The neuroprotective effect of exogen melatonin upon fetal hippocampus damage caused by high-dose caffeine administration in pregnant rats.

OBJECTIVE: The aim of this study is to evaluate whether exogenous melatonin (MEL) mitigates the deleterious effects of high-dose caffeine (CAF) administration in pregnant rats upon the fetal hippocampus. MATERIALS AND METHODS: A total of 32 adult Wistar albino female rats were divided into four groups after conception (n = 8). At 9-20 days of pregnancy, intraperitoneal (i.p.) MEL was administered at a dose of 10 mg/kg/day in the MEL group, while i.p. CAF was administered at a dose of 60 mg/kg/day in the CAF group. In the CAF plus MEL group, i.p. CAF and MEL were administered at a dose of 60 and 10 mg/kg/day, respectively, at the same period. Following extraction of the brains of the fetuses sacrificed on the 21st day of pregnancy, their hippocampal regions were analyzed by hematoxylin and eosin and Cresyl Echt Violet, anti-GFAP, and antisynaptophysin staining methods. RESULTS: While there was a decrease in fetal and brain weights in the CAF group, it was found that the CAF plus MEL group had a closer weight average to that of the control group. Histologically, it was observed that the pyramidal cell layer consisted of 8-10 layers of cells due to the delay in migration in hippocampal neurons in the CAF group, while the MEL group showed similar characteristics with the control group. It was found that these findings decreased in the CAF plus MEL group. CONCLUSION: It is concluded that high-dose CAF administration causes a delay in neurogenesis of the fetal hippocampus, and exogenous MEL is able to mitigate its deleterious effects.

An upcycled fraction of Melaleuca alternifolia essential oil regenerates the skin through the skin melatonin pathway and improves sleep quality.

BACKGROUND: Sleep is one of the most important factors affecting overall health. During the night, the skin repairs damage caused by daily stresses. Melatonin plays a key role in this process. Toxins are removed, and cellular repair and growth hormone production are increased. Inter alia, this also decreases signs of intrinsic aging. AIMS: The current study was intended to demonstrate the impact of a unique fraction of Melaleuca alternifolia (FMA) essential oil, on sleep and skin quality. METHODS: The effect of FMA was investigated in vitro on skin cells, evaluating its antioxidant and anti-inflammatory properties, and in an ex-vivo study on human skin biopsies treated with FMA following stress induction. In addition, two clinical studies were performed on volunteers with life-style-related sleep complaints. In one study, sleep was measured using a noncontact monitoring device (SleepScore Labs, Max). A second study was conducted to assess skin anti-aging effects. RESULTS: In vitro application of FMA reduced IL-8 and reactive oxygen species (ROS) generation in skin cells. This was confirmed ex vivo through a decrease in inflammatory markers and an increase in antioxidant enzymes after stress induction. Interestingly, FMA also upregulated melatonin-associated genes. Real-world sleep tracking revealed that FMA significantly improved sleep quality, relative to unscented control. In vivo applications also showed a reduction in signs of aging. CONCLUSION: These results provide initial data to suggest that this unique FMA delivers skin anti-aging benefits via a two-pronged mode of action, improving sleep quality, and reducing skin inflammatory and oxidative stress.

Melatonin and zinc supplements with physical and mental activities subside neurodegeneration and hepatorenal injury induced by aluminum chloride in rats: Inclusion of GSK-3ß-Wnt/ß-catenin signaling pathway.

Alzheimer's disease (AD) is an irreversible, progressive cognitive dysfunction. Inflammaging is the greatest common factor between AD and hepatorenal malfunction. This study aimed to use melatonin (MEL) and zinc sulfate (Zn) in addition to physical and mental activities (PMA) to ameliorate AlCl3-induced AD as well as investigate their impact on the associated hepatorenal impairment. METHODS: Seven groups of rats each received: saline (control group), AlCl3 (70 mg/kg, i.p.), PMA, either alone or with a combination of Mel (10 mg/kg, p.o) and/or Zn (16 mg/kg, p.o). Neurological deterioration was assessed after 5 weeks using behavioral tests, histopathological examination, and measurements of acetylcholinesterase (ACHE), brain monoamines, oxidative stress, and inflammatory markers, Amyloid precursor protein (APP), amyloid-ß (Aß), tau levels, and brain derived neurotrophic factor (BDNF). Moreover, the GSK-3ß-Wnt/ß-catenin signaling pathway was assessed. Additionally, oxidative stress and inflammatory markers were determined in liver and kidney tissues with concurrent evaluation of hepatic and renal functions. RESULTS: The histopathological examination revealed a cerebral cortex and hippocampus deterioration in the AD group with a decline in spatial learning and memory, besides a significant increase in AD markers in the brain and disturbance in GSK-3ß-Wnt/ß-catenin signaling. The AD group showed hepatorenal injuries supported by elevated oxidative stress and inflammatory markers. However, adding Mel and Zn to PMA significantly attenuated the neurodegeneration and enhanced hepatic and renal functions by ameliorating oxidant and inflammatory markers. CONCLUSIONS: Combining Mel and Zn supplements with PMA defends against AlCl3-induced AD by modulating GSK-3ß-Wnt/ß-catenin signaling and palliates the associated hepatorenal dysfunction.

Topical Melatonin Exerts Immunomodulatory Effect and Improves Dermatitis Severity in a Mouse Model of Atopic Dermatitis.

Oral melatonin supplement has been shown to improve dermatitis severity in children with AD, but the mechanism of the effect is unclear, and it is uncertain whether melatonin has a direct immunomodulatory effect on the dermatitis. Topical melatonin treatment was applied to DNCB-stimulated Balb/c mice, and gross and pathological skin findings, serum IgE, and cytokine levels in superficial lymph nodes were analyzed. Secretion of chemokines and cell proliferative response after melatonin treatment in human keratinocyte HaCaT cells were also studied. We found that in DNCB-stimulated Balb/c mice, topical melatonin treatment improved gross dermatitis severity, reduced epidermal hyperplasia and lymphocyte infiltration in the skin, and decreased IP-10, CCL27, IL-4, and IL-17 levels in superficial skin-draining lymph nodes. Melatonin also reduced cytokine-induced secretion of AD-related chemokines IP-10 and MCP-1 and decreased IL-4-induced cell proliferation in HaCaT cells. Melatonin seems to have an immunomodulatory effect on AD, with IP-10 as a possible target, and topical melatonin treatment is a potentially useful treatment for patients with AD.

Influence of Melatonin on Behavioral and Neurological Function of Rats with Focal Cerebral Ischemia-Reperfusion Injury via the JNK/FoxO3a/Bim Pathway.

OBJECTIVE: To investigate the influence of melatonin on behavioral and neurological function of rats with focal cerebral ischemia-reperfusion injury via the JNK/FoxO3a/Bim pathway. METHODS: One hundred and twenty healthy male SD rats were randomized into the model group (Model: the middle cerebral artery occlusion (MCAO) model was constructed and received an equal volume of normal saline containing 5% DMSO), sham operation group (Sham: received no treatment except normal feeding), and low, medium, and high dose of melatonin group (L-MT, M-MT, and H-MT intraperitoneally injected 10, 20, and 40 mg/kg melatonin 30 min after IR, respectively), with 24 rats in each group. Following 24 h of reperfusion, the rats in each of the above groups were tested for neurological deficit symptoms and behavioral changes to screen the rats included in the study. HE and TUNEL stainings were performed to observe pathological changes. Levels of oxidative stress-related indexes, inflammatory factor-related indexes, nuclear factor-κB p65 (NF-κB p65), and interferon-γ (IFN-γ) in the rat brain were measured by ELISA. The JNK/FoxO3a/Bim pathway-related proteins as well as Bcl-2, Caspase-3, and Bax were examined using Western blot. RESULTS: Detection of behavioral indicators showed that the MACO model was successfully constructed in rats. L-MT, M-MT, and L-MT groups presented reduced malondialdehyde (MDA), reactive oxygen species (ROS), tumor necrosis factor- (TNF-) α, interleukin- (IL-) 6, IL-1ß, IFN-γ, NF-κB p65, and apoptosis compared with the Model group (P < 0.05), and the improvement degree was better in the M-MT group versus the L-HT group. Bcl-2 protein expression in the brain tissue of L-MT, M-MT, and H-MT groups increased significantly, while Bax, Caspase-3, p-JNK, p-FoxO3a, and Bim protein expression declined markedly, versus the Model group (P < 0.05). The changes of indexes were greater in the M-MT group compared with that in the L-MT group. No significant difference was observed in all the above indexes between the M-MT group and the H-MT group (P > 0.05). CONCLUSIONS: In the MACO rat model, melatonin can effectively reduce Bax and Caspase-3 levels by modulating the JNK/FoxO3a/Bim pathway, inhibit neuronal apoptosis, and alleviate neurological deficits by reducing the release of proinflammatory mediators, with anti-inflammatory and antioxidant effects. In addition, 20 mg/kg is the optimal melatonin concentration.

Adjuvant use of melatonin for pain management in dysmenorrhea - a randomized double-blinded, placebo-controlled trial.

PURPOSE: Dysmenorrhea is a common, recurring, painful condition with a global prevalence of 71%. The treatment regime for dysmenorrhea includes hormonal therapies and NSAID, both of which are associated with side effects. A dose of 10 mg melatonin daily has previously been shown to reduce the level of pelvic pain in women with endometriosis. We chose to investigate how this regime, administered during the week of menstruation, would affect women with dysmenorrhea but without any signs of endometriosis, as adjuvant analgesic treatment. METHODS: Forty participants with severe dysmenorrhea were randomized to either melatonin or placebo, 20 in each group. Our primary outcome was pain measured with numeric rating scale (NRS); a difference of at least 1.3 units between the groups was considered clinically significant. Secondary outcomes were use of analgesics, as well as absenteeism and amount of bleeding. Mixed model was used for statistical analysis. RESULTS: Eighteen participants completed the study in the placebo group and 19 in the melatonin group. Mean NRS in the placebo group was 2.45 and 3.18 in the melatonin group, which proved to be statistically, although not clinically significant. CONCLUSION: This randomized, double-blinded, placebo-controlled trial could not show that 10 mg of melatonin given orally at bedtime during the menstrual week had better analgesic effect on dysmenorrhea as compared with placebo. However, no adverse effects were observed. CLINICAL TRIALS: NCT03782740 registered on 17 December 2018.

Protective role of melatonin against adipose-hepatic metabolic comorbidities in experimentally induced obese rat model.

BACKGROUND: Adipose and hepatic metabolic dysfunctions are critical comorbidities that also aggravate insulin resistance in obese individuals. Melatonin is a low-cost agent and previous studies suggest that its use may promote metabolic health. However, its effects on some comorbidities associated with obesity are unknown. Herein, we investigated the hypothesis that melatonin supplementation would attenuate adipose-hepatic metabolic dysfunction in high fat diet (HFD)-induced obesity in male Wistar rats. MATERIALS AND METHODS: Twenty-four adult male Wistar rats (n = 6/group) were used: Control group received vehicle (normal saline), obese group received 40% high fat diet, melatonin-treated group received 4 mg/kg of melatonin, and obese plus melatonin group received 40% HFD and melatonin. The treatment lasted for 12 weeks. RESULTS: HFD caused increased food intake, body weight, insulin level, insulin resistance and plasma and liver lipid but decreased adipose lipid. In addition, HFD also increased plasma, adipose and liver malondialdehyde, IL-6, uric acid and decreased Glucose-6-phosphate dehydrogenase, glutathione, nitric oxide and circulating obestatin concentration. However, these deleterious effects except food intake were attenuated when supplemented with melatonin. CONCLUSION: Taken together, the present results indicate that HFD exposure causes adipose-hepatic metabolic disturbance in obese animals, which are accompanied by oxidative stress and inflammation. In addition, the present results suggest that melatonin supplementation attenuates adipose-hepatic metabolic dysfunction, accompanying obesity by suppression of oxidative stress/inflammation-dependent mechanism and increasing circulating obestatin.

Antioxidant Effect of Melatonin in Preterm Newborns.

INTRODUCTION: Preterm infants are at risk of free radical-mediated diseases from oxidative stress (OS) injury. Increased free radical generation has been demonstrated in preterm infants during the first seven days of life. Melatonin (MEL) is a powerful antioxidant and scavenger of free radicals. In preterm neonates, melatonin deficiency has been reported. Exogenous melatonin administration appears a promising strategy in the treatment of neonatal morbidities in which OS has a leading role. OBJECTIVE: The aim was to evaluate plasma MEL concentrations and OS biomarkers in preterm newborns after early administration of melatonin. METHODS: A prospective, randomized double-blind placebo-controlled pilot study was conducted from January 2019 to September 2020. Thirty-six preterm newborns were enrolled. Starting from the first day of life, 21 received a single dose of oral melatonin 0.5 mg/kg once a day, in the morning (MEL group); 15 newborns received an equivalent dose of placebo (placebo group). Samples of 0.2 mL of plasma were collected at 24 and 48 hours after MEL administration. Plasma concentrations of melatonin, non-protein-bound iron (NPBI), advanced oxidation protein products (AOPP), and F2-isoprostanes (F2-Isopr) were measured. Babies were clinically followed until discharge. RESULTS: At 24 and 48 hours after MEL administration, the MEL concentrations were significantly higher in the MEL group than in the placebo group (52759.30 ± 63529.09 vs. 28.57 ± 46.24 pg/mL and 279397.6 ± 516344.2 vs. 38.50 ± 44.01 pg/mL, respectively). NPBI and AOPP did not show any statistically significant differences between the groups both at 24 and 48 hours. At 48 hours, the mean blood concentrations of F2-Isopr were significantly lower in the MEL group than in the placebo group (36.48 ± 33.85 pg/mL vs.89.97 ± 52.01 pg/mL). CONCLUSIONS: Early melatonin administration in preterm newborns reduces lipid peroxidation in the first days of life showing a potential role to protect high-risk newborns. Trial Registration. This trial is registered with NCT04785183, Early Supplementation of Melatonin in Preterm Newborns: the Effects on Oxidative Stress.

Oral melatonin supplementation during in vitro fertilization treatment: a systematic PRISMA review and meta-analysis of randomized controlled trials.

OBJECTIVE: High levels of reactive oxygen species (ROS) have been suspected of reducing the success rate of assisted reproductive technology (ART). Melatonin has anti-oxidative properties and could therefore be of interest as a supplement in in vitro-fertilization (IVF) protocols. The objective of this study was to evaluate if a melatonin supplementation given in vivo to women undergoing IVF-treatment can improve the outcome. METHODS: A systematic literature search was performed on PubMed, Embase and Cochrane. The methodological quality of the included studies was assessed using the version 2 of the Cochrane risk-of-bias tool (RoB2). Primary outcome was clinical pregnancy rate (CPR). Secondary outcomes were total number of oocytes, number of mature oocytes, embryo quality, biochemical pregnancy rate, miscarriage rate and live birth rate (LBR). RESULTS: Seven randomized controlled trials (RCT) were included. The meta-analysis demonstrated a significantly higher mature oocyte count when melatonin was used (Mean Diff. = 1,82; 95% CI 0.37-3.27; p = .01). All seven studies showed a trend for increase in CPR, although not significant. No other measured outcomes showed a significant improvement. Two studies had 'low risk', three 'some concerns' and two studies had 'high risk' of bias. CONCLUSION: This meta-analysis including RCT indicates that an oral melatonin supplement during IVF-treatment can increase the number of mature oocytes, and a trend for increase CPR, albeit not significant. Most of the included studies were small. The methodological quality in three of the seven studies was moderate and two were low. Further investigations are needed to support the positive findings.

Effects of Melatonin Supplementation on Insulin Levels and Insulin Resistance: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Insulin resistance (IR) is a pivotal process in various metabolic diseases. The well-known treatment is lifestyle modification and medication therapy, which may result in poor compliance and side effects. Melatonin has been suggested to have a role in glucose metabolism, yet the results across studies have been inconsistent. Therefore, we performed a systematic review to evaluate the effects of melatonin supplementation on insulin levels and IR. We searched PubMed, Embase, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov, and identified randomized controlled trials (RCTs) published prior to August 2020. Articles were reviewed, selected and extracted by two reviewers independently. In total, 8 RCTs of 376 participants were included. Data were pooled using a random-effects model, with mean differences (MDs) and 95% confidence intervals (CIs). Our results showed that melatonin administration significantly reduced insulin levels and homeostasis model assessment of insulin resistance (HOMA-IR), and increased the quantitative insulin sensitivity check index (QUICKI). We conclude that melatonin ameliorated hyperinsulinemia, insulin resistance, and insulin sensitivity, and the results are an update of a previous meta-analysis. Although more investigations are required, we clearly provide evidence for the use of melatonin as an adjuvant treatment for metabolic disorders involving IR.

Melatonin Supplementation and Anthropometric Indices: A Randomized Double-Blind Controlled Clinical Trial.

Obesity, as the most common metabolic disorder in the world, is characterized by excess body fat. This study is aimed at determining the effects of melatonin supplementation on body weight, nody mass index (BMI), waist circumference (WC), and body fat mass percentage (BFMP) in people with overweight or obesity. Thirty eight overweight or class-I obese adult individuals were recruited in the study (8 men and 30 women). Participants prescribed a weight-loss diet and then randomly were allocated to melatonin or placebo groups. Participants received either a 3-milligram melatonin or placebo tablet per day for 12 weeks. In order to assess differences at the significance level of 0.05, repeated measure ANOVA and paired t-test were used. According to the results, a significant reduction was found in participants' body weight, WC, and BMI in both groups (p = 0.001). However, for the last six weeks, significant reductions of these parameters were observed only in the melatonin group (p = 0.01). The BFMP of participants in the melatonin group showed a significant reduction at the end of the study compared to the initial measurements (p = 0.008). Nevertheless, the results of the present study alone are not sufficient to conclude on the effects of melatonin consumption on anthropometric indices, and it seems that further studies are required in this regard.

Effects of melatonin supplementation on diabetes: A systematic review and meta-analysis of randomized clinical trials.

BACKGROUND & AIMS: Melatonin appears as a supplement capable of helping with diabetes. However, there is no evidence from meta-analyses that showed significant results in insulin resistance and glycated hemoglobin. This study aimed to review the literature on randomized clinical trials that evaluated melatonin supplementation effects, compared to placebo, on diabetes parameters in humans. METHODS: We conducted a systematic review and meta-analysis in the following databases: Pubmed, LILACS, Scielo, Scopus, Web of Science, Cochrane, and Embase. We included randomized clinical trials investigating melatonin supplementation's effects, compared to placebo, on fasting blood glucose, insulin resistance, and glycated hemoglobin. Non-randomized clinical trials, observation studies, and animal models were excluded. The Cochrane scale assessed the quality of the studies. We conducted a meta-analysis on fasting blood glucose, insulin resistance, and glycated hemoglobin. RESULTS: Sixteen studies were included, of which 56% showed benefits from supplementation with melatonin in diabetes parameters compared with placebo. Our meta-analysis showed significant results for fasting blood glucose [mean difference: -4.65; 95% CI: -8.06, -1.23; p = < 0.01; I2 = 58%], glycated hemoglobin [mean difference: -0.38; 95% CI: -0.67, -0.10; p = 0.30; I2 = 18%], and insulin resistance [mean difference: -0.58; 95% CI: -1.00, -0.15; p = 0.17; I2 = 35%]. CONCLUSIONS: Our results showed that melatonin supplementation was useful for reducing diabetes parameters when compared to placebo.

Dietary Melatonin and Glycine Decrease Tumor Growth through Antiangiogenic Activity in Experimental Colorectal Liver Metastasis.

Despite multimodal treatment strategies, clinical outcomes of advanced stage colorectal cancer (CRC) patients remain poor. Neoadjuvant/adjuvant chemotherapy efficacy is limited due to chemoresistance, toxicity, and negative side effects. Since both melatonin and glycine have anti-cancer activities without relevant side effects, this study was designed to investigate their combined effects in experimental CRC liver metastases. CRC metastasis with CC531 cells were induced in male Wistar rats. Melatonin and glycine alone or their combination were supplemented for 14 days (n = 100). Blood parameters, a micro-computed tomography scan (tumor volume over time), and immunohistochemistry for Ki67 and CD31 expression in tumor tissue were compared between groups. Melatonin and glycine alone significantly reduced the tumor volume by 63.2% (p = 0.002) and 43% (p = 0.044) over time, respectively, while tumor volume increased by 8.7% in the controls. Moreover, treatment with melatonin and glycine alone reduced the tumor proliferation index. Most interestingly, the combination therapy did not have any influence on the above-mentioned tumor parameters. The leukocyte count was significantly increased with melatonin at the end of the experiment (p = 0.012) which was due to a high lymphocytes count. Tumor microvascular density was significantly reduced in all treatment groups. The results of this study suggest an inhibitory function for melatonin and glycine alone in the case of CRC liver metastasis growth by acting as natural antiangiogenic molecules, followed by angiogenesis-dependent cancer proliferation and immunomodulation.

The Mechanism of Oral Melatonin Ameliorates Intestinal and Adipose Lipid Dysmetabolism Through Reducing Escherichia Coli-Derived Lipopolysaccharide.

BACKGROUND & AIMS: Gut microbiota have been reported to be sensitive to circadian rhythms and host lipometabolism, respectively. Although melatonin-mediated beneficial efforts on many physiological sites have been revealed, the regulatory actions of oral melatonin on the communication between gut microbiota and host are still not clear. Angiopoietin-like 4 (ANGPTL4) has been shown to be strongly responsible for the regulation of systemic lipid metabolism. Herein, we identified that oral melatonin improved lipid dysmetabolism in ileum and epididymal white adipose tissue (eWAT) via gut microbiota and ileac ANGPTL4. METHODS: Analyses of jet-lag (JL) mice, JL mice with oral melatonin administration (JL+MT), and the control for mRNA and protein expression regarding lipid uptake and accumulation in ileum and eWAT were made. Gut microbiome sequencing and experimental validation of target strains were included. Functional analysis of key factors/pathways in the various rodent models, including the depletion of gut microbiota, mono-colonization of Escherichia coli, and other genetic intervention was made. Analyses of transcriptional regulation and effects of melatonin on E coli-derived lipopolysaccharide (LPS) in vitro were made. RESULTS: JL mice have a higher level of ileal lipid uptake, fat accumulation in eWAT, and lower level of circulating ANGPTL4 in comparison with the control mice. JL mice also showed a significantly higher abundance of E coli and LPS than the control mice. Conversely, oral melatonin supplementation remarkably reversed these phenotypes. The test of depletion of gut microbiota further demonstrated that oral melatonin-mediated improvements on lipometabolism in JL mice were dependent on the presence of gut microbiota. By mono-colonization of E coli, LPS has been determined to trigger these changes similar to JL. Furthermore, we found that LPS served as a pivotal link that contributed to activating toll-like receptor 4 (TLR4)/signal transducer and activator of transcription 3 (STAT3_/REV-ERBα) signaling to up-regulate nuclear factor interleukin-3-regulated protein (NFIL3) expression, resulting in increased lipid uptake in ileum. In MODE-K cells, the activation of NFIL3 has further been shown to inhibit ANGPTL4 transcription, which is closely associated with lipid uptake and transport in peripheral tissues. Finally, we confirmed that melatonin inhibited LPS via repressing the expression of LpxC in E coli. CONCLUSIONS: Overall, oral melatonin decreased the quantity of E coli-generated LPS, which alleviated NFIL3-induced transcriptional inhibition of ANGPTL4 through TLR4/IL-22/STAT3 signaling in ileum, thereby resulting in the amelioration of ileal lipid intake and lower fat accumulation in eWAT. These results address a novel regulation of oral melatonin originating from gut microbiota to host distal tissues, suggesting that microbe-generated metabolites are potential therapies for melatonin-mediated improvement of circadian rhythm disruption and related metabolic syndrome.

The effects of melatonin on the healing of burn wounds in pinealectomized rats.

BACKGROUND: The present study aims to investigate the favorable effects of melatonin on burn wound healing in rats. METHODS: In this study, forty Wistar-albino-type male rats were divided into four groups. Group 1 was the control group, Group 2 rats were treated using exogenous melatonin, Group 3 rats were pinealectomized, and Group 4 rats were pinealectomized then treated with exogenous melatonin. In all groups, a deep second-degree burn was created on the backs of the rats with a metal plate heated in boiling water. We monitored the progress of burn healing for seven days. At the end of them, we evaluated hydroxyproline levels, type III collagen, edema, inflammatory infiltration, congestion, vascular proliferation, fibrosis, the thickness of the zone of stasis and the epithelium to assess the progress of healing. RESULTS: The zone of stasis was less thick in Group 2 than the other groups (p=0.009). Type III collagen dyeing (p=0.031), fibrosis (p=0.011) and edema (p=0.031) were higher in Group 2 than the other groups. Congestion was higher in the control group than Group 4 (p=0.031). Other evaluated parameters showed no significant differences among the groups. CONCLUSION: In this study, it was noted that once total melatonin levels exceeded a certain threshold, a preventive effect was exerted on burn wound damage progression by reducing the zone of stasis. Melatonin may also prevent the development of hypertrophic scarring. Melatonin may be a potential therapeutic option that can supplement traditional treatment in burn wounds; however, further studies with higher doses of exogenous melatonin administered over longer periods are needed to further evaluate the effects noted in this study.

Enhanced Synergistic-Antioxidant Activity of Melatonin and Tretinoin by Co-encapsulation into Amphiphilic Chitosan Nanocarriers: During Mice In Vitro Matured Oocyte/Morula-Compact Stage Embryo Culture Model.

The use of exogenous antioxidants or the combination of them during in vitro oocyte/embryo culture media is reasonable. Co-delivery by nanocarrier has been designed to overcome the limitations of combining them traditionally. In this work, amphiphilic chitosan nanocarrier (ACN) was applied to co-encapsulate melatonin (Mel) and tretinoin (TTN) by the self-assembled method and evaluate their synergistic antioxidant efficacy in mice oocytes/embryos. The formation of single/dual-ACN was confirmed by Fourier-transformed infrared spectroscopy (FT-IR). The average particle diameter, size distribution, polydispersity index (PDI), and zeta potential of them were measured by dynamic light scattering (DLS), and the morphology was evaluated by TEM and SEM technologies. Also, the encapsulation efficiency (EE%) and drug loading content (DL%) of the nanocapsules were determined by UV-vis spectrophotometry. Studies of the in vitro release showed a continued drug release without any bursting effect of Mel+TTN-ACNs compared with single Mel/TTN-ACNs. Then, in both experiments, nuclear staining (Aceto-orcein and Hoechst 33342), fluorescent staining of H2DCFDA, chemiluminescence test, and qRT-PCR technique were performed as in vitro toxicity studies. The results of all these evaluations demonstrated that the dual delivery of Mel and TTN could accumulate a safety (without high-dose toxicity) synergistic anti-oxidative effect in oocyte/embryo by passive controlled, and inhibit intra/extracellular ROS levels by an enhanced intracellular penetration.

Adjuvant use of melatonin for relieving symptoms of painful diabetic neuropathy: results of a randomized, double-blinded, controlled trial.

PURPOSE: The trial aimed to investigate the effectiveness of exogenous melatonin as an adjuvant to pregabalin for relief of pain in patients suffering from painful diabetic neuropathy (PDN). PATIENTS AND METHODS: This randomized, double-blind, placebo-controlled trial was carried out between October 2019 and December 2020 in an outpatient specialty clinic in Iran. One-hundred-three type 2 diabetic patients suffering from PDN were randomized into either the melatonin group (n = 52) or the placebo group (n = 51). Besides pregabalin at a dose of 150 mg per day, patients started with melatonin or an identical placebo, at a dose of 3 mg/day at bedtime for 1 week, which was augmented to 6 mg/day for further 7 weeks. The primary outcomes were changes in mean NRS (numerical rating scale) pain score from baseline to endpoint and responder rate (patients with a reduction of 50% and higher in average pain score compared with baseline). Secondary endpoints were changes in mean NRS pain-related sleep-interference score, overall improvement evaluated by Patient and Clinical Global Impressions of Change (PGIC, CGIC), and impact of the intervention on patient's Health-related quality of life (QOL). All analyses were conducted on an Intention-to-Treat (ITT) analysis data set. RESULTS: At the study endpoint, treatment with melatonin resulted in a considerably higher reduction in the mean NRS pain score in comparison with placebo (4.2 ± 1.83 vs. 2.9 ± 1.56; P-value < 0.001). In terms of treatment responders, a greater proportion of melatonin-treated patients satisfied the responder criterion than placebo-treated patients (63.5% vs. 43.1%). Melatonin also reduced pain-related sleep interference scores more than did placebo (3.38 ± 1.49 vs. 2.25 ± 1.26; P-value < 0.001). Further, at the endpoint, more improvement was also seen in terms of PGIC, CGIC, and Health-related QOL in patients treated with melatonin than placebo. Melatonin was also well tolerated. CONCLUSION: The present results showed that melatonin as an adjunct therapy to pregabalin might be helpful for use in patients with PDN. However, confirmation of these results requires further studies.

Evaluation of Th1 and Th2 mediated cellular and humoral immunity in patients with COVID-19 following the use of melatonin as an adjunctive treatment.

Coronavirus (SARS-CoV-2) is spreading rapidly in the world and is still taking a heavy toll. Studies show that cytokine storms and imbalances in T-helper (Th)1/Th2 play a significant role in most acute cases of the disease. A number of medications have been suggested to treat or control the disease but have been discontinued due to their side effects. Melatonin, as an intrinsic molecule, possesses pharmacological anti-inflammatory and antioxidant properties that decreases in concentration with age; as a result, older people are more prone to various diseases. In this study, patients who were hospitalized with a diagnosis of coronavirus disease 2019 (COVID-19) were given a melatonin adjuvant (9 mg daily, orally) for fourteen days. In order to measure markers of Th1 and Th2 inflammatory cytokines (such as interleukin (IL)-2, IL-4, and interferon (IFN)-γ) as well as the expression of Th1 and Th2 regulatory genes (signal transducer and activator of transcription (STAT)4, STAT6, GATA binding protein 3 (GATA3), and T-box expressed in T cell (T-bet)), blood samples were taken from patients at the beginning and end of the treatment. Adjuvant therapy with melatonin controlled and reduced inflammatory cytokines in patients with COVID-19. Melatonin also controlled and modulated the dysregulated genes that regulate the humoral and cellular immune systems mediated by Th1 and Th2. In this study, it was shown for the first time that melatonin can be used as a medicinal adjuvant with anti-inflammatory mechanism to reduce and control inflammatory cytokines by regulating the expression of Th1 and Th2 regulatory genes in patients with COVID-19.

Does Evidence Exist to Blunt Inflammatory Response by Nutraceutical Supplementation during COVID-19 Pandemic? An Overview of Systematic Reviews of Vitamin D, Vitamin C, Melatonin, and Zinc.

More than one year has passed since the first cases of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome (SARS)-CoV-2 coronavirus were reported in Wuhan (China), rapidly evolving into a global pandemic. This infectious disease has become a major public health challenge in the world. Unfortunately, to date, no specific antivirals have been proven to be effective against COVID-19, and although a few vaccines are available, the mortality rate is not decreasing but is still increasing. One therapeutic strategy has been focused on infection prevention and control measures. In this regard, the use of nutraceutical supports may play a role against some aspect of the infection, particularly the inflammatory state and the immune system function of patients, thus representing a strategy to control the worst outcomes of this pandemic. For this reason, we performed an overview including meta-analyses and systematic reviews to assess the association among melatonin, vitamin C, vitamin D, zinc supplementation and inflammatory markers using three databases, namely, MEDLINE, PubMed Central and the Cochrane Library of Systematic Reviews. According to the evidence available, an intake of 50,000 IU/month of vitamin D showed efficacy in CRP. An amount of 1 to 2 g per day of vitamin C demonstrated efficacy both in CRP and endothelial function, and a dosage of melatonin ranging from 5 to 25 mg /day showed good evidence of efficacy in CRP, TNF and IL6. A dose of 50 mg/day of elemental zinc supplementation showed positive results in CRP. Based on the data reported in this review, the public health system could consider whether it is possible to supplement the current limited preventive measures through targeted nutraceutical large-scale administration.