Persistent estrus rat models of polycystic ovary disease: an update

Pancreastatin inhibitor PSTi8 improves ovarian health in Letrozole-HFD induced PCOS rats by ameliorating metabolic and reproductive parameters

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine and metabolic disorder associated with insulin resistance (IR) and hyperandrogenism. IR plays a crucial role in the etiology of PCOS. An insulin-sensitizing agent like metformin is most commonly used as an off-label drug for the treatment of PCOS. PSTi8 (a pancreastatin inhibitor) is known as a promising therapeutic insulin-sensitizing agent for the treatment of IR in metabolic diseases. Thus, this study evaluates the insulin-sensitizing effects of PSTi8 compared to metformin on IR, hyperandrogenism, ovarian, and metabolic dysfunction in a PCOS model. To induce PCOS, rats were administered letrozole at a dose of 2 mg/kg via oral administration and fed a 60 % high-fat diet. Metformin and PSTi8 lowered serum insulin, testosterone, luteinizing hormone (LH) levels, and the LH/follicle-stimulating hormone ratio in the blood serum and improved steroidogenic gene expression in the PCOS ovaries. Both treatments increased the levels of sex hormone-binding globulin and estrogen hormone. Metformin and PSTi8 restore ovarian and uterine histomorphometry and improve the estrous cycle in PCOS rats. Metformin and PSTi8 treatments also improve blood glucose level and increase insulin sensitivity, inflammation, reactive oxygen species accumulation, lipid parameters, body weight, and fat mass in PCOS rats. This study revealed that PSTi8 is as helpful as metformin in decreasing hyperandrogenism by improving insulin sensitivity, free testosterone level and restoring disturbed reproductive and metabolic parameters in PCOS rats. PSTi8 has potential to serve as a therapeutic molecule for preventing IR induced by a western diet in PCOS.

Rodent models in polycystic ovarian syndrome: Dissecting reproductive and metabolic phenotypes for therapeutic advancements

The most prevalent reason for female infertility is polycystic ovarian syndrome (PCOS) exhibiting two of three phenotypes including biochemical or clinical hyperandrogenism, anovulation and polycystic ovaries. Insulin resistance and obesity are common in PCOS-afflicted women. Androgens are thought to be the primary cause of PCOS causing symptoms including anovulation, follicles that resemble cysts, higher levels of the luteinizing hormone (LH), increased adiposity, and insulin resistance. However, due to the heterogeneity of PCOS, it is challenging to establish a single model that accurately mimics all the reproductive and metabolic phenotypes seen in PCOS patients. In this review, we aimed to investigate rodent models of PCOS and related phenotypes with or without direct hormonal treatments and to determine the underlying mechanisms to comprehend PCOS better. We summarized rodent models of PCOS that includes direct and indirect hormone intervention and discussed the aetiology of PCOS and related phenotypes produced in rodent models. We presented combined insights on multiple rodent models of PCOS and compared their reproductive and/or metabolic phenotypes. Our review indicates that there are various models for studying PCOS and one should select a model most suitable for their purpose. This review will be helpful for consideration of rodent models for PCOS which are not conventionally used to determine mechanisms at the molecular/cellular levels encouraging development of novel treatments and control methods for PCOS.

Inositol Restores Appropriate Steroidogenesis in PCOS Ovaries Both In Vitro and In Vivo Experimental Mouse Models

Androgen excess is a key feature of several clinical phenotypes of polycystic ovary syndrome (PCOS). However, the presence of FSH receptor (FSHR) and aromatase (CYP19A1) activity responses to physiological endocrine stimuli play a critical role in the pathogenesis of PCOS. Preliminary data suggest that myo-Inositol (myo-Ins) and D-Chiro-Inositol (D-Chiro-Ins) may reactivate CYP19A1 activity. We investigated the steroidogenic pathway of Theca (TCs) and Granulosa cells (GCs) in an experimental model of murine PCOS induced in CD1 mice exposed for 10 weeks to a continuous light regimen. The effect of treatment with different combinations of myo-Ins and D-Chiro-Ins on the expression of Fshr, androgenic, and estrogenic enzymes was analyzed by real-time PCR in isolated TCs and GCs and in ovaries isolated from healthy and PCOS mice. Myo-Ins and D-Chiro-Ins, at a ratio of 40:1 at pharmacological and physiological concentrations, positively modulate the steroidogenic activity of TCs and the expression of Cyp19a1 and Fshr in GCs. Moreover, in vivo, inositols (40:1 ratio) significantly increase Cyp19a1 and Fshr. These changes in gene expression are mirrored by modifications in hormone levels in the serum of treated animals. Myo-Ins and D-Chiro-Ins in the 40:1 formula efficiently rescued PCOS features by up-regulating aromatase and FSHR levels while down-regulating androgen excesses produced by TCs.

Overexpression of Pde4d in rat granulosa cells inhibits maturation and atresia of antral follicles to induce polycystic ovary

BACKGROUND

Follicle dysplasia can cause polycystic ovary syndrome, which can lead to anovulatory infertility. This study explored gene(s) that may contribute to polycystic ovary syndrome.

METHODS

Three animal models of polycystic ovary syndrome were created by treating 3-week-old rats respectively with estradiol valerate, testosterone propionate, or constant illumination for 8 weeks. Granulosa cells from the three disease groups and from healthy controls were transcriptionally profiled to identify differentially expressed genes. The phosphodiesterase-4d (Pde4d) was screened as the most promising candidate pathogenic gene. The Pde4d was overexpressed in rats via intrabursal infection with recombinant lentivirus to see the effect of Pde4d on ovarian morphology. The potential roles of the candidate gene and interactors of the encoded protein were explored using polymerase chain reaction, western blotting, transfection and co-immunoprecipitation.

RESULTS

All three rat models of polycystic ovary syndrome showed polycystic ovary phenotype. Seven promising candidate genes were obtained by transcriptomics and verifications. Pde4d was further investigated because it could trigger downstream signaling pathways. The Pde4d overexpression in rat ovary induced cystic follicles. It inhibited follicle maturation through a mechanism involving inhibition of cAMP-PKA-CREB signaling. The Pde4d also inhibited phosphorylation of c-Jun N-terminal kinase to reduce apoptosis in the ovary, through a mechanism involving interaction of its poly-proline domain with the protein POSH.

CONCLUSION

Upregulation of Pde4d may contribute to polycystic ovary syndrome by impeding follicle maturation and preventing apoptotic atresia.

Comparison of female rat reproductive effects of pubertal versus adult exposure to known endocrine disruptors

A prevailing challenge when testing chemicals for their potential to cause female reproductive toxicity is the lack of appropriate toxicological test methods. We hypothesized that starting a 28-day in vivo toxicity study already at weaning, instead of in adulthood, would increase the sensitivity to detect endocrine disruptors due to the possibility of including assessment of pubertal onset. We compared the sensitivity of two rat studies using pubertal or adult exposure. We exposed the rats to two well-known human endocrine disruptors, the estrogen diethylstilbestrol (DES; 0.003, 0.012, 0.048 mg/kg bw/day) and the steroid synthesis inhibitor ketoconazole (KTZ; 3, 12, 48 mg/kg bw/day). Specifically, we addressed the impact on established endocrine-sensitive endpoints including day of vaginal opening (VO), estrous cyclicity, weights of reproductive organs and ovarian histology. After 28 days of exposure, starting either at weaning or at 9 weeks of age, DES exposure altered estrous cyclicity, reduced ovary weight as well as number of antral follicles and corpora lutea. By starting exposure at weaning, we could detect advanced day of VO in DES-exposed animals despite a lower body weight. Some endpoints were affected mainly with adult exposure, as DES increased liver weights in adulthood only. For KTZ, no effects were seen on time of VO, but adrenal and liver weights were increased in both exposure scenarios, and adult KTZ exposure also stimulated ovarian follicle growth. At first glance, this would indicate that a pubertal exposure scenario would be preferrable as timing of VO may serve as sensitive indicator of endocrine disruption by estrogenic mode of action. However, a higher sensitivity for other endocrine targets may be seen starting exposure in adulthood. Overall, starting a 28-day study at weaning with inclusion of VO assessment would mainly be recommended for substances showing estrogenic potential e.g., in vitro, whereas for other substances an adult exposure scenario may be recommended.

The effects of low-level laser therapy on polycystic ovarian syndrome in rats: three different dosages

The main objective of this in vivo study was to investigate the effect of different low-level laser therapy (LLLT) doses on polycystic ovary syndrome (PCOS). In the present experimental study, a single dosage of estradiol valerate (EV) was administered to induce PCOS in female rats. After administration of the EV for induction of PCOS, rats were divided into 5 groups (n = 8/group): C group (animals that were not exposed to any form of procedure), PC group (no treatment following EV induction), L1 group (1 J/cm2 LLLT treatment following EV induction), L2 group (2 J/cm2 LLLT treatment following EV induction), L3 group (6 J/cm2 LLLT treatment following EV induction). The results indicated that no significant difference was found in the serum levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), and progesterone (P4) between the C and L2 groups (p < 0.05). Although the serum levels of testosterone (T) were significantly higher in the C group compared with other groups (p < 0.05), the L2 group was determined to be the closest to the C group. Additionally, the LH, FSH, and T receptor level of the L2 group was closest to the C group. In conclusion, a 2 J/cm2 dosage of LLLT (L2 group) can be considered the most potentially effective treatment of PCOS in the rat. However, more studies are needed to determine the optimal dose of LLLT for the treatment of PCOS.

Timed restricted feeding cycles drive daily rhythms in female rats maintained in constant light but only partially restore the estrous cycle

Light at night is an emergent problem for modern society. Rodents exposed to light at night develop a loss of circadian rhythms, which leads to increased adiposity, altered immune response, and increased growth of tumors. In female rats, constant light (LL) eliminates the estrous cycle leading to a state of persistent estrus. The suprachiasmatic nucleus (SCN) drives circadian rhythms, and it interacts with the neuroendocrine network necessary for reproductive function. Timed restricted feeding (RF) exerts a powerful entraining influence on the circadian system, and it can influence the SCN activity and can restore rhythmicity or accelerate re-entrainment in experimental conditions of shift work or jet lag. The present study explored RF in female rats exposed to LL, with the hypothesis that this cyclic condition can rescue or prevent the loss of daily rhythms and benefit the expression of the estrous cycle. Two different feeding schedules were explored: 1. A 12-h food/12-h fasting schedule applied to arrhythmic rats after 3 weeks in LL, visualized as a rescue strategy (LL + RFR, 3 weeks), or applied simultaneously with the first day of LL as a preventive strategy (LL + RFP, 6 weeks). 2. A 12-h window of food intake with food given in four distributed pulses (every 3 h), applied after 3 weeks in LL, as a rescue strategy (LL + PR, 3 weeks) or applied simultaneously with the first day of LL as a preventive strategy (LL + PP, 6 weeks). Here, we present evidence that scheduled feeding can drive daily rhythms of activity and temperature in rats exposed to LL. However, the protocol of distributed feeding pulses was more efficient to restore the day–night activity and core temperature as well as the c-Fos day–night change in the SCN. Likewise, the distributed feeding partially restored the estrous cycle and the ovary morphology under LL condition. Data here provided indicate that the 12-h feeding/12-h fasting window determines the rest-activity cycle and can benefit directly the circadian and reproductive function. Moreover, this effect is stronger when food is distributed along the 12 h of subjective night.

Recent updates on animal models for understanding the etiopathogenesis of polycystic ovarian syndrome

Polycystic ovarian syndrome (PCOS) is the primary cause of female infertility affecting several women worldwide. Changes in hormonal functions such as hyperandrogenism are considered a significant factor in developing PCOS in women. In addition, many molecular pathways are involved in the pathogenesis of PCOS in women. To have better insights about PCOS, it is data from clinical studies carried on women suffering from PCOS should be collected. However, this approach has several implications, including ethical considerations, cost involved and availability of subject. Moreover, during the early drug development process, it is always advisable to use non-human models mimicking human physiology as they are less expensive, readily available, have a shorter gestation period and less risk involved. Many animal models have been reported that resemble the PCOS pathways in human subjects. However, the models developed on rats and mice are more preferred over other rodent/non-rodent models due to their closer resemblance with human PCOS development mechanism. The most extensively reported PCOS models for rats and mice include those induced by using testosterone, letrozole and estradiol valerate. As the pathophysiology of PCOS is complex, none of the explored models completely surrogates the PCOS related conditions occurring in women. Hence, there is a need to develop an animal model that can resemble the pathophysiology of PCOS in women. The review focuses on various animal models explored to understand the pathophysiology of PCOS. The article also highlights some environmental and food-related models that have been used to induce PCOS.

Immunohistochemical and histophysiological study of prolonged use of nandrolone on reproductive organs and fertility

We investigated possible changes in morphology and immunohistochemistry of the uterus and ovaries of rats caused by nandrolone (ND); we also investigated effects on fertility. We used 30 rats divided into three experimental groups: control (C), control vehicle (CV) and 5 mg/kg ND. Rats treated with ND exhibited loss of estrous cyclicity with predominance of the estrus phase, increased body weight and an organosomatic index that was decreased for the ovaries, but increased for the uterus. In the ovary, we observed a reduction in primary and secondary follicles and an increase in tertiary follicles; no corpora lutea were observed. Estrogen and progesterone levels were reduced. In the uterus, the endometrium was edematous with hyperplasic glands. The cytokines, TNFα and IL6, and the apoptotic index were increased in rats treated with ND. VEGF-A was increased in the ovaries and decreased in the uterus. We conclude that ND disrupts ovarian and uterine histophysiology by establishing an anovulatory and inflammatory condition, which directly affects reproduction.

A combination of spearmint and flaxseed extract improved endocrine and histomorphology of ovary in experimental PCOS

Background

Polycystic ovary syndrome (PCOS) is a complex reproduction and endocrine disorder of women in the reproductive age. Spearmint (Mentha spicata L.) has anti-androgenic activity and flaxseed (Linum usitatissimum L.) contains phytoestrogen and was reported to improve PCOS conditions. This study aimed to evaluate PCOS conditions following administration of a mixture of these two plants.

Methods

Twenty-four rats with regular cycles were randomly divided into four groups as control (C) and treatment-control (TC) received a combination of spearmint extract (SE) + flaxseed extract (FE). PCOS was induced in PCOS and treatment (T) groups by a single intramuscular injection of estradiol valerate. The treatment group received a combination of SE and FE for 30 days, 7 weeks after injection of estradiol valerate. Estrous cycles were monitored for 10 days and in the last day animals were sacrificed, ovaries were collected for the histomorphometric study and the serum levels of progesterone, testosterone, estradiol, and dehydroepiandrosterone (DHEA) were measured.

Result

Significant rise in progesterone and a decrease in testosterone and estradiol with no significant change of DHEA in the T group, was observed in comparison with the PCOS group (P < 0.05). No significant difference noticed between T and control groups (C &CT) regarding evaluated hormones. A significant increase in primary, pre-antral and antral follicles noticed in the T group compared to the PCOS group. The number of cystic follicles decreased in the T group compared with the PCOS group. Granulosa layer thickness increased while the thickness of theca decreased significantly in the T group compared to the PCOS group (P < 0.05). No significant endocrine or histological differences noticed between C and TC groups.

Conclusion

A combination of flaxseed and spearmint extract improved the endocrine profile and the histomorphometric features of the ovary in the T group compared to the PCOS group.

Maternal nutrient restriction impairs young adult offspring ovarian signaling resulting in reproductive dysfunction and follicle loss

Reproductive abnormalities are included as health complications in offspring exposed to poor prenatal nutrition. We have previously shown in a rodent model that offspring born to nutrient restriction during pregnancy are born small, enter puberty early, and display characteristics of early ovarian aging as adults. The present study investigated whether key proteins involved in follicle recruitment and growth mediate ovarian follicle loss. Pregnant rats were randomized to a standard diet throughout pregnancy and lactation (CON), or a calorie-restricted (50% of control) diet (UN) during pregnancy. Offspring reproductive phenotype was investigated at postnatal days 4, 27, and 65. Maternal UN resulted in young adult (P65) irregular estrous cyclicity due to persistent estrus, a significant loss of antral follicles, corpora lutea, and an increase in atretic follicles. This decrease in growing follicles in UN offspring appears to be due to increased apoptosis as seen by immunopositive staining of pro-apoptotic factor CASP3 (caspase 3) in ovaries of young adult offspring. UN prepubertal offspring had reduced expression levels of Fshr in antral follicles, which may contribute to a decrease in PI3K/AKT activation evident as a decrease in pAKT immunolocalization in prepubertal antral follicles. Moreover, neonatal ovaries of UN offspring show decreased levels of immunopositive staining for AMHR2 (anti-mullerian hormone receptor 2). Collectively, these data demonstrate that maternal UN during pregnancy impacts ovarian function in offspring as early as P65 and provides a model for understanding the mechanisms driving early life UN-induced follicle loss and reproductive dysfunction.

Animal Models for Human Polycystic Ovary Syndrome (PCOS) Focused on the Use of Indirect Hormonal Perturbations: A Review of the Literature

Hormonal disturbances, such as hyperandrogenism, are considered important for developing polycystic ovary syndrome (PCOS) in humans. Accordingly, directly hormone-regulated animal models are widely used for studying PCOS, as they replicate several key PCOS features. However, the pathogenesis and treatment of PCOS are still unclear. In this review, we aimed to investigate animal PCOS models and PCOS-like phenotypes in animal experiments without direct hormonal interventions and determine the underlying mechanisms for a better understanding of PCOS. We summarized animal PCOS models that used indirect hormonal interventions and suggested or discussed pathogenesis of PCOS-like features in animals and PCOS-like phenotypes generated in other animals. We presented integrated physiological insights and shared cellular pathways underlying the pathogenesis of PCOS in reviewed animal models. Our review indicates that the hormonal and metabolic changes could be due to molecular dysregulations, such as upregulated PI3K-Akt and extracellular signal-regulated kinase (ERK) signalling, that potentially cause PCOS-like phenotypes in the animal models. This review will be helpful for considering alternative animal PCOS models to determine the cellular/molecular mechanisms underlying PCOS symptoms. The efforts to determine the specific cellular mechanisms of PCOS will contribute to novel treatments and control methods for this complex syndrome.

Myo-inositol and D-chiro-inositol (40:1) reverse histological and functional features of polycystic ovary syndrome in a mouse model

Mice exposed to continuous light undergo functional and histological changes that mimic those of human Polycystic Ovary Syndrome (PCOS). We herein induced the syndrome by exposing 30-day-old females to 10 weeks of permanent light. Ovarian morphology and histology, as well as reproductive parameters (time of observed pregnancy/delivery) were investigated. Ovaries of PCOS-modeled mice showed lack of tertiary follicles and corpora lutea, altered ovarian architecture, and increased thickness of the theca layer. When mice were returned to a normal light-dark regimen for 10 days, a slight, spontaneous improvement occurred, whereas a quick and almost complete recovery from PCOS signs and symptoms was obtained by treating animals with a daily supplementation of 420 mg/kg myo-inositol and D-chiro-inositol (MyoIns/DCIns) in a 40:1 molar ratio. Namely, ovaries from mice treated by this protocol recovered normal histological features and a proper ratio of theca/granulosa cell layer thickness (TGR), suggesting that the androgenic phenotype was efficiently reversed. Indeed, we identified TGR as a useful index of PCOS, as its increase in PCOS-modeled mice correlated linearly with reduced reproductive capability ( r = 0.75, p < 0.0001). Mice treated with a 40:1 formula regained low TGR values and faster recovery of their fertility, with a physiological delivery time after mating. On the other hand, a higher D-chiro-inositol treatment formula, such as MyoIns versus DCIns 5:1, was ineffective or even had a negative effect on clinical-pathological outcomes.

Preclinical Models of Altered Early Life Nutrition and Development of Reproductive Disorders in Female Offspring

Early epidemiology studies in humans have and continue to offer valuable insight into the Developmental Origins of Health and Disease (DOHaD) hypothesis, which emphasises the importance of early-life nutritional and environmental changes on the increased risk of metabolic and reproductive disease in later life. Human studies are limited and constrained by a range of factors which do not apply to preclinical research. Animal models therefore offer a unique opportunity to fully investigate the mechanisms associated with developmental programming, helping to elucidate the developmental processes which influence reproductive diseases, and highlight potential biomarkers which can be translated back to the human condition. This review covers the use and limitations of a number of animal models frequently utilised in developmental programming investigations, with an emphasis on dietary manipulations which can lead to reproductive dysfunction in offspring.

Licorice ethanol extract improves symptoms of polycytic ovary syndrome in Letrozole-induced female rats

BACKGROUND

Licorice (Glycyrrhizae radix et rhizome, GRR) has long been used as an ingredient in Korean traditional medicinal herbal formulas for various metabolic and reproductive diseases. Polycystic ovary syndrome (PCOS) is a common endocrine disorder in premenopausal women. In the present study, we examined the effects of GRR extract on PCOS-like symptoms in female rats.

METHODS

Symptoms of PCOS were induced by Letrozole treatment for 4 weeks in 6-week-old female SD rats, after which the effects of GRR extract on recovery of normal hormonal levels and polycystic ovaries were assessed. Serum levels of luteinizing hormone (LH), follicular-stimulating hormone (FSH), LH/FSH ratio, and follicular cysts were evaluated, followed by the expression levels of known follicular phase markers such as Kitl, Cyp11a1, and Ptgs2.

RESULTS

The serum level of FSH was reduced only in the Lestrozole treatment group (PCOS), whereas significant recovery of FSH level was observed in the Letrozole and GRR co-treatment group (PCOS + GRR). Serum LH levels were not altered in any of the groups. Furthermore, the LH/FSH ratio (known biomarker for PCOS) was elevated only in the Letrozole treatment group (PCOS), whereas it was significantly reduced in the Letrozole and GRR co-treatment group (PCOS + GRR). For histological changes, follicular cysts, antral follicles, and increased thickness of the theca- and granulosa layers were observed in the PCOS group, whereas these alterations were remarkably reversed by GRR treatment.

CONCLUSION

These results suggest that GRR extract inhibits the symptoms of PCOS by regulating imbalanced hormonal levels and irregular ovarian follicles.

Protective effect of melatonin on cadmium-induced changes in some maturation and reproductive parameters of female Prussian carp (Carassius gibelio B.)

The aim of this study was to determine whether melatonin (Mel), which is a known antioxidant and free radical scavenger, could perform the role of a preventive agent against the toxic effects of cadmium (Cd²⁺) on mortality, fish growth, gonadosomatic index (GSI), luteinizing hormone (LH) secretion, the response to hormonal stimulation of spawning, and also tissue accumulation of Cd in Prussian carp females. These females received melatonin implants and were exposed to 0.4 or 4.0 mg/L of Cd (as CdCl₂·2.5H₂O) over either a 5- or 3-month period, followed by further 2 months of purification in clear water. Negative changes caused by exposure to cadmium in the water were as follows: higher fish mortality, lower body weight, increased accumulation of cadmium in the brain and ovary, lowered GSI, impaired spontaneous LH secretion during exposure, and impaired LH secretion during stimulation of spawning. All of these effects were observed in the group of fish exposed to 0.4 and/or 4.0 mg Cd/L but did not occur or were less pronounced in the groups exposed to cadmium in the presence of melatonin released from the implants. During depuration, in the group of fish which had been exposed to the highest Cd concentration, we observed a significant improvement in fish survival rate, body growth, inhibition of further cadmium accumulation in tissues, and gradual return of spontaneous LH secretion as well as normalization of the GSI value to the control group levels. In conclusion, these findings indicate that melatonin can be a preventive agent for some toxic effects on fish reproduction induced by environmental cadmium contamination.

ANP promotes proliferation and inhibits apoptosis of ovarian granulosa cells by NPRA/PGRMC1/EGFR complex and improves ovary functions of PCOS rats

Polycystic ovary syndrome (PCOS) is a complicated reproductive endocrine disease characterized by polycystic ovaries, hyperandrogenism and anovulation. It is one of the main causes of infertility. RU486 is an antagonist of progesterone receptor, and most commonly used as a contraceptive. However, whether RU486 is correlated with PCOS remains unclear. Atrial natriuretic peptide (ANP) is a small peptide with natriuretic and diuretic functions, and its availability to be used in PCOS treatment is unknown. Here, we showed that the serum ANP level was lower in PCOS patients than that in healthy women, and it was also decreased in the serum and ovarian tissues of RU486-induced PCOS rats compared with the control rats. We also found that RU486 inhibited the proliferation and promoted the apoptosis of human KGN ovarian granulosa cells by downregulating progesterone receptor membrane component 1 (PGRMC1). Meantime, ANP promoted the proliferation and inhibited the apoptosis of KGN cells through upregulating ANP receptor A (NPRA). The promotive effects of ANP on ovarian functions were mediated through the formation of an NPRA/PGRMC1/EGFR complex, which further activated MAPK/ERK signaling and transcription factor AP1. Moreover, ANP treatment reversed the PCOS symptoms, and improved the fertility of RU486-induced PCOS rats. Collectively, these findings highlight that RU486 is associated with the pathogenesis of PCOS, and ANP treatment may be a promising therapeutic option for PCOS.

Premenstrual Dysphoric Disorder Symptoms Following Ovarian Suppression: Triggered by Change in Ovarian Steroid Levels But Not Continuous Stable Levels

OBJECTIVE

Premenstrual dysphoric disorder (PMDD) symptoms are eliminated by ovarian suppression and stimulated by administration of ovarian steroids, yet they appear with ovarian steroid levels indistinguishable from those in women without PMDD. Thus, symptoms could be precipitated either by an acute change in ovarian steroid levels or by stable levels above a critical threshold playing a permissive role in expression of an underlying infradian affective "pacemaker." The authors attempted to determine which condition triggers PMDD symptoms.

METHOD

The study included 22 women with PMDD, ages 30 to 50 years. Twelve women who experienced symptom remission after 2-3 months of GnRH agonist-induced ovarian suppression (leuprolide) then received 1 month of single-blind (participant only) placebo and then 3 months of continuous combined estradiol/progesterone. Primary outcome measures were the Rating for Premenstrual Tension observer and self-ratings completed every 2 weeks during clinic visits. Multivariate repeated-measure ANOVA for mixed models was employed.

RESULTS

Both self- and observer-rated scores on the Rating for Premenstrual Tension were significantly increased (more symptomatic) during the first month of combined estradiol/progesterone compared with the last month of leuprolide alone, the placebo month, and the second and third months of estradiol/progesterone. There were no significant differences in symptom severity between the last month of leuprolide alone, placebo month, or second and third months of estradiol/progesterone. Finally, the Rating for Premenstrual Tension scores in the second and third estradiol/progesterone months did not significantly differ.

CONCLUSIONS

The findings demonstrate that the change in estradiol/progesterone levels from low to high, and not the steady-state level, was associated with onset of PMDD symptoms. Therapeutic efforts to modulate the change in steroid levels proximate to ovulation merit further study.

Amitriptyline plays important roles in modifying the ovarian morphology and improving its functions in rats with estradiol valerate-induced polycystic ovary

Previous studies demonstrated that depression is more prevalent in women with polycystic ovary syndrome (PCOS). In this study, we aimed to determine whether amitriptyline (AMT), an antidepressant drug, plays a role in preventing PCOS. The results showed that AMT modified ovarian morphology improved the ovarian functions and estrus cycle in estradiol valerate (EV)-induced polycystic ovary (PCO). AMT restored the levels of estradiol (E₂), testosterone (T) and progesterone (P₄) to normal, and elevated the level of luteinizing hormone (LH) in EV-induced PCO. No significant changes in follicle stimulating hormone (FSH) levels were observed in rats with EV or AMT treatment. The restoration of norepinephrine (NE) level was detected in rats with EV-induced PCO. AMT also altered the expression levels of steroidogenesis genes and beta2-adrenoceptor (beta2-AR) in EV-induced PCO. Our data revealed that AMT improves the ovarian morphology and modifies ovarian expression of beta2-AR and steroidogenesis genes in rats with EV-induced rat PCO. Our data provide support for the hypothesis that AMT is considered as a candidate drug for preventing and treating PCOS along with depression.

ATP synthase β-subunit abnormality in pancreas islets of rats with polycystic ovary syndrome and type 2 diabetes mellitus

This study investigated the abnormal expression of ATP synthase β-subunit (ATPsyn-β) in pancreas islets of rat model of polycystic ovary syndrome (PCOS) with type 2 diabetes mellitus (T2DM), and the secretion function changes after up-regulation of ATP5b. Sixty female SD rats were divided into three groups randomly and equally. The rat model of PCOS with T2DM was established by free access to the high-carbohydrate/high-fat diet, subcutaneous injections of DHEA, and a single injection of streptozotocin. The pancreas was removed for the detection of the ATPsyn-β expression by immunohistochemical staining, Western blotting and reverse transcription-PCR (RT-PCR). The pancreas islets of the rats were cultured, isolated with collagenase V and purified by gradient centrifugation, and the insulin secretion after treatment with different glucose concentrations was tested. Lentivirus ATP5b was successfully constructed with the vector of GV208 and transfected into the pancreas islets for the over-expression of ATPsyn-β. The insulin secretion and intracellular ATP content were determined after transfection of the PCOS-T2DM pancreas islets with Lenti-ATP5b. The results showed that the expression of ATPsyn-β protein and mRNA was significantly decreased in the pancreas of PCOS-T2DM rats. The ATP content in the pancreas islets was greatly increased and the insulin secretion was improved after the up-regulation of ATPsyn-β in the pancreas islets transfected with lenti-ATP5b. These results indicated that for PCOS, the ATPsyn-β might be one of the key factors for the attack of T2DM.

The effects of 6-Gingerol on reproductive improvement, liver functioning and Cyclooxygenase-2 gene expression in estradiol valerate - Induced polycystic ovary syndrome in Wistar rats

6-Gingerol is the major pungent ingredient of ginger with anti-inflammatory and antioxidant properties. In this study, we evaluate the effects of 6-gingerol on the biochemical parameters and ovarian histological improvements in estradiol valerate (EV) induced PCOS rats. Thirty six female Wistar rats were divided into 4 groups: control, received normal diet, PCOS control, received 4 mg/kg EV injection for 28 days and two experimental groups, received an EV injection for 28 days and followed by 6-gingerol (200 μg/_kg and 400 μg/_kg) for 14 days. The administration of EV led to increase body and ovarian weights, abnormality in serum sex steroid profile, decrease in antioxidant activity and increase in COX-2 gene expression. 6-gingerol treatments, particularly the 400 μg/_kg dose, markedly attenuated these alterations. 6-gingerol showed beneficial effects in the EV induced PCOS rats via decreased expression of COX-2, restored biochemical parameters to normal and decreased of cysts in the ovaries.

Current aspects of polycystic ovary syndrome: A literature review

SUMMARY Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine disorder with variable prevalence, affecting about one in every 15 women worldwide. The diagnosis of polycystic ovary syndrome requires at least two of the following criteria: oligoovulation and/or anovulation, clinical and/or biochemical evidence of hyperandrogenism and morphology of polycystic ovaries. Women with PCOS appear to have a higher risk of developing metabolic disorders, hypertension and cardiovascular disorders. The aim of this article was to present a review of the literature by searching the databases Pubmed and Scielo, focusing on publications related to polycystic ovaries, including its pathogenesis, clinical manifestations, diagnosis and therapeutic aspects, as well as its association with cardiovascular and arterial hypertensive disorders.

Characterization of embryonic stem cell model of polycystic ovary syndrome

The aims of this study are to establish an embryonic stem (ES) cell model of polycystic ovary syndrome and to characterize this ES cell line. ES cells were isolated and cultured from 322 wasted fertilized embryos from polycystic ovary syndrome (PCOS) patients in vitro. They were also characterized by development and differential markers. ES cells from PCOS subject present normal development profile with ES-specific markers such as OCT-4 and SSEA-4. These ES cells can also differentiate into three germ layer derivatives and form teratomas in vivo. ES cells from PCOS patients pose development and differentiation potentials as you would expect of cells from non-PCOS patients; therefore, they can be used as a cellular model to study the pathology of PCOS.

Does metformin improve in vitro maturation and ultrastructure of oocytes retrieved from estradiol valerate polycystic ovary syndrome-induced rats

Background

Metformin decreases polycystic ovary syndrome (PCOS) symptoms, induces ovulation, and may improve developmental competence of in vitro oocyte maturation. This study was designed to define the effects of metformin on the characteristics of in vitro oocyte maturation in estradiol valerate (EV) PCOS-induced rats.

Methods

Forty-five adult female Sprague–Dawley rats were randomly divided into control; sham and PCOS-induced (treated by a single dose of estradiol valerate, 4 mg/rat, IM) groups. The body weight was measured weekly for 12 weeks. At the end of week 12, the serum levels of testosterone, estrogen, progesterone, LH, and FSH and blood glucose of all the rats were measured. About 380 cumulus oocyte complexes (control, 125; sham, 122; PCOS-induced rats, 133) were incubated in Ham’s F10 in the absence and/or presence of metformin (M 5⁻¹⁰) for 12, 24, 36, and 48 h. The cumulus cells expansion and nuclear and cytoplasmic maturation of the oocytes was evaluated using 1 % aceto-orcein staining, and transmission electron microscopy (TEM).

Results

No significant differences were observed in the body weight of the rats. The serum level of testosterone was reduced, and progesterone and LH were significantly increased in the PCOS-induced rats (p < 0.05). However, no significant differences were observed in the serum levels of estrogen and FSH among the groups. Blood glucose level was higher in the PCOS-induced rats than control, (p < 0.01). The expansion of cumulus cells was observed in the metformin-treated oocytes. The oocytes retrieved from PCOS-induced rats show a stage of meiotic division (GVBD, MI, A-T, and MII) in 57.12 % of metformin-untreated and fairly significantly increased to 64.28 % in metformin-treated oocytes, (p < 0.05), but no differences were observed in the MII stage within groups. The redistribution of some cytoplasmic organelles throughout the ooplasm, particularly the peripheral cortical granules, was defined in the metformin-treated oocytes.

Conclusions

Single dose of EV can creates a reversible PCO adult rat model. Metformin enhances the COCs to initiate meiotic resumption at the first 6 h of IVM. In our study the metformin inability to show all aspects of in vitro oocyte maturation and may be resulted from deficiency of EV to induce PCOS.

Bak Foong pills combined with metformin in the treatment of a polycystic ovarian syndrome rat model

The aim of the present study was to investigate the treatment effects and associated mechanism of Bak Foong pills (BFPs) combined with metformin in the treatment of polycystic ovarian syndrome (PCOS). BFPs and/or metformin were administrated to treat the PCOS rats, and the weights and morphologies of the ovary, uterus and adrenal gland were measured. The levels of fasting blood glucose (FBG), serum testosterone (T), luteinizing hormone, fasting insulin (FIN) and insulin-like growth factor-1 were also measured, and the homeostasis model assessment of insulin resistance (HOMA-IR) was calculated. The expression level of androgen receptor (AR) in the ovarian tissue, and the cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc) mRNA levels in the ovary and adrenal tissues were detected. The levels of T, FIN, FBG and HOMA-IR in the combination group were significantly reduced; the wet weights of the ovary and the adrenal gland were decreased significantly, while that of the uterus was increased, and the histological morphology benignly recovered. The rats of each treatment group all experienced restored ovulation. The AR expression level in the treatment group was reduced, and the P450scc mRNA levels in the ovary and the adrenal gland of the combined treatment group were decreased. BFPs combined with metformin significantly affected PCOS, and the possible mechanism involved in the treatment may have been through the reduction of P450scc generation. BFPs may reduce the androgen levels, thus allowing the ovary to restore ovulation.

Evaluation of follicular synchronization caused by estrogen administration and its reproductive outcome

To evaluate multiple follicular development synchronization after estrogen stimulation in prepubertal mice, follicular responsiveness to gonadotropin superovulation, the prospective reproductive potential and ovarian polycystic ovary syndrome (PCOS)-like symptoms at adulthood, prepubertal mice were intraperitoneally injected with estrogen to establish an animal model with solvent as control. When synchronized tertiary follicles in ovaries, in vitro oocyte maturation and fertilization rates, blastocyst formation rate, developmental potential into offspring by embryo transfer, adult fertility and PCOS-like symptoms, and involved molecular mechanisms were focused, it was found that estrogen stimulation (10 μg/gBW) leads to follicular development synchronization at the early tertiary stage in prepubertal mice; reproduction from oocytes to offspring could be realized by means of the artificial reproductive technology though the model mice lost their natural fertility when they were reared to adulthood; and typical symptoms of PCOS, except changes in inflammatory pathways, were not remained up to adulthood. So in conclusion, estrogen can lead to synchronization in follicular development in prepubertal mice, but does not affect reproductive outcome of oocytes, and no typical symptoms of PCOS remained at adulthood despite changes related to inflammation.

Protective effects of melatonin against metabolic and reproductive disturbances in polycystic ovary syndrome in rats

OBJECTIVES

This study was undertaken to study the effects of melatonin on metabolic and reproductive aspects of polycystic ovary syndrome (PCOS) in rats.

METHODS

PCOS was induced by daily subcutaneous administration of testosterone (20 mg/kg) to 21-day-old female rats for 35 days. Rats were given metformin (500 mg/kg), melatonin (1 mg/kg) or melatonin (2 mg/kg) along with testosterone. One group served as vehicle control. On the 36th day, the animals were euthanised, and anthropometrical, biochemical (glucose, insulin, lipids, testosterone, C reactive protein (CRP)), oral glucose tolerance test, and histopathological evaluation of ovaries, uterus and intraabdominal fat (IAF), were carried out. Daily colpocytological examination was carried out from 14(th) day of study until termination.

KEY FINDINGS

Both the doses of melatonin significantly reduced body weight, body mass index, IAF, insulin and CRP. A favourable lipid profile, normal glucose tolerance and a decrease in the percentage of estrus smears were observed. Histopathological examination of ovary, uterus and IAF revealed a decrease in the number of cystic follicles, decrease in neoplastic endometrial glands, and decrease in adipocyte hypertrophy, respectively. The effects observed with melatonin were comparable to that with metformin.

CONCLUSION

The study provides evidence of the potential beneficial effects of melatonin in PCOS.

Sex differences in the neurobiology of epilepsy: a preclinical perspective

When all of the epilepsies are considered, sex differences are not always clear, despite the fact that many sex differences are known in the normal brain. Sex differences in epilepsy in laboratory animals are also unclear, although robust effects of sex on seizures have been reported, and numerous effects of gonadal steroids have been shown throughout the rodent brain. Here we discuss several reasons why sex differences in seizure susceptibility are unclear or are difficult to study. Examples of robust sex differences in laboratory rats, such as the relative resistance of adult female rats to the chemoconvulsant pilocarpine compared to males, are described. We also describe a novel method that has shed light on sex differences in neuropathology, which is a relatively new technique that will potentially contribute to sex differences research in the future. The assay we highlight uses the neuronal nuclear antigen NeuN to probe sex differences in adult male and female rats and mice. In females, weak NeuN expression defines a sex difference that previous neuropathological studies have not described. We also show that in adult rats, social isolation stress can obscure the normal effects of 17β-estradiol to increase excitability in area CA3 of the hippocampus. These data underscore the importance of controlling behavioral stress in studies of seizure susceptibility in rodents and suggest that behavioral stress may be one factor that has led to inconsistencies in outcomes of sex differences research. These and other issues have made it difficult to translate our increasing knowledge about the effects of gonadal hormones on the brain to improved treatment for men and women with epilepsy.

Histological evaluation of rat larynx in experimental polycystic ovary syndrome model

This study aimed at studying the histopathological effects of hyperandrogenemia and estrogen deficiency on larynx mucosa in experimentally designed polycystic ovary syndrome of female rats. Two groups of experimental polycystic ovary syndrome model were composed in healthy female rats by per oral letrozole administration of for 21 and 42 days. Also a control group which only took vehicle (saline) for 42 days was designed. Laryngeal mucosa and ovaries of all animals were examined histopathologically by light microscopy and the serum hormone levels were analyzed using a solid-phase, two-site chemiluminescent enzyme immunometric assay. Statistically significant edema, vascular engorgement, inflammation, cilia loss and differentiation of goblet cell distribution were observed when the control group and study groups were compared (p < 0.01). In serum hormonal analysis there was a significant increase in levels of androgens and decrease in levels of estrogens. In addition, polycystic appearance of ovaries in letrozole-administered groups and normal appearance of ovaries in control group have been proven histopathologically. Polycystic ovary syndrome which causes estrogen deficiency and hyperandrogenemia in fertile ages resulted in histopathological changes in laryngeal mucosa.

Immunohistochemical localization of CD31, NOTCH1 and JAGGED1 proteins in experimentally induced polycystic ovaries of immature rats

We analyzed histomorphometrical changes and blood vessel immunohistochemical staining of CD31, NOTCH1 and JAGGED1 in induced polycystic ovaries of immature female Wistar rats, as well as serum hormone levels. The rats were randomly divided into control (n=18) and treated (n=18) groups. Treated animals received intramuscularly testosteronenantat weekly (0.1mg/g). Controls received the same amount of ricinus oil. Rats were weighed daily. Control and treated subgroups (6 rats per subgroup) were subsequently sacrificed after 21, 28 and 35 days of treatment. In ovaries of treated rats we found large cystic follicles, thick stromal tissue, many atretic preantral follicles, no ovulation and a thinner granulosa cell layer. CD31 stained blood vessels in the theca layer were reduced, with reduced JAGGED1 and NOTCH1 immunostaining. In controls, preantral and antral follicles were larger than in the treated group. Treated animals showed statistically significant lower progesterone and higher testosterone levels. They gained more weight than controls. Reduced immunostaining for NOTCH1 and JAGGED1 of reduced blood vessels of the theca layer was found in all stages of folliculogenesis with a distinct reduction in cystic and atretic follicles. Our results provide evidence of intrinsic abnormality during all stages of folliculogenesis in polycystic ovaries and this may result from crosstalk between circulating gonadotropins and follicular angiogenesis.

Exposing cultured mouse ovarian follicles under increased gonadotropin tonus to aromatizable androgens influences the steroid balance and reduces oocyte meiotic capacity

Acquisition of oocyte developmental competence relies on the well-controlled events accompanying antral follicular development. Elevated basal androgen levels, as in PCOS, potentially affect oocyte quality. Current experiments in an in vitro follicle bioassay studied dose-effects of androstenedione and testosterone on FSH and hCG stimulated antral follicle growth and meiotic maturation. The addition of either androgens altered follicle's endogenous production of androstenedione, testosterone, estradiol, and progesterone and affected the oocyte's capacity to resume meiosis. Exposure to 200 nM androstenedione induced an increased production of testosterone and estradiol. Exposure to a concentration of ≥200 nM testosterone induced elevated levels of estradiol and progesterone. Significant dose-dependent negative effects on polar body extrusion were seen at concentrations of ≥200 nM of either androgen. In addition, chromosome displacement on the metaphase plate was observed in oocytes obtained from androstenedione-treated follicles. Follicles exposed to a combination of 25 mIU/ml FSH and 3 mIU/ml hCG and elevated aromatizable androgens altered the steroid production profile, affected the follicular development and impaired oocyte meiotic competence.

Unilateral sectioning of the superior ovarian nerve of rats with polycystic ovarian syndrome restores ovulation in the innervated ovary

The present study tested the hypothesis that if polycystic ovary syndrome (PCOS) results from activating the noradrenergic outflow to the ovary, unilaterally sectioning the superior ovarian nerve (SON) will result in ovulation by the denervated ovary, and the restoration of progesterone (P4), testosterone (T) and estradiol (E2) normal serum level. A single 2 mg dose of estradiol valerate (EV) to adult rats results in the development of a syndrome similar to the human PCOS. Ten-day old rats were injected with EV or vehicle solution (Vh) and were submitted to sham surgery, unilateral or bilateral sectioning of the SON at 24-days of age. The animals were sacrificed at 90 to 92 days of age, when they presented vaginal estrus preceded by a pro-estrus smear. In EV-treated animals, unilateral sectioning of the SON restored ovulation by the innervated ovary and unilateral or bilateral sectioning of the SON normalized testosterone and estradiol levels. These results suggest that aside from an increase in ovarian noradrenergic tone in the ovaries, in the pathogenesis of the PCOS participate other neural influences arriving to the ovaries via the SON, regulating spontaneous ovulation. Changes in P4, T and E2 serum levels induced by EV treatment seem to be controlled by neural signals arising from the abdominal wall and other signals arriving to the ovaries through the SON, and presents asymmetry.

Relevance of an opioid, noscapine in reducing cystogeneses in rat experimental model of polycystic ovary syndrome

AIM

Owing to grave socio-medical consequences, polycystic ovary syndrome (PCOS) is a highly alarming endocrinopathy. For searching better therapeutics for PCOS, we present a rat model for PCOS using antiprogestin RU486 and evaluate the efficacy of noscapine for its treatment.

MATERIAL AND METHODS

Female Wistar rats weighing 200+/-10 g bwt, exhibiting regular estrous cycle were administered an oral dose of RU486 [20 mg/kg body weight (bwt)/day] in olive oil for 13 consecutive days and compared with controls receiving 0.1 ml olive oil/100 g bwt/day. PCOS induced rats were administered varying dosing regimens of noscapine and were further compared with flutamide, the conventional drug for PCOS. Consecutively, vaginal smears and ovulation was noted and rats from all the groups were sacrificed and serum hormone levels for LH, FSH, PRL, estradiol, and testosterone were measured by enzyme-linked immunosorbent assay. Uteri and ovaries were excised free of adjacent tissue, weighed and further recruited for ascertaining ovary histologic parameters.

RESULTS

Our data go in accordance with previous studies where RU486 administered rats mimicked classical PCOS parameters seen in women. PCOS induced rats with ovulation blockade, persistent estrus and polycystic ovary resumed estrous cycle in 3-4 days post noscapine administration (120 mg/kg bwt/day). Folliculogenesis was followed by ovulation with reduced cystic manifestation and restored ovary and uterus weight. Biochemically, serum LH, PRL, estradiol, and testosterone concentration showed reduction while FSH and progesterone concentration increased significantly when compared with the conventional drug flutamide.

DISCUSSION

The amelioration of PCOS by noscapine is a novel observation that makes it a potential candidate for being a better therapeutic modality.

A rat model of epilepsy in women: a tool to study physiological interactions between endocrine systems and seizures

Epilepsy in women is influenced by endocrine status and antiepileptic drugs, but without an animal model, the effects of endocrine variables and antiepileptic drugs cannot be easily dissociated from the influence of epilepsy itself. Animal models have had limited utility because experimentally induced seizures typically result in reproductive failure. This study was conducted to develop an improved animal model. The muscarinic convulsant pilocarpine was used to elicit status epilepticus (SE) in adult female Sprague Dawley rats. The selective estrogen receptor modulator raloxifene was administered 30 min before pilocarpine. An anticonvulsant barbiturate, pentobarbital, was injected 5-10 min after the onset of SE and at least once thereafter to minimize acute convulsions. Mortality, morbidity, estrous cyclicity, and the ultimate success of the procedure (i.e. induction of recurrent, spontaneous seizures) were monitored. The combination of raloxifene and pentobarbital led to significantly improved estrous cyclicity compared with previous methods. Animals treated with raloxifene and pentobarbital became epileptic, as defined by the recurrence of spontaneous convulsions in the weeks after SE. The results of this study provide an improved animal model to examine the interactions between seizures and ovarian hormone secretion. The results also suggest that treatment of SE with raloxifene may benefit women with SE.

A unique rodent model of cardiometabolic risk associated with the metabolic syndrome and polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is characterized by hyperandrogenism, oligo-/anovulation, and polycystic ovarian morphology and is a complex endocrine disorder that also presents with features of the metabolic syndrome, including obesity, insulin resistance, and dyslipidemia. These latter symptoms form cardiometabolic risk factors predisposing individuals to the development of type 2 diabetes and cardiovascular disease (CVD). To date, animal models to study PCOS in the context of the metabolic syndrome and CVD risk have been lacking. The aim of this study was to investigate the JCR:LA-cp rodent as an animal model of PCOS associated with the metabolic syndrome. Metabolic indices were measured at 6 and 12 wk, and reproductive parameters including ovarian morphology and estrous cyclicity were assessed at 12 wk or adulthood. At 6 wk of age, the cp/cp genotype of the JCR:LA-cp strain developed visceral obesity, insulin resistance, and dyslipidemia (hypertriglyceridemia and hypercholesterolemia) compared with control animals. Serum testosterone concentrations were not significantly different between groups at 6 wk of age. However, at 12 wk, the cp/cp genotype had higher serum testosterone concentrations, compared with control animals, and presented with oligoovulation, a decreased number of corpora lutea, and an increased number of total follicles, in particular atretic and cystic follicles. The cardiometabolic risk factors in the cp/cp animals were exacerbated at 12 wk including obesity, insulin resistance, and dyslipidemia. The results of this study demonstrate that the JCR:LA-cp rodent may be a useful PCOS-like model to study early mechanisms involved in the etiology of cardiometabolic risk factors in the context of both PCOS and the metabolic syndrome.

The role of IGF1 in the in vivo production of bovine embryos from superovulated donors

IGF1 plays an important role in bovine follicular growth, acquisition of oocyte competence and embryo viability. Current data also indicate a critical role for IGF1 in both the ovarian response and the embryo yield following the superovulatory treatments. IGF1 can have either positive or negative effects on embryo viability which is related to the concentration of IGF1 induced by superovulation treatment. These effects impact either on oocyte competence or directly on the embryo. Concentrations in the physiological range appear to result in the production of higher quality embryos, mainly due to the mitogenic and the anti-apoptotic activities of IGF1. However, high superovulatory responses are associated with decreased embryo viability and a concomitant increase in apoptosis. Studies in mice suggest that this increase in apoptosis is related to the downregulation of the IGF1 receptor in the embryo associated with high IGF1 concentrations. Strategies capable of controlling the IGF1 concentrations could be one approach to improve superovulation responses. A range of possible approaches for research within the IGF system in gonadotrophin-stimulated cattle is discussed in this review, including the possible use of superovulated female cattle as an alternative animal experimental model for research on reproductive disorders in humans associated with abnormal IGF1 concentrations.

Seizures and reproductive function: insights from female rats with epilepsy

OBJECTIVE

Chronic seizures in women can have adverse effects on reproductive function, such as polycystic ovarian syndrome, but it has been difficult to dissociate the effects of epilepsy from the role of antiepileptic drugs. To distinguish the effects of chronic seizures from medication, we used the laboratory rat, because an epileptic condition can be induced without concomitant anticonvulsant drug treatment.

METHODS

Adult female rats were administered the chemoconvulsant pilocarpine to initiate status epilepticus, which was decreased in severity by the anticonvulsant diazepam. These rats developed spontaneous seizures in the ensuing weeks, and are therefore termed epileptic. Controls were saline-treated rats, or animals that were injected with pilocarpine but did not develop status epilepticus. Ovarian cyclicity and weight gain were evaluated for 2 to 3 months. Serum hormone levels were assayed from trunk blood, which was collected at the time of death. Paraformaldehyde-fixed ovaries were evaluated quantitatively.

RESULTS

Rats that had pilocarpine-induced seizures had an increased incidence of acyclicity by the end of the study, even if status epilepticus did not occur. Ovarian cysts and weight gain were significantly greater in epileptic than control rats, whether rats maintained cyclicity or not. Serum testosterone was increased in epileptic rats, but estradiol, progesterone, and prolactin were not.

INTERPRETATIONS

The results suggest that an epileptic condition in the rat leads to increased body weight, cystic ovaries, and increased testosterone levels. Although caution is required when comparing female rats with women, the data suggest that recurrent seizures have adverse effects, independent of antiepileptic drugs.

Permselectivity of blood follicle barriers in mouse ovaries of the mifepristone-induced polycystic ovary model revealed by in vivo cryotechnique

Despite the potential association of polycystic ovary (PCO) syndrome with hemodynamic changes, follicular microenvironment and the involvement of blood follicle barriers (BFB), a histopathological examination has been hampered by artifacts caused by conventional preparation methods. In this study, mouse ovaries of a mifepristone-induced PCO model were morphologically and immunohistochemically examined byin vivocryotechnique (IVCT), which prevents those technical artifacts. Ovarian specimens of PCO model mice were prepared by IVCT or the conventional perfusion fixation after s.c. injection of mifepristone. Their histology and immunolocalization of plasma proteins, including albumin (molecular mass, 69 kDa), immunoglobulin G (IgG, 150 kDa), inter-α-trypsin inhibitor (ITI, 220 kDa), fibrinogen (340 kDa), and IgM (900 kDa), were examined. In the PCO model, enlarged blood vessels with abundant blood flow were observed in addition to cystic follicles with degenerative membrana granulosa. The immunolocalization of albumin and IgM in the PCO model were similar to those in normal mice. Albumin immunolocalized in the blood vessels, interstitium or follicles, and IgM was mostly restricted within the blood vessels. In contrast, immunolocalization of IgG, ITI, and fibrinogen changed in the PCO model. Both IgG and ITI were clearly blocked by follicular basement membranes, and hardly observed in the membrana granulosa, though fibrinogen was mostly observed within blood vessels. These findings suggest that increased blood flow and enhanced selectivity of molecular permeation through the BFB are prominent features in the PCO ovaries, and changes in hemodynamic conditions and permselectivity of BFB are involved in the pathogenesis and pathophysiology of PCO syndrome.

Sex differences in mouse models of asthma

Differences in disease susceptibility and prognosis between men and women are known to occur in the incidence and development of neurodegenerative, cardiovascular, and immunological disorders. In the lung there are also sex-based differences in the incidence, prevalence, and pathogenesis of lung cancer, cystic fibrosis, COPD, and asthma. In the general population, sex-based differences in asthma have been shown by epidemiologic studies, but unfortunately these studies are not consistent in their conclusions. This variability in human epidemiological studies justifies the need for more focused studies of the effects of specific hormones. Such specific mechanistic studies can most easily be performed in animal models, and since mouse models have the potential for separating specific genetic factors from environmental and exogenous factors, this species has become increasingly important in the design, analysis, and interpretation of asthma research. This review will document the male and female differences in airway function of naïve and sensitized mouse models, as well as the great variability in the functional measurements of airway tone. Until the situation is better understood, this variability between males and females should be kept in mind when designing, analyzing, and interpreting studies of smooth muscle responses in animal models and human subjects.

Exposure of adult rats to estradiol valerate induces ovarian cyst with early senescence of follicles

Environmental and therapeutic estrogens are known to play an important role in modulating the reproductive life and pubertal maturation in males as well as in females. Animal studies have shown that exogenously administered estrogen induces follicular cysts. However, the probable mechanisms underlying this abnormal ovarian development and its impact on steroidogenesis have been ill defined. The present study was therefore carried out to understand the ontogeny of ovarian pathology owing to adult estrogenisation. Regularly cycling female Holtzman rats were sacrificed at one week, two weeks, three weeks and four weeks after a subcutaneous administration of 2 mg of estradiol valerate (E(2)V). The effect of this supra-physiological estrogen on serum endocrine profiles, development of follicular cysts, follicular apoptosis and expression of markers of folliculogenesis viz., estrogen receptor (ER)-beta, inhibin A and progesterone receptor (PR) were studied. Results indicate a temporal augmentation of steroidogenesis, which was associated with induction of follicular cyst with theca cell hyperplasia and induction of apoptosis in the primary and secondary follicles of the ovaries. Immuno-histochemical localization showed an increase in inhibin A with a reduction in ER-beta and PR indicating early maturation, poor follicle growth and granulosa cell differentiation. Results indicate that exposure to exogenous estrogen in adulthood can have deleterious effects on the ovarian physiology and endocrinology which may ultimately lead to cystogenesis, loss of follicle pool and early senescence.

Altered expression of Fas/Fas ligand/caspase 8 and membrane type 1-matrix metalloproteinase in atretic follicles within dehydroepiandrosterone-induced polycystic ovaries in rats

One of the characteristics of polycystic ovary syndrome (PCOS) is the presence of cystic follicles in various stages of growth and atresia, the latter of which is known to be the result of apoptosis and tissue remodeling. To further investigate the process of follicular atresia, we compared ovarian expression and localization of Fas, Fas ligand (FasL), casapse-8 and membrane-type1 matrix metalloproteinase (MT1-MMP) in rats treated with dehydroepiandrosterone (DHEA) as a model of PCOS, and in control rats. We found that the numbers of TdT-mediated dUTP-biotin nick end-labeling (TUNEL)-positive follicles were significantly higher in ovaries from PCOS rats than in those from control rats (P < 0.05), as were ovarian levels of FasL mRNA and protein, processed caspase-8 protein and MT1-MMP mRNA. Correspondingly, we also observed an increase in the level of MTI-MMP catalytic activity and a decrease in the level of pro-caspase-8 protein. In addition, immunohistochemical analyses showed that MT1-MMP and FasL co-localize with TUNEL-positive apoptotic granulosa cells within atretic follicles of PCOS ovaries. Our results suggest that under the PCOS-like conditions induced by DHEA, the Fas/FasL/Caspase-8 (death receptor dependent) pathway is pivotal for follicular atresia, and that increased levels of MT1-MMP likely play an important role in tissue remodeling during structural luteolysis.