Melatonin Research Articles

Differential effects of melatonin on adipose tissues under normoestrogenic and estrogen-deficient conditions in rats

In post-menopause, oxidative stress due to the decline of natural antioxidants increases the susceptibility to metabolic syndromes (MetS). Estrogen and melatonin (MEL) share antioxidant properties; however, few studies have reported the impact of estrogen deficiency and MEL treatment on morphology, redox status, and antioxidant defense capacity of diverse adipose tissue (AT) subtypes. To investigate this issue, MEL was administered to ovariectomized (OVX) rats and sham-operated rats for 16 weeks (10 mg/kg). The adipocyte morphology, oxidative stress parameters and antioxidant enzyme activity were evaluated in the visceral retroperitoneal adipose tissue (rVAT), subcutaneous inguinal adipose tissue (iSAT) and brown adipose tissue (BAT). In OVX rats, MEL treatment suppressed rVAT hypertrophy and increased the prevalence of small adipocytes in iSAT, suggesting a better lipid distribution among ATs. MEL treatment increased glutathione reductase and glucose-6-phosphate dehydrogenase activity in iSAT; therefore, restored the glutathione level. In rVAT, MEL increased glutathione peroxidase and glutathione reductase activity. MEL minimized the risks for the development of metabolic abnormalities due to estrogen deficiency. However, under normoestrogenic condition, MEL decreased plasma estradiol levels and uterine mass, raising the concerning of its effect on reproductive functions.

Local application of melatonin associated or not to xenogeneic material, in critical defects of rat calvaria.

Melatonin (MLT) is a hormone that can stimulate bone formation and inhibit bone resorption, among other functions. Aim: To evaluate the effect on new bone formation of MLT applied locally to critical defects created in the calvaria of rats, compared to the effect of Bio-Oss® xenogeneic bone substitute (BO), by analyzing histomorphometry, microtomography and gene expression. Materials and Method: Two critical defects (5.0 mm in diameter) were created in the calvaria of 36 adults male Wistar rats. The rats were divided randomly into two groups: a test group, in which one of the defects was filled with MLT, and the other with MLT with Bio-Oss® (MLTBO), and a control group, in which one of the defects was filled only with the clot (C), and the other with BO. The rats were euthanized 30 days after surgery. Samples of the calvaria containing the critical defects were collected for analysis by histomorphometry, microtomography, and the expression of the genes for type I collagen (COL-I), osteopontin (OPN) and bone morphogenetic protein 2 (BMP-2). Results: A qualitative improvement was observed in bone healing when MLT was used, though there was no statistical difference in the quantification of newly formed bone (p>0.05). Micro-CT showed that bone volume was significantly smaller in absence of BO (p=0.006). Bone trabeculae thickness (p=0.590) and number (p=0.150) were not significantly affected by MLT. Regarding the expression of the genes COL-I, OPN and BMP-2, no significant differences were observed between the MLT, BO and MLTBO groups. Conclusion: Topical application of MLT resulted in a qualitative improvement in bone healing, although it did not affect bone formation quantitatively. In the absence of BO, less bone volume and less bone trabecular thickness were observed.

Phytohormones enhanced carbon fixation and biomass production in CO2 absorption-microalgae conversion system under light stress

CO2 absorption-microalgae conversion (CAMC) system can be a sustainable technology to achieve low-energy carbon capture and resource utilization in response to zero carbon. However, light stress could restrict the carbon utilization efficiency of CAMC system. In this study, melatonin (MT) and indole-propionic acid (IPA) as phytohormones, were used to promote the carbon fixation capacity and biomass yield of CAMC system under light stress, and the potential mechanism was also discussed. Both MT and IPA promoted the growth of Spirulina, and 10 mg-MT group obtained the highest biomass and carbon fixation capacity, which were 27.61 % and 30.62 % higher than control. MT and IPA promoted the activity of superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GR), enhancing antioxidant activity to avoid oxidative damage. The results of transmission electron microscopy (TEM) and cell apoptosis showed MT and IPA reduced cell membrane damage and apoptosis. Phytohormones induced the carbon flux flow to the synthesis of carbohydrate and protein, and increased carbohydrate and protein productivity. Moreover, the maximum phycocyanin content and yield were 13.74 % and 43.25 % higher than the control. Therefore, adding phytohormones was an effective strategy to achieve high-value bioresources of microalgae in CAMC system under light stress.

Effectiveness of antioxidants on in vitro regeneration of Musa paradisiaca var. raja to prevent browning and enhance embryo development

The cultivation of raja banana is widespread in Indonesia. The process of increasing banana propagation through in vitro culture encounters a specific issue, namely the occurrence of browning during the initiation stage, which hinders the regeneration process. The objective of this study is to determine the effectivenessof antioxidants on the in vitro regeneration of raja banana to prevent browning and enhance embryo development. The study was conducted using a completely randomized design with the treatment of the antioxidant compounds ascorbic acid (AS) and melatonin (MN). The treatments consisted of control (without antioxidants), ascorbic acid (100 mg L-1, 150 mg L-1, and 200 mg L-1) and melatonin (10 mg L-1, 12 mg L-1, and 14 mg L-1). The results showed that ascorbic acid and melatonin treatment had no significant effect on the percentage of viable explants and the level of browning intensity, but provided significant results on the regeneration process. The application of melatonin at 14 mg L-1 significantly increased callus regeneration. Furthermore, at a concentration of 12 mg L-1 showed the highest callus percentage value compared to other treatments. The melatonin 12 mg L-1 treatment showed the earliest scutellar embryo formation, whereas ascorbic acid at a concentration of 100 mg L-1 resulted in the most optimal regeneration of globular and scutellar embryos. The highest concentrations of ascorbic acid and melatonin inhibit the formation of coleoptilar embryos

Vascular wall microenvironment: Endothelial cells original exosomes mediated melatonin-suppressed vascular calcification and vascular ageing in a m6A methylation dependent manner

Vascular calcification and vascular ageing are “silent” diseases but are highly prevalent in patients with end stage renal failure and type 2 diabetes, as well as in the ageing population. Melatonin (MT) has been shown to induce cardiovascular protection effects. However, the role of MT on vascular calcification and ageing has not been well-identified. In this study, the aortic transcriptional landscape revealed clues for MT related cell-to-cell communication between endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) in vascular calcification and vascular ageing. Furthermore, we elucidated that it was exosomes that participate in the information transportation from ECs to VSMCs. The exosomes secreted from melatonin-treated ECs (MT-ECs-Exos) inhibited calcification and senescence of VSMCs. Mechanistically, miR-302d-5p was highly enriched in MT-ECs-Exos, while depletion of miR-302d-5p blocked the ability of MT-ECs-Exos to suppress VSMC calcification and senescence. Notably, Wnt3 was a bona fide target of miR-302d-5p and modulated VSMC calcification and senescence. Furthermore, we found that maturation of endothelial derived exosomal miR-302d-5p was promoted by WTAP in an N6-methyladenosine (m6A)-dependent manner. Interestingly, MT alleviated vascular calcification and ageing in 5/6-nephrectomy (5/6 NTP) mice, a chronic kidney disease (CKD) induced vascular calcification and vascular ageing mouse model. MT-ECs-Exos was absorbed by VSMCs in vivo and effectively prevented vascular calcification and ageing in 5/6 NTP mice. ECs-derived miR-302d-5p mediated MT induced anti-calcification and anti-ageing effects in 5/6 NTP mice. Our study suggests that MT-ECs-Exos alleviate vascular calcification and ageing through the miR-302d-5p/Wnt3 signaling pathway, dependent on m6A methylation.

Nutraceutical formulation based on a synergic combination of melatonin and palmitoylethanolamide for the management of allergic events.

The management of allergic events is a growing global health issue, especially in industrialized countries. This disease is an immune-mediated process, regulated by the interaction of IgE with an allergen, resulting in mast cell activation, which concerns the release of several immune-inflammatory modulators, i.e., histamine, β-hexosaminidase, COX-2, IL-6, and TNF-α, responsible for the main allergic-reaction associated symptoms. The aim of the present study was the efficacy evaluation of an alternative remedy, an innovative nutraceutical formulation (NF) based on the synergic combination of melatonin (MEL) and palmitoylethanolamide (PEA) for the prevention and treatment of immune disease. At first, the intestinal bioaccessibility of PEA and MEL in NF was assessed at 1.6 and 36%, respectively. Then the MEL and PEA ability to modulate the release of immune-inflammatory modulators in the human mast cell line (HMC-1.2) at their bioaccessible concentration was investigated. Our results underline that NF treatment was able to reduce COX-2 mRNA transcription levels (-30% vs. STIM, p < 0.0001) in stimulated HMC-1.2 and to contract COX-2 enzymatic activity directly (IC50: 152 μg/mL). Additionally, NF showed valuable ability in reducing histamine and β-hexosaminidase release in stimulated HMC-1.2, as well as in decreasing TNF-α and IL-6 mRNA transcription levels and protein production.

Blunted Melatonin Circadian Rhythm in Parkinson's Disease: Express Bewilderment.

Melatonin (MTN) is a neuro-hormone released from the pineal gland. MTN secretion is regulated by different neuronal circuits, including the retinohypothalamic tract and suprachiasmatic nucleus (SCN), which are affected by light. MTN is neuroprotective in various neurodegenerative diseases, including Parkinson's disease (PD). MTN circulating level is highly blunted in PD. However, the underlying causes were not fully clarified. Thus, the present review aims to discuss the potential causes of blunted MTN levels in PD. Distortion of MTN circadian rhythmicity in PD patients causies extreme daytime sleepiness. The underlying mechanism for blunted MTN response may be due to reduction for light exposure, impairment of retinal light transmission, degeneration of circadian pacemaker and dysautonomia. In conclusion, degeneration of SCN and associated neurodegeneration together with neuroinflammation and activation of NF-κB and NLRP3 inflammasome, induce dysregulation of MTN secretion. Therefore, low serum MTN level reflects PD severity and could be potential biomarkers. Preclinical and clinical studies are suggested to clarify the underlying causes of low MTN in PD.

Characterization and Functional Analysis of the 17-Beta Hydroxysteroid Dehydrogenase 2 (hsd17b2) Gene during Sex Reversal in the Ricefield Eel (Monopterus albus).

In mammals, 17-beta hydroxysteroid dehydrogenase 2 (Hsd17b2) enzyme specifically catalyzes the oxidation of the C17 hydroxyl group and efficiently regulates the activities of estrogens and androgens to prevent diseases induced by hormone disorders. However, the functions of the hsd17b2 gene involved in animal sex differentiation are still largely unclear. The ricefield eel (Monopterus albus), a protogynous hermaphroditic fish with a small genome size (2n = 24), is usually used as an ideal model to study the mechanism of sex differentiation in vertebrates. Therefore, in this study, hsd17b2 gene cDNA was cloned and its mRNA expression profiles were determined in the ricefield eel. The cloned cDNA fragment of hsd17b2 was 1230 bp, including an open reading frame of 1107 bp, encoding 368 amino acid residues with conserved catalytic subunits. Moreover, real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) analysis showed that hsd17b2 mRNA expressed strongly in the ovaries at early developmental stages, weakly in liver and intestine, and barely in testis and other tissues. In particular, hsd17b2 mRNA expression was found to peak in ovaries of young fish and ovotestis at the early stage, and eventually declined in gonads from the late ovotestis to testis. Likewise, chemical in situ hybridization results indicated that the hsd17b2 mRNA signals were primarily detected in the cytoplasm of oogonia and oocytes at stage I-II, subsequently concentrated in the granulosa cells around the oocytes at stage Ⅲ-Ⅳ, but undetectable in mature oocytes and male germ cells. Intriguingly, in ricefield eel ovaries, hsd17b2 mRNA expression could be significantly reduced by 17β-estradiol (E2) or tamoxifen (17β-estradiol inhibitor, E2I) induction at a low concentration (10 ng/mL) and increased by E2I induction at a high concentration (100 ng/mL). On the other hand, both the melatonin (MT) and flutamide (androgen inhibitor, AI) induction could significantly decrease hsd17b2 mRNA expression in the ovary of ricefield eel. This study provides a clue for demonstrating the mechanism of sexual differentiation in fish. The findings of our study imply that the hsd17b2 gene could be a key regulator in sexual differentiation and modulate sex reversal in the ricefield eel and other hermaphroditic fishes.

Circadian alignment, cardiometabolic disease, and sex specific differences in adults with overweight/obesity.

Circadian disruption promotes weight gain and poor health. The extent to which sex plays a role in the relationship between the circadian timing of behaviors and health outcomes in individuals with overweight/obesity is unclear. We investigated the sex-specific associations between circadian alignment and cardiometabolic health markers in females and males with overweight/obesity. Thirty volunteers with overweight/obesity (15 female; BMI≥25.1kg/m2) underwent an evening in-laboratory assessment for dim-light melatonin onset (DLMO), body composition via dual energy x-ray absorptiometry, and a fasted blood sample. Circadian alignment was determined as the time difference between DLMO and average sleep onset over 7-days (phase angle), with participants categorized into narrow/wide phase angle groups based on median phase angle split. Due to known differences in metabolic markers between sexes, participants were subdivided based on sex into narrow and wide phase angle groups. Males in the narrow phase angle group had higher android/gynoid body fat distribution, triglycerides, and Metabolic Syndrome risk scores, while females had higher overall body fat percentage, glucose, and resting heart rates (all p<0.04). Furthermore, a narrower phase angle in males was negatively associated with android/gynoid body fat (r=-0.53, p=0.04) and negatively associated with body fat (r=-0.62, p=0.01) and heart rate (r=-0.73, p<0.01) in females. Circadian disruption may not only promote a trajectory of weight gain but could also contribute to negative health consequences in a sex-dependent manner in those already with overweight/obesity. These data may have implications for clinical utility in sex-specific sleep and circadian interventions for adults with overweight/obesity.

Melatonin mitigates the lipopolysaccharide-induced myocardial injury in rats by blocking the p53/xCT pathway-mediated ferroptosis.

This article examined the therapeutic effect of melatonin (MT) on the lipopolysaccharide (LPS)-induced myocardial injury, and the mechanisms involved. Septic rat model was constructed by exposing to lipopolysaccharide (LPS), and treated by MT, Ferrostatin-1 (Fer-1) and Erastin (Era). Hematoxylin-eosin staining was executed to appraise myocardial injury. H9c2 cells that exposed to LPS to induce in vitro sepsis cell model were treated by MT. p53 overexpression vectors were transfected into H9c2 cells. Inflammation- and ferroptosis-related indicators were examined by enzyme-linked immunosorbent assay. Expression of p53, xCT and GPX4 was scrutinized by quantitative real-time polymerase chain reaction and Western blot. MT relieved myocardial injury in septic rats. It decreased IL-6 and TNF-α, elevated GPX4 and GSH, and reduced MDA and Fe2+ in myocardial tissues of septic rats. LPS induced p53 elevation and xCT reduction in rats' myocardial tissues. Nevertheless, MT treatment declined p53 and increased xCT in myocardial tissues of septic rats. Interestingly, the relieving effect of MT on myocardial injury in septic rats was enhanced by Fer-1, but reversed by Era. The LPS-induced H9c2 cell damage was relieved by MT treatment. Besides, MT decreased LDH, IL-6 and TNF-α, elevated xCT, GPX4 and GSH, and reduced MDA and Fe2+ in the LPS-induced H9c2 cells. Conversely, these influences of MT on the LPS-induced H9c2 cells were reversed by p53 overexpression. MT is proposed to be a promising agent for treating the LPS-induced myocardial injury, as it relieves myocardial injury by hindering the p53/xCT-mediated ferroptosis in the LPS-induced septic rats.

Melatonin prevents bone loss in osteoporotic rats with valproic acid treatment by anti-inflammatory and anti-oxidative stress

Melatonin (MEL) has shown positive effects in anti-inflammatory and anti-oxidative stress research. This study investigates whether MEL can positively impact bone loss induced by valproic acid (VPA) in rats. The study examines changes in MC3T3-E1 cell viability and osteogenic potential, along with osteoclast differentiation in RAW264.7 cells in the presence of VPA using CCK-8, ALP staining, AR staining, and TRAP staining. In vitro experiments reveal that VPA-induced inhibition of osteogenic differentiation and promotion of osteoclastic differentiation are linked to increased inflammation and oxidative stress. Furthermore, MEL has demonstrated the ability to reduce oxidative stress and inflammation, boost osteogenic differentiation, and inhibit osteoclast differentiation. Animal experiments confirm that MEL significantly increases SOD2 expression and decreases TNF-α expression, leading to the restoration of impaired bone metabolism, enhanced bone strength, and higher bone mineral density. The combined experimental results strongly suggest that MEL can enhance osteogenic activity in the presence of VPA by reducing inflammation and oxidative stress, impeding osteoclast differentiation, and alleviating bone loss in VPA-treated rat models.

The role of melatonin in delaying senescence and maintaining quality in postharvest horticultural products.

The postharvest lifespan of horticultural products is closely related to loss of nutritional quality, accompanied by a rapid decline in shelf life, commercial value, and marketability. Melatonin (MT) application not only maintains quality but also delays senescence in horticultural products. This paper reviews biosynthesis and metabolism of endogenous MT, summarizes significant effects of exogenous MT application on postharvest horticultural products, examines regulatory mechanisms of MT-mediated effects, and provides an integrated review for understanding the positive role of MT in senescence delay and quality maintenance. As a multifunctional molecule, MT coordinates other signal molecules, such as ABA, ETH, JA, SA, NO, and Ca2+, to regulate postharvest ripening and senescence. Several metabolic pathways are involved in regulation of MT during postharvest senescence, including synthesis and signal transduction of plant hormones, redox homeostasis, energy metabolism, carbohydrate metabolism, and degradation of pigment and cell wall components. Moreover, MT regulates expression of genes related to plant hormones, antioxidant systems, energy generation, fruit firmness and colour, membrane integrity, and carbohydrate storage. Consequently, MT could become an emerging and eco-friendly preservative to extend shelf life and maintain postharvest quality of horticultural products.

Target of rapamycin coordinates auxin are involved in exogenous melatonin regulated low temperature tolerance in cucumber seedlings

Low temperature (LT) is an important environmental factor affecting the growth and yield of plants. Melatonin (MT) can effectively enhance the LT tolerance of cucumber. This study found that LT stress induced the expression of Comt1 (caffeic acid O-methyltransferase 1), with the highest expression being about 2-times that of the control. Meanwhile, the content of MT was found to be roughly 63.16% of that in the control samples. Compared with LT treatment alone, exogenous MT pretreatment upregulated the expression levels of TOR (Target of rapamycin), PIN1 (Pin-formed 1), and YUC4 (YUCCA 4), with maximum upregulations reaching approximately 66.67%, 79.32%, and 42.86%, respectively. These results suggest that MT may modulate the tolerance of cucumber seedlings to LT stress by regulating the expression of TOR, PIN1, and YUC4. In addition, co-treatment with AZD-8055 (a TOR inhibitor) or NPA (N-1-naphthylphthalamic acid, an auxin polar transport inhibitor) and MT attenuated MT-induced resistance to LT stress, leading to higher levels of reactive oxygen species (ROS), reduced antioxidant defense capacity, and increased damage to the membrane system in cucumber seedlings. Concurrently, the content of osmoregulatory substances and the photosynthesis decreased. These results demonstrate that both TOR and auxin were required for MT to alleviate LT-induced damage in cucumber. In summary, the present study demonstrates that TOR and auxin signaling synergistically contribute to alleviating LT damage in cucumber seedlings by exogenous MT. These findings help us understand the function of MT and provide insights into the regulatory network of MT that regulates the LT tolerance of plants.

Melatonin alleviates brain injury in copper-laden rats: Underlying benefits for Wilson’s disease

Copper serves as an indispensable cofactor for all living organisms, and its excessive accumulation has been associated with a variety of diseases. Wilson’s disease (WD) serves as an illustrative example of copper toxicity in humans, frequently presenting with liver and/or neuropsychiatric symptoms. The current therapeutic drugs, penicillamine (PA) and zinc gluconate (ZnG), have constraints, and research on their combination efficacy remains insufficient. It has been reported that melatonin (MLT) plays a vital role in binding to transition metals and exhibits strong antioxidant capacity. To investigate the therapeutic efficacy of MLT and combined treatment, rats were randomly divided into the following seven groups: the control (Con) group, copper-laden model rat (Mod) group, PA-treated group, ZnG-treated group, MLT- treated group, PA-ZnG-treated group, and PA-MLT-treated group. Then potential mechanisms and targets were investigated using a combination of metabolomics and network pharmacology and verified by molecular docking and qPCR. The findings revealed that MLT and the combination significantly improved behavior, pathology and copper levels in copper-laden rats. The results of the metabolomics study showed that profoundly altered metabolites were identified, and alanine, aspartate and glutamate metabolism, pyruvate metabolism, citrate cycle (TCA cycle), and glycolysis/gluconeogenesis were explored. In addition, molecular docking showed that MLT had high binding affinity with key targets, and qPCR results revealed that MLT could reverse the mRNA expression of targets GOT2 and PKM2. It was concluded that MLT effectively improves brain injury in copper-laden rats, and this effect was linked with the altered features of the metabolite profiles.

Exploring the impact of exogenous melatonin on agro-morphological characteristics, carvacrol, and rosmarinic acid production in Satureja rechingeri Jamzad under drought stress

Satureja rechingeri Jamzad (known as “Jatra” in Persian), which belongs to the Lamiaceae family, is a rich source of essential oil particularly carvacrol, and rosmarinic acid. Drought stress has a detrimental impact on the physiological and biochemical parameters of plants, leading to a decline in plant productivity. Melatonin (MT), a new plant growth regulator found abundantly in plants, has been found to enhance the plant's internal resistance to various environmental stresses. The present study aimed to examine the impact of exogenously applied MT on the agro-morphological, physio-biochemical, and phytochemical traits of S. rechingeri plants cultivated under different levels of drought stress. The results indicated that plants treated with 200 µM MT obtained the highest plant height, length and width of leaf, fresh, dry and drug weight under different drought stress levels. The highest values of relative water content (RWC) (93.5%) and chlorophyll content (15.4 mg/g FW) were recorded by MT 200 µM and 100 µM, respectively, in 100% FC. Drought stress treatments (40, 60, and 80% FC) without foliar spray of MT significantly enhanced the H2O2 content, electrolyte leakage, and malondialdehyde content in leaves, whereas MT treatment under drought stress significantly decreased the above parameters. The lowest H2O2 content (11.5 nmol/g), electrolyte leakage (3.08%), and malondialdehyde content (0.78 µM/g) were obtained by 200 µM MT at 100% FC. In contrast, drought stress treatment increased the total phenol content (TPC), rosmarinic acid (RA), essential oils (EOs) content and yield, and carvacrol. The maximum values of TPC (28.1 mg GAE/g DW), EOs content (3.63%) and yield (0.96%), and carvacrol (95.66%) were achieved by 200 µM MT at 40% FC. The highest RA content (7.43 mg GAE/g DW) was recorded in 100 µM MT at 40% FC. Thus, foliar spray MT has the potential to enhance plant growth through the mitigation of reactive oxygen species (ROS)-induced oxidative harm, as well as the augmentation of photosynthesis pigments, secondary metabolites such as phenolics, EOs levels, overall antioxidant scavenging capacity, and the preservation of RWC during periods of drought stress.Graphical

Alamandin and especially melatonin attenuate pulmonary arterial hypertension induced by monocrotalin.

Despite the available treatments, pulmonary arterial hypertension (PAH) prognosis is poor. We aimed to investigate the effects of the alamandine (ALA), melatonin (MEL), and ALA + MEL in PAH. The rats were randomly divided into Control (n = 10), monocrotaline (MCT) (n = 12), ALA (n = 12), MEL (n = 12), and ALA + MEL (n = 12) groups. PAH was induced by MCT. The ALA, MEL, and ALA + MEL groups received 50 μg/kg/day ALA, 10mg/kg/day MEL, and ALA + MEL, respectively, for 35 days. Echocardiographic and hemodynamic measurements and tissue analyses (morphometric, histopathological, ELISA, and western blot) were performed. Monotherapies, especially MEL, reduced the right ventricular (RV) systolic pressure. Only MEL increased the pulmonary artery acceleration time. MCT increased the RV/left ventricle (LV) + interventricular septum (IVS) ratio. While ALA and ALA + MEL slightly decreased the RV/(LV + IVS), MEL significantly restored it. MCT increased the tunica intima-media (TIM) thickness, PCNA and α-SMA of pulmonary arterioles, histopathological score (HS) (inflammatory infiltration etc.) of the lung, and RV. All treatments reduced the TIM thickness (especially MEL), PCNA, and α-SMA. All treatments significantly decreased the HS of the lung; however, MEL and ALA + MEL produced greater benefits. All treatments attenuated the HS of RV. MCT caused a significant increase in lung lysyl oxidase (LOX) activity. All treatments restored the LOX; however, MEL and ALA + MEL provided greater improvement. While lung Nrf-2 was increased in MCT-treated rats, MEL reduced it. ALA, MEL, and ALA + MEL attenuate PAH and protect RV via antiproliferative, anti-remodeling, antihypertrophic, anti-inflammatory, and free radical scavenging (only MEL) capabilities. Overall, MEL produced the best outcomes.

Melatonin loaded nanostructured lipid carriers for the treatment of uveal melanoma

Uveal melanoma, a highly aggressive intraocular tumor and the second most common form of ocular malignancy, currently lacks effective therapeutic options. Therefore, this study addresses an unmet medical need by developing nanostructured lipid carriers (NLC) as a potential delivery system for melatonin (MEL) to target uveal melanoma. NLC were optimized for ophthalmic administration by the addition of a cationic surfactant to increase mucoadhesivity to the negatively charged ocular surface. MEL-loaded NLC (MEL-NLC) exhibited suitable particle size (<200 nm), good colloidal stability (5 months), and sustained MEL release. In vitro cytotoxicity assays demonstrated antiproliferative activity against uveal melanoma cells while maintaining corneal cell viability, further confirmed by in vitro HET-CAM test and in vivo ocular tolerance studies. Additionally, inflammation studies were performed since inflammation constitutes one of the main hallmarks of cancer development and progression. Consequently, MEL-NLC displayed anti-inflammatory properties. Furthermore, preliminary biodistribution results suggested their ability to reach the posterior segment of the eye, mainly the retina and the ciliary body, positioning them as a promising strategy for uveal melanoma treatment.

Melatonin alleviates palmitic acid-induced mitochondrial dysfunction by reducing oxidative stress and enhancing autophagy in bovine endometrial epithelial cells

BackgroundNegative energy balance (NEB) typically occurs in dairy cows after delivery. Cows with a high yield are more likely to experience significant NEB. This type of metabolic imbalance could cause ketosis, which is often accompanied by a decline in reproductive performance. However, the molecular mechanisms underlying NEB have yet to be fully elucidated. During excessive NEB, the body fat is extensively broken down, resulting in the abnormal accumulation of non-esterified fatty acids (NEFAs), represented by palmitic acid (PA), within the uterus. Such an abnormal accumulation has the potential to damage bovine endometrial epithelial cells (BEECs), while the molecular mechanisms underlying its involvement in the PA-induced injury of BEECs remains poorly understood. Melatonin (MT) is recognized for its regulatory role in maintaining the homeostasis of mitochondrial reactive oxygen species (mitoROS). However, little is known as to whether MT could ameliorate the damage incurred by BEECs in response to PA and the molecular mechanism involved.ResultsAnalysis showed that 0.2 mmol/L PA stress increased the level of cellular and mitochondrial oxidative stress, as indicated by increased reactive oxygen species (ROS) level. In addition, we observed mitochondrial dysfunction, including abnormal mitochondrial structure and respiratory function, along with a reduction in mitochondrial membrane potential and mitochondrial copy number, and the induction of apoptosis. Notably, we also observed the upregulation of autophagy proteins (PINK, Parkin, LC3B and Ubiquitin), however, the P62 protein was also increased. As we expected, 100 μmol/L of MT pre-treatment attenuated PA-induced mitochondrial ROS and restored mitochondrial respiratory function. Meanwhile, MT pretreatment reversed the upregulation of P62 induced by PA and activated the AMPK-mTOR-Beclin-1 pathway, contributing to an increase of autophagy and decline apoptosis.ConclusionsOur findings indicate that PA can induce mitochondrial dysfunction and enhance autophagy in BEECs. In addition, MT is proved to not only reduce mitochondrial oxidative stress but also facilitate the clearance of damaged mitochondria by upregulating autophagy pathways, thereby safeguarding the mitochondrial pool and promoting cellular viability. Our study provides a better understanding of the molecular mechanisms underlying the effect of an excess of NEB on the fertility outcomes of high yielding dairy cows.

Melatonin and copper oxide nanoparticles synergistically mitigate clubroot disease and enhance growth dynamics in Brassica rapa

Clubroot, a devastating soil borne disease affecting 30%∼50% of Brassicaceae crops worldwide, lacks effective control measures. In the present study, we explored the potential of melatonin (MT) and copper oxide nanoparticle (CuO-NPs) in mitigating clubroot severity in the Brassica rapa ssp. pekinensis. Following 18 h priming with MT, CuO-NPs, or both seeds were grown in controlled environment using synthetic potting mix. Inoculated with Plasmodiophora brassicae spores on 5th day, followed by a soil drench phyto-nano treatment with a week interval. Plants were assessed for various health and growth indices including disease, biometrics, photosynthesis, reactive oxygen species (ROS), antioxidant enzyme activity, hormones and genes expression at onset of secondary clubroot infection using established protocols. Statistical analysis employed ANOVA with Fisher's LSD for significance assessment (P < 0.05). Our results revealed that seed priming with both MT (50 μMol/L) and CuO-NPs (200 mg/L), followed by soil drenching significantly reduced clubroot incidence (38%) and disease index (57%), compared to control treatments. This synergistic effect was associated with enhanced plant growth (shoots: 48% and roots: 59%). Plants treated with both MT and CuO-NPs showed robust antioxidant defenses, significantly increased superoxide dismutase (SOD (25/29%)), catalase (CAT (83/55%)), and ascorbate peroxidase (APX (83/46%)) activity in both shoots/roots, respectively, compared to infected control. Notably, salicylic acid and jasmonic acid levels doubled in treated plants, while stress hormone abscisic acid (ABA) decreased by 80% in roots and 21% in shoots. Gene expression analysis corroborated these findings, showing that the combined treatment activated antioxidant defense genes (SOD, APX and CAT) by 1.9–7.2-fold and upregulated hormone signaling genes JAZ1 (7.8-fold), MYC2 (3.9-fold) and SABP2 (36-fold). Conversely, ABA biosynthesis genes (ABA1 and NCED1) were downregulated up to 7.2-fold, while plant resistance genes NPR1, PRB1 and PDF1.2 were dramatically increased by up to 6.3-fold compared to infected plants. Overall, our combined treatment approach significantly reduces clubroot severity in B. rapa via enhanced antioxidant defenses, improved ROS scavenging, coordinated hormonal regulation and increased pathogen response genes. This study offers promising strategy for developing effective control measures against clubroot in susceptible cruciferous crops.

Older adults exercising ON TIME: protocol for a randomized controlled cross-over study to assess the effect of physical activity timing on insomnia severity

BackgroundThere are increased indications that physical activity timing, irrespective of intensity, impacts insomnia and circadian clock function. Here, we describe the rationale and design of a randomized cross-over study, called ON TIME, to examine the effects of (changing) physical activity timing on insomnia severity and on multiple exploratory outcomes that are linked to circadian clock function.MethodsWe will conduct a randomized cross-over trial in 40 healthy older adults (aged 65 to 75 years) with subclinical or clinical insomnia (Insomnia Severity Index (ISI) scores of ≥ 10) from the Dutch municipality of Leiden and surroundings. Participants will undergo 3 intervention periods (14 days each) consecutively: one sedentary period and two periods of increased physical activity (one period with morning activity and one period with evening activity). The intervention periods are separated by a wash-out period of 1 week. In both active intervention arms, participants will follow coached or uncoached outdoor physical exercise sessions comprising endurance, strength, and flexibility exercises for 14 days. The primary outcome is change in insomnia severity as measured by the ISI. Additional exploratory outcomes include multiple components of objective sleep quality measured with tri-axial accelerometry and subjective sleep quality assessed by questionnaires as well as dim light melatonin onset and 24-h rhythms in heart rate, heart rate variability, breathing rate, oxygen saturation, mood, and objective emotional arousal and stress. Additionally, we will collect diary data on eating patterns (timing and composition). Finally, fasting blood samples will be collected at baseline and after each intervention period for measurements of biomarkers of metabolic and physiological functioning and expression of genes involved in regulation of the biological clock.DiscussionWe anticipate that this study will make a significant contribution to the limited knowledge on the effect of physical activity timing. Optimizing physical activity timing has the potential to augment the health benefits of increased physical exercise in the aging population.Trial registrationTrial was approved by the Medical Ethics Committee Leiden, The Hague, Delft, The Netherlands (June, 2023). The trial was registered in the CCMO-register https://www.toetsingonline.nl/to/ccmo_search.nsf/Searchform?OpenForm under study ID NL82335.058.22 and named (“Ouderen op tijd in beweging” or in English “Older adults exercising on time”). At time of manuscript submission, the trial was additionally registered at ClinicalTrials.gov under study ID: NL82335.058.22 and is awaiting approval.