Morphological Changes in Ovaries in Rats with Experimental Polycystic Ovary (original) (raw)
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International Journal of Emerging Technologies and Innovative Research, 2022
PCOS is identified as most common endocrinal disorder affecting reproductive span of women's life. PCOS is burden on social life, medical systems and also its economical drain. This data gives more focus in research fields also, basically to study any disease some pathways is need to define. In the form of preclinical study and the clinical studies. Animal studies plays an important role to study the pathophysiology of any disease due to its mimic systems like human. PCOS is also being studied with the help of various animals. To study PCOS, common animal models of mice, rhesus monkeys, rats and ewes are used, induced with the route of subcutaneous injection or implantation of androgens, anti-progesterone, estrogens, and letrozole, prenatal coverage to excess androgens and by exposure to constant light. (1-6) MATERIAL-Various scientific research and review articles published in last 10 years were identified through pubmed and Google scholar websites using MeSH terms regarding the animal models of PCOS. With the combination of PCOS, all these key words were used to specify the pointed results: animal model, sheep, rodent, mouse, rat and fish. METHODOLOGY-Animal experimental models for PCOS are searched from more than 150 research articles and the review papers. These articles were grouped according to similar activity and the working mechanism and compiled accordingly. RESULTS AND DISCUSSION Etiology of PCOS is still exactly not unrevealed, but many of the survey studies mentions some major causing factors are sedentary life style, hormonal imbalance, genetic factors, environmental factors and some unknown factors. Considering all the events probable animal's models are generated. Most commonly used animals models according to major causative factors of PCOS are demonstrated in fig 1.
Pathological characteristics of uterus in rats with polycystic ovary
2013
A B S T R A C T Background and Objective: Uterus of rat with polycystic ovary (PCO) may show pathological features. We provided pathological evidence for the rat uterus with NO-induced PCO. Materials and Methods: Wistar rats (weighing 200-250 g) were kept diestrous to receive L-arginine (50 mg/kg) intraperitoneally (i.p.) for 9 days/once a day. Control group solely received saline (1 ml/kg, 9 days/once per day). At the end of the treatment period, all animals were surgically studied. The rats’ ovaries and uteri were examined biometrically and collected in 10% formalin. The pathological data were collectively determined. Results: The treated ovaries of rats showed polycystic characteristics when compared with the control. The uteri of treated rats also showed pathological changes as compared to those that belonged to the controls. Conclusion: The pathological aspect of rat uterus may be linked with the cystic characteristic of ovary in PCO model. This study provides pathological evid...
Seminars in Reproductive Medicine, 2014
Polycystic ovary syndrome (PCOS) is the most common endocrine and metabolic disorder affecting women of reproductive age. 1 Endocrine and reproductive symptoms of PCOS are hyperandrogenism (hirsutism, acne, and alopecia), irregular menstrual cycles, subfertility, and polycystic ovary morphology. Women with PCOS also tend to suffer from insulin resistance with compensatory hyperinsulinemia, type 2 diabetes, and cardiovascular disease, 2,3 but these symptoms is not part of the PCOS diagnosis. Obesity worsens all reproductive and metabolic symptoms of PCOS 4 and demonstrates the importance of prevention and treatment of obesity in women with PCOS. Women with PCOS also often suffer from symptoms of anxiety and depression that lead to reduced healthrelated quality of life.
Rat Models of Polycystic Ovary Syndrome
Sourcebook of Models for Biomedical Research, 2008
Polycystic ovary (PCO) syndrome is a common endocrine disorder of unknown etiology. This condition is a major cause of menstrual irregularity and infertility in women with chronic anovulation. This chapter reviews the literature on methods of producing experimental PCO models in the laboratory rat, and the fi ndings that support their resemblance to the human condition. The principal rat PCO models that have been validated include constant light exposure, hypothalamic lesions, sex steroid-induced models, and the mifepristone (RU486) model. The biological systems involved in developing chronic anovulation and PCO in these models include the hypothalamus, the pituitary gland, the adrenals, and the ovary with its paracrine, autocrine, and intracrine regulators. Animal models are central to making the transition from scientifi c concepts to understanding the reality of a human disease. Validated animal models can be used for therapeutic screens, in preclinical trials, and for basic research in reproductive biology. However, animal models of chronic anovulation and PCO may not fully reproduce the reproductive events seen in the human syndrome.
A New Rat Model Exhibiting Both Ovarian and Metabolic Characteristics of Polycystic Ovary Syndrome
Endocrinology, 2007
Polycystic ovary syndrome (PCOS) is a complex endocrine and metabolic disorder associated with ovulatory dysfunction, hyperandrogenism, abdominal obesity, and insulin resistance. However, its etiology is unclear, and its management is often unsatisfactory or requires a diversified approach. Here, we describe a new rat PCOS model, the first to exhibit both ovarian and metabolic characteristics of the syndrome. Female rats received the nonaromatizable androgen dihydrotestosterone (DHT) or the aromatase inhibitor letrozole by continuous administration, beginning before puberty, to activate androgen receptors. Adult DHT rats had irregular cycles, polycystic ovaries characterized by cysts formed from atretic follicles, and a diminished granulosa layer. They also displayed metabolic features, including increased body weight, increased body fat, and enlarged mesenteric adipocytes, as well as elevated leptin levels and insulin resistance. All letrozole rats were anovulatory and developed polycystic ovaries with structural changes strikingly similar to those in human PCOS. Our findings suggest that the formation of a "hyperplastic" theca interna reflects the inclusion of luteinized granulosa cells in the cyst wall rather than true hyperplasia. We conclude that the letrozole model is suitable for studies of the ovarian features of human PCOS, while the DHT model is suitable for studies of both ovarian and metabolic features of the syndrome. First
Induction by Estradiol-17β of Polycystic Ovaries in the Guinea Pig1
Biology of Reproduction, 1993
In the present study we wished to develop a model for polycystic ovarian syndrome (PCOS) using the guinea pig, because this animal's cycle, compared to other rodent models, more closely emulates that of humans. Four silastic capsules, either empty or containing cholesterol or estradiol-17, were placed subcutaneously for 48 h on Day 10 or 12 of the cycle. Vaginal smears were taken daily. Cardiac blood was drawn at various intervals. At necropsy, trunk blood was collected and ovaries were excised and analyzed histologically. Cycle length was extended over that in controls in animals treated with estradiol-170 (E,) on Day 12 of the cycle. Treatment with E, resulted in an increase in serum estrogen 2 h after capsule insertion. No changes were evident in progesterone or androstenedione concentrations with treatment. Animals treated with E, and killed late (54 days after capsule removal) showed cysts grossly (group A), while occult cysts were present in E,-treated animals killed early (17 days; group B); no cysts were observed in control groups. Ovarian weight and size were increased in group A over controls. There was an increase in the fraction of atretic:total follicles < 500 mm in size in group A compared to group B as well as compared to controls. Since these results are similar to those seen in human PCOS, we conclude that the guinea pig may serve as an exceptional and unique model for the study of PCOS and may be applicable to humans.
Persistent estrus rat models of polycystic ovary disease: an update
Fertility and Sterility, 2005
Objective: To critically review published articles on polycystic ovary (PCO) disease in rat models, with a focus on delineating its pathophysiology. Design: Review of the English-language literature published from 1966 to March 2005 was performed through PubMed search. Keywords or phrases used were persistent estrus, chronic anovulation, polycystic ovary, polycystic ovary disease, and polycystic ovary syndrome. Articles were also located via bibliographies of published literature. Setting: University Health Sciences Center. Intervention(s): Articles on persistent estrus and PCO in rats were selected and reviewed regarding the methods for induction of PCO disease. Main Outcome Measure(s): Changes in the reproductive cycle, ovarian morphology, hormonal parameters, and factors associated with the development of PCO disease in rat models were analyzed. Result(s): Principal methods for inducing PCO in the rat include exposure to constant light, anterior hypothalamic and amygdaloidal lesions, and the use of androgens, estrogens, antiprogestin, and mifepristone. Conclusion(s): The validated rat PCO models provide useful information on morphologic and hormonal disturbances in the pathogenesis of chronic anovulation in this condition. These studies have aimed to replicate the morphologic and hormonal characteristics observed in the human PCO syndrome. The implications of these studies to human condition are discussed.
Animal models of the polycystic ovary syndrome phenotype
Steroids, 2013
The etiology of the polycystic ovary syndrome (PCOS) remains unclear, despite its high prevalence among infertility disorders in women of reproductive age. Although there is evidence for a genetic component of the disorder, other causes, such as prenatal insults are considered among the potential factors that may contribute to the development of the syndrome. Over the past few decades, several animal models have been developed in an attempt to understand the potential contribution of exposure to excess steroids on the development of this syndrome. The current review summarizes the phenotypes of current animal models exposed to excess steroid during the prenatal and early postnatal period and how they compare with the phenotype seen in women with PCOS.
Brazilian Journal of Veterinary Research and Animal Science, 2004
Numerous experimental models have been developed for the study of the polycystic ovarian syndrome in the rat. In the present study, the syndrome was induced by exposure to constant light. The process was evaluated during its induction and also during its reversion. The estral cycle was analyzed through the vaginal cytology; reproductive parameters were evaluated by mating, as well as the ovarian morphology. All the animals developed the syndrome after 13 weeks of permanent light. The histologic characteristics of the ovaries, at week 15, were similar to those observed in the polycystic ovarian syndrome in human and other species. After regression of the syndrome, there was not difference in any of the evaluated reproductive parameters, when compared with the control group.
Physiological research / Academia Scientiarum Bohemoslovaca, 2007
Numerous hypotheses have been proposed about the pathogenesis of the polycystic ovarian syndrome (PCOS). However, hormonal control of persistent follicles has not been established. The objective of the present study was to compare the follicular structure and hormonal profiles of rats treated with the adrenocorticotrophic hormone (ACTH) with two experimental models of PCOS. ACTH-treated animals were compared with those exposed to continuous light, those treated with estradiol valerate, and with control (in proestrous and diestrous). Serum hormone levels, histomorphometrical changes, and immunoexpression of vimentin, cytokeratins, cadherins, and proliferating cell nuclear antigen (PCNA) were examined. Treatment with ACTH resulted in an elevation of corticosterone secretion with LH reduction but without changes in ovarian morphology. Although stress (or ACTH) stimulation may be only one of pathophysiological mechanisms involved in follicular cyst pathogenesis in other species, we do n...