Melatonin Research Articles

Physio-biochemical mechanism of melatonin seed priming in stimulating growth and drought tolerance in bread wheat

Drought stress (DS) adversely affects a plant’s development and growth by negatively altering the plant’s physio-biochemical functions. Previous investigations have illustrated that seed priming with growth regulators is an accessible, affordable, and effective practice to elevate a plant’s tolerance to drought stress. Melatonin (MT) is derived from the precursor tryptophan and can improve germination, biomass, and photosynthesis under stress conditions. The current study examined the effect of melatonin seed priming on two wheat cultivars (Fakhar-e-Bhakkar and Akber-19) cultivated under severe drought conditions (35% FC). There were 6 levels of melatonin (i.e., M0 = control, M1 = 1 mg L− 1, M2 = 2 mg L− 1, M3 = 3 mg L− 1, M4 = 4 mg L− 1 and M5 = mg L− 1) which were used for seed priming. Our results confirmed that seed priming with M2 = 2 mgL− 1 concentration of MT alleviates the negative effects of DS by boosting the germination rate by 54.84% in Akber-19 and 33.33% in Fakhar-e-Bhakkar. Similarly, leaf-relative water contents were enhanced by 22.38% and 13.28% in Akber-19 and Fakhar-e-Bhakkar, respectively. Melatonin pre-treatment with 2 mgL− 1 significantly enhanced fresh and dry biomass of shoot and root, leaf area, photosynthetic pigments, osmoprotectants accumulation [total soluble proteins (TSP), total free amino acids (TFAA), proline, soluble sugars, glycine betaine (GB)] and lowered the amount of malondialdehyde (MDA) and hydrogen peroxide (H2O2) production by elevating antioxidants [Ascorbic acid, catalase (CAT), Phenolics, peroxidase (POD) and superoxide dismutase (SOD)] activity under drought stress (DS). Meanwhile, under control conditions (NoDS), the melatonin treatment M1 = 1 mgL− 1 effectively enhanced all the growth-related physio-biochemical attributes in both wheat cultivars. In the future, more investigations are suggested on different crops under variable agroclimatic conditions to declare 2 mgL− 1 melatonin as an efficacious amendment to alleviate drought stress.

Integrative transcriptomics and lipidomics unravels the amelioration effects of Radix Bupleuri on non-alcoholic fatty liver disease

Ethnopharmacological relevanceRadix Bupleuri (Bupleurum chinense DC.) is the most commonly used traditional Chinese medicine (TCM) for the treatment of liver diseases. While the effects of Radix Bupleuri (BR) on lipid-lowering and liver protection have been established, its role in the development of non-alcoholic fatty liver disease (NAFLD) induced by a high-fat diet remains unclear. Aim of the studyThe objective of this study was to evaluate the alleviation effects of the active fraction of BR on NAFLD in vivo and to explore the underlying mechanisms through an analysis of liver transcriptome and lipidomics. Materials and methodsThe NAFLD model was established in SD rats by administering a high-fat diet (HFD) for 8 weeks. Subsequently, the NAFLD model rats were continuously gavaged with different polarity fractions of BR (25 g/kg/d) and melatonin (MT) (30 mg/kg/d) for an additional 6 weeks to assess therapeutic effects. The potential mechanism of the low polarity fraction of BR (LBR) in treating NAFLD was investigated through hepatic transcriptome analysis, non-targeted lipidomics, RT-qPCR, protein-protein interaction (PPI) network construction, molecular docking, and Western blotting, aiming to elucidate the underlying mechanisms by which LBR may ameliorate NAFLD. ResultsThese results demonstrated that LBR significantly alleviated the effects of HFD-induced NAFLD, as evidenced by reductions in body weight (BW), liver weight (LW), and epididymal fat weight (EFW) compared to model rats and other polarity fractions of BR. Furthermore, LBR notably down-regulated serum and liver levels of total cholesterol (TC), triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C), while up-regulating high-density lipoprotein cholesterol (HDL-C) in serum. Mechanistically, liver transcriptome analysis indicated that fatty acid metabolism may be a crucial pathway for the improvement of NAFLD following LBR treatment. Lipidomics data suggested that LBR can modulate the metabolic profile in NAFLD rats. Enrichment analysis revealed that glycerophospholipid and glycerolipid metabolism might be key pathways involved in the development of NAFLD. RT-qPCR analysis demonstrated that LBR could regulate the expression of lipid-related genes in these critical pathways. Additionally, Spearman correlation analysis showed a strong relationship between lipid metabolic biomarkers, pathological indices, and lipid-related genes. Moreover, protein-protein interaction (PPI) network and molecular docking analyses identified seven key targets with six ingredients of LBR exhibiting good binding capacity (< -5.0 kcal/mol). Finally, Western blotting analysis indicated that LBR up-regulates the expression levels of PPARα, CPT1, and FABP1 while down-regulating the expression levels of SREBF1 and SCD1, thereby improving metabolism and exerting a lipid-lowering effect. ConclusionIn conclusion, the present research elucidated the lipid-lowering mechanisms of the active fractions of BR. Both BR and LBR presented themselves as promising candidates for the development of novel pharmacological agents targeting NAFLD. LBR effectively ameliorated lipid disturbances associated with HFD-induced NAFLD by modulating the metabolism of fatty acids, cholesterol, glycerolipid, and glycerophospholipids. Consequently, LBR held significant potential for development as an effective lipid-lowering therapeutic.

Porous mesh poly-L-Cysteine and lamellar polynicotinamide-based electrochemical sensor for melatonin detection in milk and tablets

An poly L-Cys/NADH/GCE electrochemical sensor for melatonin (MT) detection was developed by electropolymerising reticulated poly L-cysteine (poly L-Cys) and lamellar poly-nicotinamide adenine dinucleotide (NADH) on a glassy carbon electrode (GCE). The morphology, elemental composition, and elemental states of the fabricated electrochemical sensor were characterized through scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). Additionally, the electrochemical behavior of melatonin on poly L-Cys/NADH/GCE was investigated through electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and differential pulse voltammetry (DPV). The results showed a linear relationship for MT across the concentration range of 0.1 to 1000.0 µmol/L, with linear equations Ip(µA) = 0.0978c(µmol/L) + 0.0981, R2 = 0.9937 (concentration range: 0.1–40.0 µmol/L), and Ip(µA) = 0.0137c(µmol/L) + 5.2741, R2 = 0.9636 (concentration range: 40.0–1000.0 µmol/L). The recoveries in milk samples ranged from 98.71 % to 107.98 %, with relative standard deviations (RSD) for actual tablet samples below 8.60 %. Furthermore, the electro-oxidation sites of MT and its reaction process were deduced by calculating electron orbitals and electron cloud diagrams.

Sustainable poultry practices: integrating green light interventions to control pecking in chicken

BackgroundThe present study aimed to investigate the impact of the light-emitting diode (LED) green light alone or in combination with melatonin on pecking-related hormone regulation during incubation under normal and under hormonal stress conditions in breeder eggs. This study was divided into 2 experiments: In the first experiment effect of LED green light incubation on pecking-related hormones under normal conditions, on Hy-line brown (low pecking phenotype) and Roman pink (high pecking phenotype) eggs were tested. The 296 eggs of each strain were divided into two groups: LED green light incubation and dark incubation (control), each containing four replicates (37 eggs/replicate). The second experiment was conducted to evaluate the effect of LED green light incubation alone or in combination with melatonin under hormonal stress conditions on Roman pink eggs. A total of 704 Roman pink eggs were taken and divided into four groups, each consisting of 176 eggs. Each group was further divided into 2 subgroups, LED green light-regulated incubation and dark incubation with 88 eggs per subgroup, having 4 replicates of 22 eggs each. The groups were as follows: corticosterone solution injection (CI), corticosterone + melatonin mixed solution injection (CMI), Phosphate buffer solution injection (PI), and no injection (UI).ResultsResults of the first experiment revealed a higher level of serotonin hormone and lower corticosterone hormone in Hy-Line brown embryos compared to Roman pink embryos during dark incubation. The LED green light incubation significantly (P < 0.05) increased the level of 5-HT while decreasing the CORT level in Roman pink embryos indicating its regulatory effect on pecking-related hormones. Results of the second experiment showed that LED green light incubation significantly (P < 0.05) alleviated the CORT-induced hyperactivity of plasma 5-HT in Roman pink embryos. Furthermore, Melatonin (MLT) injection and LED green light together significantly (P < 0.05) reduced the hormonal stress caused by corticosterone injection in the eggs.ConclusionsOverall, the LED green light regulatory incubation demonstrated a regulatory effect on hormones that influence pecking habits. Additionally, when coupled with MLT injection, it synergistically mitigated hormonal stress in the embryos. So, LED green light incubation emerged as a novel method to reduce the damaging pecking habits of poultry birds.

Enhancing sweet cherry resilience to spring frost and rain-induced cracking with pre-harvest melatonin treatments

Sweet cherry producers annually confront climatic challenges such as spring frost and fruit cracking. This vulnerability arises primarily from spring frost during bloom or cracking at critical maturity stages during persistent rainfall. With changing climate patterns, innovative strategies are essential to mitigate these adversities. Foliar applications of melatonin (MT) at 0, 0.01, 0.05 and 0.1 mM were tested on the ‘Prime Giant’ and ‘Sweetheart’ cultivars over four different production cycles (2020–2023) to evaluate the effect on frost resilience on flower buds and fruit cracking reduction. MT-treated flower buds showed reduced malondialdehyde content and increased fruit set in most seasons, reducing their vulnerability to extreme weather events. In addition, MT consistently decreased sweet cherry cracking incidence across all studied seasons, indicating a strong effect between the fruit ripening stage and susceptibility to fruit cracking, which was cultivar dependent. Quality parameters at harvest, including fruit firmness, and colour at harvest, were either delayed or unaffected in MT-treated fruits compared with controls. However, other ripening parameters were stimulated by pre-harvest MT applications in several growing cycles, such as total soluble solids, which slightly reduced total acidity in MT-treated fruits. In summary, pre-harvest MT treatments can be a promising strategy for climate change adaptation and stress mitigation, potentially increasing sweet cherry production under extreme weather conditions.

An exploratory pilot study on social rhythm regularity, and its associations with sleep, circadian, affective, and alcohol use outcomes in late adolescents.

The current exploratory pilot study examined whether social rhythm regularity, as measured by a social rhythm metric, was associated with: (1) the regularity of circadian rhythms and/or sleep regularity metrics; and (2) sleep quality, affective function and alcohol use. Late adolescents (18-22 years old) who drink alcohol (n = 36; 61.1% female, Mage = 21.26 years) completed a 14-day ecological momentary assessment protocol, wore a wrist actigraph for 14 days, and completed two overnight visits (Thursday and Sunday) to assess dim light melatonin onset. Sleep regularity metrics included standard deviation, composite phase deviation, social jet lag and inter-daily stability. We used dim light melatonin onset data to calculate the stability of the circadian phase (Sunday minus Thursday). Participants completed surveys and ecological momentary assessments that assessed global and daily sleep quality, affective function, and alcohol use. Correlational analysis and robust regression modelling were used. More regular social rhythms were associated with higher regularities of mid-sleep timing based on standard deviations, but were not associated with other sleep regularity metrics or stability of the circadian phase. More regular social rhythms were associated with better sleep quality, but were not associated with affective function or alcohol use. Social rhythm regularity is a unique construct compared with existing sleep quality metrics. In contrast with the social zeitgeber hypothesis, social rhythm regularity was not associated with circadian rhythm regularity measured by dim light melatonin onset. However, social rhythm regularity may be an under-recognized contributor to better sleep quality.

Programmed cell death and melatonin: A comprehensive review.

Melatonin (MLT), a main product of pineal gland, recently has attracted the attention of scientists due to its benefits in various diseases and also regulation of cellular homeostasis. Its receptor scares widely distributed indicating that it influences numerous organs. Programmed cell death (PCD), of which there several types, is a regulated by highly conserved mechanisms and important for development and function of different organs. Enhancement or inhibition of PCDs could be a useful technique for treatment of different diseases and MLT, due to its direct effects on these pathways, is a good candidate for this strategy. Many studies investigated the role of MLT on PCDs in different diseases and in this review, we summarized some of the most significant studies in this field to provide a better insight into the mechanisms of modulation of PCD by MLT modulation.

Melatonin alleviates high glucose-induced cardiomyocyte injury through suppressing mitochondrial FUNDC1-DRP1 axis.

To use H9c2 cardiomyocytes to establish a diabetic cardiomyopathic model by exposing these cells to high glucose (HG), followed by treating them with melatonin (MEL) or plasmid vectors overexpressing FUN14 Domain Containing 1 (FUNDC1). We employed quantitative real-time PCR, mitochondrial staining, and biochemical assays to measure the activity of various antioxidant and mitochondrial complex functions under various treatment conditions. Our results showed that HG induced the expression of FUNDC1 and increased mitochondrial oxidative stress and fragmentation, while MEL treatment reversed most of these pathological effects. Moreover, HG exposure activated dynamin-related protein 1 expression and its translocation to mitochondria. Modulation of AMP-activated protein kinase level was found to be another pathological hallmark. In silico molecular docking, analysis revealed that MEL could directly bind the catalytic groove of FUNDC1 through Van der Waal's force and hydrogen bonding. Finally, MEL ameliorated diabetic cardiomyopathy-induced mitochondrial injury through FUNDC1 in vivo. Hyperglycemia induced mitochondrial fragmentation and altered electron transport chain complex functions, which could be ameliorated by MEL treatment, suggesting its potential as a cardiovascular therapeutic.

Unlocking the health benefits of melatonin supplementation: A promising preventative and therapeutic strategy.

Melatonin (MLT) is crucial in controlling human sleep-wake patterns. While it has long been recognized for regulating circadian rhythms, its demonstrated efficacy in managing various diseases has recently gained considerable attention. This review discusses MLT's potential preventative and therapeutic effects on various diseases. Several studies have focused on examining the molecular mechanisms through which MLT brings about its protective or therapeutic effects on various diseases, including cancer, obesity, coronavirus, and cardiovascular diseases. Numerous preventative and therapeutic applications of MLT have been proposed, resulting from its ability to function as an antioxidant, anti-cancer, anti-inflammatory, and immune-regulating agent. There is a need for further research to determine MLT's long-term effects on antioxidant defense systems, its preventative and therapeutic benefits, and its molecular basis.

Exogenous Melatonin Alleviates NaCl Injury by Influencing Stomatal Morphology, Photosynthetic Performance, and Antioxidant Balance in Maize.

Maize (Zea mays L.) is sensitive to salt stress, especially during seed germination and seedling morphogenesis, which limits maize growth and productivity formation. As a novel recognized plant hormone, melatonin (MT) participates in multiple growth and developmental processes and mediates biotic/abiotic stress responses, yet the effects of salt stress on maize seedlings remain unclear. Herein, we investigated the effects of 150 μM exogenous MT on multiple phenotypes and physiologic metabolisms in three-leaf seedlings across eight maize inbred lines under 180 mM NaCl salt stress, including growth parameters, stomatal morphology, photosynthetic metabolisms, antioxidant enzyme activities, and reactive oxygen species (ROS). Meanwhile, the six gene expression levels controlling antioxidant enzyme activities and photosynthetic pigment biosynthesis in two materials with contrasting salt resistance were examined for all treatments to explore the possible molecular mechanism of exogenous MT alleviating salt injury in maize. The results showed that 150 μM exogenous MT application protected membrane integrity and reduced ROS accumulation by activating the antioxidant system in leaves of maize seedlings under salt stress, their relative conductivity and H2O2 level average reduced by 20.91% and 17.22%, while the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) averaged increased by 13.90%, 17.02%, 22.00%, and 14.24% relative to salt stress alone. The improvement of stomatal size and the deposition of photosynthetic pigments were more favorable to enhancing photosynthesis in leaves when these seedlings treated with MT application under salt stress, their stomatal size, chlorophyll content, and net photosynthetic rate averaged increased by 11.60%, 19.64%, and 27.62%. Additionally, Gene expression analysis showed that MT stimulation significantly increased the expression of antioxidant enzyme genes (Zm00001d009990, Zm00001d047479, Zm00001d014848, and Zm00001d007234) and photosynthetic pigment biosynthesis genes (Zm00001d011819 and Zm00001d017766) under salt stress. At the same time, 150 μM MT significantly promoted seedling growth and biomass accumulation. In conclusion, our study may unravel crucial evidence of the role of MT in maize seedlings against salt stress, which can provide a novel strategy for improving maize salt stress resistance.

Melatonin protects against defects induced by methoxychlor in porcine oocyte maturation

ABSTRACT Methoxychlor (MXC) is a widely used organochlorine pesticide primarily targeting pests. However, MXC has been found to negatively impact the reproductive system of both humans and animals, triggering oxidative stress and apoptosis. Melatonin (MLT), an endogenous hormone, possesses various benefits, including circadian rhythm regulation and anti-inflammatory and antioxidative stress effects. Moreover, MLT plays a crucial role in the development of animal germ cells and embryos. This study aimed to investigate the impact of MLT on porcine oocytes exposed to MXC. The experimental findings revealed that 200 μM MXC had detrimental effects on the maturation of porcine oocytes. However, the addition of 10−8 M MLT mitigated the toxic effects of MXC. MXC induced oxidative stress in porcine oocytes, leading to an increase in reactive oxygen species and impairing mitochondrial function. Consequently, oocyte quality was affected, resulting in elevated levels of early apoptosis and DNA damage, ultimately negatively impacting subsequent embryonic development. However, the addition of MLT showed the potential to ameliorate the damage caused by MXC. In conclusion, our results suggest that MLT exhibits a protective effect against MXC-induced damage to porcine oocyte maturation.

Melatonin facilitates oocyte growth in goats and mice through increased nutrient reserves and enhanced mitochondrial function.

Oogenesis involves two phases: initial volumetric growth driven by nutrient accumulation and subsequent nuclear maturation. While melatonin (MLT) has been employed as a supplement to enhance the quality of fully grown oocytes during nuclear maturation phase, its impact on oocyte growth remains poorly studied. Here, we provide invivo evidence demonstrating that follicle-stimulating hormone increases MLT content in ovary. Administration of MLT improves oocyte growth and quality in mice and goats by enhancing nutrient reserves and mitochondrial function. Conversely, MLT-deficient mice have smaller oocytes and dysfunctional mitochondria. Exploring the clinical implications of MLT in promoting oocyte growth, we observe that a brief 2-day MLT treatment enhances oocyte quality and reproductive performance in older mice. These findings highlight the role of MLT in regulating oocyte growth and provide a specific treatment window for optimizing oocyte quality and reproductive performance in female animals.

Deciphering the Mechanism of Melatonin-Induced Enhancement of Photosystem II Function in Moderate Drought-Stressed Oregano Plants.

Melatonin (MT) is considered as an antistress molecule that plays a constructive role in the acclimation of plants to both biotic and abiotic stress conditions. In the present study, we assessed the impact of 10 and 100 μM MT foliar spray, on chlorophyll content, and photosystem II (PSII) function, under moderate drought stress, on oregano (Origanum vulgare L.) plants. Our aim was to elucidate the molecular mechanism of MT action on the photosynthetic electron transport process. Foliar spray with 100 μM MT was more effective in mitigating the negative impact of moderate drought stress on PSII function, compared to 10 μM MT. MT foliar spray significantly improved the reduced efficiency of the oxygen-evolving complex (OEC), and PSII photoinhibition (Fv/Fm), which were caused by drought stress. Under moderate drought stress, foliar spray with 100 μM MT, compared with the water sprayed (WA) leaves, increased the non-photochemical quenching (NPQ) by 31%, at the growth irradiance (GI, 205 μmol photons m-2 s-1), and by 13% at a high irradiance (HI, 1000 μmol photons m-2 s-1). However, the lower NPQ increase at HI was demonstrated to be more effective in decreasing the singlet-excited oxygen (1O2) production at HI (-38%), in drought-stressed oregano plants sprayed with 100 μM MT, than the corresponding decrease in 1O2 production at the GI (-20%), both compared with the respective WA-sprayed leaves under moderate drought. The reduced 1O2 production resulted in a significant increase in the quantum yield of PSII photochemistry (ΦPSII), and the electron transport rate (ETR), in moderate drought-stressed plants sprayed with 100 μM MT, compared with WA-sprayed plants, but only at the HI (+27%). Our results suggest that the enhancement of PSII functionality, with 100 μM MT under moderate drought stress, was initiated by the NPQ mechanism, which decreased the 1O2 production and increased the fraction of open PSII reaction centers (qp), resulting in an increased ETR.

Nanostructured electrochemical platform for sensitive detection of melatonin in human serum and tablets

Melatonin (MT) is a crucial hormone for biological rhythms that influences sleep-wake cycles. The therapeutic value of MT in neurological disorders highlights the need for precise detection. However, challenges like low concentrations in biological samples and complex matrix interferences persist, necessitating rapid and precise analytical techniques. This study presents the novelty of designing a novel sensor that combines a molecularly imprinted polymer with polytoluidine blue O (PTBO) and multi-walled carbon nanotubes on a glassy carbon electrode for MT detection and the study of the interaction between MT and the proposed sensor using density functional theory (DFT). DFT showed that MT has a high nucleophilic character and low electrophilicity compared to TBO, which is a strong electrophile. This supports electron transfer from MT to TBO/PTBO, as indicated by the electronic chemical potentials and molecular electrostatic potentials. Scanning electron microscopy was used to see the morphology. Electrochemical measurements using differential pulse voltammetry demonstrated enhanced sensitivity and selectivity. Under optimized conditions, the sensor exhibited a linear response ranging from 1 to 1000 µM with a limit of detection and limit of quantification of 0.027 µM and 0.092 µM respectively. The performance of the sensor was evaluated in pharmaceutical tablets and human serum. Validation experiments confirmed the reliability of the sensor, with recovery rates of 97.5 % for serum and 98.0 % for pharmaceutical tablets, alongside low relative standard deviations indicating good precision. Interference studies showed minimal effects from coexisting substances, highlighting the selectivity of the proposed sensor. Comparative analysis with existing sensors showed superior performance.

Melatonin protects against sarcopenia in middle-aged mice.

Sarcopenia is a common age-related disease. Melatonin (MEL) is an age-related endocrine hormone, which displays a crucial role in resisting oxidative stress during aging. Importantly, the antioxidant properties of MEL can be mediated by mitochondria. Therefore, we wondered whether MEL could mitigate oxidative stress caused by mitochondria in sarcopenia. The middle-aged mice were administered 5 mg/kg/d and 10 mg/kg/d of MEL for 2 months. Young mice were used as the control group. After treatment with MEL, the grip strength of the fore/hind limbs, running time, and distance were elevated, and the weights of the gastrocnemius (GA), tibialis anterior (TA), extensor digitorum longus (EDL), and soleus (SOL) were enhanced in middle-aged mice. Additionally, MEL was observed to alleviate histological damage and increase the cross-sectional area of muscle fibers in GA tissues of middle-aged mice. Furthermore, following MEL treatment, there was an increase in the percentage and size of normal mitochondria as well as mtDNA copy number but a reduction in the levels of malondialdehyde (MDA), protein carbonyl, and reactive oxygen species (ROS) in the GA tissues of middle-aged mice. At the molecular level, MEL repressed the levels of ATROGIN-1, muscle RING-finger protein-1 (MURF-1), and the ratio of p-P38/P38, but elevated the expression of cytochrome c oxidase subunit 4 (COX4), cystatin C (CYTC), nuclear respiratory factor 1 (NRF-1), mitochondrial transcription factor A (TFAM), and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) in the GA tissues of middle-aged mice. Importantly, 10 mg/kg MEL was more efficacious in the treatment of sarcopenia than 5 mg/kg MEL. MEL attenuates sarcopenia in middle-aged mice, and the mechanism may relate to mitochondria-induced oxidative stress and the PGC-1α/TFAM pathway.

Melatonin Induces Analgesic Effects through MT2 Receptor-Mediated Neuroimmune Modulation in the Mice Anterior Cingulate Cortex.

Neuropathic pain (NP) represents a considerable clinical challenge, profoundly impacting patients' quality of life. Presently, pharmacotherapy serves as a primary approach for NP alleviation, yet its efficacy often remains suboptimal. Melatonin (MLT), a biologically active compound secreted by the pineal gland, has long been associated with promoting and maintaining sleep. Although recent studies suggest analgesic effects of MLT, the underlying mechanism remains largely unknown, particularly its impact on the cortex. In this study, we induced an NP model in mice through spared nerve injury (SNI) and observed a considerable, dose-dependent alleviation in NP symptoms following intraperitoneal or anterior cingulate cortex (ACC) administration of MLT. Our findings further indicated that the NP management of MLT is selectively mediated by MLT-related receptor 2 (MT2R), rather than MT1R, on neurons and microglia within the ACC. Transcriptome sequencing, complemented by bioinformatics analysis, implicated MLT in the modulation of Gα(i) and immune-inflammatory signals. Specifically, MLT inhibited the excitability level of pyramidal cells in the ACC by activating the Gα(i) signaling pathway. Simultaneously, MLT attenuated M1 polarization and promoted M2 polarization of microglia, thereby mitigating the inflammatory response and type II interferon response within the ACC. These findings unveil a hitherto unrecognized molecular mechanism: an MLT-mediated neuroimmune modulation pathway in the ACC mediated by MT2R. This elucidation sheds light on the regulatory character of MLT in chronic nociceptive pain conditions, offering a prospective therapeutic strategy for NP management.

Effect of phytohormones on the carbon sequestration performance of CO2 absorption-microalgae conversion system under low light restriction

Microalgae have the potential to fix CO2 into valuable compounds. Low photosynthetic efficiency caused by low light was one of the challenges faced by microalgae carbon sequestration. In this study, Melatonin (MT) and indole-propionic acid (IPA) were used to alleviate the growth inhibition of Spirulina in CAMC system under low light restriction. The results showed that MT and IPA increased biomass and carbon fixation capacity. 10 mg/L IPA group achieved the maximum biomass and carbon fixation capacity, which were 17.11% and 21.46% higher than control. MT and IPA promoted the synthesis of chlorophyll, which in turn captured more light energy for microalgae growth. The increase of superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) activities enhanced the resistance of microalgae to low light stress. MT and IPA promoted the secretion of extracellular polymeric substances (EPS) which was benefit to protect cells. The maximum phycocyanin content and yield was found in 10 mg-IPA group, which was 20.67% and 46.67% higher than control. MT and IPA improved the synthesis of carbohydrates and proteins and increased carbohydrates and proteins yield. This indicated that adding phytohormones was an effective method to alleviate the growth of microalgae restricted by low light stress, which provided a theoretical guidance for the application of CAMC system in CO2 capture and resource utilization.

A comparison of the potential of melatonin and tryptophan to ameliorate CCl4-induced hepatic and renal toxicity in Wistar rats

CCl4 causes oxidative injury, fatty degeneration, fibrosis of the liver, renal failure, and even hepatocellular and renal carcinoma. Certain substances have the potential to neutralize the harmful effects of CCl4, so it will lead to numerous beneficial effects. Melatonin (MEL) is a powerful antioxidant that regulates circadian rhythm and has beneficial effects on organism; tryptophan (TRP) is its precursor necessary for the synthesis of MEL. The aim of the current study was to determine whether MEL and TRP, have protective effects during subchronic application of CCl4 to the liver and kidneys. Results suggest that CCl4 led to decrease of total proteins, albumins, globulins, erythrocytes, hemoglobin, and hematocrit; and increase of creatinine, AST, ALT values, and leukocytes. MEL and TRP both showing protective effects on regulation of serum proteins, albumins, globulins, A/G, AST, ALT, and creatinine levels. TRP had been shown to have potential in regulation of disbalanced hematological parameters caused by CCl4. TRP had beneficial effects on hepatocyte morphology in term of beaded chromatin and preserved cell morphology. Overall, oral supplementation of TRP had better protective effects on liver/kidneys compared to MEL.

The Physiological Mechanism of Exogenous Melatonin on Improving Seed Germination and the Seedling Growth of Red Clover (Trifolium pretense L.) under Salt Stress.

Salt stress can affect various physiological processes in plants, ultimately hindering their growth and development. Melatonin (MT) can effectively resist multiple abiotic stresses, improving plant stress resistance. To analyze the mechanism of exogenous MT to enhance salt tolerance in red clover, we conducted a comprehensive study to examine the influence of exogenous MT on various parameters, including seed germination indices, seedling morphological traits, and physiological and photosynthetic indicators, using four distinct red clover varieties (H1, H2, H3, and H4). This investigation was performed under various salt stress conditions with differing pH values, specifically utilizing NaCl, Na2SO4, NaHCO3, and Na2CO3 as the salt stressors. The results showed that MT solution immersion significantly improved the germination indicators of red clover seeds under salt stress. The foliar spraying of 50 μM and 25 μM MT solution significantly increased SOD activity (21-127%), POD activity, soluble sugar content, proline content (22-117%), chlorophyll content (2-66%), and the net photosynthetic rate. It reduced the MDA content (14-55%) and intercellular CO2 concentration of red clover seedlings under salt stress. Gray correlation analysis and the Mantel test further verified that MT is a key factor in enhancing seed germination and seedling growth of red clover under salt stress; the most significant improvement was observed for NaHCO3 stress. MT is demonstrated to improve the salt tolerance of red clover through a variety of mechanisms, including an increase in antioxidant enzyme activity, osmoregulation ability, and cell membrane stability. Additionally, it improves photosynthetic efficiency and plant architecture, promoting energy production, growth, and optimal resource allocation. These mechanisms function synergistically, enabling red clover to sustain normal growth and development under salt stress.

Exogenous Melatonin Alleviates Osmotic Stress by Enhancing Antioxidant Metabolism, Photosynthetic Maintenance, and Hormone Homeostasis in Forage Oat (Avena sativa) Seedlings

Melatonin (MT) is a multifunctional hormone that enhances crop resilience against various abiotic stresses. However, its regulatory mechanism of osmotic tolerance in forage oats (Avena sativa) plants under water-limited scenarios is still unclear. This study aimed to delineate the impact of MT pretreatment on the morphological, physiological, and biochemical functions of oat seedlings under osmotic stress. Our findings demonstrated that exogenous treatment of MT noticeably elevated leaf area while decreasing the root/shoot ratio of oat seedlings subjected to osmotic stress. Osmotic-induced 38.22% or 48.37% decrease in relative water content could be significantly alleviated by MT pretreatment on day 7 or day 14, respectively. MT treatment also significantly mitigated osmotic-induced decreases in photosynthetic parameters including net photosynthetic rate, stomatic conductance, and intercellular CO2 concentration as well as various chlorophyll fluorescence parameters, which could contribute to enhanced accumulations of free proline and soluble sugars in seedlings after being subjected to a prolonged duration of osmotic stress. Furthermore, MT markedly improved antioxidant enzyme activities including superoxide dismutase, ascorbate peroxidase, catalase, and peroxidase along with the accumulation of ascorbic acid contributing to a significant reduction in reactive oxygen species under osmotic stress. In addition, the MT application induced a 978.12%, 33.54%, or 30.59% increase in endogenous MT, indole acetic acid, or gibberellic acid content under osmotic stress but did not affect the accumulation of abscisic acid. These findings suggest that an optimal concentration of MT (100 μmol·L−1) could relieve osmotic stress via improvement in osmotic adjustment, the enzymatic antioxidant defense system, and endogenous hormonal balance, thereby contributing to enhanced photosynthetic functions and growth of oat seedlings under water-limited conditions.