High-Fat, High-Sugar Diet Disrupts the Preovulatory Hormone Surge and Induces Cystic Ovaries in Cycling Female Rats

Common Beverage Consumption and Benign Gynecological Conditions

The purpose of this article is to review the effects of four commonly consumed beverage types-sugar-sweetened beverages (SSBs), caffeinated beverages, green tea, and alcohol-on five common benign gynecological conditions: uterine fibroids, endometriosis, polycystic ovary syndrome (PCOS), anovulatory infertility, and primary dysmenorrhea (PD). Here we outline a plethora of research, highlighting studies that demonstrate possible associations between beverage intake and increased risk of certain gynecological conditions-such as SSBs and dysmenorrhea-as well as studies that demonstrate a possible protective effect of beverage against risk of gynecological condition-such as green tea and uterine fibroids. This review aims to help inform the diet choices of those with the aforementioned conditions and give those with uteruses autonomy over their lifestyle decisions.

Elderly rats fed with a high-fat high-sucrose diet developed sex-dependent metabolic syndrome regardless of long-term metformin and liraglutide treatment

Aim/Introduction

The study aimed to determine the effectiveness of early antidiabetic therapy in reversing metabolic changes caused by high-fat and high-sucrose diet (HFHSD) in both sexes.

Methods

Elderly Sprague-Dawley rats, 45 weeks old, were randomized into four groups: a control group fed on the standard diet (STD), one group fed the HFHSD, and two groups fed the HFHSD along with long-term treatment of either metformin (HFHSD+M) or liraglutide (HFHSD+L). Antidiabetic treatment started 5 weeks after the introduction of the diet and lasted 13 weeks until the animals were 64 weeks old.

Results

Unexpectedly, HFHSD-fed animals did not gain weight but underwent significant metabolic changes. Both antidiabetic treatments produced sex-specific effects, but neither prevented the onset of prediabetes nor diabetes.

Conclusion

Liraglutide vested benefits to liver and skeletal muscle tissue in males but induced signs of insulin resistance in females.

Subacute high-refined carbohydrate diet leads to abnormal reproductive control of the hypothalamic-pituitary axis in female rats

We previously reported that female rats placed on a diet containing refined carbohydrates (HCD) resulted in obesity and reproductive abnormalities, such as high serum LH concentration and abnormal ovarian function. However, the impacts at the hypothalamic-pituitary (HP) function, specifically regarding pathways linked to reproductive axis modulation are unknown. In this study, we assessed whether subacute feeding with HCD results in abnormal reproductive control in the HP axis. Female rats were fed with HCD for 15 days and reproductive HP axis morphophysiology was assessed. HCD reduced hypothalamic mRNA expression (Kiss1, Lepr, and Amhr2) and increased pituitary LHβ+ cells. These changes likely contribute to the increase in serum LH concentration observed in HCD. Blunted estrogen negative feedback was observed in HCD, with increased kisspeptin protein expression in the arcuate nucleus of the hypothalamus (ARH), lower LHβ+ cells and LH concentration in ovariectomized (OVX)+HCD rats. Thus, these data suggest that HCD feeding led to female abnormal reproductive control of HP axis.

High Fat Diet Exaggerate Metabolic and Reproductive PCOS Features by Promoting Oxidative Stress: An Improved EV Model in Rats

Background and Objectives: Polycystic ovary syndrome (PCOS) is a frequent multifactorial endocrinopathy affecting women in the reproductive period, often associated with infertility and metabolic disorders. The use of animal models helps to better understand etiopathogenesis, enabling the examination of the effects of certain drugs in order to discover the best possible therapeutic approach. We tried to investigate the additional effect of estradiol-valerate (EV) and high-fat diet (HFD) in female rats to explore PCOS-related alterations with special focus on oxidative stress. Materials and Methods: Animals were divided into three groups: control group (CTRL, n = 6), estradiol-valerate group (EV, n = 6), and estradiol-valerate group on HFD (EV + HFD, n = 6). PCOS was induced by single subcutaneous injection of long-acting EV in a dose of 4 mg/per rat. We tried to improve the metabolic characteristics of the PCOS animal model by adding HFD, so the CTRL and EV group had a regular diet, while the EV + HFD group had HFD during the induction period of 60 days. Results: We observed alterations of anthropometric parameters and hormonal disturbances, along with estrus cycle impairment reassembly to obese-type PCOS phenotype. Moreover, glucose metabolism was impaired after addition of HFD to EV protocol, contrary to EV administered alone. Histological analysis confirmed more numerous cystic follicles after the combination of EV and HFD protocol. The alterations of oxidative stress markers could be related to and serve as the mechanistic base for development of PCOS-related endocrine, reproductive, and metabolic properties. Conclusions: The additive effect of EV and HFD was obvious in the majority of the parameters observed. Our study strongly demonstrated metabolic as well as reproductive properties of PCOS in rats.

Evidence for Involvement of GIP and GLP-1 Receptors and the Gut-Gonadal Axis in Regulating Female Reproductive Function in Mice

Substantial evidence suggests crosstalk between reproductive and gut-axis but mechanisms linking metabolism and reproduction are still unclear. The present study evaluated the possible role of glucose-dependent-insulinotropic-polypeptide (GIP) and glucagon-like-peptide-1 (GLP-1) in reproductive function by examining receptor distribution and the effects of global GIPR and GLP-1R deletion on estrous cycling and reproductive outcomes in mice. GIPR and GLP-1R gene expression were readily detected by PCR in female reproductive tissues including pituitary, ovaries and uterine horn. Protein expression was confirmed with histological visualisation of incretin receptors using GIPR-Cre and GLP1R-Cre mice in which the incretin receptor expressing cells were fluorescently tagged. Functional studies revealed that female GIPR^-/- and GLP-1R^-/- null mice exhibited significantly (p < 0.05 and p < 0.01) deranged estrous cycling compared to wild-type controls, indicative of reduced fertility. Furthermore, only 50% and 16% of female GIPR^-/- and GLP-1R^-/- mice, respectively produced litters with wild-type males across three breeding cycles. Consistent with a physiological role of incretin receptors in pregnancy outcome, litter size was significantly (p < 0.001-p < 0.05) decreased in GIPR^-/- and GLP-1R^-/- mice. Treatment with oral metformin (300 mg/kg body-weight), an agent used clinically for treatment of PCOS, for a further two breeding periods showed no amelioration of pregnancy outcome except that litter size in the GIPR^-/- group was approximately 2 times greater in the second breeding cycle. These data highlight the significance of incretin receptors in modulation of female reproductive function which may provide future targets for pharmacological intervention in reproductive disorders.

The Effect of Alternating High-Sucrose and Sucrose Free-Diets, and Intermittent One-Day Fasting on the Estrous Cycle and Sex Hormones in Female Rats

Relationships between diet, sex hormone concentrations, and the estrous cycle are important from the perspective of infertility and estrogen-dependent disease prevention and treatment. Four dietary interventions reflecting modern eating behaviors were explored. The study involved 50 female rats divided into five feeding groups. The impact of the amount of sucrose consumed (9% and 18% of the dietary energy content), alternating high-sucrose and sucrose-free diets, and a high-sucrose diet combined with intermittent one-day fasting on the estrous cycle and sex hormone concentrations in female rats was assessed. Even low amounts of dietary sucrose (9% of the dietary energy content) were found to lead to increased estradiol (E2) concentrations and decreased progesterone (Pg) concentrations. A high-sucrose diet, even when periodically applied, additionally led to a reduced concentration of luteinizing hormone (LH). The largest changes in the hormones tested were observed with one-day fasting coupled with the high-sucrose diet; in addition, the estrous phase was shortened and the estrous cycle was disrupted. The results of this study show that both the amount of dietary sucrose and also its uptake pattern affect the estrous cycle and sex hormone concentrations in female rats.

Diet and lifestyle modifications for effective management of polycystic ovarian syndrome (PCOS)

Polycystic ovarian syndrome (PCOS) is caused by abnormal production of androgens resulting in the formation of small fluid-filled sacs in the ovaries. This condition worsens the life quality of women by disturbing their physiology and psychology in reproductive age. PCOS may also be associated with other morbidities like diabetes and hypertension. Numerous factors like imbalanced dietary patterns, poor lifestyle activities, improper care and medication, late diagnosis, and ignorance are involved in the prevalence of this disease in women. Hence, an early diagnosis and improved dietary and lifestyle management may improve the life quality and timely recovery of the patient from this disease. Various herbal extracts show a positive correlation in reducing the indicators associated with PCOS. This review discusses the effect of dietary and lifestyle practices on PCOS as prominent features. It has been recommended that a balanced diet with 40% energy from carbohydrates, 30% from fats, and 30% from protein with optimum physical activity could reduce severe PCOS symptoms and improve metabolic balance. Furthermore, recommendations for modification of diet and lifestyle activities are made which may positively influence the recovery from PCOS. PRACTICAL APPLICATIONS: Polycystic ovarian syndrome (PCOS) severely affects the life quality of suffering women. The dietary patterns, lifestyle activities, and co-medical conditions collectively affect the severity and related consequences of PCOS. This article provides sufficient information on dietary and lifestyle modifications to effectively manage this disease. Furthermore, dietitians, nutritionists, gynecologists, and obstetrics physicians can benefit from the information provided in it to understand and develop the management strategies to alleviate the disease symptoms and severity.

The PNA mouse may be the best animal model of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) exerts negative effects on females of childbearing age. It is important to identify more suitable models for fundamental research on PCOS. We evaluated animal models from a novel perspective with the aim of helping researchers select the best model for PCOS. RNA sequencing was performed to investigate the mRNA expression profiles in the ovarian tissues of mice with dehydroepiandrosterone (DHEA) plus high-fat diet (HFD)-induced PCOS. Meanwhile, 14 datasets were obtained from the Gene Expression Omnibus (GEO), including eight studies on humans, three on rats and three on mice, and genes associated with PCOS were obtained from the PCOSKB website. We compared the consistency of each animal model and human PCOS in terms of DEGs and pathway enrichment analysis results. There were 239 DEGs shared between prenatally androgenized (PNA) mice and PCOS patients. Moreover, 1113 genes associated with PCOS from the PCOSKB website were identified among the DEGs of PNA mice. A total of 134 GO and KEGG pathways were shared between PNA mice and PCOS patients. These findings suggest that the PNA mouse model is the best animal model to simulate PCOS.

Effect of a high-calorie diet and constant light exposure on female reproduction, metabolism and immune inflammation: A comparative study of different mouse models

PROBLEM

Excess caloric intake and irregular circadian rhythm could severely impair female reproductive, metabolic, and immune function. However, the similarities and differences between their individual and combined effects and mechanisms have not been fully elucidated. Due to limitations and confounding factors in clinical research, we used these two kinds of unhealthy factors to intervene the mice singly or in combination to explore their effects on individuals.

METHOD OF STUDY

We used a high-calorie diet (HCD), constant light exposure (CLE), and a high-calorie diet combined with constant light exposure (HCD + CLE) to build three different mouse models. During the 9 weeks modeling period, the estrous cycles were monitored, and after modeling, the indicators of glycolipid metabolism, inflammation, and reproductive endocrine function were tested.

RESULTS

We found that both HCD and CLE alone could induce ovulatory disorders, obesity, and chronic low-grade inflammation and inhibit melatonin secretion. The difference was that HCD significantly reduced the serum luteinizing hormone (LH) and testosterone (T) levels, inhibited the expression of FSH β and LH β in pituitary, increased cytochrome P450 enzymes and LH receptor expression in ovary, as well causing impaired glucose tolerance and hyperlipidemia, and significantly promoted the secretion of leptin and inhibited the secretion of adiponectin. However, CLE significantly increased blood LH and T, prompted the expression of kisspeptin in hypothalamus and LH β in pituitary, and had no effect on glycolipid metabolic indexes or the secretion of leptin or adiponectin. The phenotype of HCD + CLE model was basically the same as that of HCD model, associated with more severe visceral obesity and chronic inflammation.

CONCLUSIONS

In conclusion, we found that unhealthy lifestyle determines the phenotype of reproductive endocrine, immune, and metabolic disorders. These findings can provide theoretical support for the subsequent study of PCOS-like features.

Effect of High-Fat Diet on the Intestinal Flora in Letrozole-Induced Polycystic Ovary Syndrome Rats

Aim

The aim of this study was to explore whether letrozole and high-fat diets (HFD) can induce obese insulin-resistant polycystic ovary syndrome (PCOS) with intestinal flora dysbiosis in a rat model. We compared the changes in the intestinal flora of letrozole-induced rats fed with HFD or normal chow, to explore the effects of HFD and letrozole independently and synergistically on the intestinal flora.

Methods

Five-week-old female Sprague Dawley (SD) rats were divided into four groups: control (C) group fed with regular diet; L1 group administered with letrozole and fed with regular diet; L2 group received letrozole and fed with HFD; and HFD group fed with HFD. At the end of the experiment, ovarian morphology, hormones, metabolism, oxidative stress, and inflammatory status of all rats were studied. 16S rDNA high-throughput sequencing was used to profile microbial communities, and various multivariate analysis approaches were used to quantitate microbial composition, abundance, and diversity.

Results

Compared to the C group, the increased plasma fasting insulin and glucose, HOMA-IR, triglyceride, testosterone, and malondialdehyde were significantly higher in the L2 group, while high-density lipoprotein cholesterol was significantly lower in the L1 group and L2 group. The indices of Chao1 and the Abundance-based Coverage Estimator (ACE) (α-diversity) in the L2 and HFD groups were significantly lower than that in the C group. Bray–Curtis dissimilarity based principal coordinate analysis (PCoA) plots and analysis of similarities (ANOSIM) test showed obvious separations between the L2 group and C group, between the HFD group and C group, and between the L2 and HFD groups. At the phylum level, Firmicutes and ratio of Firmicutes and Bacteroidetes (F/B ratio) were increased in the L2 group; Bacteroidetes was decreased in the L2 and HFD groups. No significant differences in bacterial abundance between the C group and L1 group were observed at the phylum level. Based on linear discriminant analysis (LDA) effect size (LEfSe) analysis, the bacterial genera (the relative abundance > 0.1%, LDA > 3, p < 0.05) were selected as candidate bacterial signatures. They showed that the abundance of Vibrio was significantly increased in the L1 group; Bacteroides and Phascolarctobacterium were enriched in the HFD group, and Bacteroides, Phascolarctobacterium, Blautia, Parabacteroides, Akkermansia [Ruminococcus]_torques_group, and Anaerotruncus were enriched in the L2 group.

Conclusion

The effect of letrozole on intestinal flora was not significant as HFD. HFD could destroy the balance of intestinal flora and aggravate the intestinal flora dysbiosis in PCOS. Letrozole-induced rats fed with HFD have many characteristics like human PCOS, including some metabolic disorders and intestinal flora dysbiosis. The dysbiosis was characterized by an increased Firmicutes/Bacteroidetes ratio, an expansion of Firmicutes, a contraction of Bacteroidetes, and the decreased microbial richness. Beta-diversity also showed significant differences in intestinal microflora, compared with control rats.

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.

Neonatal overfeeding reduces estradiol plasma levels and disrupts noradrenergic-kisspeptin-GnRH pathway and fertility in adult female rats

This work evaluated the effects of neonatal overfeeding, induced by litter size reduction, on fertility and the noradrenaline-kisspeptin-gonadotrophin releasing hormone (GnRH) pathway in adult female rats. The litter size was adjusted to 3 pups with each mother in the small litters (SL) and 10 pups with each mother in the normal litters (NL). SL females exhibited metabolic changes associated with reproductive dysfunctions, shown by earlier vaginal opening and first estrus, later regular cyclicity onset, and lower and higher occurrences of estrus and diestrus phases, respectively, as well as reduced fertility, estradiol plasma levels, and mRNA expressions of tyrosine hydroxylase in the locus coeruleus, kisspeptin, and GnRH in the preoptic area in adult females in the afternoon of proestrus. These results suggest that neonatal overfeeding in female rats promotes reproductive dysfunctions in adulthood, such as lower estradiol plasma levels associated with impairments in fertility and noradrenaline-kisspeptin-GnRH pathway during positive feedback.

Ultrasonographic features of ovarian morphology capture nutritional and metabolic influences on the reproductive axis: implications for biomarker development in ovulatory disorders

Ultrasonographic imaging of ovarian morphology is used widely to inform reproductive health status in women. Metabolic disturbances induced by a negative energy balance (e.g. undernutrition) or positive energy balance (e.g. overnutrition, obesity) are known to drive or exacerbate reproductive dysfunction. Whether the utility of ultrasonographic metrics of ovarian morphology could be extended as biomarkers that detect and monitor the integration of metabolic and reproductive dysfunction is an emerging research area, and recent evidence is discussed. We note that unique variations in ovarian morphology emerge across the adiposity spectrum and highlight the potential for reproductive and metabolic 'tipping points' upon which such morphological variations may be detected on ultrasonography.

Animal Models in Polycystic Ovarian Syndrome

The pathogenesis of polycystic ovarian syndrome (PCOS) in women is poorly understood. With its varied endocrine and metabolic effects, it is unlikely a single genetic mutation or biological insult is the cause of the disease. Animals have been the proposed model for further studying the pathogenesis of PCOS and many modalities can be used to induce PCOS-like phenotypes in animals, most often with rodents. While there is not yet an animal model that perfectly recapitulates the classic PCOS phenotype in human women, many models allow for a better understanding of the complex disease process as well as possible treatments.

FSH/AMH Ratio and Adipocyte Size are Linked to Ovarian Dysfunction

While the relationship between obesity and reproductive dysfunction is well known, the physiological mechanism behind obesity-related infertility remains unclear. Previous work suggests that follicle development prior to ovulation is disrupted in obese individuals. Follicle-stimulating hormone (FSH) and anti-Mullerian hormone (AMH) are two key regulators of follicle development, and the poorest reproductive outcomes have been recorded when these hormones are imbalanced. In order to understand how obesity impacts the reproductive axis, the present study induces reproductive dysfunction in female rats using a high-fat, high-sugar diet (HFHS). Results: In our study, several animals on the HFHS diet displayed abnormal estrous cycles. The HFHS diet also resulted in an increased prevalence of ovarian cysts and decreased formation of corpora lutea. Across all groups, the FSH/AMH ratio displayed a strong negative correlation with pre-antral, antral, and total follicle counts. Moreover, rats on the HFHS diet displayed larger adipocytes and produced higher levels of leptin than controls. When combined with average adipocyte size in multiple regression, the FSH/AMH ratio was strongly associated with cyst formation in the ovary. Conclusions: These findings provide strong evidence for the potential relevance of a combined FSH/AMH ratio as a marker of ovarian health and follicular status. Therefore, this ratio reflects a complex interaction between the reproductive and metabolic systems.

Dietary Advanced Glycation End Products (AGEs) could alter ovarian function in mice

Nutrition is an important source of exogenous AGEs and thermally processed foods present in western-style diets contain a large amount of these pro-inflammatory AGEs. Additionally, the intake of dietary AGEs could upregulate ovarian gene expression of inflammatory macrophage markers. The objective of this study was to investigate the effect of diet rich in AGEs on estrous cyclicity and ovarian function in a mouse model. Six-week old C57BL/6 J female mice were randomly subjected to either a diet low in AGEs (L-AGE) or a diet high in AGEs (H-AGE) for a total of 13 weeks. Experiments performed included daily vaginal smears to assess estrous cyclicity, ovarian superovulation with gonadotropins to assess the number of oocytes released, whole ovarian tissue mRNA quantification by RT-PCR to quantify genes involved in folliculogenesis, steroidogenesis, and macrophage markers, and ovarian morphology for follicle count. Outcome measures included estrous cyclicity, number of oocytes following superovulation, expression of genes involved in folliculogenesis, steroidogenesis, and macrophage infiltration as well as the number of primordial, primary, secondary, antral follicles and corpora lutea. Compared to mice on L-AGE diet, mice on H-AGE spent significantly longer time in the diestrus phase, had similar number of oocytes released following ovarian superovulation, and showed significant alterations in genes involved in steroidogenesis (increase in Star mRNA expression levels) and folliculogenesis (increase in Gdf-9 and Fshr mRNA expression levels). Mouse macrophage marker F4/80 mRNA expression was upregulated in mice on H-AGE diet compared to mice on L-AGE diet. Finally, mice on H-AGE diet had significantly fewer corpora lutea in their ovaries. These results indicate that the ingestion of high amounts of dietary AGEs could disrupt folliculogenesis and steroidogenesis that might lead to abnormal estrous cyclicity. Intake of dietary AGEs could also upregulate ovarian gene expression of inflammatory macrophage markers.

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.

A free-choice high-fat, high-sucrose diet induces hyperphagia, obesity, and cardiovascular dysfunction in female cycling and pregnant rats

The main objective of these studies was to characterize metabolic, body composition, and cardiovascular responses to a free-choice high-fat, high-sucrose diet in female cycling and pregnant rats. In the nonpregnant state, female Sprague-Dawley rats offered a 3-wk free-choice high-fat, high-sucrose diet had greater energy intake, adiposity, serum leptin, and triglyceride concentrations compared with rats fed with standard chow and developed glucose intolerance. In addition, choice-diet-fed rats had larger cardiac ventricular weights, smaller kidney and pancreas weights, and higher blood pressure than chow-fed rats, but they did not exhibit resistance artery endothelial dysfunction. When the free-choice diet continued throughout pregnancy, rats remained hyperphagic, hyperleptinemic, and obese. Choice pregnant rats exhibited uterine artery endothelial dysfunction and had smaller fetuses compared with chow pregnant rats. Pregnancy normalized mean arterial blood pressure and pancreas weights in choice rats. These studies are the first to provide a comprehensive evaluation of free-choice high-fat, high-sucrose diet on metabolic and cardiovascular functions in female rats, extending the previous studies in males to female cycling and pregnant rodents. Free-choice diet may provide a new model of preconceptual maternal obesity to study the role of increased energy intake, individual food components, and preexisting maternal obesity on maternal and offspring physiological responses during pregnancy and after birth.

Histological classification of canine ovarian cyst types with reference to medical history

Ovaries of 21 bitches presented with gynecopathies were surgically removed and histologically examined. Standard histological, as well as immunohistochemical, classification of 193 cystic structures resulted in the classification of 72 cysts of subsurface epithelial structures (SES), 61 follicular cysts (FCs), 38 cystic rete ovarii (CRO), 13 lutein cysts (LCs), and 9 non-classifiable cysts (NCCs). In addition to the histological classification, results were interpreted according to subject medical history, clinical examination outcome, and macroscopic observations during ovariohysterectomy. Dogs with ovarian cysts (OCs) and associated reproductive perturbations were mostly nulliparous, of large breed, and had an average of 9.5 ± 3 years. Prolonged or shortened inter-estrus intervals of past heats, however, seemed to be relatively low-risk factors for the development of OCs in dogs. Furthermore, we provide histological observations of a rarely seen canine LC including a degenerated oocyte in the central cavity.

Effects of treadmill exercise on PI3K/AKT/GSK-3β pathway and tau protein in high-fat diet-fed rats

[Purpose]

This study aimed to clearly evaluate the effects of obesity on cerebral health. Thus, we induced obesity in rats using a long-term high-fat diet (HFD), then investigated its effects on insulin signaling and tau hyperphosphorylation. Additionally, we examined the effects of 8 weeks of treadmill exercise (TE) on insulin signaling and tau hyperphosphorylation.

[Methods]

Rats were separated into Normal Diet-Control, HFD-Control, and HFD-TE groups. TE loads were gradually increased. A passive avoidance test was used to evaluate cognitive function. Western blots were used to examine the abundance of the insulin receptor,phosphoinositide 3-kinase, protein kinase B, glycogen synthase kinase-3β, and tau proteins in the cerebral cortex; immunohistochemical analyses were used to examine the abundance of hyperphosphorylated tau in the cerebral cortex.

[Results]

TE in HFD-fed rats resulted in a significant lowering of bodyweight, abdominal visceral fat (AVF), the area under the glucose response curve, and the homeostatic model assessment-insulin resistance index, while it improved working memory. In addition, TE in HFD-fed rats decreased tau hyperphosphorylation and aggregation, while increasing insulin signaling-related protein activity.

[Conclusion]

After a 20-week HFD, the experimental animals exhibited increased weight, as well as impaired insulin resistance and blood glucose metabolism. HFD rats demonstrated abnormal insulin signaling and tau hyperphosphorylation in the cerebral cortex, as well as memory impairments that suggested reduced cerebral function. However, TE reduced AVF, improved insulin resistance in the peripheral tissues by increasing insulin sensitivity, and alleviated memory impairments by restoring insulin signaling and reducing tau hyperphosphorylation in the cerebral cortex.