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Objective: To evaluate the effect of melatonin as a protective treatment for the tongue in irradiated rats. Materials and Methods: Male Sprague Dawley rats were subjected to a single session of 50 Gy radiation and treated with melatonin 30 minutes before and after the radiotherapy session. A clinical evaluation was carried out a week and a half, third- and sixth-week post-treatment; finally, a tongue biopsy was taken for a histopathological study in the third and sixth weeks after radiation. Results: Clinical evaluation shows a clear trend, that preventive administration of melatonin could facilitate the recovery of mucosal tissue after radiation. Additionally, cellular infiltrate was 40% fewer in the melatonin-treated group compared to the control, as well as the number of the congested vessel were fewer. Conclusion: These findings showed for the first time the preventive role of melatonin in the tongue mucosa reducing the changes associated with mucositis, inflammatory infiltrate, and congestive blood vessels.
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Introduction: The reproductive system is tightly regulated by environmental and physiological signals. Melatonin, known as the hormone of darkness, plays a crucial role in regulating both the circadian and reproductive systems in mammals. Hypothyroidism is a key endocrine disorder that harms the reproductive system. Despite many studies on melatonin's effects on the reproductive system, there is conflicting information regarding melatonin synthesis modulation in hypothyroidism. The objective of this study was to investigate the modulation of plasma melatonin levels and gene expression of Aanat and Asmt in the pineal gland and gonads of rats with hypothyroidism at different times of the day. Methods: Female and male Wistar rats were divided into control and hypothyroid groups. Hypothyroidism was induced using propylthiouracil (PTU) for 15 days, rats were euthanized six hours after lights on (ZT6), before lights off (ZT11.5), and six hours after lights off (ZT18). Free thyroxine (FT4) and melatonin were quantified in plasma, and gene expressions of melatonin synthesizing enzymes (Aanat and Asmt) were measured in pineal and sexual organs (testis and ovary). Also, morphological analysis was performed in sexual organs. Results: The results reveal some disparities between the sexes. Hypothyroidism reduced antral and primary follicles in the ovary, and reduced the weight of testis, epididymis, and prostate. In relation to gene expression, we observed a reduction in Aanat expression in the pineal gland during the light phase (ZT6), and in males, this reduction occurred during the dark phase (ZT18). Regarding Asmt expression, there was a decrease in females also during the dark phase (ZT18). In the gonads, there was an increase in expression in both sexes at ZT11.5. Additionally, it was interesting to observe the association between FT4 levels and Asmt expression in the gonads. Conclusions: This study showed that acute hypothyroidism can affect components of the melatonergic system in gonads, particularly gene expression of melatonin synthesis enzymes (Aanat and Asmt) contributing to changes in reproduction organs during disease progression. These findings enhance our understanding of melatonin synthesis in the reproductive system during hypothyroidism, showing distinct responses in male and female rats, and suggest that hypothyroidism affects the circadian rhythmicity of melatonin synthesis in a sex-dependent manner.
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Acetilserotonina O-Metiltransferasa , Hipotireoidismo , Melatonina , Glândula Pineal , Ratos Wistar , Testículo , Animais , Feminino , Masculino , Ratos , Acetilserotonina O-Metiltransferasa/metabolismo , Acetilserotonina O-Metiltransferasa/genética , Arilalquilamina N-Acetiltransferase/metabolismo , Arilalquilamina N-Acetiltransferase/genética , Gônadas/metabolismo , Hipotireoidismo/metabolismo , Melatonina/sangue , Ovário/metabolismo , Ovário/patologia , Glândula Pineal/metabolismo , Propiltiouracila , Testículo/metabolismo , Testículo/patologiaRESUMO
OBJECTIVE: This study evaluated the influence of melatonin supplementation on tissue's response of endodontic sealers in Wistar rats. METHODOLOGY: Forty-eight rats received subcutaneous implants of four polyethylene tubes: one empty (control) and three filled with endodontic sealers (AH Plus, Endofill and Sealapex). Half of the animals were supplemented with melatonin (ME) and the remaining treated with water (WA) for 15 days before the implantation until euthanasia, forming the groups: control-WA, AH Plus-WA, Endofill-WA, Sealapex-WA, Control-ME, AH Plus-ME, Endofill-ME and Sealapex-ME. After 5, 15 and 30 days, (n = 8) tubes were removed and evaluated in H&E., immunohistochemistry, PSR, VK and POL. The results were statistically analyzed (p < 0.05). RESULTS: In animals treated with water, Endofill-WA evoked more intense inflammatory infiltrate compared to AH Plus-WA and Control-WA in a 30-day period (p < 0.05). In animals supplemented with melatonin, there was any difference among endodontic sealers' response in any period of analysis (p > 0.05). Comparing the individual response of each sealer, over a 30-day period, Endofill-ME and Sealapex-ME showed less inflammatory infiltrate compared to Endofill-WA and Sealapex-WA, respectively (p < 0.05). Immunostaining for IL-6 and TNF-α was less intense for all groups in animals supplemented with melatonin, in most periods, except for the Endofill sealer (p < 0.05). Furthermore, Endofill-ME at 5 days and AH-Plus-ME at 30 days showed a higher percentage of mature collagen fibers compared to the Endofill-WA and AH Plus-WA, respectively (p < 0.05). Positive structures for von Kossa staining and birefringent to polarized light were observed only for Sealapex-WA and Sealapex-ME in all periods. CONCLUSIONS: It can be concluded that melatonin influences the tissue response to endodontic sealers, modulating the inflammatory and reparative process.
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Plasmodium, a digenetic parasite, requires a host and a vector for its life cycle completion. Most Plasmodium species display circadian rhythmicity during their intraerythrocytic cycle within the host, aiding in immune evasion. This rhythmicity, however, diminishes in in vitro cultures, highlighting the importance of host-derived signals for synchronizing the parasite's asexual cycle. Studies indicate a species-specific internal clock in Plasmodium, dependent on these host signals. Melatonin, a hormone the pineal gland produces under circadian regulation, impacts various physiological functions and is extensively reviewed as the primary circadian marker affecting parasite rhythms. Research suggests that melatonin facilitates synchronization through the PLC-IP3 signaling pathway, activating phospholipase C, which triggers intracellular calcium release and gene expression modulation. This evidence strongly supports the role of melatonin as a key circadian marker for parasite synchronization, presenting new possibilities for targeting the melatonin pathway when developing novel therapeutic approaches.
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Ritmo Circadiano , Melatonina , Plasmodium , Melatonina/metabolismo , Ritmo Circadiano/fisiologia , Animais , Humanos , Plasmodium/metabolismo , Plasmodium/fisiologia , Malária/parasitologia , Malária/metabolismo , Biomarcadores , Transdução de Sinais , Interações Hospedeiro-ParasitaRESUMO
Biogenic amines are signaling molecules with multiple roles in the central nervous system and in peripheral organs, including the gonads. A series of studies indicated that these molecules, their biosynthetic enzymes and their receptors are present in the testis and that they are involved in the regulation of male reproductive physiology and/or pathology. This mini-review aims to summarize the current knowledge in this field and to pinpoint existing research gaps. We suggest that the widespread clinical use of pharmacological agonists/antagonists of these signaling molecules, calls for new investigations in this area. They are necessary to evaluate the relevance of biogenic amines for human male fertility and infertility, as well as the potential value of at least one of them as an anti-aging compound in the testis.
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Aminas Biogênicas , Testículo , Humanos , Aminas Biogênicas/metabolismo , Masculino , Testículo/metabolismo , Animais , Transdução de Sinais , Infertilidade Masculina/metabolismoRESUMO
BACKGROUND: Melatonin is a hormone produced by the pineal gland and it has antioxidant properties. AIM: This study aimed to evaluate the effects of melatonin on assisted reproductive technologies through a systematic review and a meta-analysis. MATERIALS AND METHODS: Search strategies were used in PubMed and in other databases covering the last 15 years. After screening for eligibility, 17 articles were selected for the systematic review. For the meta-analysis statistics, two groups were formed, the treatment group (with melatonin) and the control group (without melatonin) for various assisted reproduction outcomes. RESULTS: The main results were that no statistical differences were found concerning the clinical pregnancy outcome (p = 0.64), but there was a statistical difference with respect to Mature Oocytes (MII) (p = 0.001), antral follicle count (p = 0.0002), and the fertilization rate (p ≤ 0.0001). CONCLUSIONS: Melatonin had beneficial effects such as the improvement in the fertilization rate, although the authors did not obtain significance in the clinical pregnancy rate.
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Melatonina , Taxa de Gravidez , Melatonina/uso terapêutico , Melatonina/farmacologia , Humanos , Feminino , Gravidez , Técnicas de Reprodução Assistida , Antioxidantes/farmacologia , Fertilização in vitro/métodos , Fertilização in vitro/efeitos dos fármacos , Resultado da Gravidez , Fertilização/efeitos dos fármacos , Fertilização/fisiologiaRESUMO
MAIN CONCLUSIONS: In contrast to Neltuma species, S. tamarugo exhibited higher stress tolerance, maintaining photosynthetic performance through enhanced gene expression and metabolites. Differentially accumulated metabolites include chlorophyll and carotenoids and accumulation of non-nitrogen osmoprotectants. Plant species have developed different adaptive strategies to live under extreme environmental conditions. Hypothetically, extremophyte species present a unique configuration of physiological functions that prioritize stress-tolerance mechanisms while carefully managing resource allocation for photosynthesis. This could be particularly challenging under a multi-stress environment, where the synthesis of multiple and sequential molecular mechanisms is induced. We explored this hypothesis in three phylogenetically related woody species co-occurring in the Atacama Desert, Strombocarpa tamarugo, Neltuma alba, and Neltuma chilensis, by analyzing their leaf dehydration and freezing tolerance and by characterizing their photosynthetic performance under natural growth conditions. Besides, the transcriptomic profiling, biochemical analyses of leaf pigments, and metabolite analysis by untargeted metabolomics were conducted to study gene expression and metabolomic landscape within this challenging multi-stress environment. S. tamarugo showed a higher photosynthetic capacity and leaf stress tolerance than the other species. In this species, a multifactorial response was observed, which involves high photochemical activity associated with a higher content of chlorophylls and ß-carotene. The oxidative damage of the photosynthetic apparatus is probably attenuated by the synthesis of complex antioxidant molecules in the three species, but S. tamarugo showed the highest antioxidant capacity. Comparative transcriptomic and metabolomic analyses among the species showed the differential expression of genes involved in the biosynthetic pathways of key stress-related metabolites. Moreover, the synthesis of non-nitrogen osmoprotectant molecules, such as ciceritol and mannitol in S. tamarugo, would allow the nitrogen allocation to support its high photosynthetic capacity without compromising leaf dehydration tolerance and freezing stress avoidance.
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Clima Desértico , Fotossíntese , Estresse Fisiológico , Transcriptoma , Fotossíntese/genética , Estresse Fisiológico/genética , Clorofila/metabolismo , Metabolômica , Folhas de Planta/metabolismo , Folhas de Planta/genética , Folhas de Planta/fisiologia , Regulação da Expressão Gênica de Plantas , Perfilação da Expressão Gênica , Carotenoides/metabolismo , Metaboloma/genética , ChileRESUMO
Pulmonary arterial hypertension (PAH) is characterised by an increase in mean pulmonary arterial pressure and a compromised the right ventricle (RV), together with progression to heart failure and premature death. Studies have evaluated the role of melatonin as a promising therapeutic strategy for PAH. The objective of this study was to evaluate melatonin's effects on oxidative stress and on the TLR4/NF-kß inflammatory pathway in the RV of rats with PAH. Male Wistar rats were divided into the following groups: control, monocrotaline (MCT), and monocrotaline plus melatonin groups. These two last groups received one intraperitoneal injection of MCT (60 mg/kg) on the first day of experimental protocol. The monocrotaline plus melatonin group received 10 mg/kg/day of melatonin by gavage for 21 days. Echocardiographic analysis was performed, and the RV was collected for morphometric analysis oxidative stress and molecular evaluations. The main findings of the present study were that melatonin administration attenuated the reduction in RV function that was induced by monocrotaline, as assessed by TAPSE. In addition, melatonin prevented RV diastolic area reduction caused by PAH. Furthermore, animals treated with melatonin did not show an increase in ROS levels or in NF-kß expression. In addition, the monocrotaline plus melatonin group showed a reduction in TLR4 expression when compared with control and monocrotaline groups. To our knowledge, this is the first study demonstrating a positive effect of melatonin on the TLR4/NF-kß pathway in the RV of rats with PAH. In this sense, this study makes it possible to think of melatonin as a possible ally in mitigating RV alterations caused by PAH.
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Ventrículos do Coração , Melatonina , Monocrotalina , Estresse Oxidativo , Ratos Wistar , Transdução de Sinais , Receptor 4 Toll-Like , Animais , Melatonina/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Receptor 4 Toll-Like/metabolismo , Receptor 4 Toll-Like/genética , Masculino , Ventrículos do Coração/efeitos dos fármacos , Ventrículos do Coração/patologia , Ventrículos do Coração/metabolismo , Monocrotalina/toxicidade , Transdução de Sinais/efeitos dos fármacos , Hipertensão Arterial Pulmonar/tratamento farmacológico , Hipertensão Arterial Pulmonar/metabolismo , Hipertensão Arterial Pulmonar/patologia , NF-kappa B/metabolismo , Inflamação/patologia , Inflamação/tratamento farmacológico , Ratos , Hipertensão Pulmonar/tratamento farmacológico , Hipertensão Pulmonar/metabolismo , Hipertensão Pulmonar/patologia , Espécies Reativas de Oxigênio/metabolismoRESUMO
In mammal's pineal glands, ATP interacts with the high-affinity P2Y1 and the low-affinity P2X7 receptors. ATP released from sympathetic nerve terminals potentiates noradrenaline-induced serotonin N-acetyltransferase (Snat) transcription, N-acetylserotonin (NAS), and melatonin (MLT) synthesis. Circulating melatonin impairs the expression of adhesion molecules in endothelial cells, blocking the migration of leukocytes. Acute defence response induced by pathogen- and danger/damage-associated molecular patterns (PAMPs and DAMPs) triggers the NF-κB pathway in pinealocytes and blocks the transcription of Snat. Therefore, the darkness hormone is not released, and neutrophils and monocytes migrate to the lesion sites. ATP released in high amounts from apoptotic and death cells was considered a DAMP, and the blockage of P2X7 receptors was tested as a new class of drugs for treating brain damage. However, this is not a simple equation. High ATP injected in a lateral ventricle blocked MLT, but not NAS, synthesis as it impairs the transcription of acetyl serotonin N-methyltransferase. NAS is released in the plasma and the cerebral spinal fluid. NAS also blocks the rolling and adhesion of leukocytes to endothelial cells. Otherwise, it is metabolised specifically in each brain area to provide the requested concentration of MLT as a neuroprotector. As observed in physiological conditions, high extracellular ATP, different from the other DAMPs, reports the environmental light/dark cycle rhythm because NAS substitutes MLT as the nocturnal chemical indicator, the darkness hormone. Thus, blocking the P2X7R should not be considered a universal therapy for improving acute strokes, as MLT and ATP are partners in health and disease.
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The endoplasmic reticulum (ER) is crucial for protein quality control, and disruptions in its function can lead to various diseases. ER stress triggers an adaptive response called the unfolded protein response (UPR), which can either restore cellular homeostasis or induce cell death. Melatonin, a safe and multifunctional compound, shows promise in controlling ER stress and could be a valuable therapeutic agent for managing the UPR. By regulating ER and mitochondrial functions, melatonin helps maintain cellular homeostasis via reduction of oxidative stress, inflammation, and apoptosis. Melatonin can directly or indirectly interfere with ER-associated sensors and downstream targets of the UPR, impacting cell death, autophagy, inflammation, molecular repair, among others. Crucially, this review explores the mechanistic role of melatonin on ER stress in various diseases including liver damage, neurodegeneration, reproductive disorders, pulmonary disease, cardiomyopathy, insulin resistance, renal dysfunction, and cancer. Interestingly, while it alleviates the burden of ER stress in most pathological contexts, it can paradoxically stimulate ER stress in cancer cells, highlighting its intricate involvement in cellular homeostasis. With numerous successful studies using in vivo and in vitro models, the continuation of clinical trials is imperative to fully explore melatonin's therapeutic potential in these conditions.
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Melatonin is vital in human circadian rhythm and infant development. This scoping review summarized the current knowledge about melatonin's presence and effects in human milk to promote better understanding of its secretion pattern and clinical advancement of maternal-infant health. The review followed the Joanna Briggs Institute guideline and answered the question: What is the current knowledge about melatonin hormone in human milk? The databases searched were PubMed, CINAHL, SCOPUS, Web of Science, LILACS, Scielo, EMBASE, Science Direct, Eric, Cochrane, in addition to grey literature and reference lists of included sources. Research papers included English, Spanish, or Portuguese languages, regardless of study type or publication date. The study selection and data extraction involved two independent reviewers. Twenty-nine studies met inclusion criteria. The studies, conducted between 1993 and 2023, employed diverse designs, with cross-sectional studies being the most prevalent. Melatonin concentration exhibited a consistent pattern, being higher at night, and elevated in colostrum. The analysis methods for melatonin concentration evolved, with recent advancements contributing to more accurate measurements. Factors influencing melatonin levels, such as delivery type, maternal age, and health conditions, demonstrated a complex relationship, potentially impacting the health and development of infants. The dynamic nature of melatonin in human milk calls for continued interdisciplinary research, bridging gaps between clinical, biochemical, and epidemiological perspectives. Standardizing melatonin analysis methods are needed. Nurses should assess factors influencing melatonin levels in milk to promote interventions and guidance aimed at enhancing the regulation of the circadian cycle during the perinatal period and its benefits.
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Bell peppers (Capsicum annuum L.) are prone to chilling injury (CI) when stored at temperatures below 7 °C. Melatonin, a natural plant regulator, plays a critical role in defending against different pre- and post-harvest abiotic stresses, including those associated with cold storage. This study aimed to assess the effects of applying exogenous melatonin alone and in combination with a commercial wax on the CI tolerance, postharvest life, and potential biomarker search of red bell peppers. In the initial experiment, the effective melatonin concentration to reduce CI effects was determined. Peppers were sprayed with either distilled water (control) or a melatonin aqueous solution (M100 = 100 µM or M500 = 500 µM) and then stored for 33 d at 4 °C, followed by 2 d at 20 °C. The M500 treatment proved to be more effective in reducing fruit CI incidence (superficial scalds) and metabolic rate, while weight loss, softening, and color were comparable to the control. A second experiment assessed the potential synergistic effects of a combined melatonin and commercial wax treatment on pepper CI and quality. Fruits were sprayed with distilled water (control), melatonin (M500), commercial wax (Wax), or the combined treatment (Wax + M500) and stored for 28 d at 4 °C, followed by 2 d at 20 °C. The Wax + M500 was the most effective in significantly reducing the incidence of fruit CI symptoms and calyx fungal infection. Furthermore, this combined treatment enhanced fruit weight loss prevention compared with individual melatonin or wax treatment. Also, Wax + M500-treated peppers exhibited notable proline accumulation, indicative of a metabolic response counteracting the cold effects, resulting in better fruit stress acclimation. This treatment also preserved the peppers' color and antioxidant capacity. In summary, these findings highlight the suitability of applying a combined Wax + M500 treatment as a highly effective strategy to enhance the CI tolerance of peppers and extend their postharvest life.
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Melatonin is a pineal hormone that regulates testicular activity (i.e., steroidogenesis and spermatogenesis) through two complementary mechanisms, indirect effects exerted via the hypothalamic-adenohypophyseal axis and direct actions that take place on the different cell populations of the male gonad. The effects of increased age on the testis and the general mechanisms involved in testicular pathology leading to infertility are still only poorly understood. However, there is growing evidence that link testicular aging and idiopathic male infertility to local inflammatory and oxidative stress events. Because literature data strongly indicate that melatonin exhibits anti-inflammatory and anti-oxidant properties, this review focuses on the potential benefits exerted by this indoleamine at testicular level in male reproductive fertility and aging. Taking into account that the effects of melatonin supplementation on testicular function are currently being investigated, the overview covers not only promising prospects but also many questions concerning the future therapeutic value of this indoleamine as an anti-aging drug as well as in the management of cases of male infertility for which there are no medical treatments currently available.
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Envelhecimento , Anti-Inflamatórios , Antioxidantes , Infertilidade Masculina , Melatonina , Testículo , Masculino , Melatonina/uso terapêutico , Melatonina/farmacologia , Humanos , Antioxidantes/uso terapêutico , Antioxidantes/farmacologia , Testículo/efeitos dos fármacos , Testículo/metabolismo , Infertilidade Masculina/tratamento farmacológico , Envelhecimento/efeitos dos fármacos , Envelhecimento/fisiologia , Anti-Inflamatórios/uso terapêutico , Anti-Inflamatórios/farmacologia , Animais , Estresse Oxidativo/efeitos dos fármacosRESUMO
AIM: To evaluate the prevalence and types of sleep problems and their correlations with melatonin content and behavior in Attention-Deficit Hyperactivity Disorder (ADHD) children. METHOD: Sleep in ADHD children and typically developing children (TD) aged 6-14 was assessed by the Sleep Disorders Scale for Children (SDSC) and actigraphy, salivary melatonin quantified by ELISA, and behavior was analyzed using the Strengths and Difficulties Questionnaire. RESULTS: ADHD children showed a higher frequency of sleep disturbances, higher sleep latency, and lower sleep efficiency than in the TD group. The ADHD group presented lower melatonin nocturnal content compared to the TD group. Disorders of Initiating and Maintaining Sleep (DIMS) was moderately associated with nocturnal melatonin. The total behavior difficulties were correlated with Disorders of Initiating and Maintaining Sleep (DIMS), Sleep/Wake Transition Disorders (SWTD), Disorders of Excessive Somnolence (DES), Sleep Hyperhidrosis (SHY) and Total SDSC Score. The behavior was the only determinant of the total SDSC score (R2 = 0.499; p < 0.002). CONCLUSION: This study provides, for the first time, evidence that among the frequent sleep disturbances in ADHD, the disorders in initiating and maintaining sleep are associated with the low levels of melatonin found in this population. Additionally, these, along with other sleep disturbances, are linked to behavioral problems in ADHD.
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Actigrafia , Transtorno do Deficit de Atenção com Hiperatividade , Melatonina , Transtornos do Sono-Vigília , Humanos , Transtorno do Deficit de Atenção com Hiperatividade/epidemiologia , Melatonina/metabolismo , Criança , Masculino , Feminino , Transtornos do Sono-Vigília/epidemiologia , Adolescente , Saliva/metabolismo , Saliva/química , Inquéritos e QuestionáriosRESUMO
Ovarian cancer (OC) adjusts energy metabolism in favor of its progression and dissemination. Because melatonin (Mel) has antitumor actions, we investigated its impact on energy metabolism and kinase signaling in OC cells (SKOV-3 and CAISMOV-24). Cells were divided into control and Mel-treated groups, in the presence or absence of the antagonist luzindole. There was a decrease in the levels of HIF-1α, G6PDH, GAPDH, PDH, and CS after Mel treatment even in the presence of luzindole in both OC cells. Mel treatment also reduced the activity of OC-related enzymes including PFK-1, G6PDH, LDH, CS, and GS whereas PDH activity was increased. Lactate and glutamine levels dropped after Mel treatment. Mel further promoted a reduction in the concentrations of CREB, JNK, NF-kB, p-38, ERK1/2, AKT, P70S6K, and STAT in both cell lines. Mel reverses Warburg-type metabolism and possibly reduces glutaminolysis, thereby attenuating various oncogenic molecules associated with OC progression and invasion.
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Metabolismo Energético , Melatonina , Neoplasias Ovarianas , Transdução de Sinais , Humanos , Feminino , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/patologia , Neoplasias Ovarianas/tratamento farmacológico , Metabolismo Energético/efeitos dos fármacos , Melatonina/farmacologia , Linhagem Celular Tumoral , Transdução de Sinais/efeitos dos fármacos , Carcinogênese/efeitos dos fármacos , Carcinogênese/metabolismo , Carcinogênese/patologia , OncogenesRESUMO
Melatonin (ML) and dexmedetomidine (DM) are used separately as anesthetic premedication or as an anesthetic in humans and laboratory animals. In this study, we aimed to investigate the anesthetic properties of both drugs combined. The anesthetic effects of several combinations of ML (50 and 100 mg/kg) and DM (50 and 100 µg/kg) were evaluated in rats by observing behavioral manifestations and recording the duration and depth of anesthesia. Five anesthetic intervals were established according to the loss and recovery of reflexes. While each individual drug did not induce an appropriate anesthetic effect at the tested doses, ML50 + DM100, ML100 + DM50 and ML100 + DM100 combinations resulted in surgical anesthesia intervals of 60 to 360 min. Together, our results point that the use of ML allows to decrease the dose of DM, reducing the unwanted anesthetic effects of this α2-agonist.
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Anestesia , Dexmedetomidina , Melatonina , Dexmedetomidina/administração & dosagem , Dexmedetomidina/farmacologia , Animais , Melatonina/administração & dosagem , Melatonina/farmacologia , Ratos , Masculino , Anestesia/métodos , Ratos Wistar , Hipnóticos e Sedativos/administração & dosagem , Hipnóticos e Sedativos/farmacologia , Anestésicos/administração & dosagem , Anestésicos/farmacologiaRESUMO
Isoproterenol administration is associated with cardiac inflammation and decreased NO availability. Melatonin has been reported to have cardioprotective effect. The aim of this study was to investigate the effect of melatonin on NO bioavailability and inflammation in myocardial injury induced by isoproterenol. Isoproterenol was administrated in male Wistar rats for 7 days to induce cardiac injury. The animals were divided into 3 groups: Control, Isoproterenol, Isoproterenol + Melatonin. Animals received melatonin for 7 days. Echocardiographic analysis was performed and the hearts were collected for molecular analysis. Animals that received isoproterenol demonstrated a reduction in left ventricle systolic and diastolic diameter, indicating the presence of concentric hypertrophy. Melatonin was able to attenuate this alteration. Melatonin also improved NO bioavailability and decreased NF-κß, TNFα and IL-1ß expression. In conclusion, melatonin exhibited a cardioprotective effect which was associated with improving NO bioavailability and decreasing the pro-inflammatory proteins.
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Disponibilidade Biológica , Isoproterenol , Melatonina , Óxido Nítrico , Ratos Wistar , Animais , Melatonina/farmacologia , Óxido Nítrico/metabolismo , Masculino , Ratos , Cardiotônicos/farmacologia , Miocárdio/metabolismo , Miocárdio/patologia , NF-kappa B/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Interleucina-1beta/metabolismo , Traumatismos Cardíacos/metabolismo , Traumatismos Cardíacos/induzido quimicamente , Traumatismos Cardíacos/patologiaRESUMO
The aim of this study was to evaluate the effect of local administration of melatonin (MLT) on molecular biomarkers and calvaria bone critical defects in female rats with or without osteoporosis, associated or not with a xenogeneic biomaterial. Forty-eight female rats were randomly divided into two groups: (O) ovariectomized and (S) placebo groups. After 45 days of osteoporosis induction, two critical-size defects (5 mm diameter) were created on the calvaria. The groups were subdivided according to the following treatment: (C) Clot, MLT, MLT associated with Bio-Oss® (MLTBO), and Bio-Oss® (BO). After 45 days, the defect samples were collected and processed for microtomography, histomorphometry, and biomolecular analysis (Col-I, BMP-2, and OPN). All animals had one femur harvested to confirm the osteoporosis. Microtomography analysis demonstrated a bone mineral density reduction in the O group. Regarding bone healing, the S group presented greater filling of the defects than the O group; however, in the O group, the defects treated with MLT showed higher mineral filling than the other treatments. There was no difference between the treatments performed in the S group (p = 0.05). Otherwise, O-MLT had neoformed bone higher than in the other groups (p = 0.05). The groups that did not receive biomaterial demonstrated lower levels of Col-I secretion; S-MLT and S-MLTBO presented higher levels of OPN, while O-C presented statistically lower results (p < 0.05); O-BO showed greater BMP-2 secretion (p < 0.05). In the presence of ovariectomy-induced osteoporosis, MLT treatment increased the newly formed bone area, regulated the inflammatory response, and increased OPN expression.
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Abstract Objectives Narrative review evaluating the use of dietary supplements by children and adolescents. Data source The terms "dietary supplements", "children" and "adolescents" were used in combination in the PubMed, MEDLINE, and SciELO databases, between 2000 and 2023, evaluating studies in humans, published in Portuguese, English, French and Spanish. Data synthesis The use of dietary supplements by children and adolescents has increased in recent decades. The most commonly used supplements are vitamins, minerals, trace elements, proteins, amino acids, melatonin, fatty acids, probiotics and energy drinks. Conclusion Despite having specific indications, most of the time they are not prescribed by a healthcare professional. The reasons for use are varied. In children, the main reasons are protection against infections, stimulating growth, and poor food intake, with multivitamins and minerals being the most commonly used supplements. In adolescents, they are used to improve athletic performance and attain the "ideal body", with proteins and amino acids being the most often used nutrients. As they are not regulated by health agencies and are sold without a prescription, their unsupervised use can lead to inadequate doses, with inefficiency or overdose risk. As for compounding formulations, or when available in preparations with multiple nutrients, the chance of errors increases. It is essential that pediatricians advise parents and patients about the indications, risks and benefits, prescribing them when necessary.
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Melatonin is an indoleamine with crucial antioxidant properties that are used to combat inflammatory and neoplastic processes, as well as control transplants. However, the clinical applications of melatonin have not yet been fully consolidated in the literature and require in-depth analysis. OBJECTIVES: This study reviewed the literature on the antioxidant properties of melatonin in rat models. METHODS: We followed the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-analyses and used the PubMed, LILACS, and Cochrane databases, Google Scholar, and article references, irrespective of publication time. RESULTS: Ten articles involving 485 rats were selected, and the effects of melatonin on antioxidant markers were investigated. Melatonin increased superoxide dismutase in nine studies, glutathione peroxidase in seven studies, and catalase in five studies. In contrast, melatonin reduced glutathione in three studies and malonaldehyde in seven of eight studies. CONCLUSION: Our findings suggest that melatonin effectively reduces oxidative stress.