Vaginal fold histology reduces the variability introduced by vaginal exfoliative cytology in the classification of mouse estrous cycle stages

Establishment and validation of a nomogram model for predicting ovulation in the PCOS women

BACKGROUND

The mechanisms underlying ovulatory dysfunction in PCOS remain debatable. This study aimed to identify the factors affecting ovulation among PCOS patients based on a large sample-sized randomized control trial.

METHODS

Data were obtained from a multi-centered randomized clinical trial, the PCOSAct, which was conducted between 2011 and 2015. Univariate and multivariate analysis using binary logistic regression were used to construct a prediction model and nomogram. The accuracy of the model was assessed using receiver operating characteristic (ROC) curves and calibration curves.

RESULTS

The predictive variables included in the training dataset model were luteinizing hormone (LH), free testosterone, body mass index (BMI), period times per year, and clomiphene treatment. The ROC curve for the model in the training dataset was 0.81 (95% CI [0.77, 0.85]), while in the validation dataset, it was 0.7801 (95% CI [0.72, 0.84]). The model showed good discrimination in both the training and validation datasets. Decision curve analysis demonstrated that the nomogram designed for ovulation had clinical utility and superior discriminative ability for predicting ovulation.

CONCLUSIONS

The nomogram composed of LH, free testosterone, BMI, period times per year and the application of clomiphene may predict the ovulation among PCOS patients.

Gonadotropic Activity of Pituitary Extract of African Catfish, Clarias gariepinus, in Mammals using Immature Wistar Rats as Models

BACKGROUND

The pituitary glands normally produce and stores gonadotropic hormones (GnH) that are responsible for ovulation and spermiation in animals. However, whether fish pituitary extracts can elicit same effects in treated animals need elucidation as a prelude to their practical usage in animals.

OBJECTIVES

The aim of this study was to investigate the oestrus-inducing potential of the pituitary gland extract of the Africa Catfish (Clarias gariepinus) in immature Wistar rats.

METHODS

The experiment involved the use of 18 immature female Wistar rats and 10 male catfish brood stocks with the use of six Wistar rats per groups as follows: Group A had human chorionic gonadotropin (hCG) treatment. Group B had only normal saline treatment as the control whereas Group C had the C. gariepinus pituitary extract administration to induce oestrus with treatments occurring twice six hours apart in each group.

RESULTS

There was an obvious expression of visible signs of heat and the presence of uterine horn oedema with significant (p < 0.05) increase in reproductive tract weight and uterine width and length. However, only progesterone levels increased significantly (p < 0.05) in the hCG and the C. gariepinus pituitary extract treated groups compared to other assayed hormones.

CONCLUSION

These results showed that C. gariepinus pituitary extract has the capacity to induce oestrus in Wistar rats because of its gonadotropic effects, which needs further investigations at higher doses and for longer exposure periods for possible oestrus induction and synchronization in higher mammals. Further favourable results could herald the possible patent of the catfish pituitary extract for either experimental or commercial use in mammals.

A comparative analysis of depressive-like behavior: Exploring sex-related differences and insights

Profiling the variability related to the estrous cycle is essential for assessing depressive-like behavior and screening drugs. This study compares circulating plasma corticosterone levels [CORT] and behavioral alterations in mice exposed to sucrose preference, forced swimming, and tail suspension tests (SPT, FST, and TST, respectively). While SPT exposure did not significantly alter [CORT], FST and TST showed notable changes. Mice in the TST exhibited increased movement and decreased immobility time compared to FST, suggesting a lower likelihood of depressive-like behavior in male mice. Notably, during the proestrus phase, female mice displayed the highest tendency for depressive-like behavior and elevated [CORT], but similar response to antidepressants (imipramine and fluoxetine). The inherent stress of the FST and TST tasks appears to influence [CORT] as well as depressant and antidepressant effects. These comparisons provide valuable insights for further behavioral phenotyping, model sensitivity assessment, and deepen our neurobiological understanding of depression in the context of drug screening.

Extracellular Matrix-Based and Electrospun Scaffolding Systems for Vaginal Reconstruction

Congenital vaginal anomalies and pelvic organ prolapse affect different age groups of women and both have significant negative impacts on patients' psychological well-being and quality of life. While surgical and non-surgical treatments are available for vaginal defects, their efficacy is limited, and they often result in long-term complications. Therefore, alternative treatment options are urgently needed. Fortunately, tissue-engineered scaffolds are promising new treatment modalities that provide an extracellular matrix (ECM)-like environment for vaginal cells to adhere, secrete ECM, and be remodeled by host cells. To this end, ECM-based scaffolds or the constructs that resemble ECM, generated by self-assembly, decellularization, or electrospinning techniques, have gained attention from both clinicians and researchers. These biomimetic scaffolds are highly similar to the native vaginal ECM and have great potential for clinical translation. This review article aims to discuss recent applications, challenges, and future perspectives of these scaffolds in vaginal reconstruction or repair strategies.

A multi-tissue transcriptomic landscape of female mice in estrus and diestrus provides clues for precision medicine

Female reproductive cycle, also known as menstrual cycle or estrous cycle in primate or non-primate mammals, respectively, dominates the reproductive processes in non-pregnant state. However, in addition to reproductive tissues, reproductive cycle could also perform global regulation because the receptors of two major female hormones fluctuating throughout the cycle, estrogen and progesterone, are widely distributed. Therefore, a multi-tissue gene expression landscape is in continuous demand for better understanding the systemic changes during the reproductive cycle but remains largely undefined. Here we delineated a transcriptomic landscape covering 15 tissues of C57BL/6J female mice in two phases of estrous cycle, estrus and diestrus, by RNA-sequencing. Then, a number of genes, pathways, and transcription factors involved in the estrous cycle were revealed. We found the estrous cycle could widely regulate the neuro-functions, immuno-functions, blood coagulation and so on. And behind the transcriptomic alteration between estrus and diestrus, 13 transcription factors may play important roles. Next, bioinformatics modeling with 1,263 manually curated gene signatures of various physiological and pathophysiological states systematically characterized the beneficial/deleterious effects brought by estrus/diestrus on individual tissues. We revealed that the estrous cycle has a significant effect on cardiovascular system (aorta, heart, vein), in which the anti-hypertensive pattern in aorta induced by estrus is one of the most striking findings. Inspired by this point, we validated that two hypotensive drugs, felodipine and acebutolol, could exhibit significantly enhanced efficacy in estrus than diestrus by mouse and rat experiments. Together, this study provides a valuable data resource for investigating reproductive cycle from a transcriptomic perspective, and presents models and clues for investigating precision medicine associated with reproductive cycle.

RNA binding protein IGF2BP1 meditates oxidative stress-induced granulosa cell dysfunction by regulating MDM2 mRNA stability in an m6A-dependent manner

Both genetic and microenvironmental detrimental factors are involved in ovarian dysfunction, leading to the increasing rate of involuntary childlessness in recent years. Oxidative stress (OS), which is characterized by the imbalance of redox system with redundant reactive oxygen species (ROS) overwhelming the antioxidant defense, is regarded as one of the culprits of ovarian dysfunction. OS causes damage to various types of ovarian cells including granulosa cells (GCs), jeopardizing the ovarian microenvironment, disturbing follicular development and participating in various female reproductive disorders. However, the specific molecular pathological mechanisms underlying this process have not been fully elucidated. In this study, we found that 3-nitropropionic acid (3-NP) treatment led to significant IGF2BP1 downregulation via, at least partially, inducing ROS overproduction. IGF2BP1 regulates GCs viability, proliferation, cell cycle and cellular senescence by enhancing MDM2 mRNA stability in an m6A-dependant manner. IGF2BP1 overexpression partially rescued 3-NP induced GCs damages, while ectopically expressed MDM2 alleviated both 3-NP or IGF2BP1-knockdown induced GCs dysfunction. These results reveal an epigenetic molecular mechanism underlying OS-related GCs disorders, which may help to establish a novel potential clinical marker for predicting the GCs status as well as the follicular developmental potential.

Mating success of timed pregnancies in Sprague Dawley rats: Considerations for execution

This study compares three different mating techniques in Sprague-Dawley rats, using the pregnancy rate as the main indicator of success. It provides recommendations for timed-pregnancy experiments to achieve an appropriate sample size for the study of human pregnancy disorders. The implementation of a preconditioning phase, determination of the estrous cycle, the use of two mating strategies (Lee-Boot and Whitten effect), female: male mating ratios, and cohabitation duration should be considered as they improve the mating success rate.

Can animal models resemble a premenstrual dysphoric condition?

Around 80% of women worldwide suffer mild Premenstrual Disorders (PMD) during their reproductive life. Up to a quarter are affected by moderate to severe symptoms, and between 3% and 8% experience a severe form. It is classified as premenstrual syndrome (PMS) with predominantly physical symptoms and premenstrual dysphoric disorder (PMDD) with psychiatric symptoms. The present review analyzes the factors associated with PMD and the Hypothalamus-Pituitary-Ovarian or Hypothalamus-Pituitary-adrenal axis and discusses the main animal models used to study PMDD. Evidence shows that the ovarian hormones participate in PMDD symptoms, and several points of regulation of their synthesis, metabolism, and target sites could be altered. PMDD is complex and implies several factors that require consideration when this condition is modeled in animals. Of particular interest are those points related to areas that may represent opportunities to develop new approximations to understand the mechanisms involved in PMDD and possible treatments.

A Critical Assessment of the Requirement for a Single Time Point Vaginal Cytology on the Day of Necropsy in Rats

For toxicology testing of (agro)chemicals, different study types are being performed with general and/or reproductive toxicity endpoints (see Organisation for Economic Co-operation and Development guidelines). In most of these rat studies, vaginal cytology is performed on serial samples (collected by lavage) for evaluation of cycle regularity and evidence of mating, and/or on a single sample collected on the day of necropsy for information on the estrous cycle stage and allowing correlation with histopathology. In the latter case, the utility of vaginal cytology can be argued. In this article, estrous cycle stages based on vaginal cytology of samples taken on the day of necropsy and histopathology of ovaries, uterus, and vagina (gold standard for estrous cycle stage assessment) were compared. The agreement was generally low. Disagreement between the two methods could be explained by time differences between lavage and necropsy, by manipulation of vaginal epithelium during lavage which may impact epithelial morphology on histology, and by misinterpretation of vaginal cytology during or shortly after lactation. Based on the results of estrous staging within different study types, we strongly discourage vaginal cytology from samples collected on the day of necropsy since there is no added value, vaginal manipulation can be stressful and may complicate the histologic diagnosis.

Decrease in ovarian reserve through the inhibition of SIRT1-mediated oxidative phosphorylation

OBJECTIVE

To establish an oxidative stress-induced model of premature ovarian insufficiency (POI) and to explore the effect of SIRT1 and mitochondrial oxidative phosphorylation on the ovarian reserve.

METHODS

Mice were treated with intraperitoneal injections of 3-nitropropionic acid (3-NPA) at different doses and for different time periods to induce a model of POI. Subsequently, the efficiency of each regimen was evaluated. The expression of SIRT1 in ovarian tissue was examined. Then, SIRT1 was knocked down in human luteinized granulosa cells (GCs), and its function and related receptor and gene expression were examined. Finally, a SIRT1 antagonist and agonist were used to explore the effects of SIRT1 on ovarian function in vivo and on the change in mitochondrial oxidative phosphorylation complexes (OXPHOS).

RESULTS

Decreases in ovarian reserve were successfully induced through the intraperitoneal injection of 40 mg/kg 3-NPA for 3 weeks, and SIRT1 was down-regulated in the model group. The knockdown of SIRT1 impaired the estrogen synthesis capacity of human GCs and decreased the expression of related genes. 3-NPA and SIRT1 antagonist Ex-527 decreased ovarian function and inhibited OXPHOS. In contrast, the SIRT1 agonist resveratrol promoted the recovery of ovarian function in the model group and improved OXPHOS. Additionally, P53, CASPASE 3, and BAX were down-regulated and BCL2 was up-regulated in the 3-NPA and Ex-527 groups; opposite trends were observed after resveratrol treatment.

CONCLUSIONS

The intraperitoneal injection of 40 mg/kg 3-NPA for 3 weeks could effectively induce POI. The increase in oxidative stress inhibited SRIT1 and mitochondrial oxidative phosphorylation, inducing follicular apoptosis.

Effects of spaceflight aboard the International Space Station on mouse estrous cycle and ovarian gene expression

Ovarian steroids dramatically impact normal homeostatic and metabolic processes of most tissues within the body, including muscle, bone, neural, immune, cardiovascular, and reproductive systems. Determining the effects of spaceflight on the ovary and estrous cycle is, therefore, critical to our understanding of all spaceflight experiments using female mice. Adult female mice (n = 10) were exposed to and sacrificed on-orbit after 37 days of spaceflight in microgravity. Contemporary control (preflight baseline, vivarium, and habitat; n = 10/group) groups were maintained at the Kennedy Space Center, prior to sacrifice and similar tissue collection at the NASA Ames Research Center. Ovarian tissues were collected and processed for RNA and steroid analyses at initial carcass thaw. Vaginal wall tissue collected from twice frozen/thawed carcasses was fixed for estrous cycle stage determinations. The proportion of animals in each phase of the estrous cycle (i.e., proestrus, estrus, metestrus, and diestrus) did not appreciably differ between baseline, vivarium, and flight mice, while habitat control mice exhibited greater numbers in diestrus. Ovarian tissue steroid concentrations indicated no differences in estradiol across groups, while progesterone levels were lower (p < 0.05) in habitat and flight compared to baseline females. Genes involved in ovarian steroidogenic function were not differentially expressed across groups. As ovarian estrogen can dramatically impact multiple non-reproductive tissues, these data support vaginal wall estrous cycle classification of all female mice flown in space. Additionally, since females exposed to long-term spaceflight were observed at different estrous cycle stages, this indicates females are likely undergoing ovarian cyclicity and may yet be fertile.

Comparison of cannabidiol to citalopram in targeting fear memory in female mice

Background

Cannabidiol (CBD) and selective serotonin reuptake inhibitors (SSRIs) are currently used to treat post-traumatic stress disorder (PTSD). However, these drugs are commonly studied after dosing just prior to extinction training, and there are gaps in our understanding of how they affect fear memory formation, their comparative effects on various types of memory, and of sexual dimorphisms in effects. Also, more studies involving female subjects are needed to balance the gender-inequality in the literature. Therefore, the purpose of this study was to directly compare the effects of CBD to citalopram in affecting the formation of auditory cued, contextual, and generalized fear memory, and to evaluate how extinction of these different memories was altered by pre-acquisition treatment in female mice. We also evaluated the impact of the estrous cycle on each of these.

Methods

Auditory-cued trace fear conditioning was conducted shortly after dosing female C57BL/6 mice, with either CBD or citalopram (10 mg/kg each), by pairing auditory tones with mild foot shocks. Auditory-cued, contextual, and generalized fear memory was assessed by measuring freezing responses, with an automated fear conditioning system, 24 h after conditioning. Each memory type was then evaluated every 24 h, over a 4-day period in total, to create an extinction profile. Freezing outcomes were statistically compared by ANOVA with Tukey HSD post hoc analysis, N = 12 mice per experimental group. Evaluation of sexual dimorphism was by comparison to historical data from male mice.

Results

Auditory cue-associated fear memory was not affected with CBD or citalopram; however, contextual memory was reduced with CBD by 11%, p < 0.05, but not citalopram, and generalized fear memory was reduced with CBD and citalopram, 20% and 22%, respectively, p < 0.05. Extinction learning was enhanced with CBD and citalopram, but, there was considerable memory-type variability between drug effects, with freezing levels reduced at the end of training by 9 to 17% for CBD, and 10 to 12% with citalopram. The estrous cycle did not affect any outcomes.

Conclusions

Both drugs are potent modifiers of fear memory formation; however, there is considerable divergence in their targeting of different memory types which, overall, could support the use of CBD as an alternative to SSRIs for treating PTSD in females, but not males. A limitation of the study was that it compared data from experiments done at different times to evaluate sexual dimorphism. Overall, this suggests that more research is necessary to guide any therapeutic approach involving CBD.

Improvement in identification of pro-estrous mice by using a novel method of detecting vaginal mucous cells

Accurate identification of the murine estrous cycle using vaginal exfoliative cytology is the initial and crucial step for controlled reproduction of this species. However, it is generally difficult to discriminate each stage of the cycle, and thus to select pro-estrous mice for mating. To increase the accuracy of identification of the pro-estrous stage, we re-evaluated the vaginal fold histology and modified the method of exfoliative cytology. Tissue fixation using methanol in Carnoy's solution but not paraformaldehyde, combined with Alcian blue staining but not the conventional Giemsa staining, resulted in better manifestation of mucosal cell layers in the vaginal epithelium just above the keratinized layer. This mucous layer in the fold histology was found to form specifically in the pro-estrous and late di-estrous stages, and the mucous cells exfoliated in smear samples only in the pro-estrous stage. This novel method was found, by a blinded test, to increase the rate of accurate identification of the pro-estrous stage compared to the conventional method (80% vs 50%). Consistent with this finding, the mating experiment with "pro-estrous" females selected by the novel method revealed a significantly higher success rate than that with the conventional method (78.0% vs 47.5%). Thus, our study demonstrates vaginal exfoliative mucous cells as a better potential marker to detect the "receptive" state of female mice that leads to an improved success rate of mating.

Deep learning-based classification of the mouse estrous cycle stages

There is a rapidly growing demand for female animals in preclinical animal, and thus it is necessary to determine animals' estrous cycle stages from vaginal smear cytology. However, the determination of estrous stages requires extensive training, takes a long time, and is costly; moreover, the results obtained by human examiners may not be consistent. Here, we report a machine learning model trained with 2,096 microscopic images that we named the "Stage Estimator of estrous Cycle of RodEnt using an Image-recognition Technique (SECREIT)." With the test dataset (736 images), SECREIT achieved area under the receiver-operating-characteristic curve of 0.962 or more for each estrous stage. A test using 100 images showed that SECREIT provided correct classification that was similar to that provided by two human examiners (SECREIT: 91%, Human 1: 91%, Human 2: 79%) in 11 s. The SECREIT can be a first step toward accelerating the research using female rodents.

Characterization of the estrous cycle in the Amazon spiny rat (Proechimys guyannensis)

Males of Proechimys guyannensis, a rodent living in the Amazon rainforest are studied in biomedical research because of their antiepileptogenic mechanism. Females are usually taken from experimental designs, because of limited data of this sex. This study aimed to characterize the estrous cycle to include females together with males in research in a more balanced approach. The estrous cycle of P. guyannensis based through exfoliative cytology, determination of the vaginal occlusion membrane state, and hormonal analysis. In this study, cytological analyses of vaginal smears were performed for three months, three times a day. The observed length of the estrous cycle was 247 ± 81 h (mean ± SD) with a reproductive phase of 27.08 ± 17.39 h (estrus stage). We observed a frequent presence of both the open and closed states of the vaginal membrane in the estrus stage (fertile period) although only the open stage is a prerequisite for successful copulation. High levels of progesterone and estradiol were detected in proestrus. Levels of follicle-stimulating hormone peaked at the estrus stage. These data will establish the parameters and subsidies to set the grounds for future research either for investigating the biology of this species or to use P. guyannensis in research that previously excluded females. Information regarding female Proechimys is relevant to not only describe the species but also explain the interaction between sex hormones and physiological responses. Moreover, the present results will enhance rigor and reproducibility in preclinical studies. In conclusion, P. guyannensis reproductive cycles can occur spontaneously and cyclically independent of mating stimulation and the high levels of FSH in the estrus stage, suggest that ovulation occurs in the late phase of the estrus.

The estrogen-macrophage interplay in the homeostasis of the female reproductive tract

BACKGROUND

Estrogens are known to orchestrate reproductive events and to regulate the immune system during infections and following tissue damage. Recent findings suggest that, in the absence of any danger signal, estrogens trigger the physiological expansion and functional specialization of macrophages, which are immune cells that populate the female reproductive tract (FRT) and are increasingly being recognized to participate in tissue homeostasis beyond their immune activity against infections. Although estrogens are the only female gonadal hormones that directly target macrophages, a comprehensive view of this endocrine-immune communication and its involvement in the FRT is still missing.

OBJECTIVE AND RATIONALE

Recent accomplishments encourage a revision of the literature on the ability of macrophages to respond to estrogens and induce tissue-specific functions required for reproductive events, with the aim to envision macrophages as key players in FRT homeostasis and mediators of the regenerative and trophic actions of estrogens.

SEARCH METHODS

We conducted a systematic search using PubMed and Ovid for human, animal (rodents) and cellular studies published until 2018 on estrogen action in macrophages and the activity of these cells in the FRT.

OUTCOMES

Our search identified the remarkable ability of macrophages to activate biochemical processes in response to estrogens in cell culture experiments. The distribution at specific locations, interaction with selected cells and acquisition of distinct phenotypes of macrophages in the FRT, as well as the cyclic renewal of these properties at each ovarian cycle, demonstrate the involvement of these cells in the homeostasis of reproductive events. Moreover, current evidence suggests an association between estrogen-macrophage signaling and the generation of a tolerant and regenerative environment in the FRT, although a causative link is still missing.

WIDER IMPLICATIONS

Dysregulation of the functions and estrogen responsiveness of FRT macrophages may be involved in infertility and estrogen- and macrophage-dependent gynecological diseases, such as ovarian cancer and endometriosis. Thus, more research is needed on the physiology and pharmacological control of this endocrine-immune interplay.

Oviduct morphology and estrogen receptors ERα and ERβ expression in captive Chinchilla lanigera (Hystricomorpha: Chinchillidae)

Chinchilla lanigera is a hystricomorph rodent from South America whose reproductive biology presents particular characteristics that distinguishes it from other Rodentia species, such as low reproductive rate, seasonal breeding pattern, and long estrous cycle. Nevertheless, reproductive features in female chinchillas are still poorly investigated, with a scarce knowledge concerning the estrous cycle and the histology of reproductive organs. In this study, we investigate the morphology, histomorphometry, secretory activity, and immunolocalization of estrogen receptors ERα and ERβ in oviducts of nulliparous chinchillas, euthanized at fall season in Brazil. Follicular phase of estrous cycle of all studied animals was characterized by ovary and uterine morphology inspection, as well as vaginal cytology. Similar to other mammals, the oviduct wall of infundibulum, ampulla and isthmus was composed of mucosa, muscle, and serosa layers. Morphometric data of oviduct layers were used for identifying each oviduct segment. In the follicular phase, the oviduct was characterized by intense secretory activity, mainly in the ampulla, and expression of ERα and ERβ throughout the oviduct epithelium. Both ERα and ERβ were also detected in the connective tissue and smooth muscle cells. Our findings point out to the important role of estrogen in this female organ. Similar wide distribution of both ER proteins has been described for human Fallopian tube. Taken together, our data add to the understanding of the reproductive biology of female chinchillas, and may assist in the intensive breeding of this species and any eventual endeavor for conservation of chinchillas in the wild.

Evaluation of the toxicity and anti-inflammatory activities of the infusion of leaves of Campomanesia guazumifolia (Cambess.) O. Berg

ETHNOPHARMACOLOGICAL RELEVANCE

Some species of Campomanesia are used in the folk medicine due to anti-inflammatory, anti-diarrheal, anti-diabetes and hypercholesterolemic. However studies with Campomanesia guazumifolia (Cambess.) O. Berg. are scarce.

AIM OF THE STUDY

This study investigated the anti-inflammatory activity and toxicological profile of infusion obtained from leaves of Campomanesia guazumifolia in mice.

MATERIALS AND METHODS

Leaves infusion of C. guazumifolia was obtained in the proportion of 20 g/L (leaves/water) at 95-100 °C for 10 min in an enclosed container. The acute toxicity of the leaves infusion of C. guazumifolia lyophilized (ICG) was assessed by oral administration to female mice at doses of 500, 1000, 2000, and 5000 mg/kg, and the general behavior and toxic symptoms were observed for 14 days. In the subacute toxicity model, female mice were treated orally with the ICG (250, 500, and 1000 mg/kg) during 28 days, and biochemical, toxic signs and the estrous cycle were evaluated. The anti-inflammatory activity of the ICG (70, 300 and 700 mg/kg) was analyzed using carrageenan-induced pleurisy and inflammatory paw (mechanical and thermal hyperalgesia).

RESULTS

Three flavonoids glycosylated and a cyclohexanecarboxylic acid were identified in the ICG: quercetin pentose, quercetin deoxyhexoside, myricetin deoxyhexoside and quinic acid. No clinical signs of acute toxicity were observed, suggesting that the LD₅₀ (Lethal Dose) is above 5000 mg/kg. Subacute exposure of mice to the ICG did not change significantly the hematological and biochemical parameters as well as histology of organs. The ICG increased the duration of estrous cycle in all phases, showing anti-inflammatory potential by decreasing leukocyte migration, extravasation protein in the pleural cavity and antiedematogenic activity. The ICG treatment at a dose of 700 mg/kg decreased the mechanical hyperalgesia, while at doses of 300 mg/kg and 700 mg/kg, decreased the sensitivity to the cold.

CONCLUSION

The results evidenced the anti-inflammatory potential with low toxicity of infusion of the leaves of C. guazumifolia, supporting the popular use of this species.

Agonistic activity of tamoxifen, a selective estrogen-receptor modulator (SERM), on arthritic ovariectomized mice

Arthritis is positively associated with the decline of sex hormones, especially estrogen. Tamoxifen (TMX) is a selective estrogen receptor modulator, possessing agonist or antagonistic activity in different tissues. Thus, the objective of this study was to investigate the effect of TMX on the zymosan-induced arthritis model. Female Swiss normal and ovariectomized (OVX) mice were divided into groups and treated for five days with TMX (0.3, 0.9 or 2.7 mg/kg) or 17-β-estradiol (E2, 50 µg/kg). On the fifth day, arthritis was induced and 4 h later, leukocyte migration into joint cavities was evaluated. The neutrophil migration in OVX animals, but not in normal mice, treated with TMX (all tested doses) was significantly decreased compared with mice that received the vehicle (P≤0.05). Similarly, this effect was also demonstrated in the E2-treated group. Therefore, the present study demonstrates that TMX presented agonist effects in inhibiting neutrophil migration and preventing arthritis progression in OVX mice.

Influence of gonadotropins on ovarian follicle growth and developmentin vivoandin vitro

Gonadotropins are the key regulators of ovarian follicles development. They are applied in therapeutic practice in assisted reproductive technology clinics. In the present review we discuss the basic gonadotropic hormones – recombinant human follicle-stimulating hormone, its derivatives, luteinizing hormone and gonadotropin serum of pregnant mares, their origin, and application in ovarian follicle systems inin vitroculture systems.

Loss of Fertility in the Absence of Progesterone Receptor Expression in Kisspeptin Neurons of Female Mice

Ovarian steroids, estradiol and progesterone, play central roles in regulating female reproduction by acting as both positive and negative regulators of gonadotropin-releasing hormone (GnRH) secretion in the hypothalamus. Recent studies have identified kisspeptin neurons of the hypothalamus as the target of estrogenic regulation of GnRH secretion. In this study, we aimed to determine the significance of progesterone receptor (PGR) expression in the kisspeptin neurons. To this end, the Pgr gene was selectively ablated in mouse kisspeptin neurons and the reproductive consequence assessed. The hypothalamus of the Pgr deficient female mouse expressed kisspeptin, the pituitary released LH in response to GnRH stimulation, and the ovary ovulated when stimulated with gonadotropins. However, the mutant mouse gradually lost cyclicity, was unable to generate a LH surge in response to rising estradiol, and eventually became infertile. Taken together, these results indicate that the loss of PGR impairs kisspeptin secretory machinery and therefore that PGR plays a critical role in regulating kisspeptin secretion.

A simple method for inducing estrous cycle stage-specific morphological changes in the vaginal epithelium of immature female mice

The vaginal epithelium of the adult female laboratory rodent changes from mucous secretion to cornification over the course of the estrous cycle. The morphophysiological changes occur with such regularity, accuracy and precision that the specific stage of the estrous cycle in the rat can be determined by inspection of the vaginal opening and/or exfoliative vaginal cytology. However, in the mouse, post-mortem vaginal histology is often required to determine the estrous cycle stage for ensuring the required level of reliability. Consequently, an excess number of female adult mice are needed to allow for the delivery of sufficient numbers of mice in a desired estrous cycle stage. In this study, we demonstrate that the standard procedure for oocyte superovulation and collection in the laboratory mouse (e.g. injection of equine chorionic gonadotropin followed 48 h later by human chorionic gonadotropin) can also be reliably used to induce changes in the epithelium of 3.5-week-old mouse vaginas in an estrous cycle stage-specific manner (e.g. establishment and replacement of a mucous secreting epithelium with a cornified epithelium; induction of cornification-associated loricrin expression). The superovulation protocol thus allows for the efficient and economic induction of estrous cycle stage-specific characteristics in the Müllerian duct-derived vagina thereby avoiding the necessity of post-mortem identification of the estrous cycle stage. In addition, our study indicates that the laboratory mouse vagina is an excellent organ for studying the sequence of events leading to cornification.