Tumor necrosis factor-alpha inhibits follicle-stimulating hormone-induced differentiation in cultured rat granulosa cells

Mastitis impact on high-yielding dairy farm's reproduction and net present value

Poor udder health can have a negative impact on milk production and reproductive performance, which reduces the net present value (NPV) of dairy farms. The aim of this study is therefore to investigate the relationship between clinical mastitis and NPV and the financial impact of impaired reproductive function. For this purpose, 473 dairy cows were included in our study, 146 cows with clinical mastitis (CM group) and 327 clinically healthy cows (CH group) from a high-yielding dairy farm in Romania, milking approximately 780 dairy cows with an average milk production of 46 kg milk/day. We found that, in contrast to CH cows, CM cows had a significantly lower conception rate at first service (58.2% vs. 41.7%, p < 0.05), third service (45.3% vs. 30.2%, p < 0.05), and total services (49.2% vs. 36.4%, p < 0.05). However, this positive effect was not observed for the average days open, which were significantly lower in CM cows than in CH cows (112 ± 4.3 days vs. 142 ± 3.1 days, p < 0.05). The fact that the non-pregnant CH cows had higher somatic cell counts (>400,000 SCC/mL) in their milk around artificial insemination (AI) and 1 month earlier than the pregnant cows (<250,000 SCC/ml) supports the idea that poor uterine health affects the reproductive activity of high-yielding cows. However, by using the UW-DairyRepro$ decision support tool, we found that despite the impairment of reproductive function in dairy cows, the largest negative impacts on NPV are still the cost of milk loss (US$14,439.4/farm/year) and treatment costs (US$4,380/farm/year). We considered the costs associated with poor reproductive function in the CM group (US$3,577/farm/year) as an additional cost of mastitis. Finally, it appears that the impact of mastitis on reproduction is associated with a lower chance of conception than it is with a daily risk of services.

Oxidative stress and inflammatory markers in ovarian follicular fluid of women with diminished ovarian reserve during in vitro fertilization

BACKGROUND

Follicular microenvironment has been proposed as an important factor for oocyte grown and maturation. We sought to evaluate the oxidative stress and inflammatory levels in follicular fluid (FF) and association with embryo quality in patients with diminished ovarian reserve (DOR).

METHODS

The current research included 46 DOR cases and 56 normal ovarian reserve (NOR) cases. Twelve representative oxidative stress markers and eight representative inflammatory factors were measured in the FF.

RESULTS

Oxidative stress markers total GSH (T-GSH) was decreased in the FF from women with DOR compared with that in NOR group (P = 0.041). More modest differences were observed for reduced GSH (rGSH) and rGSH/GSSG. Women with DOR compared to controls had higher level of TNF-α (P = 0.000) and lower level of IL-18 (P = 0.013). Correlation analysis revealed that GSSG was negatively correlated with normal fertilization rate in NOR group (r = -0.358, P = 0.008), and reduced GSH was negatively correlated with normal fertilization rate in DOR group (r = -0.299, P = 0.049). Moreover, as the regression analysis data showed, the GSSG level was significantly associated with embryo quality indicator.

CONCLUSIONS

The FF in DOR patients was accompanied by increased oxidative stress and inflammatory levels. Follicular development of women with DOR might be influenced by unusual IL-18 and TNF-α levels in FF. And oxidative stress marker GSSG in NOR group was a negative predictor for embryo quality.

Atretic preovulatory follicles could be precursors of ovarian lutein cysts in the pig

Ovarian cysts contribute to reduced reproductive performance in pigs. Unfortunately, the mechanism of lutein cysts formation remains unknown. Here, we compared the endocrine and molecular milieus of intact, healthy preovulatory follicles (PF), gonadotropin (eCG/hCG)-induced healthy and atretic-like PF, as well as gonadotropin-provoked and spontaneous ovarian cysts in gilts. Several endocrine and molecular indicators and microRNA were compared in walls of PF and cysts. Intact and healthy PF, showed high estradiol/androstendione and low progesterone levels associated with CYP17A1, HSD17B1, and CYP19A1 elevation and reduced StAR/HSD3B1 protein expression. In contrast, low estradiol/androstendione and high progesterone concentrations, accompanied by decreased CYP17A1, HSD17B1, CYP19A1 and increased HSD3B1 protein abundance, appeared in atretic-like PF, gonadotropin-induced and spontaneous cysts. High progesterone receptor (PGR) protein abundance was maintained in intact and healthy PF, while it dropped in atretic-like PF, gonadotropins-induced and spontaneous cysts. The atretic PF showed high level of TNFα compared to healthy PF. In conclusion, follicular lutein cysts could be recruited from atretic-like PF with lost estrogenic milieu and inability to ovulate. Ovulatory cascade was presumably disrupted by a low PGR and high TNFα levels associated with earlier luteinization of follicular walls. These results suggest a novel mechanism of lutein ovarian cysts development in pigs and, perhaps, other species.

Follicular Hyperstimulation Dysgenesis: New Explanation for Adverse Effects of Excessive FSH in Ovarian Stimulation

High follicle-stimulating hormone (FSH) doses during ovarian stimulation protocols for assisted reproductive technologies (ART) are detrimental to ovulatory follicle function and oocyte quality. However, the mechanisms are unclear. In a small ovarian reserve heifer model, excessive FSH doses lead to phenotypic heterogeneity of ovulatory size follicles, with most follicles displaying signs of premature luteinization and a range in severity of abnormalities. By performing whole transcriptome analyses of granulosa cells, cumulus cells, and oocytes from individual follicles of animals given standard or excessive FSH doses, we identified progressive changes in the transcriptomes of the 3 cell types, with increasing severity of follicular abnormality with the excessive doses. The granulosa and cumulus cells each diverged progressively from their normal phenotypes and became highly similar to each other in the more severely affected follicles. Pathway analysis indicates a possible dysregulation of the final stages of folliculogenesis, with processes characteristic of ovulation and luteinization occurring concurrently rather than sequentially in the most severely affected follicles. These changes were associated with disruptions in key pathways in granulosa and cumulus cells, which may account for previously reported reduced estradiol production, enhanced progesterone and oxytocin production and diminished ovulation rates. Predicted deficiencies in oocyte survival, stress response, and fertilization suggest likely reductions in oocyte health, which could further compromise oocyte quality and ART outcomes.

Messenger RNA and protein expression of tumor necrosis factor α and its receptors in human follicular granulosa cells

To evaluate the concentration of tumor necrosis factor α (TNF-α) and its soluble receptors (sTNFR I and II) in serum and follicular fluid (FF) at the time of oocyte retrieval and to detect expression of TNF-α and its receptors by luteinized granulosa cells (GCs). In a cross-sectional study and through an in vitro fertilization-intracytoplasmic sperm injection (IVF-ICSI) program, 81 women undergoing oocyte retrieval were recruited. Serum and FF were obtained from 81 women. GCs were pooled from 20 patients (from six different days of oocyte retrievals, 5-16 follicles per patient). TNF-α and its soluble receptors concentration were determined by enzyme-linked immunosorbent assay and also their expression by immune cytochemistry and reverse-transcription polymerase chain reaction analysis. The median TNF-α concentration in serum was 4.06 pg/ml (interquartile range [IQR], 3.71-6.14) and significantly higher than that in FF with 3.50 pg/ml (IQR, 3.05-5.01), p < 0.001. The sTNFR I and II levels in serum were lower and higher than FF, respectively. The TNF-α levels in serum and FF of good responders were higher than low responders (p = 0.017 and 0.021, respectively). TNF-α cut-off level for low responders versus good responders was 4.174 pg/ml in serum with a pregnancy rate of 25.8% and 40% for below and above of this level, respectively (p = 0.19). For FF, the cut-off value was 3.89 pg/ml. TNF-α and its receptors were expressed by GCs. The presence of TNF-α and its soluble receptors in serum and FF and their expression by GCs suggest an important role for this cytokine in ovarian function.

TNF-α Suppressed FSH-Induced LH Receptor Expression Through Transcriptional Regulation in Rat Granulosa Cells

Several inflammatory cytokines regulate ovarian function. TNF-α is produced in granulosa cells under physiological conditions and has a reciprocal action on follicle development. In contrast, in pelvic inflammatory diseases, TNF-α is excessively produced in the pelvic cavity and has an adverse effect on reproductive functions. The objective of this study was to elucidate the mechanism of action of TNF-α on the expression of LH receptor (LHR) in immature rat granulosa cells. TNF-α suppressed FSH-induced LHR mRNA and protein expression and was not associated with cAMP accumulation. By using a luciferase assay, the construct containing base pairs -1389 to -1 of the rat Lhcgr promoter revealed that TNF-α decreased FSH-induced promoter activity. In response to TNF-α, nuclear factor (NF)-κB p65 was translocated to the nucleus, and the suppressive effect of TNF-α on LHR mRNA expression was abrogated by an NF-κB inhibitor. In a chromatin immunoprecipitation assay, TNF-α induced the association of NF-κB p65 with the rat Lhcgr transcriptional promoter region. NF-κB p65 and histone deacetylase (HDAC) interact to mediate expression of several genes at a transcriptional level. HDAC activity is thought to induce tight connections within local chromatin structures and repress gene transcription. Furthermore, the TNF-α-induced suppression of LHR mRNA expression was blocked by an HDAC inhibitor. Taken together, these results suggest that the interaction of NF-κB p65 with HDAC in the promoter region of rat Lhcgr might be responsible for TNF-α action on the regulation of LHR.

Interaction of adenosine 3',5'-cyclic monophosphate and tumor necrosis factor-alpha on serum amyloid A3 expression in mouse granulosa cells: dependence on CCAAT-enhancing binding protein-beta isoform

TNFalpha is an inflammatory-related cytokine that has inhibitory effects on gonadotropin- and cAMP-stimulated steroidogenesis and folliculogenesis. Because ovulation is an inflammatory reaction and TNF specifically induces serum amyloid A3 (SAA3) in mouse granulosa cells, the effect of cAMP on TNF-induced SAA3 promoter activity, mRNA and protein was investigated. Granulosa cells from immature mice were cultured with TNF and/or cAMP. TNF increased SAA3 promoter activity, mRNA, and protein, which were further increased by cAMP. cAMP alone increased SAA3 promoter activity, but SAA3 mRNA and protein remained undetectable. Thus, there appeared to be different mechanisms by which TNF and cAMP regulated SAA3 expression. SAA3 promoters lacking a nuclear factor (NF)-kappaB-like site or containing its mutant were not responsive to TNF but were responsive to cAMP. Among four CCAAT-enhancing binding protein (C/EBP) sites in the SAA3 promoter, the C/EBP site nearest the NF-kappaB-like site was required for TNF-induced SAA3. The C/EBP site at -75/-67 was necessary for responsiveness to cAMP. Dominant-negative C/EBP and cAMP response element-binding protein or short interfering RNA of C/EBPbeta blocked TNF- or cAMP-induced SAA3 promoter activity. The combination of TNF and cAMP increased C/EBPbeta protein above that induced by TNF or cAMP alone. Thus, cAMP in combination with TNF specifically induced C/EBPbeta protein, leading to enhanced SAA3 expression but requiring NF-kappaB in mouse granulose cells. In addition, like TNF, SAA inhibited cAMP-induced estradiol accumulation and CYP19 levels. These data indicate SAA may play a role in events occurring during the ovulation process.

Direct rosiglitazone action on steroidogenesis and proinflammatory factor production in human granulosa-lutein cells

BACKGROUND

Ovarian granulosa cells are the predominant source of estradiol and progesterone biosynthesis in vivo. Rosiglitazone, a synthetic agonist of the peroxisome proliferator-activated receptor gamma (PPAR gamma), is applied as the treatment of insulin resistance including women with PCOS. The aim of the study was to investigate the direct effects of rosiglitazone on steroidogenesis and proinflammatory factor production in human granulosa-lutein cells (GLCs).

METHODS

Primary human GLCs were separated during in vitro fertilization and cultured in the presence of rosiglitazone, GW9662 (an antagonist of PPAR gamma) and hCG. The mRNA expression of key steroidogenic factors including 3beta- hydroxysteriod dehydrogenase (3beta-HSD), cytochrome P-450 scc (CYP11A1), cytochrome P-450 aromatase (CYP19A1), and steroidogenic acute regulatory protein (StAR) were detected by quantitative real-time PCR. Estradiol and progesterone levels in GLCs cultures were measured by chemiluminescence immunoassay, and the proinflammtory factors (TNFalpha and IL-6) in conditioned culture media were measured by ELISA.

RESULTS

PPAR gamma mRNA levels increased up to 3.24 fold by rosiglitazone at the concentration of 30 microM compared to control (P<0.05). hCG alone or hCG with rosiglitazone had no significant effects on PPAR gamma mRNA levels. The CYP19A1 mRNA level at exposure to rosiglitazone alone showed a drop, but was not significantly reduced comparing to control. The expression levels of enzymes 3beta-HSD and CYP11A1 in all treatments did not alter significantly. The StAR mRNA expression at exposure to rosiglitazone was significantly increased comparing to control (P<0.05). The media concentrations of E2 and progesterone by rosiglitazone treatment showed a declining trend comparing to control or cotreatment with hCG, which did not reach significance. Most importantly, treatment with rosiglitazone decreased TNFalpha secretion in a statistically significant manner compared with control (P<0.05). The concentration of IL-6 following rosiglitazone exposure did not significantly decrease comparing to control.

CONCLUSION

In cultured GLCs, rosiglitazone stimulated StAR expression, but did not significantly affect steroidogenic enzymes, as well as E2 and progesterone production. Moreover, rosiglitazone significantly decreased the production of TNFalpha in human GLCs, suggesting that PPAR gamma may play a role in the regulation of GLCs functions through inhibiting proinflammatory factors.

Morphological relationships and leukocyte influence on steroid production in the epigonal organ-ovary complex of the skate, Leucoraja erinacea

In elasmobranchs, a unique association exists between an immune tissue, the epigonal organ (EO), and the gonads. In this study, the histological and vascular relationships of the EO and ovarian follicles of the little skate, Leucoraja erinacea, were assessed. Perfusions of Evans blue dye and Batson's monomer showed a shared vascular pathway from the gonadal artery into the epigonal-ovary complex, with blood first entering the EO and then perfusing the ovarian follicles. Histological studies demonstrated direct cellular contact between epigonal leukocytes and the follicle wall (FW), as well as the presence of leukocytes between the steroidogenic theca and granulosa cells. In vitro analyses demonstrated that epigonal cells co-cultured with FW cells cause a dose-dependent inhibition of estrogen (E2) and testosterone (T) production. In contrast, conditioned media from epigonal leukocytes, stimulated or unstimulated with lipopolysaccharide (10 microg/ml), increase the production of E2 and T from FW cells of the ovaries. These studies provide a basis for further investigations of leukocyte secreted factors and cell contact modulation of follicular steroid production.

Pulsatile luteinizing hormone amplitude and progesterone metabolite excretion are reduced in obese women

CONTEXT

Female obesity is linked to abnormal menstrual cycles, infertility, reproductive wastage, and deficient LH, FSH, and progesterone secretion.

OBJECTIVE AND DESIGN

To elucidate the reproductive defects associated with obesity, we sampled 18 eumenorrheic (nonpolycystic ovary syndrome) women with a mean +/- sem body mass index of 48.6 +/- 1.4 kg/m2 with daily, first morning voided urine collections, seven of whom also had early follicular phase 12-h, every 10-min blood sampling to assess LH pulses. Daily hormones were compared with 11 eumenorrheic, normal-weight controls. A separate control group of 12 eumenorrheic, normal-weight women was used for the LH pulse studies.

MAIN OUTCOME MEASURES

Assays for LH (serum and urine) and FSH, and estradiol and progesterone metabolites (estrone conjugate and pregnanediol glucuronide; urine) were performed. Daily hormones were meaned and normalized to a 28-d cycle length. LH pulsations were determined using two objective methods. Group means were compared using t tests.

RESULTS

Reduced whole-cycle mean, normalized pregnanediol glucuronide was observed in obese (38.2 +/- 2.1 microg/mg creatine) compared with normal-weight women (181.3 +/- 35.1 microg/mg creatine; P = 0.002), without significant differences in LH, FSH, or estrone conjugate. Early follicular phase LH pulse frequency did not differ from normal-weight women, but both amplitude and mean LH were dramatically reduced in obese women (0.8 +/- 0.1 and 2.0 +/- 0.3 IU/liter) compared with controls (1.6 +/- 0.2 and 3.4 +/- 0.2 IU/liter; P < 0.01).

CONCLUSIONS

A novel defect in the amplitude but not the frequency of LH pulsations appears to underlie the reproductive phenotype of obesity. The deficit in pregnanediol glucuronide appears to exceed the deficit in LH. The patterns of hypothalamic-pituitary-ovarian axis function unique to the obese state differ from other abnormal reproductive states.

Tumor necrosis factor-alpha activates transcription of inducible repressor form of 3',5'-cyclic adenosine 5'-monophosphate-responsive element binding modulator and represses P450 aromatase and inhibin alpha-subunit expression in rat ovarian granulosa cells by a p44/42 mitogen-activated protein kinase-dependent mechanism

The proinflammatory cytokine TNFalpha has important actions at the level of the ovary, including inhibition of P450 aromatase (P450AROM) activity and the secretion of inhibin, two proteins that are markers of the granulosa cell's differentiated status. Because the transcription of both P450AROM and inhibin alpha-subunit can be suppressed in the ovary by the inducible repressor isoform of cAMP-responsive element binding modulator (ICER), we have investigated whether TNFalpha and its intracellular messenger ceramide can induce ICER expression and the mechanisms whereby the induction is accomplished. ICER mRNA levels were assessed by RT-PCR in granulosa cells treated with TNFalpha, the ceramide-mobilizing enzyme sphingomyelinase (SMase), or C6-cer, a cell-permeant ceramide analog. Rapid (3 h) yet transient increases in the four isoforms of ICER were observed in response to all treatments. Likewise, ICER protein measured by immunoprecipitation with a specific antibody increases after TNFalpha, SMase, or C6-cer treatment. The mandatory phosphorylation of cAMP-responsive element binding was also observed in response to TNFalpha, SMase, or C6-cer and shown to be prevented by the p44/42 MAPK-specific inhibitor PD098059 but no other kinase blockers. Activation of p44/42 MAPK by the cytokine and its messenger was subsequently demonstrated as well as the inhibition of ICER expression by PD098059. Finally, the blocking of p44/42 MAPK activation prevented TNFalpha inhibition of FSH-dependent increases in P450AROM and inhibin alpha-subunit mRNA levels, thus indicating that p44/42 MAPK-mediated ICER expression may be accountable for the effects of TNFalpha on the expression of both proteins.

Ovarian leukocyte distribution and cytokine/chemokine mRNA expression in follicular fluid cells in women with polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) affects 5-10% of reproductive-aged women and is commonly associated with anovulatory infertility. Leukocytes, together with granulosa cells, may contribute to the pathogenesis of PCOS via their ability to secrete an array of cytokines implicated in follicle growth. The aim of this study was to examine leukocyte subtypes in follicular phase ovaries and to quantify cytokine and chemokine mRNA expression in follicular fluid cells obtained at the time of oocyte retrieval before IVF in women with and without PCOS.

METHODS

Ovaries were immunostained for various leukocyte markers [CD3, CD4, CD14, CD15, CD45, CD45RA, CD45RO, CD57 and major histocompatibility complex (MHC) class II]. In addition, follicular fluid cells were subjected to quantitative RT-PCR to evaluate colony-stimulating factor-1 (CSF-1), granulocyte-macrophage (GM)-CSF, interleukins (IL-1beta, IL-6, IL-8 and IL-10), monocyte chemotactic protein (MCP-1) and tumour necrosis factor (TNFalpha) mRNA expression relative to beta-actin.

RESULTS

CD45RO+ cells (activated/memory T lymphocytes) were reduced by 60% in the theca layer of follicles from PCOS women. The relative abundance of macrophages and neutrophils was unchanged. Cytokine and chemokine mRNA transcripts examined were not affected by PCOS status. There was an association between high BMI and high TNFalpha and low IL-6 mRNA expression in follicular cells. IL-6 expression was higher in women who subsequently achieved pregnancy.

CONCLUSIONS

T lymphocytes potentially play a role in the local pathological mechanisms of PCOS. Further studies are required to identify their contribution to the aetiology of this common condition.

Effects of Induced Clinical Mastitis During Preovulation on Endocrine and Follicular Function

The objective of the study was to determine if experimentally induced clinical mastitis before ovulation resulted in alterations of endocrine function, follicular growth, or ovulation. On d 8 (estrus = d 0), cows were challenged (TRT; n = 19) with Streptococcus uberis or were not challenged (control; n = 14). Forty-eight hours after induction of luteal regression on d 12, blood samples were collected to determine estradiol-17beta, LH pulse frequency, and occurrence of the LH surge. Ovaries were scanned to monitor follicular growth and ovulation. Cows with clinical mastitis (n = 12) had elevated rectal temperatures, somatic cell counts, and mammary scores. Estrus and ovulation occurred in 4 of 12 clinically infected cows and in all control cows. Cows that were challenged but did not develop clinical mastitis (n = 5) displayed estrus and ovulated. Due to differences in expression of estrus, cows were further subdivided for analyses into 4 groups: control, TRT-EST (infected cows that displayed estrus; n = 4), TRT-NOEST (infected cows that did not display estrus; n = 8), and NOMAS (cows that were inoculated but did not develop mastitis; n = 4). Ovulation rate was 100% for CON, NOMAS, and TRT-EST compared with 0% for TRT-NOEST cows. Size of the ovulatory follicle ("presumed" ovulatory follicle in TRT-NOEST cows) was similar for all groups. Frequency of LH pulses was decreased in TRT-NOEST compared with CON, TRT-EST, and NO-MAS. Estradiol-17beta increased over time in CON, NO-MAS, and TRT-EST cows, but did not increase in TRT-NOEST cows. Cows with clinical mastitis may exhibit estrus and ovulate normally or have disruptions in normal physiology including decreased LH pulsatility, absence of an LH surge and estrous behavior, suppressed estradiol-17beta, and failure to ovulate.

Tumor necrosis factor-alpha (TNF alpha) inhibits progesterone and estradiol-17beta production from cultured granulosa cells: presence of TNFalpha receptors in bovine granulosa and theca cells

The aim of this study was to investigate whether functional tumor necrosis factor-alpha (TNFalpha) receptors are present in the granulosa cells and the cells of theca interna (theca cells), obtained from bovine follicles classified into one of three groups. Each group was defined as either small vesicular ovarian follicles (small follicles; 3-5 mm in diameter), preovulatory mature ovarian follicles (preovulatory follicles) or atretic follicles (12-18 mm) according to gross examination of the corpus luteum in the epsilateral or contralateral ovary and the uterus (size, color, consistency and mucus), and the ratio of progesterone (P(4)) and estradiol-17beta (E(2)) concentrations in follicular fluid. A Scatchard analysis showed the presence of a high-affinity binding site on both granulosa and theca cells from all follicles examined (dissociation constant: 4.7 +/- 0.15 to 6.9 +/- 1.40 nM). Moreover, TNFalpha receptor concentrations in granulosa and theca cells obtained from atretic follicles were significantly higher than those in the cells from preovulatory follicles (P<0.05). Exposure of cultured granulosa cells from small antral follicles to recombinant human TNFalpha (rhTNFalpha; 0.06-6 nM) inhibited E(2) secretion in a dose-dependent fashion (P<0.01), but did not affect P(4) secretion. In addition, rhTNFalpha inhibited follicle stimulating hormone-, forskolin- or dibutylyl cyclic AMP-induced P(4) and E(2) secretion by the cells (P<0.01). These results indicate the presence of functional TNFalpha receptors in bovine granulosa and theca cells in small, preovulatory and atretic follicles, and suggest that TNFalpha plays a role in regulating their secretory function.

Prostaglandin F2α amplifies tumor necrosis factor-α promoter activity by the FPB prostanoid receptor

This study examines the regulation of tumor necrosis factor-alpha (TNF-alpha) promoter activity by prostaglandin F2alpha ( PGF2alpha ) in HEK cells stably expressing either the FPA or FPB prostanoid receptors. Cells were transiently transfected with a luciferase reporter plasmid under the control of a TNF-alpha promoter and luciferase activity was measured. In the absence of PGF2alpha basal TNF-alpha reporter gene activity is elevated in FPB cells as compared with FPA cells. This elevated basal activity is blocked by pretreatment with a Rho inhibitor, but not by pretreatment with an inhibitor of protein kinase C (PKC). TNF-alpha reporter activity in FPB cells is stimulated by PGF2alpha and this is decreased by pretreatment with a chelator of intracellular calcium or by a gap junction inhibitor. In FPB cells pretreatment with a Rho inhibitor combined with either a calcium chelator or a gap junction inhibitor decreases both basal and PGF2alpha stimulated TNF-alpha reporter activity. Interestingly post-treatment of FPB cells with an inhibitor of PKC decreased PGF2alpha stimulated TNF-alpha reporter gene activity even though pretreatment did not. It, therefore, appears that PGF2alpha stimulated TNF-alpha reporter activity in FPB cells is amplified by a Rho-dependent mechanism involving calcium, gap junctions, and PKC. These findings may help in understanding the function of the FPB isoform in the corpus luteum.

Tumor necrosis factor alpha (TNF) increases granulosa cell proliferation: dependence on c-Jun and TNF receptor type 1

TNF alpha has significant in vitro effects on steroidogenesis and folliculogenesis and reproductive alterations occur in TNF receptor type 1 (TNFR1) knockout mice. The present study investigated the effect of in vitro TNF on granulosa cell proliferation from immature mice at 28 d of age, with emphasis on intracellular signaling that regulates granulosa cell proliferation. TNF dose dependently increased granulosa cell proliferation and the proto-oncogene c-Jun protein. However, other Jun family members such as JunD was expressed constitutively and JunB was not expressed. In vitro TNF did not increase c-Jun and proliferation in granulosa cells from TNFR1 knockout mice. The time course of TNF-induced c-Jun revealed biphasic patterns of short-term (3 h) and long-term (24 h) induction. The time courses of Ser63- and Ser73-phospho c-Jun coincided with changes in total c-Jun. Among MAPK cascades, stress-activated protein kinase/c-Jun-NH(2)-teminal kinase signaling was increased transiently in TNF-treated cells, whereas p38MAPK and ERK1 and 2 were not changed. In addition, overexpression of nuclear factor-kappa B and addition of ceramide and 8-bromo-cAMP did not increase c-Jun or proliferation. Antisense oligonucleotides for c-Jun blocked cell proliferation induced by TNF. In conclusion, the above results demonstrate that TNF increased c-Jun by activating stress-activated protein kinase/c-Jun-NH(2)-teminal kinase signaling via TNFR1 in mouse granulosa cells, and the induced c-Jun resulted in increased cell proliferation.

Role and gonadotrophic regulation of X-linked inhibitor of apoptosis protein expression during rat ovarian follicular development in vitro

Although FSH up-regulates follicular cell X-linked inhibitor of apoptosis protein (XIAP) expression and suppresses apoptosis in vivo, if these events are coincidental or causally related remains to be investigated. The present study examined the role and gonadotrophic regulation of XIAP expression during follicular development in vitro. Follicles (160-210 microm) cultured for 0-6 days with FSH (100 ng/ml) showed significant growth, as evidenced by increases in follicular size, cell number, and DNA contents. Follicular XIAP content was low in the absence of FSH but was increased by the addition of gonadotropin. Apoptosis was evident in follicles cultured without FSH but was suppressed in the presence of gonadotropin. At low FSH concentration (5 ng/ml), adenoviral XIAP sense cDNA expression increased XIAP and DNA contents, reduced apoptosis, and enhanced follicular growth. Infection of the FSH-stimulated follicles with XIAP antisense elicited opposite responses. In primary granulosa cell cultures, FSH significantly increased XIAP content, inhibited apoptosis, and decreased cell number, a response potentiated by XIAP sense expression. In conclusion, the present studies demonstrated, to our knowledge for the first time, that XIAP plays an important role in the regulation of ovarian follicular development. In addition, a follicle culture system coupled to an adenoviral gene-manipulation procedure has been established and may prove to be a useful approach in assessing the role of specific genes in follicular development and atresia.

Influence of subclinical mastitis during early lactation on reproductive parameters

Our objective was to determine the effects of mastitis during early lactation on the reproductive performance of Jersey cows. From 1986 to 1997, quarter foremilk samples were collected every 4 to 8 wk during lactation, at drying off, near calving, and when clinical mastitis was diagnosed and were evaluated microbiologically to identify causative bacteria. Services per conception, days open, and days to first service were obtained from DHIA records on 752 cows. Cows were separated by mastitis type (clinical, n = 186; subclinical, n = 240; control, uninfected or infected after confirmed pregnancy, n = 326). Cows were reclassified based on the time of clinical or subclinical mastitis as follows: period 1, before first service (n = 374); period 2, between first service and pregnancy (n = 52); and period 3, after confirmed pregnancy or uninfected (control; n = 326). Milk production did not differ for any group separations. Reproductive performance did not differ between gram-negative or gram-positive mastitis pathogens. Cows with clinical or subclinical mastitis before first service had increased days to first service (77.3+/-2.7 and 74.8+/-2.7 d), days open (110.0+/-6.9 and 107.7+/-6.9 d), and services per conception (2.1+/-0.2 and 2.1+/-0.2) compared with controls (67.8+/-2.2 d, 85.4+/-5.8 d, 1.6+/-0.2; P < 0.05). Days to first service were not increased in cows with clinical or subclinical mastitis during period 2 (70.6+/-3.3 and 61.2+/-7.8 d). However, days open (143.6+/-8.5 d) and services per conception (3.0+/-0.2) were increased (P < 0.05) in cows with clinical mastitis during period 2, but not in cows with subclinical mastitis (90.9+/-20.2 d and 2.1+/-0.5). Cows initially diagnosed subclinical that became clinical during period 2 exhibited increased days to first service (93.9+/-10.1 d), days open (196.0+/-26.2 d), and services per conception (4.3+/-0.7) compared with control animals (P < 0.05). In conclusion, subclinical mastitis reduced reproductive performance of lactating cows similar to clinical mastitis. Subclinical mastitis followed by clinical mastitis resulted in the most severe loss in reproductive performance.

Influence of the drinking water disinfection by-product dibromoacetic acid on rat estrous cyclicity and ovarian follicular steroid release in vitro

The drinking water disinfection by-product, dibromoacetic acid (DBA) has been reported to affect gonadal functions in the male rat. However, there is little information regarding the influence of DBA on female reproductive activity. Consequently, the present study investigated the effects of DBA on estrous cyclicity and the impact in vitro of DBA on ovarian follicular steroid secretion. Regularly cycling animals were dosed with DBA (0 to 270 mg/kg/day) for 14 days and estrous cyclicity was monitored during treatment and for an additional 2-week posttreatment interval. A dose-related alteration in cyclicity was observed at 90 and 270 mg/kg/day, which persisted through the posttreatment monitoring in the high dose group. An in vitro exposure of preovulatory follicles to DBA was then used to assess the influence of DBA on steroid release. To select a concentration for use, a single oral exposure to 270 mg/kg was administered, and the mean blood levels were determined over a 5-h interval. For this in vitro work, pairs of preovulatory follicles from PMSG-primed immature rats were exposed to 0 or 50 microg/mL DBA over a 24-h period and evaluated for estradiol and progesterone release under baseline and hCG-stimulated conditions. The influence of tumor necrosis factor (TNFalpha) exposures under these conditions was also determined. In the nonstimulated condition, DBA was found to increase the release of estradiol, but had no detectable effect in response to hCG. Progesterone, however, showed marked suppression under hCG stimulation following exposure to DBA, while nonstimulated secretion was unaffected. TNFalpha by itself also suppressed stimulated progesterone release, but had no additional effect in combination with DBA. The data suggest that one factor in the disruption in estrous cyclicity could be an alteration in steroid production, which was characterized by separate effects on both estradiol and progesterone secretion.

Modulation of estrogen production and 17beta-hydroxysteroid dehydrogenase-type 1, cytochrome P450 aromatase, c-met, and protein kinase Balpha messenger ribonucleic acid content in rat ovarian granulosa cells by hepatocyte growth factor and follicle-stimulating hormone

Hepatocyte growth factor (HGF) suppresses FSH-dependent estradiol-17beta (E(2)) production in ovarian granulosa cells (GC). The mechanisms of action for HGF in GC are unknown; however, activation of the HGF receptor, c-Met, can induce c-Akt/protein kinase B (PKB)-mediated signal transduction in nonovarian cells. Using immature rat GC, the present study investigated the effects of HGF within the estrogen biosynthetic pathway, concomitant with changes in c-Met and PKBalpha mRNA expression. Granulosa cells were incubated with androstenedione and FSH, HGF, and/or dibutyryl-cAMP (Bu(2)-cAMP). Follicle-stimulating hormone and Bu(2)-cAMP each stimulated estrone (E(1)) and E(2) synthesis at 48 h. Hepatocyte growth factor suppressed FSH-dependent E(2), but not E(1), synthesis. Semiquantitative reverse transcription-polymerase chain reaction showed that HGF impaired FSH-supported 17beta-hydroxysteroid dehydrogenase type-1 (17beta-HSD) and cytochrome P450 aromatase (P450arom) mRNA levels. Hepatocyte growth factor did not reduce E(2) synthesis or 17beta-HSD and P450arom mRNA expression in the presence of Bu(2)-cAMP at 48 h. The FSH and HGF each down-modulated c-Met mRNA accumulation, whereas Bu(2)-cAMP increased c-Met mRNA content. Between 0 and 48 h a biphasic change in PKBalpha mRNA content occurred with either FSH or HGF; however, PKBalpha mRNA accumulation was augmented by HGF. Collectively, results suggest that HGF can suppress E(2) production in GC by disrupting cAMP-dependent 17beta-HSD and P450arom. Changes in c-Met and PKBalpha mRNA content provide a potential link between HGF signaling and the FSH-dependent mechanisms that control the steroidogenic differentiation of GC.

Evidence for the presence of tumor necrosis factor alpha receptors during ovarian development in the rat

Tumor necrosis factor alpha (TNFalpha) is an intraovarian cytokine that may play a role in ovarian development and function. Effects of TNFalpha are mediated by binding to at least one of two TNFalpha receptor subtypes (with molecular masses of approximately 60 and 80 kDa); therefore, the overall goal of this study was to determine whether rat ovaries have TNFalpha receptors during critical times in development. Two approaches were used: 1) demonstration of specific binding of radiolabeled TNFalpha to ovarian cells and 2) semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis for each of the two TNFalpha receptors. Ovarian cells were obtained on Embryonic Day 19, day of birth (Day 0), and Days 2, 5, 10, and 20. TNFalpha binding was present on all days, with significantly greater binding on Day 20. Messenger RNA for both receptor subtypes was detected on all days using RT-PCR analysis but was significantly greater for the 60-kDa receptor on Day 20. In conclusion, rat ovaries contained receptors capable of binding TNFalpha and mRNA for both receptor subtypes. Identification of ovarian TNFalpha receptors provides support for a role of TNFalpha in ovarian development and function.

Potentiation of Fas-mediated apoptosis of murine granulosa cells by interferon-gamma, tumor necrosis factor-alpha, and cycloheximide

The Fas antigen is a transmembrane receptor belonging to the tumor necrosis factor-alpha (TNF) receptor family that, when activated by Fas ligand or agonistic antibodies, induces death by apoptosis. Although the presence of Fas antigen in ovarian tissues has been demonstrated, little is known about whether Fas antigen is functional in the ovary. This report shows that murine granulosa cells are initially resistant to antibody-induced Fas-mediated apoptosis, but will undergo apoptosis when cotreated with TNF and interferon-gamma (IFN) or cycloheximide (CX). Granulosa cells were obtained from follicles of 23-day-old mice 2 days after injection of PMSG. Twenty-four hours after plating, cells were pretreated with either 0 or 200 U/ml IFN, which has been shown to induce Fas antigen expression and is required for Fas-mediated killing in many cell types. At 48 h, cells were treated with 2 microg/ml control IgG, 2 microg/ml anti-Fas antigen antibody (Fas mAb), 10 ng/ml TNF, or Fas mAb and TNF. Cytotoxicity (percent killing) relative to control IgG was determined at 72 h by counting granulosa cells after trypsinization. In the absence of IFN, no cytotoxicity was observed. In the presence of IFN, neither TNF or Fas mAb alone was cytotoxic, but the combination of Fas mAb and TNF resulted in 25% killing (P < 0.05). Fas antigen messenger RNA (mRNA) was detectable in cultures not treated with cytokines and was increased 5-fold by TNF, 2-fold by IFN, and 17-fold by the combination of IFN and TNF. To test whether the presence of a labile inhibitor(s) of Fas-mediated killing in granulosa cells is the cause of resistance to Fas mAb, the protein synthesis inhibitor CX was used. Experiments were performed as described above, except that cells were treated with 0.5 microg/ml CX in conjunction with other treatments at 48 h. Fas mAb treatment in the presence of CX induced 25% cell death without IFN pretreatment and 38% with IFN (P < 0.05). TNF treatment in the presence of CX had no effect alone, but potentiated the effects of Fas mAb, resulting in 56% killing in the absence of IFN and 86% killing in the presence of IFN (P < 0.05). Cells stained positively for DNA fragmentation and annexin V binding, features characteristic of apoptosis. Because initial experiments showed that treatment with TNF alone increased Fas mRNA levels, the effect of pretreating cells for 24 h with TNF before treatment with Fas mAb was tested. Pretreatment with TNF or IFN alone did not promote Fas mAb-mediated killing, but combined pretreatment with TNF and IFN resulted in 25% killing in response to Fas mAb. Treatment of cells with the combination of IFN and TNF induced a 19-fold increase in Fas antigen mRNA levels. Corresponding increases in Fas antigen protein expression on the surface of cells in response to cytokine treatments were detected by immunocytochemistry. Human TNF did not duplicate the effects of mouse TNF in inducing Fas antigen mRNA expression and Fas mAb-induced killing. As human TNF interacts exclusively with the type I, but not the type II, TNF receptor in the mouse, potentiating effects of mouse TNF on the Fas pathway are probably mediated via the type II TNF receptor. The effects of cytokine treatments on levels of mRNA for FAP-1, an inhibitor of Fas-mediated apoptosis, were determined. FAP-1 mRNA was detectable in untreated granulosa cells, and levels were not altered by treatment with TNF and/or IFN. In summary, the Fas-mediated pathway of apoptosis is functional in mouse granulosa cells that are stimulated with IFN and TNF. These cytokines may function at least partially by increasing Fas antigen expression. Granulosa cells appear to have inhibitors of the Fas antigen pathway, as treatment with CX potentiates Fas-mediated death. TNF promotes Fas-mediated killing in the presence and absence of CX. Therefore, TNF is not likely to act simply by increasing Fas antigen expression or decreasing protein inhibitors of the Fas pathway, because TNF remains effec

Tumor necrosis factor-alpha (TNF-alpha) inhibits steroidogenesis of bovine ovarian granulosa and thecal cells in vitro. Involvement of TNF-alpha receptors

The effect of recombinant bovine tumor necrosis factor-alpha (TNF-alpha) on steroidogenesis and numbers of bovine ovarian granulosa and thecal cells has been studied, and specific binding sites for 125I-TNF-alpha on ovarian cells have been determined. Granulosa cells have been examined from small (surface diameter 1-5 mm) follicles, whereas thecal cells from large (> or = 8 mm) follicles were utilized. Increasing doses of TNF-alpha significantly attenuated insulin- and IGF-I-induced estradiol production by granulosa cells from small follicles, but had no effect on basal estradiol production. Moreover, TNF-alpha significantly attenuated insulin- and LH-induced androstenedione production by thecal cells from large follicles. TNF-alpha had little or no effect on the numbers of granulosa and thecal cells in these same studies. Specific high-affinity, low-capacity binding of 125I-TNF-alpha was also demonstrable in granulosa and thecal cells. Thus, it appears that TNF-alpha inhibits insulin- and IGF-I-induced estradiol production by granulosa cells and androstenedione production by thecal cells via TNF-alpha binding to its own receptor.

Changes in ovarian follicles following acute infection with bovine viral diarrhea virus

Bovine viral diarrhea virus (BVDV) has been associated with several reproductive problems in cattle, including poor fertility, early embryonic deaths, abortion and congenital anomalies. Little is known about the cause of poor fertility in cows acutely infected with BVDV. The purpose of this study was to identify changes in ovarian function following acute infection with noncytopathic BVDV. The ovaries of 5 BVDV sero-negative and virus-negative pubertal heifers were monitored daily for 4 consecutive estrous cycles. The position and diameter of all follicles (> 5 mm) and luteal structures were recorded. Daily plasma samples were collected to measure peripheral progesterone and estradiol levels. Each heifer was infected intranasally with noncytopathic BVDV following ovulation of the second estrous cycle. The maximum diameter and growth rate of dominant anovulatory and ovulatory follicles were significantly reduced following acute BVDV infection. Similarly, the number of subordinate follicles associated with both the anovulatory and ovulatory follicle was reduced following infection. There were no significant differences in other follicle or luteal dynamic parameters or in peripheral progesterone or estradiol levels. Ovarian follicular growth was different during the first 2 estrous cycles following acute infection with BVDV when compared with the 2 estrous cycles preceding infection. These differences may be important in explaining reduced fertility in herds with acute BVDV infection.

GRO-alpha in human serum: differences related to age and sex

PROBLEM

Human GRO-alpha (GRO-alpha) is a new member of the chemokine family that is supposed to play an important role in inflammatory and immune reactions. We established a sandwich enzyme-linked immunoassay (ELISA) system with polyclonal antibodies against human GRO-alpha and investigated the serum level of healthy donors to establish normal ranges for this chemokine in adults.

METHODS

GRO-alpha concentrations were measured cross-sectionally in the sera of 240 healthy adults. The variability of serum GRO-alpha levels was also measured in normal volunteers, samples from whom were obtained by sequential venipunctures or by a small plastic cannula with a heparin-saline lock, to determine short-term variability.

RESULTS

Whereas there was no difference between the concentration of human GRO-alpha from men (logarithmic mean, 77.6 pg/ml, n = 120) and that from women with normal menstrual cycles (log mean, 71.6 pg/ml, n = 73), the concentration from postmenopausal women (log mean 45.0 pg/ml, n = 31) was lower than that from women with normal menstrual cycles (log mean 71.6 pg/ml, n = 73). However, we could not detect any significant difference between healthy donors' serum levels and those of donors with acute inflammation. Fewer variations were recognized in the case of the sequential venipunctures method than in that of the heparin-saline lock method.

CONCLUSION

We found that the GRO-alpha concentration of postmenopausal women was significantly lower than that of women with normal menstrual cycles. These results suggest the GRO-alpha serum levels of normal healthy women may have some correlation with sex hormones.

Effect of tumor necrosis factor-alpha on progesterone production by granulosa cells in laying hens of different genetic lines

In vitro progesterone production by granulosa cells in the presence or absence of human recombinant tumor necrosis factor-alpha (hrTNF-alpha) was measured at 10, 20, and 30 wk of egg production in White Leghorn hens selected for high (HA)- or low-antibody (LA) response to sheep red blood cell challenge. Isolated granulosa cells from the three largest preovulatory follicles (F1-F3) were incubated with 5 or 250 ng/ml hrTNF-alpha, and progesterone production was determined by the use of a validated radioimmunoassay. F1, F2 and F3 granulosa cells from HA hens produced more (P < or = 0.05) progesterone (140.8, 107.2, and 49.7 ng/ml) than LA hens (109.4, 78.9, and 26.9 ng/ml). The treatment of granulosa cells with hrTNF-alpha consistently inhibited (P < or = 0.05) progesterone secretion by all follicles among HA and LA hens, but not always at both doses. Generally, 5 ng/ml hrTNF-alpha was the maximum inhibitory dose. In the laying hen, a decrease in steroid production in response to cytokines may upset the steroid balance created by follicular hierarchy and inhibit or delay ovulation.

Review: cytokine involvement in ovarian processes

PROBLEM

Expression of tumor necrosis factor-alpha (TNF) and interleukins 1 alpha and 1 beta (IL-1) have been reported in ovaries of several species and humans and are implicated in ovarian follicular development and atresia, ovulation, steroidogenesis, and corpus luteum function (including formation, development, and regression). The principal abnormal processes affected by these cytokines are ovarian cancer and reduction of ovarian function during sepsis.

METHODS

A literature review.

RESULTS

Numerous studies indicate that TNF and IL-1 inhibit gonadotropin-stimulated steroidogenesis of undifferentiated ovarian cells due to inhibition of adenylyl cyclase and post-cAMP sites. In differentiated ovarian cells, these cytokines either stimulate progesterone synthesis or have little to no effect on steroidogenesis. Both cytokines participate in ovulation and levels of these cytokines increase during the preovulatory period. Endotoxin inhibits gonadotropin-stimulated ovarian steroidogenesis and follicular development and these effects are mediated, in part, by TNF and by direct effects of endotoxin on ovarian cells. IN newly formed corpora lutea, progesterone secretion is inhibited by TNF and IL-1, although each has proliferative effects. TNF also has been implicated in regression of corpora lutea because TNF stimulates prostaglandin synthesis and luteal TNF increases after initiation of the decline in progesterone secretion. TNF and IL-1 are secreted by some ovarian cancer cells and stimulate growth of these cells.

CONCLUSIONS

Thus, TNF and IL-1 are multifunctional factors affecting various ovarian processes.

Ovarian control of follicle development

A variety of ovarian autocrine and paracrine factors may modulate folliculogenesis and steroid production. The developmental program that leads to the production of a dominant follicle involves a precise quantitative and temporal pattern of expression of a large number of genes. Follicle-stimulating hormone plays an essential role in this process, and no other ligand by itself can serve in this regulatory capacity. It is clear that a variety of growth factors can modulate follicle-stimulating hormone action by autocrine and paracrine mechanisms. Advances in the understanding of the role of growth factors, particularly the family of insulin-like growth factor-related proteins, in regulating follicle-stimulating hormone action are discussed. It is likely that complex interactions exist between follicle-stimulating hormone and the growth factors. Significantly, growth factor regulation by pituitary gonadotropins is probably a central feature of their expression. With increased understanding of the ovarian control of follicle development, it is hoped that newer and more effective regimens for synchronous follicular and oocyte maturation can be realized.

Interleukin-1β inhibits luteinizing hormone-induced plasminogen activator activity in rat preovulatory folliclesin vitro

The effects of interleukin-1β (IL-1β) and tumour necrosis factor-α (TNFα) on ovulation-associated plasminogen activator (PA) activity were investigated using preovulatory follicles excised 48h after equine chorionic gonadotrophin (16IU)-priming of immature rats. Follicles were incubated for 6 and 14h with a single dose of LH (1 μg/ml) only, or various cytokine doses in the presence or absence of LH. PA activity in follicular homogenates was determined by a radioactively labelled fibrin-coated plate method and secreted levels of the ovulatory mediators progesterone (P) and prostaglandin E (PGE) were measured by radioimmunoassay. LH induced timedependent rises in PA (2.5-fold over control at 6h and fourfold over control at 14h), while IL-1β and TNFα alone had no effect over either time period. LH and cytokine coincubations over 14h revealed that IL-1β dosedependently inhibited the LH-induced increase in PA activity, up to 85%. The effects of TNFα on LH-induced PA activity were not significant. Both IL-1β and TNFα increased P and PGE secretion time- and dose-dependently. In summary, IL-1β dose-dependently inhibits the LH-induced increase in PA activity in rat preovulatory folliclesin vitro while, as with TNFα, increasing P and PGE synthesis. This study, shows that the earlier reported pro-ovulatory action of IL-1β is not likely to be mediated by activation of the PA-system and suggests that IL-1β may mediate a regulatory loop controlling the extent and distribution of LH-induced PA activity in rat preovulatory follicles.

Effects of cytokines on FSH-induced estradiol production by bovine granulosa cells in vitro: dependence on size of follicle

The objective of the present studies was to determine the effect of cytokines on FSH-induced estrogen production by granulosa cells from small (1-5 mm) and large (> or = 8 mm) bovine follicles. FSH-induced estradiol production by granulosa cells from large follicles (expressed as pg estradiol/10(5) cells/24 hr) was not affected (P > .05) by 10 or 100 ng/ml of interleukin (IL)-1 beta, 10 or 100 ng/ml of tumor necrosis factor-alpha (TNF alpha) or 100 ng/ml of IL-2. In contrast, 100 ng/ml of IL-1 beta, IL-2 or TNF alpha inhibited (P < .05) FSH-induced estradiol production by 31%, 55% or 72%, respectively in cells from small follicles. Interferon-alpha (IFN alpha; 100 U/ml) inhibited (P < .05) FSH-induced estradiol production by 61% and 20% in cultures of cells from small and large follicles, respectively. Interferon-beta (IFN beta; 100 U/ml), interferon gamma (IFN gamma; 100 U/ml) and bovine trophoblast protein-1 (bTP-1; 100 U/ml) inhibited (P < .05) estradiol production by 47%, 71% and 28%, respectively in cells from small follicles, but had no effect (P > .05) on FSH-induced estradiol production in cells from large follicles. TNF alpha binding protein-I blocked (P < .05) the inhibitory effect of TNF alpha on FSH-induced estradiol production by cells from small follicles. Viability of granulosa cells was not affected (P > .05) by the various cytokines. In summary, cytokines have little or no effect on FSH-induced estradiol production by bovine granulosa cells collected from large follicles, whereas cytokines (bTP-1 < or = IL-1 beta < IL-2 = IFN beta < IFN alpha < TNF alpha) have potent inhibitory effects on FSH-induced estradiol production by granulosa cells collected from small follicles. Thus, it appears that less differentiated granulosa cells (small follicles) are more responsive to cytokines than are highly differentiated granulosa cells (large follicles).

Tumor necrosis factor-alpha alters steroidogenesis and stimulates proliferation of human ovarian granulosal cells in vitro

OBJECTIVE

To determine if tumor necrosis factor alpha (TNF-alpha) altered human granulosa-luteal cell proliferation and steroidogenesis.

DESIGN

Aspirates of follicles from women undergoing in vitro fertilization were subjected to Percoll gradients to collect an enriched population of granulosa-luteal cells. The granulosa-luteal cells were subjected to culture for a period of 10 or 20 days in the presence or absence of various doses of human recombinant TNF-alpha (0.1 to 10.0 ng/mL).

PATIENTS

Granulosa-luteal cells from nine patients were evaluated for their response to TNF-alpha in vitro. Patients with three follicles > 16 mm and a serum estradiol (E2) concentration of > 1,836 pmol/L were selected for study.

RESULTS

Tumor necrosis factor-alpha increased granulosa-luteal cell number. By day 10 of culture, 10 ng TNF-alpha/mL doubled cell number and > 95% of the cells exhibited 3 beta-hydroxysteroid dehydrogenase. Tumor necrosis factor-alpha at 10 ng/mL increased progesterone (P) accumulation from day 4 through day 20 of culture. Tumor necrosis factor-alpha also increased E2 secretion but in a biphasic manner. During the first 14 days of culture, TNF-alpha increased E2, but thereafter E2 decreased to basal values by day 20. When steroidogenesis was expressed per 1,000 cells per days of culture, TNF-alpha did not increase P beyond controls but significantly increased E2 for the first 14 days of culture after which E2 per 1,000 cells declined.

CONCLUSIONS

The results indicate that TNF-alpha stimulates granulosal-luteal cell growth and E2 secretion in vitro, and thus TNF-alpha may promote cellular events associated with formation of the corpus luteum; i.e., granulosa-cell proliferation and steroidogenesis.

New concepts in ovarian regulation: an immune insight

The purpose of the ovary is to produce eggs. In the human, oocyte production occurs cyclically at monthly intervals. The control of egg production is provided by both the endocrine and immune systems. Successful oocyte production is the result of sophisticated communication between the two systems. These interactions allow adaptive processes necessary for continuation of the species.

The ovary

The functions of the ovary can be described as a storehouse for oocytes as well as a factory to produce mature oocytes at the appropriate time for fertilization and hormones at the appropriate time and in the appropriate quantities to assure fertility. A complex multiple-job specification such as this requires control processes which allow all facets to operate successfully at the same time, and in a co-ordinated manner. This can only be achieved by hypothesizing control at several levels, namely, externally via gonadotrophins (and perhaps GH and prolactin), and internally via local regulators, where the local regulators control the gonadotrophin-independent processes and fine tune the gonadotrophin-dependent processes. The available evidence is consistent with a role for local regulators in the control of follicular and luteal function in the ovary. In most cases, however, the nature of the local regulator involved in a particular process is not known. On the other hand, the list of candidates continues to increase (see Table 1). A priority for future research will be to firmly establish many of these substances as local regulators and to understand how and when they exert their actions, particularly in vivo. A particularly complex question concerns the potential interaction between the local regulators which have either similar or opposing actions. The clinical significance of local regulation in the ovary is yet to be fully appreciated. The addition of GH to gonadotrophin therapy for ovulation induction (Homburg et al, 1988) is the first example of the application of findings from basic research on local regulators in the ovary. It may be that clinical syndromes such as resistant ovary syndrome, polycystic ovarian disease and luteinized unruptured follicle have some perturbation of local regulator production or action, which, if defined, would underline the importance of local regulation and could offer a means of treatment.

Immunology of ovarian failure

Ovarian failure is the result of depletion of ovarian follicles. Naturally occurring ovarian failure usually takes place around 50 years of age in the human. Premature ovarian failure occurs in 1% of women and is the result of acceleration of rate of ovarian follicular depletion in the majority of cases. Cytokines are involved in the mechanisms of ovarian follicular atresia, whether it occurs at a normal or accelerated rate. It is the balance between the actions of TGF alpha and TGF beta upon the granulosa cell that determines the fate of a nonluteinized follicle and between LH and INF gamma that determines destiny of a luteinized follicle. When granulosa cells express MHC antigens in response to IFN gamma or genetic stimulus, an autoimmune reaction ensures resulting in follicular atresia. If the immune processes proceed continuously rather than cyclically, premature ovarian failure occurs. Thus, not only do the immunologic and endocrinologic systems need to communicate to allow normal ovarian function, evidence exists to support the concept that they interact in the pathophysiology of ovarian failure.