Regulation of tight junction proteins occludin and claudin 5 in the primate ovary during the ovulatory cycle and after inhibition of vascular endothelial growth factor

Ovarian follicular and corpus luteum development, including angiogenesis, are characterized by cell-cell rearrangements that may require dynamic changes in cell-cell adhesion. The present study investigates the expression of tight junction proteins occludin and claudin 5 during follicular and luteal development in the primate ovary and after inhibition of vascular endothelial growth factor (VEGF) by VEGF trap treatment. Occludin was localized to the plasma membrane of granulosa cells. During follicular development occludin staining decreased significantly (P < 0.05) and disappeared completely by the ovulatory stage. After inhibition of VEGF, occludin staining was significantly (P < 0.05) higher in the granulosa of secondary and tertiary follicles compared with controls. Claudin 5 was exclusively localized to the theca vasculature. A significant (P < 0.05) increase in staining was detected from the pre-antral to the antral and ovulatory stage. However, dual staining with CD31 revealed that within the theca endothelium the amount of claudin 5 remained constant during follicular development. Treatment with VEGF trap throughout the follicular phase revealed a lack of claudin 5 staining in the theca interna but no difference was observed in the remaining theca externa vasculature. In the corpus luteum, claudin 5 was also localized in the vasculature. Treatment with VEGF trap in the mid-luteal phase resulted in a significant increase in staining (P < 0.05). These results led us to hypothesize that tight junctions are involved in regulation of follicular growth, antrum transition and follicular angiogenesis which is compromised by VEGF inhibition. VEGF may influence luteal vascular permeability by regulation of the endothelial specific tight junction protein claudin 5.     

Development of antral follicles in human cryopreserved ovarian tissue following xenografting

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

Immunohistochemical localization of superoxide dismutase in the human ovary.

To elucidate the physiological function of superoxide dismutase (SOD) in the ovary, we examined the immunohistochemical distribution of CuZn-SOD in the human ovary. We also measured the CuZn-SOD concentration in human follicular fluid by enzyme-linked immunosorbent assay (ELISA). The germinal epithelium and tunica albuginea showed no or weak immunoreactivity. No or weak staining activity was also observed in the non-antral follicle. Once the follicle began to form the antral cavity, theca interna cells began to show intensive immunostaining of SOD, as compared with no staining in the granulosa and theca externa cells. In the gestational corpus luteum, theca and granulosa lutein cells showed intensive and moderate staining activity, respectively. The concentration of CuZn-SOD was 0.222 +/- 0.186 ng/mg protein (mean +/- SD) in the preovulatory follicular fluid. In the present study, the immunohistochemical distribution of SOD was confirmed in the human ovary for the first time. Taking into consideration the fact that SOD catalyses the dismutation reaction of superoxide anion radicals, the present results suggest that theca interna cells play an important role in the protection of the developing oocyte from oxygen radicals by acting as a blood-follicular barrier during follicle maturation.     

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

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

Immunocytochemical localization of angiotensin II receptor subtypes 1 and 2 in the porcine fetal,prepubertal and postpubertal ovary

There is considerable evidence for a mammalian ovarian renin-angiotensin system, which may influence ovulation, angiogenesis and steroidogenesis via the autocrine and/or paracrine actions of the biologically active product of the cascade, angiotensin II (AngII). There are two characterized AngII receptors--type 1, AT1 and type 2, AT2. We report the localization of these receptor subtypes within porcine fetal, prepubertal and postpubertal ovaries. Positive staining for AT1 and AT2 receptors was observed in egg nests in all fetal ovaries studied, as well as in a defined two-cell layer at the ovarian periphery. In prepubertal tissue, positive AT1 and AT2 staining was localized to granulosa cells adjacent to the basement membrane of pre-antral and antral follicles, with no staining in the thecal layer. There was immunostaining for both receptors in prepubertal oocytes and zona pellucida. In postpubertal tissue, positive AT1 and AT2 immunostaining was localized to areas of putative neovascularization, the zona pellucida and the oocyte. Further AT1 staining was located to the postpubertal antral follicle granulosa cells. The results indicate that there are higher densities of AT1 receptors than AT2 receptors in the porcine fetal, prepubertal and postpubertal ovary, and this has profound implications for the role of AngII in ovarian development.     

Distribution of Adenylyl Cyclases in the Rat Ovary by Immunofluorescence Microscopy

In the mammalian ovary both gonadotropins and local cytokines, acting through G‐protein coupled receptors, govern the physiology of the ovary in part by regulating the cyclic adenosine 3′,5′‐monophosphate via adenylyl cyclases. The nine transmembrane adenylyl cyclases and a soluble adenylyl cyclase are regulated by a diversity of ligands. In this study we have examined the rat ovaries, prior to and subsequent to gonadotropin treatment, for the presence of different transmembrane adenylyl cyclases by indirect immunofluorescence microscopy. Adenylyl cyclase I immunoreactivity was observed in the nuclei of oocytes in preantral and antral follicles along with some staining in granulosa cells. Equine chorionic gonadotropin injection increased adenylyl cyclase I staining in granulosa cells. Adenylyl cyclase I staining was also observed in luteal and endothelial cells. Adenylyl cyclase II was observed throughout the ovary, including granulosa cells and the ovarian surface epithelium. Adenylyl cyclase II staining was also found to increase in granulosa cells after equine chorionic gonadotropin injection. Adenylyl cyclase III was distributed primarily in theca and smooth muscle cells of arterioles, with faint staining in the oocytes of equine chorionic gonadotropin‐injected ovaries. Adenylyl cyclase IV staining was present throughout the ovary, including the nuclei of oocytes. Adenylyl cyclase VIII staining in granulosa cells increased subsequent to equine chorionic gonadotropin injection and remained in luteal cells. Our study reveals the redundancy of adenylyl cyclases present in the rat ovary and, therefore, implies potential regulation of follicular and corpus luteum physiology by cyclic adenosine 3′,5′‐monophosphate generated through distinct adenylyl cyclases. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.     

Expression and localization of Smad2 and Smad4 proteins in the porcine ovary

The objective of the present study was to investigate the temporal and spatial expression of Smad2 and Smad4 proteins, the downstream signaling molecules of the transforming growth factor beta (TGF-β) superfamily, in the porcine ovary. Cellular localization of Smad2 and Smad4 proteins was examined using immunohistochemistry. The specificity of the antibodies was examined using Western blot assay. Western blot analyses demonstrated that 52 kDa Smad2 and 60 kDa Smad4 proteins were expressed in the porcine ovary. Immunohistochemistry revealed that Smad2 and Smad4 were widely expressed in the porcine ovary, mainly localized in the oocyte, granulosa and thecal cells at different stages of folliculogenesis. Within the primordial and primary follicles, Smad2 and Smad4 showed strong staining in oocytes and follicular cells. In the antral follicle, strong staining was observed in oocytes, granulosa and theca cells. These findings suggest that Smad2 and Smad4 may be a key regulator of follicular development and growth of oocytes in the porcine ovary.     

Location and developmental regulation of androgen receptor in primate ovary

Locally produced androgens act via granulosa cell androgen receptors to modulate follicular responsiveness to gonadotrophins and thereby contribute to the paracrine regulation of ovarian function. We used quantitative androgen receptor immunocytochemistry to assess androgen receptor distribution in relation to pre-ovulatory follicular development in the common marmoset (Callithrix jacchus), a New World primate that ovulates two to four follicles in each approximately 28 day ovarian cycle. Ovaries from four adult females in the late follicular phase and from four in the luteal phase were fixed in 4% paraformaldehyde and subjected to an immunocytochemical analysis using a polyclonal androgen receptor antibody with detection by a standard avidin-biotin-peroxidase technique for alkaline phosphatase. Specific androgen receptor immunostaining occurred mainly in granulosa cell nuclei, with little or no specific staining in theca, stroma or oocytes. Granulosa cell androgen receptor immunostaining was most abundant in healthy preantral/early antral follicles, being low or absent from pre-ovulatory follicles and corpora lutea. Differences in granulosa cell androgen receptor immunostaining between immature (0.1- 1.0 mm diameter) and pre-ovulatory (> or = 2.0 mm diameter) follicles were quantified using a videodensitometric analysis of grey-scale values. Readings were taken from the granulosa cell layers of 53 immature follicles and 10 pre-ovulatory follicles in late follicular phase ovaries. The average androgen receptor level in granulosa cells of immature follicles proved to be 4.2-fold higher (P < 0.01) than that in granulosa cells of pre-ovulatory follicles. Because other evidence suggests that paracrine androgen action in granulosa cells converts from stimulation to inhibition as follicles mature, we speculate that a development-related reduction in androgen receptor numbers serves to "protect' granulosa cells against the inhibitory action of androgen, thereby promoting pre-ovulatory follicular dominance in primate ovarian cycles.      

Localization of Smad4 in the ovary of the European hedgehog (Erinaceus europaeus L.)

Ovarian follicular development, follicle selection, and the process of ovulation remain poorly understood in most species. Numerous endocrine, paracrine, and autocrine factors, including the ligands represented by the transforming growth factor β (TGFβ) superfamily, TGFβ, activin, inhibin, bone morphometric protein (BMP), and growth differentiation factor (GDF) are present in the ovaries of many animals. In the present study, we investigated the immunolocalization of Smad4, a signaling molecule of the TGFβ superfamily, during folliculogenesis in the ovary of the European hedgehog (Erinaceus europaeus L., 1758). Immunolocalization studies revealed that Smad4 was widely seen in the ovary, mainly in the follicle, though its location and staining intensity varied with the different stages of the developing follicle. In the primordial follicles and early growing follicles, Smad4 protein was mainly localized in the cytoplasm of the oocyte with a half-moon staining pattern. In the pre-antral follicles, Smad4 protein was mainly located in the granulosa cells, theca cells and diffusely distributed in the interstitial cells surrounding the follicle. In the corpora lutea, the immunostaining for Smad4 was very intense. These results suggested that Smad signal transduction may play an important role in folliculogenesis and conceivably may participate in subsequent pregnancy.     

Analysis of the expression of Fas, FasL and Bcl-2 in the pathogenesis of autoimmune thyroid disorders

To investigate the expression of apoptosis-related protein (Fas, FasL, and Bcl-2) in the pathogenesis of autoimmune thyroid disorders (ATDs), immunohistochemical staining was performed on 20 Hashimoto‘s thyroiditis (HT), 20 Graves‘ disease (GD), and 20 thyroid follicular adenoma (TFA, as control). All the cases expressed Fas, mainly on the cell surface and cytoplasm. FasL was found in 17 cases of the TFA. Bcl-2 was detected in 15 cases of HT, 19 of GD and 17 of TFA. In T FA, a moderate Fas expression and a minimal or no FasL expression was detected on follicular cells. In HT, the follicles adjacent to infiltrating lymphocytes showed increased levels of Fas and FasL expression. A weaker staining of Fas and FasL was exhibited on infiltrating lymphocytes than on thyrocytes. In a comparison of GD with HT, thyrocytes and lymphocytes showed similar Fas staining, but for FasL the staining was rather weaker in HT. The expression of Bcl-2 was nearly identical in GD and TFA, but much weaker on the follicular cells in vicinity of lymphocytes and on the lymphocytes located in germinal centers of HT tissues. The expression of Fas, FasL, Bcl-2 in Hashimoto‘s thyroiditis and Graves‘ disease were almost same. FasL strong expression and Bcl-2 weak expression on the follicles in HT may induce apoptosis. These results provided evidence for expression of Fas, FasL and Bcl-2 in the pathogenesis of autoimmune thyroid disease. The lymphocytes seem not to be directly engaged in the process v/a their own FasL, but they may provide some cytokines that, in turn, upregulate Fas and/or FasL expression to induce apoptosis.     

Characterization of cytoskeletal proteins in follicular structures of cows with cystic ovarian disease

The distribution of intermediate filaments (vimentin, cytokeratins, desmin) and microfilaments (alpha-smooth muscle actin and muscle specific actin) was studied immunohistochemically in bovine ovaries, with and without cystic ovarian disease. The immunohistochemically stained area (IHCSA), was quantified by image analysis, to evaluate the expression of these cytoskeletal proteins in the follicular wall of healthy antral, atretic, and cystic follicles. The granulosa cell layer of cystic follicles and atretic follicles had a significantly larger IHCSA for vimentin than did healthy antral follicles. Cytokeratins reacted lightly in the granulosa cells of antral follicles of normal ovaries, whereas granulosa cells of atretic and cystic follicles showed significantly higher IHCSA values. Immunohistochemical localization of desmin, muscle specific actin, and alpha-smooth muscle actin was restricted to the theca externa. This study supports earlier suggestions that strongly positive reactions with vimentin and cytokeratin antibodies observed in the granulosa cells of cystic follicles are due to the reorganization that occurs in the follicle during the process of cystic development, and are associated with changes in the expression of cytoskeletal proteins that are essential to proper cellular functioning.     

Selective alterations in insulin receptor substrates-1, -2 and -4 in theca but not granulosa cells from polycystic ovaries

The elevated insulin concentrations that occur in many women with polycystic ovary syndrome (PCOS) can contribute significantly to ovarian hyperandrogenism. The objective of the present study was to compare the content of proximal insulin signalling molecules in theca and granulosa cells between polycystic ovaries and regular cycling controls. Individual follicles (3-7 mm) were obtained from 11 women with PCOS and 10 regularly cycling control women. The theca and granulosa cells were microdissected from each follicle. Total protein was extracted and signalling proteins were measured by western blot analysis. There was no difference in insulin receptor content between PCOS and controls in either theca or granulosa cells. Insulin receptor substrate (IRS)-1 and -2 were increased (P<0.05), but IRS-4 was decreased (P<0.03) in PCOS theca cells. There were no changes in IRS-1, -2 or -4 in granulosa cells. IRS-3 was undetectable in all samples. There were no changes in phosphatidyl inositol-3 kinase catalytic subunits p110alpha or p110beta in either theca or granulosa cells. These data demonstrate cell-specific alterations in IRS protein concentrations in theca cells from polycystic ovaries that are consistent with an exaggerated amplification of the insulin signal and which may play an important role in ovarian hyperandrogenism and thecal hyperplasia.     

Serum and follicular fluid levels of soluble Fas, soluble Fas ligand and apoptosis of luteinized granulosa cells in PCOS patients undergoing IVF

BACKGROUND: There are limited data about the levels of soluble apoptotic factors and their modulation with therapeutic regimens in IVF cycles. The aim of the current study was to determine follicular fluid, and serum levels of soluble Fas (sFas) and soluble Fas ligand (sFasL) in PCOS patients undergoing IVF/ICSI cycles; also to investigate the effects of metformin on these factors and on apoptosis of luteinized granulosa cells. METHODS: We investigated the serum and follicular fluid levels of sFas and sFasL in patients with PCOS (n = 28) and compared them with those of the patients with infertility due to male factor (n = 12) undergoing IVF cycles. Effects of metformin therapy on these parameters and apoptosis of luteinized granulosa cells were also investigated among the patients with PCOS. RESULTS: Serum levels of sFas were significantly lower in the PCOS group compared to those in women with infertility due to male factor. Metformin therapy in PCOS patients preceding IVF cycles increased serum levels of sFas and decreased follicular fluid levels of sFasL compared to those on placebo. Follicular fluid from PCOS patients demonstrated luteinized granulosa cell DNA fragmentation in agarose gel, whereas a similar pattern was not observed among PCOS patients undergoing metformin therapy. CONCLUSION: Decreased serum levels of sFas and luteinized granulosa cell DNA fragmentation is observed in patients with PCOS undergoing IVF cycles. Metformin therapy preceding IVF demonstrates an antiapoptotic effect with increased serum levels of sFas, decreased follicular fluid levels of sFasL and prevention of luteinized granulosa cell DNA fragmentation.     

Distribution of apoptosis-related proteins in the quail ovary during folliculogenesis: BCL-2, BAX and CPP32

It is suggested that follicular apoptosis is driven by the status of the BCL-2: BAX rheostat, and that CPP32 is a key effector of granulosa cell death. In the present study, we have immunohistochemically localized two BCL-2 family members, BCL-2 and BAX, and one caspase, CPP32, in the quail ovary during folliculogenesis. BCL-2 was predominantly found in the granulosa cells of developing follicles. BAX was detected in some follicular cells of atretic follicles, and in the nucleus of some prelampbrush oocytes. Expression of CPP32 was detected in leukocytes and in follicular cells of atretic follicles. Immunostaining was also found in interstitial cells, in surface epithelial and vascular endothelial cells, and in some thecal cells of post-ovulatory follicles. In the granulosa cells of non-growing and small prehierarchal follicles, a weak immunostaining was observed. We can conclude that in the avian ovary, BAX and CPP32 are involved in atresia. The present results support the BCL-2: BAX rheostat hypothesis.     

Localization of the progesterone receptor in the porcine ovary

Regulation of progesterone receptor (PR) expression has been studied in many species. However, precise studies have not yet been performed in the porcine ovary. We have examined the localization of PR in follicles and corpora lutea of the porcine ovary at different stages of their development. The effects of LH and FSH on PR expression in granulosa cells of small antral follicles was also studied. Immunohistochemistry was applied to determine the distribution of PR while immunoblot analysis showed that two isoforms A and B were present. Early antral follicles contained PR in the granulosa layer. In granulosa cells of small and medium antral follicles PR was not detected whereas it was present in the theca layer. Before ovulation, PR was found in both granulosa and theca cells of large follicles and the staining intensity was very strong. FSH or LH treatment of small follicles (100 ng/ml) induced changes in cellular distribution patterns of PR. In both cases, PR was expressed in granulosa cells. PR was detected in corpora lutea in all 3 stages of the luteal phase. Our data show that in the pig ovary changes in PR localization are stage-specific and suggest that expression of PR is positively regulated by both LH and FSH.     

Serum anti-Müllerian hormone expression in women with premature ovarian failure

BACKGROUND: Premature ovarian failure (POF) is generally irreversible. However, developing follicles up to the antral stage are reported in POF and anti-Müllerian hormone (AMH) might be a good indicator of follicular presence. This study analysed serum AMH, ovarian histology and AMH immunoexpression in POF patients. METHODS: A cross-sectional study of 48 POF patients in an Endocrinology Department setting. Patients had an ovarian biopsy simultaneously with serum AMH sampling and/or ovarian AMH immunostaining. RESULTS: Mean serum AMH was 1.04 +/- 1.66 ng/ml. Serum AMH was significantly higher in women with 15 or more follicles at ovarian histology (P = 0.001). Comparison of ovarian AMH immunostaining from POF patients and 10 normal controls revealed a normal AMH expression in POF pre-antral follicles, but a decreased expression at the early antral stages. Serum AMH was undetectable in 77% of the patients with 0-5 AMH immunopositive follicles and detectable in 100% of the patients with more than 15 AMH immunopositive follicles. CONCLUSIONS: AMH levels in POF patients could identify women with persistent follicles. The decrease of AMH immunoexpression in POF antral follicles could suggest a defect of antral development.     

Smad4蛋白及mRNA在卵巢不同发育阶段的表达

目的：探讨Smad4在不同发育阶段大鼠卵巢中蛋白及mRNA的表达。 方法： 选择不同发育时期大鼠卵巢，运用免疫组化方法检测卵巢中Smad4蛋白表达，并进行图像分析；采用半定量逆转录聚合酶链反应(RT-PCR)方法检测Smad4 mRNA在卵巢中的表达。 结果： 免疫组化结果显示Smad4主要表达在各级卵泡中，在卵巢发育早期，Smad4主要在原始卵泡和窦前卵泡中表达；随着卵巢的发育成熟，Smad4在窦状及成熟卵泡颗粒细胞和卵泡膜细胞的表达与间质细胞比较无显著差异（P>0.05）。Smad4在卵泡中的表达强度也发生了变化：随着卵泡的发育，Smad4在窦状及成熟卵泡卵母细胞的表达与窦前卵泡卵母细胞比较明显减弱（P<0.05，P<0.01）；在卵泡膜细胞的表达逐渐增强（P<0.01），而在各级卵泡颗粒细胞中的表达无显著差异（P>0.05）。RT-PCR结果显示各阶段卵巢均有mRNA的表达，从第3周起Smad4 mRNA的表达明显增强，与生后1 d比较差异显著（P<0.05）。 结论： 卵巢内存在Smad4，提示TGF-β家族对卵泡发育的调节很可能是通过Smad信号转导模式实现的。     

The relationship between anti-Mullerian hormone, androgen and insulin resistance on the number of antral follicles in women with polycystic ovary syndrome

BACKGROUND: Anti-Müllerian hormone (AMH) is a biomarker that predicts the number of antral follicles and is involved in follicle arrest for women with polycystic ovary syndrome (PCOS). We investigated the association between the characteristic hyperandrogenemia, insulin resistance (IR), AMH, and the morphology and size of ovaries for women with PCOS. METHODS: A total of 99 Taiwanese women with PCOS who were willing to undergo vaginal ultrasonography were enrolled in this cross-sectional study. RESULTS: The number of antral follicles and the ovarian volume showed a significant correlation with AMH, total testosterone and the free androgen index, but not with age, body mass index (BMI) or the homeostasis model assessment of insulin resistance (HOMA-IR). AMH had a significant negative association with both BMI and HOMA-IR. Multiple stepwise regression analysis demonstrated that AMH, BMI and total testosterone were independently related to the number of antral follicles. AMH and total testosterone were the main determinants for ovarian volume in a stepwise regression model. CONCLUSIONS: Our results suggest that not only the AMH level, but also obesity, IR and elevated androgen levels may relate to the development of the large size of antral follicle pool and ovarian volume in women with PCOS. Obesity and IR may enhance the follicular excess through the dysregulation of AMH or through the pathway of hyperandrogenemia. These findings might partly explain why adequate body weight management and improvement in IR can improve the ovulatory function for women with PCOS.