 20 min) of ovarian tissue to 1,2-propanediol (PROH) on morphology and viability of caprine preantral follicles; and 2) the effect of supplementing cryopreservation medium supplementation with Trolox(®) (0.1, 0.5, or 1.0 mM) or catalase (5, 10, or 20 IU/mL) on follicular morphology, viability, and lipid peroxidation. Cryopreservation decreased (p<0.05) percentages of normal follicles relative to the control (84%). Although supplementation of the cryopreservation medium (1.0 M PROH) with catalase (10 or 20 IU/mL) or Trolox(®) (0.1 mM) resulted in follicular morphology and viability similar to that in the controls (P>0.05), lipid peroxidation was reduced only when 20 IU/mL catalase was added to the cryopreservation medium.

Sex- and tissue-specific expression of P450 aromatase (cyp19a1a) in the yellowtail clownfish, Amphiprion clarkii.

To investigate the role of estrogen in the gonad of yellowtail clownfish Amphiprion clarkii, we isolated cDNA encoding cytochrome P450 aromatase (Cyp19a1a) from the adult ovary. The full-length cDNA of clownfish cyp19a1a is 1928-bp long and encodes 520 amino acids. Real-time quantitative RT-PCR analysis showed that cyp19a1a was expressed mainly in the ovary of female-phase fish. In situ hybridization and immunohistochemical observations showed that positive signals were restricted to the ovarian follicle of the female-phase fish. In contrast, Cyp19a1a signal was not detected in the ambisexual gonad of the male-phase fish. These findings suggest that Cyp19a1a is involved in oogenesis in the female-phase fish, but not in the ambisexual gonad of male-phase fish.

Characterization of a cDNA encoding P-450 aromatase (CYP19) from Japanese eel ovary and its expression in ovarian follicles during induced ovarian development.

A cDNA encoding P450 aromatase (CYP19) was isolated from a Japanese eel (Anguilla japonica) ovarian cDNA library. This cDNA contains a complete open reading frame encoding 511 amino acid residues. The deduced amino acid sequence is 59% and 65% identical to the catfish and rainbow trout forms, respectively, and 52-54% to mammalian and chicken forms. Non-steroidogenic COS-7 cells transfected with the eel CYP19 cDNA converted exogenous androstenedione to estrone, thus verifying its identity. Northern blot analysis indicated that there was a single 2.1 kb transcript in the ovary. A 2.1 kb transcript was also found in the brain but not in the spleen, head kidney, kidney, or liver. Throughout ovarian development induced by weekly injections of salmon pituitary homogenate (SPH, 20 microg/g body weight), the 2.1 kb transcript was barely or not detectable in the ovaries. However, signals greatly increased in intensity in oocytes in the migratory nucleus stage and then decreased slightly in the post-ovulatory ovary. These changes in transcript levels are consistent with the changes in aromatase activity of ovarian follicles, suggesting that aromatase activity in ovarian follicles is mainly regulated at the transcriptional level. In addition, fadrozole was found to significantly inhibit aromatase activity in a heterologous expression system using COS-7 cells, which indicates that fadrozole treatment could be useful to control E(2) production during artificial maturation of eels.

Folliculogenesis and ovarian expression of mRNA encoding aromatase in anoestrous sheep after 5 days of glucose or glucosamine infusion or supplementary lupin feeding.

Improved nutrition increases ovulation rate in sheep and there is evidence that intra-ovarian pathways mediate responses to nutrition. An experiment was conducted to examine the effect of dietary energy on folliculogenesis. Anoestrous Merino ewes were fed a diet of wheat straw alone (control, n = 5), or wheat straw supplemented with lupins (500 g day(-1), n = 5). Other ewes were fed wheat straw and infused with glucose (50 mmol h(-1), n = 5) or with glucosamine (3.5 mmol h(-1), n = 5). Intravaginal progestagen sponges were inserted for 12 days, and nutritional treatments were started 5 days before sponge removal. At sponge removal, the ewes were injected with a regimen of GnRH pulses (500 ng every 4 h from 0 to 12 h; 250 ng every 2 h from 14 to 24 h; and 200 ng every 1 h from 25 to 36 h) to simulate normal follicular development. Thirty-six hours after sponge removal, the animals were killed and the ovaries were collected and stored at -80 degrees C. The ovaries were sectioned serially every 10 microm. Every 20th section was stained (to estimate number and diameter of follicles) and every 17-19th section was probed by in situ hybridization for P(450) aromatase. Data were analysed using ANOVA and chi-squared tests. There was an effect of treatment (P < 0.05) on the number of follicles 2-3, 3-4 and 6-7 mm in diameter. Aromatase-positive follicles (1.6-7.9 mm) were detected in 31 follicles from 15 ewes across all four groups. In ten animals, the largest follicle was aromatase-positive. The diameters of aromatase-positive follicles were larger (P = 0.004) in lupin fed compared with glucose-infused ewes (4.9 +/- 0.5, 3.6 +/- 0.7, 5.3 +/- 0.5 and 4.2 +/- 0.5 mm for control, glucose-infused, lupin-fed and glucosamine-infused groups, respectively). Treatment did not affect the plasma concentration of FSH when compared with controls, indicating that the energy supplements were modifying recruited (2-3 mm and 3-4 mm) and selected follicles (> 6 mm) directly. In conclusion, dietary energy can directly stimulate folliculogenesis in recruited and selected follicles, and this effect may be mediated by changes in systemic leptin concentrations and the hexosamine energy-sensing pathway in the follicle.

Medaka (Oryzias latipes) FTZ-F1 potentially regulates the transcription of P-450 aromatase in ovarian follicles: cDNA cloning and functional characterization.

Our previous findings suggest the activity of cytochrome P-450 aromatase (P-450arom), the enzyme which converts testosterone to estradiol-17beta, in the ovarian follicle of medaka (Oryzias latipes) is regulated at the transcriptional level. In this study, we cloned a cDNA encoding a FTZ-F1-like protein (mdFtz-F1) from ovarian follicles of medaka. In vitro translated mdFTZ-F1, and nuclear extract from medaka ovarian follicles, formed complexes with oligonucleotide probes containing putative orphan nuclear receptor binding motifs, which are present in the promoter region of the medaka P-450arom gene. The expression pattern of mdFtz-F1 transcripts during oogenesis coincides with that of P-450arom transcripts. Transfection assays further suggest a potential transcriptional regulatory activity of mdFTZ-F1 upon the medaka P-450arom promoter. Taken together, these results suggest a potential role of mdFTZ-F1 in the transcriptional regulation of P-450arom in the ovarian follicle of medaka.

Molecular characterization of equine prostaglandin G/H synthase-2 and regulation of its messenger ribonucleic acid in preovulatory follicles.

To increase our understanding of the molecular control of PG synthesis in equine preovulatory follicles, the specific objectives of this study were to clone and determine the primary structure of equine prostaglandin G/H synthase-2 (PGHS-2) and to characterize the regulation of PGHS-2 messenger RNA (mRNA) in follicles before ovulation. A complementary DNA (cDNA) library prepared from follicular mRNA and a genomic library were screened with a mouse PGHS-2 cDNA probe to isolate the equine PGHS-2 cDNA and gene, respectively. The expression library yielded three nearly full-length clones that differed only in their 5'-ends; clones 3, 5, and 6 were 2946, 3138, and 3398 bp in length, respectively. The longest clone was shown to start 9 bp downstream of the transcription initiation site, as determined by primer extension analysis, and to contain 120 bp of 5'-untranslated region (UTR), 1812 bp of open reading frame, and 1466 bp of 3'-UTR. The open reading frame encodes a 604-amino acid protein that is more than 80% identical to PGHS-2 homologs in other species. Numerous repeats (n = 11) of the Shaw-Kamen's sequence (ATTTA) are present in the 3'-UTR, a motif typically indicative of mRNAs with a short half-life. The complete equine PGHS-2 gene was isolated and sequenced from a approximately 17-kilobase clone obtained from the genomic library. The equine PGHS-2 gene structure (10 exons and 9 introns; total length of 6991 bp) is similar to its human homolog except for lacking sequence elements in introns 4, 8, and 9 and in the 3'-UTR region of exon 10. To characterize the regulation of PGHS-2 mRNA in equine follicles before ovulation, preovulatory follicles were isolated during estrus, 0, 12, 24, 30, 33, 36, and 39 h (n = 4-5 follicles/time point) after an ovulatory dose of hCG. Results from Northern blots showed significant changes in steady state levels of PGHS-2 mRNA in preovulatory follicles after hCG treatment (P < 0.05). The transcript remained undetectable between 0-24 h post-hCG, first appeared (approximately 4 kilobases) only at 30 h, and reached maximal levels 33 h post-hCG. PGHS-2 mRNA was selectively induced in granulosa cells and not in theca interna. Thus, this study provides for the first time the primary structure of the equine PGHS-2 gene, transcript, and protein. It also demonstrates that the induction of PGHS-2 gene expression in equine granulosa cells is a long molecular process (30 h post-hCG), thereby providing a model to study the molecular basis for the late transcriptional activation of PGHS-2 in species with a long ovulatory process.

Isolation and characterization of the cDNA encoding the tilapia (Oreochromis niloticus) cytochrome P450 aromatase (P450arom): changes in P450arom mRNA, protein and enzyme activity in ovarian follicles during oogenesis.

A cDNA clone encoding the complete tilapia (a teleost fish, Oreochromis niloticus) cytochrome P450 aromatase (P450arom) was isolated from an ovarian follicle cDNA library. The deduced amino acid sequence (522 amino acid residues) had 72.2% and 59.5% homology with rainbow trout and catfish P450arom respectively, and about 50% homology with mammalian and avian P450arom. Expression of this cDNA in COS-7 cells produced a protein that converted exogenous testosterone to estrogens. Northern blots using a tilapia P450arom cDNA fragment and Western blots using an antiserum against a tilapia P450arom polypeptide fragment revealed a single P450arom mRNA (2.6 kb) and a single protein (59 kDa) in tilapia ovarian tissue respectively. These analyses also revealed that the levels of both P450arom mRNA and protein were low in early vitellogenic follicles, increased in midvitellogenic follicles, and declined to non-detectable levels in post-vitellogenic follicles. Changes in the ability of follicles to convert exogenous testosterone to estrogens (aromatase activity) were similar to those of P450arom mRNA and protein. These observations indicated that the capacity of tilapia ovarian follicles to synthesize estradiol-17 beta is closely related to the contents of P450arom mRNA and protein within them.

Induction of prostaglandin endoperoxide synthase-2 by human chorionic gonadotropin in bovine preovulatory follicles in vivo.

Gonadotropins have recently been shown to induce prostaglandin endoperoxide synthase-2 (PGHS-2) in rat preovulatory follicles before ovulation, but hormonal induction of this enzyme has not yet been reported in preovulatory follicles of any other species. To determine whether the selective induction of PGHS-2 by the ovulatory gonadotropin surge is a molecular process that has been conserved in other mammalian species with different reproductive cycles, the regulation of PGHS isoforms was studied in bovine preovulatory follicles isolated 0, 6, 12, 18, 20, 22, 24, and 26 h after an ovulatory dose of hCG. Each follicle was dissected into three preparations: the intact follicle wall (i.e. theca interna with attached granulosa cells), theca interna, and isolated granulosa cells. Solubilized cell extracts were obtained from each preparation and analyzed by Western blots, using polyclonal antibodies that selectively recognize PGHS-2 and PGHS-1 isoforms. RNA extracts were prepared and analyzed by Northern blots, using a mouse PGHS-2 complementary DNA. The results indicated that the expression of PGHS-2 messenger RNA (mRNA) and protein, but not that of PGHS-1, was regulated by hCG in bovine preovulatory follicles before ovulation. Levels of PGHS-2 protein (mol wt, 74,000) in the follicle wall were undetectable at 0, 6, and 12 h, but increased dramatically after 18 h to reach maximal levels 24 h post-hCG treatment. Northern blots revealed a similar temporal induction of PGHS-2 mRNA (4.0 kilobases). Analyses of isolated preparations of theca interna and granulosa cells clearly showed that PGHS-2 was expressed exclusively in granulosa cells and not in theca interna. Significant increases in follicular fluid concentrations of prostaglandins E2 and F were associated with the induction of follicular PGHS-2 protein and mRNA. Thus, this study establishes that the induction by gonadotropin of PGHS-2 in granulosa cells before ovulation appears to be a conserved mechanism by which the synthesis of prostaglandins necessary for the ovulation process is regulated in different species. However, the striking difference between the time course of PGHS-2 induction previously reported in rat follicles (4 h post-hCG treatment) and that observed in bovine follicles (18 h post-hCG treatment) suggests that the control of PGHS-2 expression could be one of the determinants involved in dictating the species-specific progression (length) of the ovulation process.

Localization of 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4-isomerase in rat gonads and adrenal glands by immunocytochemistry and in situ hybridization.

The enzyme complex delta 5-3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta HSD) is involved in the biosynthesis of all classes of steroids, namely glucocorticoids, mineralocorticoids, progesterone, and sex steroids. To obtain information on the precise localization of 3 beta HSD in rat gonads and adrenal glands, two complementary cytochemical techniques were used; immunocytochemical localization was achieved with antibodies developed against purified human placental 3 beta HSD, while 3 beta HSD mRNA localization was achieved by in situ hybridization performed with a recently cloned rat 3 beta HSD cDNA. In the testis, specific immunostaining was restricted to the cytoplasm of the interstitial cells, while by in situ hybridization, specific silver grains were also seen over the interstitial cells. In the ovary, immunostaining was found in the cytoplasm of cells of the corpus luteum and theca interna, while the granulosa cells of the follicles showed no positive reaction. By in situ hybridization, a specific hybridization signal was observed over granulosa cells of the corpus luteum, which are mainly responsible for progesterone secretion, and to a lesser extent over theca interna cells, known for their role in secreting C19 androgens. In the adrenals, the three zones of the cortex were equally immunolabeled, whereas no staining could be detected in the medulla. Similarly, by in situ hybridization, silver grains were located over the zona glomerulosa, fasciculata, and reticularis, while no specific autoradiographic reaction could be observed on the chromaffin cells of the medulla. The present study provides new information about the precise cellular localization of 3 beta HSD in the adrenal glands and gonads in the rat, thus providing useful information about the site of action of 3 beta HSD, especially in the gonads. Moreover, the approaches used for localization studies, especially quantitative in situ hybridization, should provide a useful tool for assessing the role of hormones on 3 beta HSD expression in the different compartments of the gonads and adrenal glands.

[Stimulatory action of shakuyaku on aromatase activity in cultured rat follicles].

The direct action of herbal medicines on aromatase activity was investigated in cultured rat follicles. Mature follicles were obtained from PMSG-treated immature rats. Aromatase inhibitor, 4-hydroxy-4-androstene-3,17-dione (4-OHA) was also used in the experiment. Follicles were incubated in the medium for 24 hour with toki-shakuyaku-san, Keisi-bukuryo-gan. unkei-to (10-500 micrograms) or their ingredients (100 micrograms), respectively. The addition of 4-OHA reduced estradiol secretion in a dose-response manner. The addition of each medicine (100, 500 micrograms) as well as 4-OHA (10(-5) M) restored estradiol secretion to the control level. Among the ingredients, Shakuyaku stimulated estradiol secretion in the medium in the presence or absence of 4-OHA. It is noteworthy that shakuyaku alone had a stimulatory action on aromatase activity and is the only one which is equally contained in the three medicines.

Hachimijiogan and Tokishakuyakusan enhance deoxyribonucleic acid alpha-nucleotidyltransferase activity in relationship to DNA synthesis by ovarian follicles via a cyclic AMP system.

The ovaries resected from twenty-nine day old female rats primed with 10 IU of PMS for 48 hours were incubated for 120 minutes with 2-20 micrograms/ml of Hachimijiogan (HZ) and Tokishakuyakusan (TS). The animals in another group were injected intravenously with 20 micrograms of HZ and TS 48 hours after PMS injection, and 20 minutes later decapitated. Deoxyribonucleic acid (DNA) alpha-nucleotidyltransferase activity and cyclic AMP accumulation in ovarian tissue were significantly increased by HZ and TS. These results suggest that HZ and TS enhance DNA alpha-nucleotidyltransferase activity via cyclic AMP by ovarian follicles.