Letrozole Rat Model Mimics Human Polycystic Ovarian Syndrome and Changes in Insulin Signal Pathways

Resveratrol protects against letrozole-induced renal damage in a rat model of polycystic ovary syndrome: A biochemical, histological, and immunohistochemical study

BACKGROUND

Polycystic ovary syndrome (PCOS) is a common endocrine disorder that affects 9-18 % of women, often associated with metabolic and renal complications. This study aimed to investigate the renoprotective effects of resveratrol (RSV) in a letrozole-induced rat model of PCOS, focusing on biochemical, histological, ultrastructural, and immunohistochemical alterations.

METHODS

Thirty female rats were randomly divided into five groups: negative control, only RSV-treated, PCOS-induced (sham), metformin-treated, and RSV-treated. Serum testosterone, urea, and creatinine levels were assessed. Renal tissues underwent histological, immunohistochemical, ultrastructural, and morphometric analyses. Additionally, TGF-β1 mRNA expression was evaluated using qRT-PCR.

RESULTS

Letrozole administration significantly elevated serum testosterone, urea, and creatinine levels, indicating PCOS-associated renal dysfunction. Histological and ultrastructural analysis revealed severe glomerular and tubular alterations in the sham group. The administration of RSV significantly restored renal architecture and function more effectively than metformin. Immunohistochemistry analysis showed that RSV reduced Proliferating Cell Nuclear Antigen (PCNA) overexpression and restored B-cell Lymphoma 2 (BCL-2) expression, suggesting a protective effect against cellular stress and apoptosis. Moreover, RSV significantly downregulated TGF-β1 expression, indicating its anti-fibrotic and anti-inflammatory role in PCOS-related renal damage.

CONCLUSION

In a PCOS rat model, RSV protects effectively against letrozole-induced structural and functional renal damage. It demonstrates superior efficacy over metformin in restoring renal function, reducing apoptosis, and mitigating fibrosis. These findings suggest that RSV may serve as a potential adjunct therapy for preventing PCOS-associated renal complications, emphasizing the need for further investigations.

Evaluating spironolactone monotherapy against combined treatment with metformin in rat PCOS model

Polycystic ovarian syndrome (PCOS) is a common gynecological disorder with multifactorial pathogenic risk factors. Combination therapy with metformin and thiazolidinedione derivatives is frequently used, but its synergistic effects have not been thoroughly evaluated. This study aims to compare the therapeutic efficacy of low-dose spironolactone (LDS) at 0.25 mg/kg for 28 days, metformin at 500 mg/kg for 28 days, and a combination of LDS and metformin, against a letrozole (1 mg/kg/day) and 0.5 % carboxymethylcellulose (CMC)-induced PCOS rat model. The study involved five groups of laboratory animals: Group I (Healthy control), Group IIa (Disease control), Group IIb (Metformin), Group IIc (LDS), and Group IId (Metformin + LDS). Therapeutic efficacy was evaluated based on phenotypic, hormonal, and genotypic determinants. Letrozole successfully induced PCOS in the animals, evidenced by elevated levels of Sex Hormone Binding Globulin (SHBG), Follicle Stimulating Hormone (FSH), and progesterone, as well as the presence of multiple ovarian cysts. Hierarchical Cluster Analysis indicated that LDS was superior to metformin and the combination therapy in ameliorating PCOS symptoms. The findings suggest that there is little to no benefit in adding metformin to LDS for the clinical management of PCOS. Although these results are from preclinical studies, further case-controlled, randomized placebo studies on a larger patient sample are necessary to confirm these findings in clinical settings.

(-)-Epigallocatechin-3-gallate and chlorogenic acid in combination with vitamin D as a therapeutic approach for letrozole-induced polycystic ovary syndrome (PCOS) rats: Biochemical and hormonal modulation

Treatment with phytochemicals have shown promising results in managing various diseases including Polycystic ovary syndrome (PCOS) which is an endocrine gynecological disorder affecting reproductive aged women. This study has demonstrated that Epigallocatechin-3-gallate (EGCG) and chlorogenic acid (CGA) in combination with vitamin D can significantly reduce PCOS like characteristics including ovarian cysts, hyperandrogenism, fasting blood glucose level, insulin resistance, hyperlipidaemia, ROS formation, oxidative stress, DNA damage, and ovarian histomorphology in letrozole induced PCOS rats. PCOS was induced in female Wistar rats by giving 1 mg/kg/day letrozole for 21 days through oral gavage. EGCG (100 mg/kg/day) and CGA (120 mg/kg/day) in combination with vitamin D (25 mcg/kg/day) was given orally for 15 days, from day 21-35. Metformin treatment was used as a positive control. Histological, microscopic analysis, and chemiluminescent immunoassays were performed to evaluate decrement in PCOS like symptoms. Nitric oxide (RNS) production, antioxidant status, and the generation of reactive oxygen species (ROS) were also assessed. Ovary homogenates and plasma samples of rats were also examined for markers of protein, lipid, and DNA oxidation. Activities of enzymatic antioxidants (superoxide dismutase, catalase, glutathione reductase, Paraoxonase-1 status) were also evaluated. EGCG + vitamin D and CGA + vitamin D has been found to restore hormonal balance by modulating steroidogenic enzymes, they also improved antioxidant enzyme activity including SOD, catalase, glutathione reductase, PON-1 arylesterase, PON-1 CMPAase, etc. Similarly, EGCG + vitamin D and CGA + vitamin D treatment have shown efficacy in normalizing the estrus cycle, reducing ovarian cysts, and improving ovarian histomorphology. They also assisted in alleviating triglycerides and cholesterol levels and maintained liver function enzymes level. However, EGCG + vitamin D proves to have better therapeutic potential modulates glucose metabolic pathways, by reducing blood glucose levels, advanced glycation end product formation, decreasing ROS generation and oxidative stress; consequently, lowers hyperandrogenism and insulin resistance. Overall, EGCG + vitamin D treatment offers a comprehensive approach in managing PCOS by targeting multiple pathways associated with this disorder, making it a potential alternative to conventional therapies.

Adipokines level in plasma, hypothalamus, ovaries and adipose tissue of rats with polycystic ovary syndrome

RESEARCH QUESTION

Do the levels of adipokines (adiponectin, apelin, chemerin and vaspin) in plasma, hypothalamus, ovaries and periovarian adipose tissue differ during polycystic ovarian syndrome (PCOS)?

DESIGN

The PCOS was induced in rats by oral administration of non-steroidal aromatase inhibitor letrozole. To determine the plasma levels of adiponectin, apelin, chemerin and vaspin enzyme-linked immunosorbent assays were carried out. To assess the expression (gene and protein) and immunolocalization of these adipokines and their receptors, namely Adipor1 and Adipor2 for adiponectin, Aplnr for apelin, Ccrl2, Cmklr1 and Gpr1 for chemerin and Grp78 for vaspin in the hypothalamus, real-time polymerase chain reaction, and Western blot and immunohistochemistry were used to analyse ovaries and periovarian adipose tissue respectively.

RESULTS

In PCOS, the plasma level of adiponectin decreased (P = 0.0003), whereas apelin, chemerin and vaspin increased (P ≤ 0.0479). Moreover, PCOS modulates the expression of adipokines and their receptors in the hypothalamus, ovaries and periovarian adipose tissue compared with healthy rats (P ≤ 0.487).

CONCLUSIONS

A strong relationship was found between PCOS and adipokines, which suggests that adipokines may be a biomarker of PCOS.

Investigating the self-healing potential of polycystic ovary syndrome in a mouse model: Implications for offspring health

Polycystic ovarian syndrome (PCOS) is a prevalent metabolic endocrine disorder in reproductive-aged women. This study aims to investigate the self-healing ability of PCOS and its potential impact on offspring. Methods: Female C57 BL/6J mice aged 4-5 weeks were administered letrozole (1 mg/kg/d) and a high-fat diet for 21 days to establish a PCOS model, and a control group was established. After modeling, the mice were divided into a PCOS model group and a self-healing group. After 14 days, the mice were mated, and the growth of their offspring was recorded. Subsequently, all mice were euthanized to collect serum, ovaries, and testes. The results showed that the self-healing group PCOS phenotype has shown improvement when compared to the model group. The findings from the offspring study indicate that all offspring in the model group died, while the self-healing group had offspring with a lower weight at 7 days and higher blood glucose levels. Additionally, the testicular morphology of male offspring in the self-healing group was poor. The conclusion drawn is that, after removing the pathogenic factors, the PCOS model group can self-heal. However, fertility remains impaired, which has an impact on their offspring.

Study on the effects of Mogroside V in inhibiting NLRP3-mediated granulosa cell pyroptosis and insulin resistance to improve PCOS

OBJECTIVE

Polycystic Ovary Syndrome (PCOS) is a prevalent endocrinopathy in reproductive-aged women, contributing to 75% of infertility cases due to ovulatory dysfunction. The condition poses significant health and psychological challenges, making the study of its pathogenesis and treatment a research priority. This study investigates the effects of Mogroside V (MV) on PCOS, focusing on its anti-inflammatory and anti-insulin resistance properties.

METHODS

Forty-five female Sprague-Dawley rats were divided into three groups: control, PCOS model, and MV treatment. The PCOS model was induced using a high-fat diet and letrozole. The MV treatment group was subsequently administered MV after the establishment of the PCOS model. The study monitored body mass, assessed estrous cycle changes, and measured serum hormone levels. Transcriptome sequencing and bioinformatics were used to identify differentially expressed genes related to inflammation and insulin resistance. Expression of pyroptosis and insulin resistance markers was analyzed using qRT-PCR, Western blot, and IHC. Additionally, an in vitro model assessed MV's impact on inflammation and insulin resistance.

RESULTS

The PCOS group exhibited elevated serum testosterone (T), luteinizing hormone (LH), insulin, and fasting glucose levels, along with increased insulin resistance (HOMA-IR) and decreased estradiol (E2), which were reversed by MV treatment. Transcriptome analysis identified significant gene expression changes between groups, particularly in pathways related to NLRP3 inflammation and insulin metabolism. MV treatment normalized the expression of ovarian pyroptosis factors (NLRP3, Caspase-1, GSDMD) and inflammatory cytokines (IL-1β, IL-18). In cellular models, MV increased E2 levels, reduced LDH release, and decreased the expression of insulin resistance and pyroptosis markers. Correlation analysis showed pyroptosis factors were positively correlated with HOMA-IR and IGF1, and negatively with IGF1R and E2 levels.

CONCLUSION

MV improves PCOS by reducing pyroptosis and insulin resistance, enhancing insulin sensitivity, and promoting estrogen synthesis, thereby restoring granulosa cell function and follicular development.

Characteristics of polycystic ovary syndrome rat models induced by letrozole, testosterone propionate and high-fat diets

RESEARCH QUESTION

What are the long-term effects of different models of polycystic ovary syndrome (PCOS), and which model could be used in future research?

DESIGN

PCOS models induced by letrozole, letrozole plus high-fat diet (LE+HFD), testosterone propionate (TP) or testosterone propionate plus HFD (TP+HFD) were established in rats. Body weight, energy intake, blood glucose, sex hormone concentrations, lipid profiles and the oestrus cycle were observed. Histology of ovaries, large intestine and fat was displayed. Protein and mRNA levels relating to hormone synthesis, oocyte maturation, the gut barrier, lipid metabolism and inflammation were evaluated using western blotting, immunohistochemistry and PCR. The composition of the microbial community was measured using 16S RNA sequencing.

RESULTS

Letrozole treatment induced hyperandrogenaemia, polycystic ovarian morphology, a disrupted oestrus cycle and impaired ovarian function, which could be restored within 42 days. Concurrently, letrozole disturbed glucose, fat, and energy metabolism, affected the inflammatory state and compromised intestinal homeostasis. HFD could amplify the disturbances in the metabolism and intestinal microenvironment, and the pituitary-ovarian axis was more efficiently and consistently affected by testosterone propionate. Testosterone propionate and TP+HFD treatment also disturbed the intestinal microenvironment. Although the metabolic effects of testosterone propionate were not as profound as those of letrozole, they were enhanced by HFD.

CONCLUSIONS

Letrozole is useful for studies on metabolic disturbances in PCOS, and LE+HFD treatment is suitable for investigations on PCOS metabolic abnormalities and the gut-PCOS link. Testosterone propionate injection is appropriate for studying reproductive abnormalities in PCOS, while TP+HFD treatment is the most comprehensive for studying PCOS reproductive abnormalities, metabolic disturbances and the gut-PCOS link.

A Review on In-vivo and In-vitro Models of Obesity and Obesity-Associated Co-Morbidities

BACKGROUND

Obesity is becoming a global pandemic with pandemic proportions. According to the WHO estimates, there were over 1.9 billion overweight individuals and over 650 million obese adults in the globe in 2016. In recent years, scientists have encountered difficulties in choosing acceptable animal models, leading to a multitude of contradicting aspects and incorrect outcomes. This review comprehensively evaluates different screening models of obesity and obesity-associated comorbidities to reveal the advantages and disadvantages/limitations of each model while also mentioning the time duration each model requires to induce obesity.

METHODS

For this review, the authors have gone through a vast number of article sources from different scientific databases, such as Google Scholar, Web of Science, Medline, and PubMed.

RESULTS

In-vivo models used to represent a variety of obesity-inducing processes, such as diet-induced, drug-induced, surgical, chemical, stress-induced, and genetic models, are discussed. Animal cell models are examined with an emphasis on their use in understanding the molecular causes of obesity, for which we discussed in depth the important cell lines, including 3T3-L1, OP9, 3T3-F442A, and C3H10T1/2. Screening models of obesity-associated co-morbidities like diabetes, asthma, cardiovascular disorders, cancer, and polycystic ovarian syndrome (PCOS) were discussed, which provided light on the complex interactions between obesity and numerous health problems.

CONCLUSION

Mimicking obesity in an animal model reflects multifactorial aspects is a matter of challenge. Future studies could address the ethical issues surrounding the use of animals in obesity research as well as investigate newly developed models, such as non-mammalian models. In conclusion, improving our knowledge and management of obesity and related health problems will require ongoing assessment and improvement of study models.

Fisetin mitigates letrozole-induced polycystic ovarian syndrome in rats: crosstalk of AMPK/PI3K/AKT-mediated-Nrf2 antioxidant defense mechanism and the inflammasome NLRP3/NF-κB P65/IL-1β signaling pathways

Polycystic ovarian syndrome (PCOS) is a highly prevalent condition affecting reproductive-aged women, causing insulin resistance, hyperandrogenism, weight gain, and menstrual problems. The present study intended to investigate the potential role of fisetin (FT) in letrozole (LZ)-induced PCOS in adult female rats and the possible mechanism underlying its action. PCOS was induced by oral administration of LZ (1 mg/kg) for 21 days. Treated rats received FT (1.25 or 2.5 mg/kg) orally once daily for 14 consecutive days. Following the experimental duration, blood samples and ovary tissues were isolated and preserved for biochemical and histopathological examinations. The results revealed that LZ-induced PCOS led to significant abnormalities in sex hormones and metabolic parameters. Additionally, it initiated an inflammatory cascade, evidenced by activation of the NF-κB p65/IL-1β and AMPK/PI3K/AKT pathways, alongside downregulation of Nrf2 ovarian gene expression and NLRP3 inflammasome activity, which enhanced the production of proinflammatory cytokines. FT demonstrated its beneficial impacts by restoring hormonal disturbance and reversing the imbalanced metabolic parameters. Moreover, FT increased the mRNA of ovarian Nrf2 levels and suppressed the up-regulated inflammatory IL-1β/NF-κB p65 signaling pathway, consequently alleviating the elevated levels of ovarian NLRP3. The histopathological examination also confirmed that FT has a beneficial effect in ameliorating PCOS, consistent with the aforementioned parameters. Finally, the present results demonstrated that FT ameliorates LZ-induced PCOS through the intricate interplay between the AMPK/PI3K/AKT-mediated Nrf2 antioxidant defense mechanism and the regulation of the inflammasome NLRP3/NF-κB p65/IL-1β signaling pathways.

Acetate attenuates hypothalamic pyroptosis in experimentally induced polycystic ovarian syndrome

This study hypothesized that SCFA, acetate impacts positively on hypothalamic pyroptosis and its related abnormalities in experimentally induced PCOS rat model, possibly through NrF2/HIF1-α modulation. Eight-week-old female Wister rats were divided into groups (n = 5), namely control, PCOS, acetate and PCOS + acetate groups. Induction of PCOS was performed by administering 1 mg/kg body weight of letrozole for 21 days. After PCOS confirmation, the animals were treated with 200 mg/kg of acetate for 6 weeks. Rats with PCOS were characterized with insulin resistance, leptin resistance, increased plasma testosterone as well as degenerated ovarian follicles. There was also a significant increase in hypothalamic triglyceride level, triglyceride-glucose index, inflammatory biomarkers (SDF-1 and NF-kB) and caspase-6 as well as plasma LH and triglyceride. A decrease was observed in plasma adiponectin, GnRH, FSH, and hypothalamic GABA with severe inflammasome expression in PCOS rats. These were accompanied by decreased level of NrF2/HIF1-α, and the alterations were reversed when treated with acetate. Collectively, the present results suggest the therapeutic impact of acetate on hypothalamic pyroptosis and its related comorbidity in PCOS, a beneficial effect that is accompanied by modulation of NrF2/HIF1-α.

Diacerein mitigates endocrine and cardio-metabolic disruptions in experimental PCOS mice model by modulating AdipoR1/ PON 1

BACKGROUND

This study aimed to explore the impact of Diacerein (DIC) on endocrine and cardio-metabolic changes in polycystic ovarian syndrome (PCOS) mouse model.

METHODS

A total of 18 adult female mice (Parkes strain), aged 4-5 weeks, were randomly assigned to three groups, each comprising 6 animals, as follows: Group I (control), received normal diet and normal saline as vehicle for 51 days; Group II received Letrozole (LET; 6 mg/kg bw) for 21 days to induce PCOS; Group III received LET, followed by daily oral gavage administration of DIC (35 mg/kg bw) for 30 days.

RESULTS

This study indicates that treatment with LET resulted in PCOS with characteristics such as polycystic ovaries, elevated testosterone, weight gain, visceral adiposity, high levels of insulin as well as fasting blood glucose in addition to insulin resistance, improper handling of ovarian lipids, atherogenic dyslipidemia, impaired Na + /K + -ATPase activity and serum, cardiac, and ovarian oxidative stress. Serum/ovarian adiponectin levels were lowered in LET-treated mice. In mice treated with LET, we also discovered a reduction in cardiac and serum paraoxonase 1 (PON1). Interestingly, DIC restored ovarian andcardio-metabolic abnormalities in LET-induced PCOS mice. DIC prevented the endocrine and cardio-metabolic changes brought on by letrozole-induced PCOS in mice.

CONCLUSION

The ameliorative effects of DIC on letrozole-induced PCOS with concurrent oxidative stress, abdominal fat deposition, cardiac and ovarian substrate mishandling, glucometabolic dysfunction, and adiponectin/PON1 activation support the idea that DIC perhaps, restore compromised endocrine and cardio-metabolic regulators in 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.

Insights into Vitamin E with Combined Oral Contraceptive on INSR Gene in PCOS by Integrating In Silico and In Vivo Approaches

Polycystic ovarian syndrome (PCOS) is a hormone disorder common among reproductive-aged women. This is associated with the symptoms like an irregular menstrual cycle, excess androgens, and polycystic ovary. Interestingly, vitamin E acts like the hormone progesterone and improves insulin sensitivity in PCOS. The study aims to evaluate the therapeutic effect of vitamin E in combination with combined oral contraceptive (COC) against PCOS by in silico and in vivo methods. The therapeutic effect of vitamin E (25 and 50mg/kg) in combination with COC (0.4mg/kg) was screened by the in silico method using Auto dock vina 4.2.6. Additionally, in vivo studies with a letrozole-induced PCOS model were performed in 30 female SD rats (n = 6 in each group) for 8 weeks with different doses of vitamin E. Furthermore, histopathological features and the insulin receptor (INSR) gene were scrutinized. An in silico study showed that drospirenone and vitamin E have an excellent affinity to bind to INSR and have higher binding energy (- 8.5 kcal/mol and - 8.7 kcal/mol, respectively). In vivo results showed a significant reduction in elevated testosterone levels compared to that of the PCOS group; follicle-stimulating hormone (FSH) and insulin levels also showed significant changes and reversed anti-oxidant levels in a dose-dependent manner. Ovarian histopathological changes were observed in different follicle counts in addition to the INSR gene, which showed changes in densitometry values. Supplementation of vitamin E combined with COC could be effective against PCOS, and clinical studies must be carried out further.

Activity of isoflavone in managing polycystic ovary syndrome symptoms (Review)

Polycystic ovary syndrome (PCOS), a hormonal and metabolic disorder manifested in women of reproductive age, is still being treated using drugs with side effects. As an alternative to these drugs, isoflavone, also identified as phytoestrogen, has anti-PCOS activity. Isoflavone can help relieve PCOS symptoms by lowering the level of testosterone, which causes hyperandrogenism, thereby normalizing the menstrual cycle and restoring normal ovarian morphology. Furthermore, isoflavone influences the improvement of the metabolic profile, which changes because of PCOS, as well as the reduction of inflammatory markers and oxidative stress. However, both significant and non-significant results have been generated on the activity of isoflavones in PCOS. The present review aims to discuss the existing literature on the effect of isoflavone on PCOS symptoms based on in vivo and clinical trial studies.

An Experimental Study on The Oxidative Status and Inflammatory Levels of A Rat Model of Polycystic Ovary Syndrome Induced by Letrozole and A New High-Fat Diet

BACKGROUND

Although there are numerous animal models of polycystic ovary syndrome (PCOS), they often fail to accurately replicate the reproductive and metabolic phenotypes associated with PCOS. The objective of this study is to assess oxidative status and inflammatory levels in a rat model of PCOS subjected to a new high-fat diet (HFD) in combination with letrozole.

MATERIALS AND METHODS

In this experimental study, mature, six-week-old female Sprague-Dawley rats (n=20) were divided into four groups: control (standard diet); letrozole (letrozole plus a standard diet); HFD; and letrozole+HFD. After 16 weeks, the rats underwent vaginal smear analysis, measurement of hormonal and lipid profiles, and an oral glucose tolerance test (OGTT). Ovarian tissue morphology, oxidative parameters, and inflammatory status were evaluated.

RESULTS

The experimental groups exhibited anoestrus profiles in the vaginal smears and abnormal ovarian morphology, which was not observed in the control group. Steroid hormone levels were significantly higher in the letrozole+HFD group compared to the other groups (P=0.00). The experimental groups also showed abnormal glucose levels and lipid metabolism. The relative expression levels of inflammatory genes were significantly elevated in the experimental groups compared to the control group (P=0.00), and the letrozole+HFD group exhibited the highest expression level (P=0.00). The HFD, letrozole, and letrozole+HFD groups demonstrated significantly increased levels of malondialdehyde (MDA) and reactive oxygen species (ROS), while the levels of enzymatic antioxidants were significantly reduced compared to the control group (P=0.00).

CONCLUSION

The combination of a new HFD and letrozole treatment induces inflammation and oxidative stress (OS) in a rat model of PCOS. This model accurately exhibits abnormal metabolic phenotypes and disruptions in hormonal profiles associated with PCOS.

Therapeutic exploration of polyherbal formulation against letrozole induced PCOS rats: A mechanistic approach

Objective

This study aimed to develop an effective alternative medicine with multi potential herbs against polycystic ovarian syndrome (PCOS) in rats induced by letrozole treatment.

Materials and method

Polyherbal syrup was prepared with a combination of S. asoca bark, G. sylvestre leaves, P. daemia aerial parts, C. zeylanium stem bark, C. bonduc seeds, and W. somnifera roots ethanolic extract. In vitro cell viability study, adenosine monophosphate-activated protein kinase (AMPK), and glucose transporter 4 (GLUT4) gene expression assay were carried out on the Chinese Hamster Ovarian (CHO) cell line. For the PCOS induction letrozole (1 mg/kg p. o.) was given for 21 consecutive days. The PCOS induction was confirmed by measuring estrus irregularity, insulin resistance by oral glucose tolerance test (OGTT), and hyperandrogenism by measuring serum total testosterone level 21 days after completion of letrozole treatment. After induction of PCOS, metformin (155 mg/kg p. o.), and polyherbal syrup (100 mg/kg, 200 mg/kg, and 400 mg/kg p. o.) were administered for further 28 days. The treatment efficacy was measured by measuring serum lipid profile, fasting insulin level, sex hormones level, ovarian steroidogenic enzymes, ovarian tissue insulin receptor, AMPK, and GLUT4 protein expression levels, and histomorphological studies. The post-treatment effect was confirmed by reproductive performance studies.

Results

Letrozole-induced PCOS rats showed significant estrus irregularity, abnormal sex hormones levels, and hyperandrogenism indicated by showing increased free androgenic index and decreased sex hormones binding globulin (SHBG) level. The insulin resistance in PCOS rats was indicated by increased fasting glucose levels with impaired glucose clearance in the OGT test. Homeostasis Model Assessment Index of Insulin Resistance (HOMA-IR) increased level, also decreases INSR, GLUT4, and AMPK mRNA expression in ovarian cells confirming the insulin resistance in PCOS rats. Ovarian histology in PCOS rats also showed many follicular cysts, atretic follicles, and the absence of corpus luteum. The administration of polyherbal syrup, in a dose-dependent manner, effectively restored these alterations. The treatment of polyherbal formulation 400 mg/kg possesses highly significant efficacy over the treatment of metformin in PCOS rats. It mainly acts by reducing peripheral and ovarian hyperandrogenism and improves insulin sensitivity via activating the insulin receptor and AMP-activated kinase-mediated transcription and translation of GLUT4 from the cytoplasm to the ovarian membrane improves glucose uptake and promotes the follicular development and ovulation. The higher fertility rate, delivery index, and survival of delivered pups confirm the broader and superior efficacy of PCOS. These beneficial actions are mainly attributable to the formulation's inclusion of the key secondary metabolites flavonoids and phytosterols. In conclusion, the prepared polyherbal syrup was found to be the safest and most effective alternative medicine for both endocrinal and metabolic complications of PCOS women.

LINC00092 derived from follicular fluid alleviated the symptoms of PCOS through inactivation of phosphatase and tensin homolog by recruiting KDM5A

Mounting literatures suggest that follicular fluid-derived exosomes (FF-Evs) influence the progression of progression of polycystic ovary syndrome (PCOS). The present study was designed to dissect the underlying mechanisms by which FF-Evs affect the PCOS. A rat model of PCOS was established using Letrozole induction. After treatment with FF-Evs, rats were examined for alterations in hormones, blood glucose, and lipid levels in serum, oestrus cycle, pathology in the ovaries, and apoptosis of ovarian cells. The functional rescue assays were performed to analyze the impact of long non-coding RNA 00092 (LINC00092) on PCOS rats. The cis-regulatory elements involved in the regulation of phosphatase and tensin homolog (PTEN) expression were analyzed using bioinformatic analysis, followed by verification of the mechanism. FF-Evs treatment ameliorated Letrozole-induced enhancement of weight, insulin resistance, dyslipidemia, and LH/FSH ratio, reduction of luteal cells, granulosa cells, and healthy follicles, prolonged oestrus, oestrous cycle arrest, ovarian tissue fibrosis, and ovarian cell apoptosis in rats, which were counteracted by treatment with shRNA targeting LINC00092. Regarding the mechanism, FF-Evs augmented LINC00092 expression in rats. LINC00092 bound to lysine demethylase 5 A (KDM5A), and KDM5A facilitated the demethylation of H3K4me3 to restrain the transcriptional activity of PTEN. Taken together, FF-Evs delivered LINC00092 repressed the transcriptional activity of PTEN by binding to KDM5A to enhance demethylation of H3K4me3, thereby reducing apoptosis in ovarian cells and alleviating PCOS symptoms.

Molecular mechanism of modified Huanglian Wendan decoction in the treatment of polycystic ovary syndrome

To investigate the mechanism of modified Huanglian Wendan decoction in the intervention of polycystic ovary syndrome (PCOS) by network pharmacology and molecular docking. The ingredients and targets of modified Huanglian Wendan decoction were retrieved from the traditional Chinese medicine Systems Pharmacology database. Related targets of PCOS were screened by Comparative Toxicogenomics Database database. Cytoscape 3.7.2 (https://cytoscape.org/) was used to draw the target network diagram of "traditional Chinese medicine - ingredient - PCOS," STRING database was used to construct the target protein interaction network. NCA tool of Cystoscape 3.7.2 was used to carried out topology analysis on PPI network, core components and key targets were obtained. Gene ontology and Kyoto encyclopedia of genes and genomes enrichment analysis were carried out for the intersection targets by David database. AutoDockTools 1.5.6 software (https://autodock.scripps.edu/) was used to conduct molecular docking verification of key components and key targets. Ninety-one ingredients of the modified Huanglian Wendan decoction and 23,075 diseases targets were obtained, 155 Intersection targets of the drug and disease were obtained by R language, Veen plot was drawn. Gene ontology enrichment analysis obtained 432 biological processes, 67 cell components, 106 molecular functions. Fifty-four Kyoto encyclopedia of genes and genomes enrichment pathways (P < .05) including tumor necrosis factor, hypoxia-induced factors-1, calcium, and drug metabolism-cytochrome P450 signaling pathway. Molecular docking showed quercetin, luteolin, kaempferol, and baicalein were stable in docking with core targets. Network pharmacology and molecular docking were used to preliminarily study the mechanism of action of modified Huanglian Wendan decoction in the treatment of PCOS, which laid foundation for future experimental research and clinical application.

Insulin resistance in polycystic ovary syndrome across various tissues: an updated review of pathogenesis, evaluation, and treatment

Polycystic ovary syndrome (PCOS) is a common endocrine disorder characterized by chronic ovulation dysfunction and overabundance of androgens; it affects 6-20% of women of reproductive age. PCOS involves various pathophysiological factors, and affected women usually have significant insulin resistance (IR), which is a major cause of PCOS. IR and compensatory hyperinsulinaemia have differing pathogeneses in various tissues, and IR varies among different PCOS phenotypes. Genetic and epigenetic changes, hyperandrogenaemia, and obesity aggravate IR. Insulin sensitization drugs are a new treatment modality for PCOS. We searched PubMed, Google Scholar, Elsevier, and UpToDate databases in this review, and focused on the pathogenesis of IR in women with PCOS and the pathophysiology of IR in various tissues. In addition, the review provides a comprehensive overview of the current progress in the efficacy of insulin sensitization therapy in the management of PCOS, providing the latest evidence for the clinical treatment of women with PCOS and IR.

Therapeutic effects of aqueous extract of bioactive active component of Ageratum conyzoides on the ovarian-uterine and hypophysis-gonadal axis in rat with polycystic ovary syndrome: Histomorphometric evaluation and biochemical assessment

Background

Polycystic ovary syndrome (PCOS) is an endocrine disorder, affecting women of reproductive age. Ageratum conyzoïdes (AGC) is used traditionally in the treatment of fever, rheumatism, and ulcer. This study investigates the effects of AGC on ovarian-uterine in PCOS rats.

Methods

Female rats were randomized into four groups (n = 6). Group A control received 2 ml distilled water. Group B received a single dose of 4 mg/kg body weight (bwt) i.p estradiol valerate (EV). Group C received 500 mg/kg bwt AGC and group D received a single dose of 4 mg/kg bwt i.p EV followed by 500 mg/kg bwt AGC orally for 30 days. Parameters tested include follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone (T), estradiol (E2), progesterone (P), C-reactive protein (CRP), interleukin (IL)-6, IL-18 and tumor necrosis factor (TNF)- α, malondialdehyde (MDA), superoxide dismutase (SOD), Catalase (CAT), total protein (TP), total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), and ovary and uterus histomorphometric.

Results

Ageratum conyzoides decrease insulin resistance, obesity indices, TC, TG, LDL, MDA, T, LH, FSH, CRP, IL-6, IL-18, and TNF- α in PCOS rats. And increase HDL, E2, P, TP, CAT, and SOD in PCOS rats. AGC improved ovary and uterus histo-architecture, tertiary, and Graafian follicles, corpus luteum and endometrial thickness increased,and cystic and atretic follicles decreased.

Conclusion

Ageratum conyzoides improved insulin sensitivity, antioxidant activities, hormonal imbalance, inflammatory makers, and histological changes in PCOS rats. Therefore AGC can be used as a potential adjuvant agent in the treatment of PCOS.

Distinctions in PCOS Induced by Letrozole Vs Dehydroepiandrosterone With High-fat Diet in Mouse Model

Polycystic ovarian syndrome (PCOS) is a complex health condition associated with metabolic disturbances and infertility. Recent data suggest that the prevalence of PCOS is increasing among women globally, although the etiology of these trends is undefined. Consequently, preclinical models that better reflect the biology of PCOS are urgently needed to facilitate research that can lead to the discovery of prevention strategies or improved management. The existing animal models have several limitations as they do not reflect all the PCOS features metabolically and/or phenotypically. Therefore, there is no clear consensus on the use of appropriate animal model and selection of the most appropriate PCOS-inducing agent. To that end, we have established a Swiss albino mouse model of PCOS based on 3 weeks of daily treatment with letrozole (50 μg/day; intraperitoneal) and dehydroepiandrosterone (DHEA, 6 mg/100 g body weight; subcutaneous) in 5-week-old female mice fed on normal or high-fat diet (HFD). Mice were regularly assessed for body weight, blood glucose, and estrous cycle. Three weeks after drug administration, mice were sacrificed and assessed for blood-based metabolic parameters as well as ovarian function. Our results indicate that DHEA combined with HFD produces changes mimicking those of clinical PCOS, including elevated serum testosterone and luteinizing hormone, dyslipidemia, poor ovarian microenvironment, and development of multiple ovarian cysts, recapitulating cardinal features of PCOS. In comparison, normal diet and/or letrozole produced fewer features of PCOS. The data from the experimental models presented here can improve our understanding of PCOS, a growing concern in women's health.

Polycystic Ovary Syndrome: Insights from Preclinical Research

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age, affecting approximately 10%. PCOS is diagnosed by the presence of at least two of these three criteria: hyperandrogenemia, oligo- or anovulation, and polycystic ovaries. The most common type (80%) of PCOS includes hyperandrogenemia. PCOS is also characterized by obesity or overweight (in 80% of US women with PCOS), insulin resistance with elevated plasma insulin but not necessarily hyperglycemia, dyslipidemia, proteinuria, and elevated BP. Although elevated compared with age-matched controls, BP may not reach levels considered treatable according to the current clinical hypertension guidelines. However, it is well known that elevated BP, even modestly so, increases the risk of cardiovascular disease. We have developed a model of hyperandrogenemia in rodents that mimics the characteristics of PCOS in women, with increases in body weight, insulin resistance, dyslipidemia, andproteinuria and elevated BP. This review discusses potential mechanisms responsible for the elevated BP in the adult and aging PCOS rat model that may be extrapolated to women with PCOS.

The Role of a High-Fat, High-Fructose Diet on Letrozole-Induced Polycystic Ovarian Syndrome in Prepubertal Mice

This study aims to investigate the effects of a high-fat, high-fructose (HF/HFr) diet on metabolic/endocrine dysregulations associated with letrozole (LET)-induced Polycystic Ovarian Syndrome (PCOS) in prepubertal female mice. Thirty-two prepubertal C57BL/6 mice were randomly divided into four groups of eight and implanted with LET or a placebo, with simultaneous administration of an HF/HFr/standard diet for five weeks. After sacrifice, the liver and blood were collected for selected biochemical analyses. The ovaries were taken for histopathological examination. The LET+HF/HFr group gained significantly more weight than the LET-treated mice. Both the LET+HF/HFr and the placebo-treated mice on the HF/HFr diet developed polycystic ovaries. Moreover the LET+HF/HFr group had significantly elevated testosterone levels, worsened lipid profile and indices of insulin sensitivity. In turn, the HF/HFr diet alone led to similar changes in the LET-treated group, except for the indices of insulin sensitivity. Hepatic steatosis also occurred in both HF/HFr groups. The LET-treated group did not develop endocrine or metabolic abnormalities, but polycystic ovaries were seen. Since the HF/HFr diet can cause substantial metabolic and reproductive dysregulation in both LET-treated and placebo mice, food items rich in simple sugar-particularly fructose-and saturated fat, which have the potential to lead to PCOS progression, should be eliminated from the diet of young females.

Effects of Kelulut Honey on Oestrus Cycle Regulation and Histomorphological Changes in Letrozole-Induced Polycystic Ovary Syndrome Rats: A Preliminary Study

Polycystic ovary syndrome (PCOS) is a complex reproductive, metabolic, and endocrine disorder that affects women of reproductive age. Kelulut honey is stingless bee honey that possesses anti-inflammatory, anti-cancer, anti-diabetic, and potent antioxidative activities in most conditions. However, its value in improving PCOS remains to be elucidated. Thus, this preliminary study aimed to determine the effective dose of Kelulut honey in oestrus cycle regulation and ovarian histomorphological changes in letrozole-induced PCOS rats. PCOS was induced in all-female Sprague Dawley (SD) rats with 1 mg/kg/day of letrozole except for the control group for 21 days. Kelulut honey was then orally administered to the PCOS rats at the dose of 0.5, 1, or 2 g/kg/day, respectively, for 35 days. The oestrous cycle was determined through vaginal smears, while ovarian histomorphological changes were observed by haematoxylin and eosin (H&E) staining. The untreated PCOS rats were characterised by irregular oestrous cyclicity, hyperglycaemia, and aberrant ovarian histology. In this study, Kelulut honey (1 g/kg/day) increased the number of corpus luteum and antral follicles (p < 0.05), improved the cystic follicle, and normalised the oestrus cycle (p < 0.05). This preliminary study demonstrated that Kelulut honey, particularly at a dose of 1 g/kg/day, has the potential to alleviate oestrus cycle dysregulation and ovarian histomorphological changes occurring in PCOS.

Effects of N-acetylcysteine and metformin treatment on the stereopathological characteristics of uterus and ovary

In this study, the stereo-pathological effect of metformin and N-acetyl cysteine is evaluated on the uterus and ovary of polycystic ovary syndrome (PCOS) mice. 96 mature females (8-weekold, weight of 20–30 gr) BALB/c mice were classified into 6 groups including the control group (n= 16), letrozole-induced PCOS group (n=16), PCOS + metformin (n=16), PCOS+NAC (n=16) and a separate control group for NAC (n=16). Another PCOS group was maintained for a month to make sure that features remain till the end of the study. Testosterone level, vaginal cytology and stereological evaluations were assessed. Vaginal cytology in letrozole-receiving mice showed a diestrus phase continuity. Testosterone level, body weight, uterine weight, endometrial volume, myometrial volume, gland volume, stromal volume, epithelial volume, vessel volume, daughter and conglomerate glands, endometrial thickness, and myometrial thickness exhibited an increasing trend in the uterus of PCOS mice. While normal gland and vessel length decreased in the PCOS group. Ovarian volume, corticomedullary volume, primary follicles, secondary follicles, and ovarian cysts were increased in PCOS ovaries. While corpus luteum, primordial, graafian, and atretic follicles showed a decline in the PCOS group. NAC and metformin, however, managed to restore the condition to normal. Given the prevalence of PCOS and its impact on fertility, the use of noninvasive methods is of crucial significance. NAC can control and treat pathological parameters and help as a harmless drug in the treatment of women with PCOS.

Polycystic Ovary Syndrome in Insulin-Resistant Adolescents with Obesity: The Role of Nutrition Therapy and Food Supplements as a Strategy to Protect Fertility

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in young reproductive-aged women. PCOS is often associated with obesity and impairs reproductive health. Even though several theories have been proposed to explain the pathogenic mechanism of PCOS, the role of insulin resistance (IR) as a key etiological component, independently of (but amplified by) obesity, is well recognized. The consequent hyperinsulinemia activates excessive ovarian androgen production, leading to PCOS. Additionally, the state of chronic inflammation related to obesity impacts ovarian physiology due to insulin sensitivity impairment. The first-line treatment for adolescents with obesity and PCOS includes lifestyle changes; personalized dietary interventions; and, when needed, weight loss. Medical nutrition therapy (MNT) and the use of specific food supplements in these patients aim at improving symptoms and signs, including insulin resistance and metabolic and reproductive functions. The purpose of this narrative review is to present and discuss PCOS in adolescents with obesity, its relationship with IR and the role of MNT and food supplements in treatment. Appropriate early dietary intervention for the management of adolescents with obesity and PCOS should be considered as the recommended approach to restore ovulation and to protect fertility.

The evolutionary biology of endometriosis

We provide the first analysis and synthesis of the evolutionary and mechanistic bases for risk of endometriosis in humans, structured around Niko Tinbergen's four questions about phenotypes: phylogenetic history, development, mechanism and adaptive significance. Endometriosis, which is characterized by the proliferation of endometrial tissue outside of the uterus, has its phylogenetic roots in the evolution of three causally linked traits: (1) highly invasive placentation, (2) spontaneous rather than implantation-driven endometrial decidualization and (3) frequent extensive estrogen-driven endometrial proliferation and inflammation, followed by heavy menstrual bleeding. Endometriosis is potentiated by these traits and appears to be driven, proximately, by relatively low levels of prenatal and postnatal testosterone. Testosterone affects the developing hypothalamic-pituitary-ovarian (HPO) axis, and at low levels, it can result in an altered trajectory of reproductive and physiological phenotypes that in extreme cases can mediate the symptoms of endometriosis. Polycystic ovary syndrome, by contrast, is known from previous work to be caused primarily by high prenatal and postnatal testosterone, and it demonstrates a set of phenotypes opposite to those found in endometriosis. The hypothesis that endometriosis risk is driven by low prenatal testosterone, and involves extreme expression of some reproductive phenotypes, is supported by a suite of evidence from genetics, development, endocrinology, morphology and life history. The hypothesis also provides insights into why these two diametric, fitness-reducing disorders are maintained at such high frequencies in human populations. Finally, the hypotheses described and evaluated here lead to numerous testable predictions and have direct implications for the treatment and study of endometriosis. Lay summary: Endometriosis is caused by endometrial tissue outside of the uterus. We explain why and how humans are vulnerable to this disease, and new perspectives on understanding and treating it. Endometriosis shows evidence of being caused in part by relatively low testosterone during fetal development, that 'programs' female reproductive development. By contrast, polycystic ovary syndrome is associated with relatively high testosterone in prenatal development. These two disorders can thus be seen as 'opposite' to one another in their major causes and correlates. Important new insights regarding diagnosis, study and treatment of endometriosis follow from these considerations.