The effect of Melatonin on histological changes of ovary in induced polycystic ovary syndrome model in mice

Exploring melatonin's multifaceted role in female reproductive health: From follicular development to lactation and its therapeutic potential in obstetric syndromes

BACKGROUND

Melatonin is mainly secreted by the pineal gland during darkness and regulates biological rhythms through its receptors in the suprachiasmatic nucleus of the hypothalamus. In addition, it also plays a role in the reproductive system by affecting the function of the hypothalamic-pituitary-gonadal axis, and by acting as a free radical scavenger thus contributing to the maintenance of the optimal physiological state of the gonads. Besides, melatonin can freely cross the placenta to influence fetal development. However, there is still a lack of overall understanding of the role of melatonin in the reproductive cycle of female mammals.

AIM OF REVIEW

Here we focus the role of melatonin in female reproduction from follicular development to delivery as well as the relationship between melatonin and lactation. We further summarize the potential role of melatonin in the treatment of preeclampsia, polycystic ovary syndrome, endometriosis, and ovarian aging.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Understanding the physiological role of melatonin in female reproductive processes will contribute to the advancement of human fertility and reproductive medicine research.

Incredible Combination of Lifestyle Modification and Herbal Remedies for Polycystic Ovarian Syndrome Management

A relatively frequent endocrine-metabolic illness called polycystic ovarian syndrome (PCOS) is characterized by polycystic ovaries, persistent anovulation, and hyperandrogenism, which cause symptoms such as irregular menstruation, infertility, and hirsutism. PCOS is linked to obesity, insulin resistance, and increased amounts of androgens, or male hormones. The sedentary lifestyle, dietary fluctuations, inactivity, and stress are other contributing variables. According to estimates from India in 2021, around 22.5% of women, or one in five Indian women, suffer from PCOS. Evidence-based medical care for PCOS places a strong focus on a multidisciplinary approach, as standard pharmacological treatment frequently targets a single symptom, may be contraindicated, has adverse effects, and is ineffective in certain circumstances. However, long-term treatments have drawbacks and are likely to be ineffective, making complementary and alternative therapies a worthwhile choice. Yoga science is a thorough treatment plan for a healthy body and mind that may eradicate PCOS's primary causes, stress and obesity. Some common herbal remedies, including Foeniculum vulgare, Tinospora cordifolia, Asparagus racemosus, Ocimum tenuiflorum, Areca catechu, and Lepidium meyenii, have been highly regarded sources that have the benefits of lowering PCOS as well as having hypoglycemic and antiobesity effects. In light of existing literature, women with PCOS experienced symptomatic relief, improvement in hormonal balance, and the quality of life by utilizing yoga practices as well as herbal remedies. In conclusion, combining lifestyle modifications with herbal remedies can be used in the management of PCOS as a holistic approach. Therefore, this review opens a new window for researchers all across the world to validate such findings.

Melatonin effective to reduce the microscopic symptoms of polycystic ovary syndrome-related infertility: An experimental study

Polycystic ovary syndrome (PCOS) is an endocrine disorder seen in women of reproductive age and has been gradually increasing over the years. The mechanism of the syndrome has still not been clearly understood. In this study, the possible effects of exogenously administrated melatonin on melatonin (MT1) receptor, Growth Differentiation Factor-9 (GDF9), and Bone Morphogenetic Protein-15 (BMP15) in experimental PCOS were investigated. Thirty-two 6-8-week-old Sprague-Dawley rats were randomly divided into four groups (n = 8 in each) as Sham control (Group 1), Melatonin (Group 2), PCOS (Group 3), and PCOS + Melatonin (Group 4) groups. At the end of the 21st day, the experiment was terminated, the ovary tissues were taken, and Hematoxylin-Eosin staining, MT1, GDF9, BMP15 immunohistochemical labeling, western blot, and quantitative real-time polymerase chain reaction (qPCR) analyses were performed. Serum Luteinizing Hormone (LH)/Follicle Stimulating Hormone (FSH) levels and colpo-cytological examinations were also carried out. The results revealed that melatonin administration increased the expression levels of the MT1 receptor, GDF9, and BMP15 in PCOS at protein and mRNA levels. It was determined that melatonin administration reduced the microscopic symptoms of PCOS. Melatonin was found to be effective via the MT1 receptor in the pathogenesis of PCOS, and it suppressed the transport pathways of GDF9 to granulosa cells in antral follicles.

Association of Oxidative Stress with Kidney Injury in a Hyperandrogenemic Female Rat Model

Background

Polycystic ovary syndrome (PCOS) is the most common reproductive dysfunction in premenopausal women. PCOS is associated with oxidative stress (OS), which is the main risk factor for renal diseases. This study aimed to investigate the mechanisms responsible for renal injury in a hyperandrogenemic female rat model.

Methods

This study was conducted from December 2019 to September 2021 at Shiraz Nephro-Urology Research Centre, Shiraz University of Medical Sciences (Shiraz, Iran). Thirty female Sprague-Dawley rats were randomly divided into three groups (n=10), namely control, sham, and dehydroepiandrosterone (DHEA). Plasma total testosterone, plasma creatinine (Cr), and blood urea nitrogen (BUN) levels were measured. In addition, total oxidant status (TOS), total antioxidant capacity (TAC), oxidative stress index (OSI), and histopathological changes in the ovaries and kidneys were determined. Data were analyzed using the GraphPad Prism software, and P<0.05 was considered statistically significant.

Results

Plasma total testosterone levels increased by nine-fold in DHEA-treated rats compared to controls (P=0.0001). Administration of DHEA increased Cr and BUN levels and caused severe renal tubular cell injury. In addition, plasma and tissue (kidney and ovary) TAC levels decreased significantly, but TOS levels and OSI values were significantly increased (P=0.019). Significant damage to both glomerular and tubular parts of the kidney and ovarian follicular structure was observed in the DHEA group.

Conclusion

Hyperandrogenemia caused systemic abnormalities through OS-related mechanisms and damaged renal and ovarian tissues. DHEA treatment in rat models is recommended to study the mechanisms that mediate PCOS-associated renal injury.

Nasturtium officinale L. and metformin alleviate the estradiol- induced polycystic ovary syndrome with synergistic effects through modulation of Bax/Bcl-2/p53/caspase-3 signaling pathway and anti-inflammatory and anti-oxidative effects

Polycystic ovary syndrome (PCOS) is one of the most common causes of infertility in women, which is associated with metabolic, hereditary and hormonal disorders. The aim of this study was to evaluate the therapeutic effects of Nasturtium officinale L. (N. officinale) on biochemical and molecular parameters in estradiol-induced PCOS in rats. Seventy Wistar rats in 7 groups (n = 10) were randomly assigned to normal (NC), PCOS, metformin (MET - 300 mg/kg), N. officinale (50 and 100 mg/kg) and co-treatment with MET and N. officinale groups. After 21 days of treatment, biochemical parameters levels of estrogen, LH and FSH along with serum levels of (IL-6 and IL-1β cytokines) and serum antioxidant parameters (enzymatic activity of catalase and superoxide dismutase) were measured. Finally, by measuring the expression of apoptosis related genes (Bax/Bcl-2/p53/caspase-3) with the help of real-time PCR and the expression of p53 with the help of immunohistochemistry in ovarian cells. N. officinale modulates hormones through its hypothalamic-pituitary-gonadal pathway with its synergistic effects along with MET. Also, in co-treatment groups (MET and N. officinale), the activity of serum antioxidant enzymes increased and also the serum level of inflammatory cytokines decreased. N. officinale, along with MET, amplified the Bax/Bcl2/p53/caspase-3 pathways, which eventually increased the number of p53 positive cells. These findings indicate that N. officinale extract along with MET can improve the physiological function of the ovaries in PCOS-induced disorders. PRACTICAL APPLICATIONS: Polycystic ovary syndrome (PCOS) is one of the most common causes of infertility in women, which is associated with metabolic, hereditary and hormonal disorders. The extract of Nasturtium officinale L. was able to intensify mitochondrial apoptotic pathway in cystic follicles and prevent their formation. It seems that pro-drugs containing N. officinale along with effective commercial drugs in PCOS can help ovulation and fertility in woman with this disease.

Intergenerational protein deficiency and adolescent reproductive function of subsequent female generations (F1 and F2) in rat model

Background

Efficient reproductive function is an important characteristic that has evolved through natural selection. Nutrition can modulate reproductive activities at different levels, and its effect on reproduction is deemed complex and less predictable.

Objective

This study aims at investigating the underlying effect of persistent dietary protein deficiency during early life on reproductive parameters of subsequent (F₁ and F₂) generations.

Method

Rats in group of four (4) were fed daily, different ration of protein diet (PD) formulated as: 21% protein diet, 10%protein diet, 5%protein diet and control diet (rat chow, containing 16–18% protein). They were fed ad libitum before mating, throughout gestation and lactation, and next generations were weaned to the maternal diet. Reproductive function analysis (which include; gestation and pubertal hormonal profiling, onset of puberty, oestrus cyclicity, sexual response) and morphometric analysis of the ovarian structure were carried out to assess associated consequences.

Results

There was significant reduction in the fertility index (Control; 85.8%., 21%PD; 88.43%., as compared to 10%PD; 65.9%., 5%PD; 35.78%.,) at F_1, also recurring in F₂ respectively as a consequence of altered reproductive function in the protein deficient models at P ≤ 0.05. Low protein diet posed suboptimal intrauterine condition, which was linked to increased prenatal morbidity and mortality (control; 11.3%., 21%PD; 3.3%., 10%PD; 27.4%., 5%PD; 32.9%), low birthweight (control; 5.29, 4.9 g., 21%PD; 5.5, 5.06 g., 10%PD; 4.05, 3.86 g., 5%PD; 2.7, 2.5 g) at F₁ and F₂ respectively, delayed onset of puberty (with average pubertal age set at: control; PND 36, 21%PD; PND 38 while 10%PD; PND 62., and 5%PD; PND 67), followed by induced cycle irregularity, altered follicular maturation and endocrine dysfunction, more severe in 5%PD.

Conclusion

Reproductive status of a female organism depends on the maintenance of ovarian structure and function that has been associated with the hypothalamic pituitary-gonadal axis, hormonal events and sexual maturity. There is therefore an association between persistent early life protein deficiency and reproductive response which mechanistically involves life-long changes in key ovarian cytoarchitecture and function.

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Intergenerational protein malnutrition exerts female hormonal dysregulation and irregular cyclicity at adolescence.

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It delayed pubertal attainment and reproductive performance that persists to the next–generation of rats.

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Perinatal protein deficiency also altered the ovarian morphology with an implication on fertility index across generations.

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.

Assessment of the toxicity effects of nicotine on sperm and IVF and the potential protective role of silymarin—an experimental study in mice

Background

Male infertility is usually caused via the inability to produce adequate quantities of healthy and active sperms. Nicotine (NIC) is an alkaloid organic compound, predominantly found in the leaves of the tobacco plant. The major part of the nicotine is not ionized, so it can easily pass through cell membranes. Meanwhile, most of the disorders are caused by oxidative stress due to oxygen free radicals and other reactive species. Antioxidant supplements and antioxidant-rich foods can reduce induced oxidative stress without becoming destabilized themselves. This study aimed to examine spermato-protective potential of silymarin (SIL), on sperm and in vitro fertility (IVF) rate in nicotine-treated mice.

Results

Our results show a significant increase in the number of abnormal sperm morphology after nicotine exposure, when compared to control groups (p < 0.05). On the other hand, SIL had a significant effect on the sperm count at each of the treated doses. Further, in the mice that received nicotine plus silymarin, the viable sperm percentage and the progressive sperm motility were significant (p < 0.05). Also, a significant reduction in the number of two-cell embryos and blastocyst-derived embryo was seen with increment in the number of dead embryos in mice receiving nicotine alone (p < 0.05).

Conclusions

In conclusion, SIL could support prevention of the adverse reproductive effects of nicotine. Moreover, SIL200 mg/kg may be therefore considered as a spermato-protective agent in dietary and herbal supplements.

Radioprotective effects of Silymarin on the sperm parameters of NMRI mice irradiated with γ-rays

Free radicals and reactive oxygen species (ROS) are generated using various endogenous systems or from external sources such as exposure to different physiochemicals. Ionizing radiation damage to the cell can be caused by the direct or indirect effects of radiotherapy processes. Silymarin (SM), a flavanolignan compound, has been identified as a natural potent antioxidant with cytoprotection activities due to scavenging free radicals. The aim of the present study was to evaluate the radioprotective effect of SM on sperm parameters of mice induced by γ-rays. A total number of 40 adult, male NMRI mice were randomly divided into four equal groups. The control group was neither treated with SM nor irradiated by γ-rays. The second group was only irradiated with 2Gy of γ-rays. The third group was firstly treated with 50mg/kg of SM for 7 consecutive days, and one day later, last injections were irradiated by 2Gy of γ-rays. The fourth groups received only 50mg/kg of SM for 7 consecutive days. All the animals were treated intraperitoneally. Histopathological and morphometrical examinations were performed. The data were analyzed using ANOVA and Tukey post hoc test. A value of p<0.05 was considered significant. The results showed that in the radiation-only group when compared with those treated with SM and irradiated, a significant different was observed in testicular parameters and DNA damage (p<0.05). In conclusion, SM can be considered as a promising herbal radioprotective agent in complementary medicine which may play an important role to protect normal spermatocytes against possible effects of γ-radiation-induced cellular damage.