Alterations in mast cell degranulation and ovarian histamine in the proestrous hamster

Male and female gonadal ageing: its impact on health span and life span

Ageing is linked to changes in the hypothalamic-pituitary-gonadal axis and a progressive decline in gonadal function. While women become infertile when they enter menopause, fertility decline in ageing men does not necessarily involve a complete cessation of spermatogenesis. Gonadal dysfunction in elderly people is characterized by morphological, endocrine and metabolic alterations affecting the reproductive function and quality of life. With advancing age, sexuality turns into a critical emotional and physical factor actually defining the number of years that ageing people live a healthy life. Gonadal ageing correlates with comorbidities and an increased risk of age-related diseases including diabetes, kidney problems, cardiovascular failures and cancer. This article briefly summarizes the current state of knowledge on ovarian and testicular senescence, explores the experimental models used in the study of gonadal ageing, and describes the local pro-inflammatory, oxidative and apoptotic events and the associated signalling pathways that take place in the gonads while people get older. Overall, literature reports that ageing exacerbates a mutual crosstalk among oxidative stress, apoptosis and the inflammatory response in the gonads leading to detrimental effects on fertility. Data also highlight the clinical implications of novel therapeutic interventions using antioxidant, anti-apoptotic and anti-inflammatory drugs on health span and life span.

Possible protective effects of crocin on destructive side effects of cyclo-phosphamide in mice ovarian tissue: Evaluation of histomorphometrical and biochemical changes

One of the side effects of cyclophosphamide (CP) is low fertility. In this study, we investigated the protective role of crocin (Cr) against CP chemotherapy-induced changes in ovarian tissue. In the current study, we treated 15 female mice aged 6-8 weeks old for 21 days. The mice were distributed into three groups including control received normal saline (0.10 mL; IP), CP or sham-control group (CP once a week, 15.00 mg kg-1; IP) and experimental (CP + Cr) group received CP along with Cr (200 mg kg-1 daily; IP). After completing the procedure, levels of total anti-oxidant capacity (TAC), superoxide dismutase (SOD) and sex hormones in serum as well as malondialdehyde (MDA) in the left ovarian tissue were measured. The right ovaries were used for histological and morphological tests. The obtained data were statistically analyzed by SPSS software using ANOVA and Tukey follow-up studies. Results showed that in the CP group a significant decrease was observed in ovarian follicles, the number of corpus luteum, levels of TAC, SOD and sex hormones; while, there was a significant increase in the number of atretic follicles and mast cells and level of MDA compared to control group. Administration of Cr along with CP caused a significant ameliorative effect on the studied parameters. In conclusion, the Cr could significantly decrease the side effects caused by CP chemotherapy in mice ovarian tissue.

The rat oocyte synthesises melatonin

Melatonin (N-acetyl-5-methoxytryptamine) is an indoleamine originally identified in the pineal gland, where it is synthesised enzymatically from serotonin (5-hydroxytryptamine) by the sequential action of arylalkylamine N-acetyltransferase (AANAT) and acetylserotonin O-methyltransferase (ASMT; also known as hydroxyindole O-methyltransferase). Melatonin directly affects ovarian functions and previous studies have suggested that melatonin is synthesised in the ovary. In the present study, we examined whether AANAT and ASMT are expressed in the adult rat ovary. Reverse transcription-polymerase chain reaction analyses demonstrated that both AANAT and ASMT mRNAs are expressed in the ovary. Western blotting for AANAT protein showed that the ovary, like the pineal gland, contains this enzymatic protein with a molecular mass of 24kDa. Immunohistochemistry revealed that the AANAT protein is localised to the oocyte, corpus luteum and medulla, including mast cells. AANAT protein was found in oocytes at all stages of follicular development, and its levels in oocytes increased progressively throughout follicular development. Furthermore, isolated oocytes metabolised exogenous serotonin to melatonin. These findings demonstrate that melatonin is synthesised from serotonin in oocytes. Melatonin synthesised in the oocyte may be implicated in its own growth or maturation, for example, by acting as a calmodulin antagonist or an antioxidant.

Dual role of histamine in modulation of Leydig cell steroidogenesis via HRH1 and HRH2 receptor subtypes

Although several reports indicate effects of histamine (HA) on female reproductive functions, scant literature exists to suggest a physiological role of HA in the male gonad. In the present study, we report a dual concentration-dependent effect of HA on steroidogenesis in MA-10 murine Leydig cells and purified rat Leydig cells. Although 1 nM HA can stimulate steroid production and significantly increase the response to LH/hCG in these cells, 10 microM HA exerts an inhibitory effect. We also provide confirming evidence for the existence of functional HRH1 and HRH2 receptors in both experimental models. The use of HRH1 and HRH2 selective agonists and antagonists led us to suggest that HRH2 activation would be largely responsible for stimulation of steroidogenesis, while HRH1 activation is required for inhibition of steroid synthesis. Our results regarding signal transduction pathways associated with these receptors indicate the coupling of HRH2 to the adenylate cyclase system through direct interaction with a Gs protein. Moreover, we show HRH1 activation mediates increases in inositol phosphate production, possibly due to coupling of this receptor to Gq protein and phospholipase C activation. The data compiled in this report clearly indicate that HA can modulate Leydig cell steroidogenesis in the testis and suggest a possible new physiological site of action for HA. Given that many drugs binding to HRH1, HRH2, or both, are widely prescribed for the treatment of diverse HA-related pathologies, it seems necessary to increase the knowledge regarding histaminergic regulation of testicular functions, to avoid possible unexpected side effects of such substances in the testis.

Inhibition of the increased 17β-estradiol-induced mast cell number by melatonin in the testis of the frog Rana esculenta, in vivo and in vitro

In the present study, we have utilized 17β-estradiol to induce the increase of mast cell number in order to verify the melatonin effect on mast cell accumulation in the frog testicular interstitium. Data obtained from in vivo experiments confirm that 17β-estradiol increases the mast cell number and indicate a melatonin-inhibitory role in their accumulation in the frog testis. In addition, melatonin interferes with the effects of estradiol on the increase of mast cell number in short-term cultured testes, and this result has also been obtained in a dose-response experiment at physiological concentration. The data suggest that melatonin acts on mast cell number directly via its local action in the frog gonads. In conclusion, our study shows, for the first time, that melatonin may interfere, probably via estrogen receptors, with the differentiation and/or proliferation of mast cells induced by estradiol treatment either in vivo or in vitro in the testis of the frog Rana esculenta.

Granulocyte-macrophage colony-stimulating factor enhances interleukin-1beta stimulated histamine release in the preovulatory rat ovary

The existence of immune cells including macrophages and mast cells in rat ovary implies that various cytokines from these cells may play a role in ovarian functions. The aim of the present study was to investigate whether granulocyte-macrophage colony stimulating factor (GM-CSF) and interleukin-1beta are capable of stimulating histamine release and steroidogenesis in rat ovary, and to determine the sites of histamine production in the ovary. Histamine release from preovulatory ovarian tissues was stimulated in a dose-dependent manner at 3-30 ng/ml of GM-CSF in the presence of interleukin-1beta (10 ng/ml). However, treatment with GM-CSF and interleukin-1beta did not cause any significant change in the levels of ovarian steroids. Intense staining of histidine decarboxylase in the ovary was immunohistochemically detected in large granular cells on the morning of the pro-oestrus day. These results indicate that GM-CSF may be involved in the regulation of ovarian histamine secretion in mast cells partially by enhancing interleukin-1beta-induced histamine release in the process of ovulation.

Distribution of histamine in laying hen ovary

In a laying hen, histamine was found to be present in all compartments of the ovary, i.e. stroma with follicles < 1 mm, small white (1-4 mm), large white (4-8 mm), atretic white, yellow preovulatory (8-35 mm) and postovulatory follicles. Stroma containing non-yolky follicles exhibited the highest histamine concentration (6080 +/- 331 ng/g wet wt. tissue) which differed significantly (P < 0.01) from histamine levels observed in all examined classes of ovarian follicles. High histamine concentration was found in small, large and atretic white follicles as well as in older postovulatory follicles whereas low levels of histamine contained yellow preovulatory and younger postovulatory follicles. Population of yolky white follicles presented significant (P < 0.01) differences in histamine level among small (4280 +/- 333), atretic (2940 +/- 193) and large (2010 +/- 110 ng/g) follicles. Within hierarchy of yellow preovulatory (F7-F1) follicles initial decrease in histamine concentration, from 859.3 +/- 51.5 ng/g in F7 follicle to 363.9 +/- 28.3 ng/g in F4 follicle, was followed by the increase as follicle matured, reaching the highest level in F1 follicle (711.4 +/- 35.9 ng/g). In postovulatory (P1-P5) follicles histamine concentration gradually increased as they were getting older, from 604.3 +/- 49.3 ng/g in P1 follicle to 2253 +/- 197 ng/g in P5 follicle. Determination of histamine in relation to ovulation revealed significant (P < 0.01) difference both in histamine concentration and content between the largest preovulatory F1 follicle and the largest postovulatory P1 follicle, being 0.5 h before and 0.5 h after ovulation, respectively. It is suggested that in chicken, ovarian histamine may play a role in the follicular development and/or the ovulatory process.

Oocyte sensitivity to serotonergic regulation during the follicular cycle of the teleost Fundulus heteroclitus

In the teleost Fundulus heteroclitus, serotonin (5-HT) reversibly inhibits oocyte maturation induced in vitro by the maturation-inducing steroid (MIS) 17,20beta-dihydroxy-4-pregnen-3-one (17,20betaP). The 5-HT inhibition of 17,20betaP-induced meiotic maturation was examined in ovarian follicles at different developmental stages or isolated at different times during the follicular cycle. Steroid treatment of late vitellogenic and early maturing follicles (1.2- to 1.7-mm diameter) promoted oocyte maturation in a size-dependent manner, and this maturation was inhibited by 5-HT in follicles of < 1.6- to 1.7-mm diameter. Thus, the 5-HT inhibition progressively decreased as follicles developed the ability to mature in the absence of 17,20betaP. The effectiveness of 5-HT to increase follicular cAMP remained similar within the same developmental stages, indicating that the reduction of 5-HT inhibitory action was not related to the competence of 5-HT to activate inhibitory signals in the oocyte. During the follicular cycle, fully grown follicles (1.3- to 1.4-mm diameter) showed a decreased maturational competence in response to gonadotropin or MIS stimulation after the follicular recruitment into maturation and spawning occurred, which coincided with an increase of the effectiveness of 5-HT at inhibiting 17,20betaP-induced maturation. In further experiments, preincubation of follicles with hCG was found to reduce 5-HT inhibitory action, but when follicles were incubated with either hCG in the presence of a steroidogenesis inhibitor or estradiol-17beta (E2), the 5-HT inhibition was unaffected. These findings suggest that 5-HT inhibition of the MIS-induced meiotic maturation is not under direct gonadotropin or E2 regulation but that it might be regulated in vivo by changes in the competence of the oocytes to undergo oocyte maturation after MIS stimulation.

Number of mast cells in the Harderian gland of the lizard Podarcis sicula sicula (Raf): the annual cycle and its relation to environmental factors and estradiol administration

The Harderian gland of the lizard Podarcis sicula sicula (Raf) contains connective tissue type mast cells whose numbers vary during the year showing two peaks, one in spring the other in winter. No sex differences are found throughout the year. Thermal and photoperiodic manipulations indicate that only temperature influences mast cell number (MCN) both in winter and in summer but not in spring. In animals exposed to high temperatures in February (but not in May) MCN declined, while exposure to low temperature in July had the opposite effect. Estradiol treatment of the February and April lizards increased MCN, an effect counteracted by the synthetic antiestrogen tamoxifen; in July lizards, this did not occur. In animals exposed to a high temperature in February, estradiol had no effect, as in animals exposed to low temperatures in July. These data suggest that in spring MCN seems to be more responsive to hormonal stimuli rather than external cues (temperature), while in summer MCN is more sensitive to temperature than to hormonal stimuli (estradiol). Both humoral and external factors are concluded to influence mast cell numbers in the Harderian gland of the lizard P. sicula sicula.

The equine endometrial mast cell during the puerperal period: evaluation of mast cell numbers and types in comparison to other inflammatory changes

Endometrial biopsies of 44 broodmares were histologically examined on days 3, 6, and 9 postpartum. The mares were subdivided into three groups according to the course of the puerperal period. In 29 mares, parturition and expulsion of the placenta was normal, six mares showed dystocia, and in nine mares, the placenta was retained for > 2 hours. Tissue samples were evaluated histologically, and the average numbers of granulocytes, lymphocytes, macrophages, siderophages, and mast cells was determined. Protease content of mast cells was examined with a double-enzyme immunohistochemical staining technique, using a histochemical reaction for chloroacetate esterase and fast blue to detect chymase activity and an immunohistochemical staining method with a polyclonal antibody and fast red for the detection of tryptase. Analyzing the cell numbers using the statistical software Statistica, a marked inflammatory reaction was observed in the endometrium postpartum. Although the number of granulocytes decreased during the first 9 days postpartum, the number of lymphocytes, macrophages, and siderophages increased. No significant difference in the number of any of these cell types could be demonstrated in the three different courses of the puerperal period, although the numbers of these cells seemed to be lower in mares with dystocia. In contrast with other cells, no change in the number of endometrial mast cells was observed during the puerperal period, but a significantly lower number were found in the endometrium of mares with retained placenta. The enzyme immunohistochemical double-labeling technique could demonstrate only tryptase-positive mast cells; no chymase activity was detectable in any endometrial mast cells. The number of mast cells detected with the metachromatic staining technique was significantly higher than that detected with double labeling. These results support the hypothesis that a sufficient number of mast cells may be necessary for a normal postnatal period and suggest a mast cell subtype in the equine endometrium that is tryptase and chymase negative.

Progesterone-induced urticaria--need it be autoimmune?

A patient with persistent urticaria related to the premenstrual phase of the menstrual cycle is presented. Although systemic administration of progesterone provoked the eruption, we were unable to confirm that there was an immunological reaction to endogenous progesterone or oestrogen. Mechanisms whereby progesterone can augment subclinical types I and IV hypersensitivity reactions are discussed.

The effects of testosterone and estradiol on mast cell number in the harderian gland of the frog, Rana esculenta

The Harderian gland (HG) of the frog Rana esculenta contains mast cells in the interstitial tissue. The mast cell number (MCN) is influenced by sex hormones. Gonadectomy in both sexes provoked a decrease in MCN in January, while no effect was observed in September. Sex hormone-replacement therapy gave different results; estradiol treatment in castrated males and females always increased MCN, while testosterone did not. Acute estradiol treatment provoked an increase in MCN on days 2 and 4 of treatment and the morphology of the glandular compartment appeared normal. On days 8, 10 and 12 of treatment the MCN drastically decreased. The majority of glandular acini appeared strongly disorganized and the interstitial tissue became hypertrophic in concomitance with an increased vascularization. Our results suggest that estradiol acts by stimulating mast cells and acute estradiol treatment provokes proliferation of interstitial connective tissue together with glandular cells damage.

The effect of sex hormones on lipid content and mast cell number in the harderian gland of the female toad, Bufo viridis

The Harderian gland of the toad Bufo viridis is a dimorphic gland owing to the presence of lipid droplets in the female glandular cells present only during summer months. Ovariectomy causes the disappearance of sudanophilia and estrogen-treatment completely prevents this change, while testosterone-injection has little effect. Estradiol-treatment also provokes a proliferation of the interstitial connective tissue concomitantly with the mast cell number increase. Our results suggest that estradiol acts, stimulating both mast cell and connective tissue proliferation, and plays a role in determining the expression of the female type of the toad Harderian gland.

Number and state of rat ovarian mast cells after exogenous administration of luteinizing hormone

Diestrous rats were treated with an injection of luteinizing hormone (LH), and their ovaries were examined for mast cell number and stage of degranulation at 2 and 4 hr post-injection. LH tripled the number of medullary mast cells at 2 hr. The source or origin of the additional mast cells is unknown. Comparison of the present results with other studies of rat ovarian mast cell dynamics suggests the occurrence of a reduction in mast cell number in early to mid-proestrus followed by an LH-induced increase in late proestrus.

Regulation of ovarian follicular development: a review of microscopic studies

Follicular development in the mammalian ovary is a complex process regulated by an orchestrated action of the pituitary gonadotropins, e.g., follicle stimulating hormone (FSH) and luteinizing hormone (LH), and local ovarian factors, such as peptide growth factors and steroids. The mechanism of endocrine/paracrine/autocrine regulation of folliculogenesis (i.e., cell proliferation and functions) has been addressed largely by biochemical means. However, the availability of immunological and molecular tools now enables us to undertake critical microscopic studies revealing the ovarian cell-type specific synthesis and/or accumulation of many of these local peptide modulators, their roles in the proliferation and differentiation of follicular cells, and their regulation by gonadotropins and local factors. The objective of this review is to provide a comprehensive yet complete picture of the endocrine/autocrine regulation of mammalian folliculogenesis as revealed by microscopic studies. Efforts have been made to include adequate research information relevant to update our understanding of the process of follicular development; however, to maintain the brevity, many equally important studies could not be included. This review confirms that FSH and LH are still the primary stimuli for follicular development. However, it is clear that the actions of these hormones at the cell level involve a host of peptide factors which are produced locally by different follicular cell types and which are powerful modulators of gonadotropin actions. The temporal and spatial expression of the genes of these modulators, the synthesis of active factors, their interactions, and the dynamics of their receptors on the follicular cell surface may be the ultimate determinants of cellular events which are crucial to coordinated growth and differentiation of follicular cells leading to folliculogenesis and ovulation.

The effect of histamine on progesterone and estradiol secretion of human granulosa cells in serum-free culture

The aim of this study was to explore the direct action of histamine on progesterone and estradiol secretion of human granulosa cells cultured in serum-free medium. Human granulosa cells were isolated from preovulatory follicular fluid aspirated from 17 women (32 +/- 3 years old, mean +/- SD) undergoing in vitro fertilization treatment at the University Women's Hospital of Tübingen. Progesterone and estradiol production was measured in the presence and absence of histamine, terfenadine or cimetidine using radioimmunoassays. Statistical analysis of the data was performed by analysis of variance and Newmann-Keul tests. Histamine stimulated a dose-related increase in estradiol secretion with a maximal stimulatory effect at 10(-3) mol/l. This response was blocked specifically by the H1-receptor antagonist terfenadine. Progesterone production in response to histamine stimulation was independent of dose at the limit of significance. The specific H2-receptor antagonist cimetidine did not block the stimulatory effect of histamine. We suggest that histamine has a direct stimulatory effect on steroid production of granulosa cells mediated via the H1-receptor. This effect may have a physiological role in the regulation of granulosa cell function during the menstrual cycle.

Distribution and characteristics of mast cells in the chick ovary

1. Distribution and characteristics of mast cells have been studied in the ovaries of 5 and 17 week old chickens. 2. Mast cells were mainly present in the stroma, hilum and theca of normal and atretic follicles. No significant age-related differences in percentage distribution of mast cells were observed in the stroma and hilar regions of the ovary. However, the percentage of mast cells associated with follicles in both age groups was significantly less compared to stromal and hilar regions. 3. The number of mast cells present in the theca of normal and atretic follicles of stage 301 to 500 microns increased significantly compared to the preceding stages in 17-week old chicken ovaries. Moreover, the number of mast cells associated with the follicles of this stage in 17-week old chick ovaries was also higher compared to 5-week old chicken ovaries. 4. The mast cells showing variable shapes were divided into two types: compact and degranulating. More degranulating mast cells were observed in the 17-week old chicken ovary compared to those observed at 5-weeks.

The potential relevance of cytokines to ovarian physiology

Elucidating the secrets of intraovarian intercellular communication constitutes a central area of investigation. While most attention has been directed thus far at the somatic cellular components of the ovary, the potential role(s) and relative importance of the resident ovarian white blood cell have received relatively limited attention. Efforts are currently under way to reconcile traditional ovarian physiology with observations relevant to intraovarian components of the white blood cell series. In this connection, it is important to note that unlike some gonadal compartments, the ovary does not constitute an immunologically privileged site. Thus, resident ovarian representatives of the white blood cell series can be observed at various stages of the ovarian life cycle. Current concepts suggest that regulatory cellular networks formerly viewed in immune terms now fall within the broad domain of endocrinology. Viewed in this light, resident ovarian representatives of the white blood cell series may constitute potential in situ modulators of ovarian function acting in all likelihood through the local secretion of regulatory cytokines. As the flow of information is probably multi directional, the very same cells are probably targeted for steroidal and peptidergic input in keeping with the existence of multiple autocrine and paracrine loops.

Mast cells in the testis, epididymis and accessory glands of the rat: effects of neonatal steroid treatment

Mast cells in the testis of control adult rats were found almost exclusively around subcapsular blood vessels. Discrete mast cells were distributed throughout the stroma of the epididymis and sex accessory glands. In neonatally estrogen-treated rats, a greater number of mast cells was present in the testicular interstitium, whereas no significant increase in the number of mast cells per square millimeter of stroma was found for the epididymis and sex accessory glands, despite stromal proliferation. On the other hand, androgen-treated rats did not have increased mast cell numbers in any organ. These results indicate that the increase in mast cell numbers was estrogen-dependent, specifically related to the testis and did not seem to be a consequence of the increase in the connective interstitial tissue.

Mast cells in the ovary of Gallus gallus domesticus

1. Histamine or mast cells are involved in mammalian ovary function. Their role in the avian ovary is not known. In the present study mast cell distribution in the ovary of the domestic fowl was studied. 2. Mast cells were distributed throughout the ovary, both in the stroma of medullary and cortical regions as well as in the thecae of normal and atretic follicles. In the stroma, mast cells were especially abundant in the area just below the germinal epithelium (GE) and followed the contours of the GE. 3. In the follicles, mast cells were more obvious in the thecae of small non-yolky follicles, whereas they were compressed and scattered in the larger yolky follicles. They were more frequently seen in the theca externa than in the theca interna and in their ultrastructure showed characteristic mast cell granules. 4. Some of the atretic follicles showed increased mast cells in their thecae. Postovulatory follicles had very few mast cells. 5. The possible role of the mast cells in the ovarian activity of domestic fowl is discussed.

Alteration by histamine of the sympathetic nerve-mediated contractions in the bovine ovarian follicle wall in vitro

The histaminergic effect on electrically induced contractions and tritium release was studied in vitro, using strips from the wall of mature bovine ovarian follicles. Follicular fluid and blood plasma from the animals were analysed for electrolyte, bicarbonate, glucose and total protein concentrations in order to compare them with the concentrations of these components in the Krebs-Ringer solution used in the experiments. Electrical field stimulation (EFS) of the follicle strip caused a contraction which was completely blocked by tetrodotoxin and was predominantly of adrenergic origin since phentolamine, in contrast to atropine, blocked the response. The neurogenic response was inhibited by histamine in a concentration-dependent way via the H1-receptor since the H1-antagonist, pyrilamine, counteracted the inhibitory effect of histamine while the H2-antagonist, cimetidine, potentiated the effect. This histaminergic response of EFS-induced contractions could be reproduced in experiments where the H1-agonist, 2-methylhistamine, was inhibitory while the H2-agonist, 4-methylhistamine, had no obvious influence on the twitch response. Histamine reduced the contractile response to exogenous noradrenaline via the H1-receptor, because pyrilamine counteracted, and cimetidine potentiated the effect. The histamine-induced depression of the motor response to EFS and exogenous noradrenaline was probably due to a postjunctional effect mediated by the H1-receptor. Experiments utilizing [3H]noradrenaline release during EFS did not suggest prejunctional effects of histamine. Chemical determinations on follicle fluid and plasma showed that the artificial follicular fluid imitated well the environmental conditions the follicle wall is exposed to in situ.