Therapeutic potential of stem cell and melatonin on the reduction of CCl4-induced liver fibrosis in experimental mice model

Abstract Liver fibrosis is initial stage of any chronic liver disease and its end stage is develops into cirrhosis. Chronic liver diseases are a crucial global health issue and the cause of approximately 2 million deaths per year worldwide. Cirrhosis is currently the 11th most common cause of death globally. Mesenchymal stem cell (MSCs) treatment is the best way to treat acute and chronic liver disease. The aim of this study is to improve the therapeutic potential of MSCs combined with melatonin (MLT) to overcome CCl4-induced liver fibrosis and also investigate the individual impact of melatonin and MSCs against CCl4-induced liver impairment in animal model. Female BALB/c mice were used as CCL4-induced liver fibrotic animal model. Five groups of animal model were made; negative control, Positive control, CCl4+MSCs treated group, CCl4+MLT treated group and CCl4+MSCs+MLT treated group. Cultured MSCs from mice bone marrow were transplanted to CCl4-induced liver injured mice model, individually as well as together with melatonin. Two weeks after MSCs and MLT administration, all groups of mice were sacrificed for examination. Morphological and Histopathological results showed that combined therapy of MSCs+MLT showed substantial beneficial impact on CCl4-induced liver injured model, compared with MSCs and MLT individually. Biochemically, considerable reduction was observed in serum bilirubin and ALT levels of MLT+MSC treated mice, compared to other groups. PCR results shown down-regulation of Bax and up-regulation of Bcl-xl and Albumin, confirm a significant therapeutic effect of MSCs+MLT on CCI4-induced liver fibrosis. From the results, it is concluded that combined therapy of MSCs and MLT show strong therapeutic effect on CCL4-induced liver fibrosis, compared with MSCs and MLT individually.

Resumo A fibrose hepática é a fase inicial de qualquer doença hepática crônica, e em sua fase final desenvolve-se para cirrose. As doenças hepáticas crônicas são uma questão de saúde global crucial e a causa de aproximadamente 2 milhões de mortes por ano em todo o mundo. A cirrose, hoje em dia, é a 11ª causa mais comum de morte globalmente. O tratamento da célula-tronco mesenquimal (MSCs) é uma maneira eletiva de tratar a doença hepática aguda e crônica. O objetivo deste estudo é melhorar o potencial terapêutico dos MSCs combinados com a melatonina (MLT) para superar a fibrose hepática induzida por CCl4 e também investigar o impacto individual da melatonina e MSCs contra o comprometimento do fígado induzido por CCl4 no modelo animal. Os ratos BALB / C fêmeas foram usados como modelo de animal fibrótico de fígado induzido por CCl4. Cinco grupos de modelo animal foram feitos: Controle Negativo, Controle Positivo, CCl4 + MSCs Tratados Grupo, Grupo Tratado CCl4 + MLT e Grupo Tratado CCl4 + MSCs + MLT. MSCs cultivados da medula óssea dos ratos foram transplantados para o modelo de camundongos de fígado induzido por CCl4, individualmente, bem como em conjunto com a melatonina. Duas semanas após a administração MSCs e MLT, todos os grupos de camundongos foram sacrificados para o exame. Os resultados morfológicos e histopatológicos mostraram que a terapia combinada do MSCs + MLT mostrou impacto benéfico substancial no modelo ferido no fígado induzido pelo CCl4, em comparação com o MSCs e o MLT individualmente. A redução bioquimicamente considerável foi observada em bilirrubina sérica e níveis ALT de ratinhos tratados com MLT + MSCs, em comparação com outros grupos. Os resultados de PCR mostraram regulação negativa do BAX e regulação positiva do BCL-XL e da albumina, confirmando um efeito terapêutico significativo do MSCs + MLT na fibrose hepática induzida por CCl4. Dos resultados, conclui-se que a terapia combinada de MSCs e MLT mostram um forte efeito terapêutico na fibrose hepática induzida por CCl4, em comparação com MSCs e MLT individualmente.

Association of polymorphisms of the acetyl-coA acetyltransferase 1 gene and the melatonin receptor 1B gene with the susceptibility to nonalcoholic fatty liver disease / 临床肝胆病杂志

ObjectiveTo investigate the association of the polymorphisms of the acetyl-CoA acetyltransferase 1 （ACAT1） gene and the melatonin receptor 1B （MTNR1B） gene with the susceptibility to nonalcoholic fatty liver disease （NAFLD）. MethodsA total of 164 healthy controls and 228 NAFLD patients were enrolled in this study. PCR and sequencing methods were used to determine the genotypes of the polymorphisms of the ACAT1 gene at the rs1044925 and rs1157651 loci and the MTNR1B gene at the rs10830963 locus， and fasting venous blood samples were collected for biochemical analysis. The t-test was used for comparison of normally distributed continuous data between groups， and the non-parametric Mann-Whitney U test was used for comparison of non-normally distributed continuous data between groups； the chi-square test was used for comparison of categorical data between groups. ResultsThere were no significant differences between the NAFLD group and the healthy control group in the genotype distribution of the ACAT1 gene at the rs1044925 and rs1157651 loci and the MTNR1B gene at the rs10830963 locus （all P>0.05）. The carriers of AA genotype at the rs1044925 locus of the ACAT1 gene had a significantly higher level of low-density lipoprotein than the carriers of C allele （Z=-2.08， P=0.04）， and the carriers of G allele at the rs10830963 locus of the MTNR1B gene had a significantly higher level of fasting blood glucose than the carriers of CC genotype （Z=-3.01， P<0.01）. ConclusionThe polymorphisms of the ACAT1 gene at the rs1044925 and rs1157651 loci and the MTNR1B gene at the rs10830963 locus were not associated with the susceptibility to NAFLD. The rs1044925 locus of the ACAT1 gene and the rs10830963 locus of the MTNR1B gene are associated with the levels of low-density lipoprotein and fasting blood glucose， respectively.

Melatonin inhibits arrhythmias induced by increased late sodium currents in ventricular myocytes / 药学学报

Melatonin (Mel) has been shown to have cardioprotective effects, but its action on ion channels is unclear. In this experiment, we investigated the inhibitory effect of Mel on late sodium currents (INa.L) in mouse ventricular myocytes and the anti-arrhythmic effect at the organ level as well as its mechanism. The whole-cell patch clamp technique was applied to record the ionic currents and action potential (AP) in mouse ventricular myocytes while the electrocardiogram (ECG) and monophasic action potential (MAP) were recorded simultaneously in mouse hearts using a multichannel acquisition and analysis system. The results demonstrated that the half maximal inhibitory concentration (IC50) values of Mel on transient sodium current (INa.T) and specific INa.L opener 2 nmol·L-1 sea anemone toxins II (ATX II) increased INa.L were 686.615 and 7.37 μmol·L-1, respectively. Mel did not affect L-type calcium current (ICa.L), transient outward current (Ito), and AP. In addition, 16 μmol·L-1 Mel shortened ATX II-prolonged action potential duration (APD), suppressed ATX II-induced early afterdepolarizations (EADs), and significantly reduced the incidence of ventricular tachycardia (VT) and ventricular fibrillation (VF) in Langendorff-perfused mouse hearts. In conclusion, Mel exerted its antiarrhythmic effects principally by blocking INa.L, thus providing a significant theoretical basis for new clinical applications of Mel. Animal welfare and experimental process are in accordance with the regulations of the Experimental Animal Ethics Committee of Wuhan University of Science and Technology (2023130).

A rapid and sensitive High-Performance Liquid Chromatography method with fluorescence detection for quantification of melatonin in small volume rat plasma samples: application to a preclinical study to determine the oral pharmacokinetics of melatonin under gestational conditions

Abstract A novel, simple and sensitive high-performance liquid chromatography with fluorescence detection method was developed and validated for the characterization of the preclinical pharmacokinetics of melatonin under pregnant conditions. Plasma samples (25 µL) were treated with 30 µL of ethanol absolute (containing the internal standard, IS). After a centrifugation process, aliquots of supernant (5 µL) were injected into the chromatographic system. Compounds were eluted on a Xbridge C18 (150 mm x 4.6 mm i.d., 5 µm particle size) maintained at 30°C. The mobile phase consisted in a mixture of aqueous solution of 0.4% phosphoric acid and acetonitrile (70:30 v/v). The wavelengths were set at 305 nm (excitation) and 408 nm (emission) and the total analysis time was 8 min/sample. All validation tests were obtained with accuracy and precision, according to FDA guidelines, over the concentration range of 0.005-20 µg/mL. Pharmacokinetic study showed that melatonin systemic exposure increased from day 14, with a significant difference at 19 days of gestation compared to the control group. Our findings suggest a decreased metabolism of melatonin as result of temporary physiological changes that occur throughout pregnancy. However, other maternal physiological changes cannot be ruled out.

Therapeutic potential of stem cell and melatonin on the reduction of CCl4-induced liver fibrosis in experimental mice model / Potencial terapêutico de células-tronco e melatonina na redução da fibrose hepática induzida por CCl4 no modelo de ratos experimentais

Liver fibrosis is initial stage of any chronic liver disease and its end stage is develops into cirrhosis. Chronic liver diseases are a crucial global health issue and the cause of approximately 2 million deaths per year worldwide. Cirrhosis is currently the 11th most common cause of death globally. Mesenchymal stem cell (MSCs) treatment is the best way to treat acute and chronic liver disease. The aim of this study is to improve the therapeutic potential of MSCs combined with melatonin (MLT) to overcome CCl4-induced liver fibrosis and also investigate the individual impact of melatonin and MSCs against CCl4-induced liver impairment in animal model. Female BALB/c mice were used as CCL4-induced liver fibrotic animal model. Five groups of animal model were made; negative control, Positive control, CCl4+MSCs treated group, CCl4+MLT treated group and CCl4+MSCs+MLT treated group. Cultured MSCs from mice bone marrow were transplanted to CCl4-induced liver injured mice model, individually as well as together with melatonin. Two weeks after MSCs and MLT administration, all groups of mice were sacrificed for examination. Morphological and Histopathological results showed that combined therapy of MSCs+MLT showed substantial beneficial impact on CCl4-induced liver injured model, compared with MSCs and MLT individually. Biochemically, considerable reduction was observed in serum bilirubin and ALT levels of MLT+MSC treated mice, compared to other groups. PCR results shown down-regulation of Bax and up-regulation of Bcl-xl and Albumin, confirm a significant therapeutic effect of MSCs+MLT on CCI4-induced liver fibrosis. From the results, it is concluded that combined therapy of MSCs and MLT show strong therapeutic effect on CCL4-induced liver fibrosis, compared with MSCs and MLT individually.

A fibrose hepática é a fase inicial de qualquer doença hepática crônica, e em sua fase final desenvolve-se para cirrose. As doenças hepáticas crônicas são uma questão de saúde global crucial e a causa de aproximadamente 2 milhões de mortes por ano em todo o mundo. A cirrose, hoje em dia, é a 11ª causa mais comum de morte globalmente. O tratamento da célula-tronco mesenquimal (MSCs) é uma maneira eletiva de tratar a doença hepática aguda e crônica. O objetivo deste estudo é melhorar o potencial terapêutico dos MSCs combinados com a melatonina (MLT) para superar a fibrose hepática induzida por CCl4 e também investigar o impacto individual da melatonina e MSCs contra o comprometimento do fígado induzido por CCl4 no modelo animal. Os ratos BALB / C fêmeas foram usados ​​como modelo de animal fibrótico de fígado induzido por CCl4. Cinco grupos de modelo animal foram feitos: Controle Negativo, Controle Positivo, CCl4 + MSCs Tratados Grupo, Grupo Tratado CCl4 + MLT e Grupo Tratado CCl4 + MSCs + MLT. MSCs cultivados da medula óssea dos ratos foram transplantados para o modelo de camundongos de fígado induzido por CCl4, individualmente, bem como em conjunto com a melatonina. Duas semanas após a administração MSCs e MLT, todos os grupos de camundongos foram sacrificados para o exame. Os resultados morfológicos e histopatológicos mostraram que a terapia combinada do MSCs + MLT mostrou impacto benéfico substancial no modelo ferido no fígado induzido pelo CCl4, em comparação com o MSCs e o MLT individualmente. A redução bioquimicamente considerável foi observada em bilirrubina sérica e níveis ALT de ratinhos tratados com MLT + MSCs, em comparação com outros grupos. Os resultados de PCR mostraram regulação negativa do BAX e regulação positiva do BCL-XL e da albumina, confirmando um efeito terapêutico significativo do MSCs + MLT na fibrose hepática induzida por CCl4. Dos resultados, conclui-se que a terapia combinada de MSCs e MLT mostram um forte efeito terapêutico na fibrose hepática induzida por CCl4, em comparação com MSCs e MLT individualmente.

Effect of melatonin on otoprotection in rodents: a systematic review with meta-analysis

Abstract Objectives: To determinate the otoprotective efficacy of melatonin.in experimental models of rodents through a systematic review of the literature. Methods: Altogether, 154 articles were found in four databases. The PICOS strategy (Population, Intervention, Comparison, and Outcome) was used to define the eligibility criteria. Studies that met the inclusion criteria for the second step were included in a qualitative synthesis. Each study type was analyzed with the CAMARADES quality of assessment's checklist and the SYRCLE RoBS risk of bias. Results: Seven articles were selected, and four were included in the meta-analysis. It was possible to obtain seven outcomes according to the standard auditory frequencies presented among the studies, considering a minimum of three standard frequencies. The outcomes analyzed were for the frequencies of 1500, 2000, 3000, 4000, 5000, 6000, and 8000 Hz. Conclusion: Melatonin can provide protection against the ototoxic effects of cisplatin and aminoglycosides at 5000 Hz, 6000 Hz, and 8000 Hz, thereby minimizing the reduction in Otoacustic Emissions (OAE) amplitude. The same effect was not observed in the lower frequencies. Despite the limited number of studies that were evaluated, the results appeared consistent in higher frequencies. However, the methodology of the available studies did not meet the necessary methodological rigor that promotes the safe replicability of these studies.

Maternal obesity and its repercussions on melatonin and cortisol in breast milk and human colostrum

Introduction: scientific evidence has highlighted the role of chronobiological disruptions in promoting obesity through mechanisms involving important circadian rhythm hormones: melatonin and cortisol. These hormones are present in human colostrum and serve as crucial maternal and child protection mechanisms against obesity and childhood infections, owing to the intense interaction between mother and child during pregnancy and breastfeeding. Consequently, the melatonin and cortisol hormones present in human colostrum hold promise as potential candidates for yielding clinically applicable results and supporting future intervention strategies aimed at reducing obesity and neonatal infections. However, there is a scarcity of literature on this subject. Objective: the objective of this study is to to analyze the impact of maternal obesity on the levels and functions of melatonin and cortisol in colostrum and breast milk. Methods: a systematic review of the scientific literature was conducted following the recommendations outlined in the PRISMA protocol. Original articles published in English were searched in the PubMed, Medline, Lilacs, and Scopus databases. There were no restrictions on the publication year. Results: a total of 37 articles were identified from the searched databases. After removing duplicates and applying the inclusion and exclusion criteria, only five studies were relevant to the topic: two studies addressing melatonin and three studies analyzing cortisol. This review revealed that melatonin levels are elevated in the colostrum of obese women, and for this particular group, it has the potential to restore phagocyte activity and increase lymphocyte proliferation. Studies on cortisol have demonstrated that maternal obesity does not alter the levels of this hormone in breast milk. Conclusion: breastfeeding should be encouraged for all populations, and further original research should be conducted to elucidate the protective mechanisms of colostrum and breast milk.

Introdução: evidências científicas enfatizam que disrupções cronobiológicas podem promover a obesidade por mecanismos envolvendo ação de importantes hormônios marcadores do ritmo circadiano: a melatonina e cortisol. Estes hormônios estão presentes no colostro humano e representam importante mecanismo de proteção materno infantil frente à obesidade e infecções infantis, devido à intensa interação entre mãe e filho durante a gravidez e amamentação. Assim, os hormônios melatonina e cortisol presentes no colostro humano representam promissores candidatos para fornecer resultados com capacidade de aplicação clínica e de embasamento de futuras estratégias de intervenção com enfoque na redução da obesidade e de infecções neonatais. Entretanto, são escassos os estudos na literatura sobre o tema. Objetivo: analisar as repercussões da obesidade materna sobre os níveis e as ações da melatonina e do cortisol no colostro e leite materno. Método: foi realizada uma revisão sistematizada da literatura científica seguindo as recomendações do protocolo Prisma. Foram pesquisados artigos originais, publicados em inglês, nas bases de dados PubMed, Medline, Lilacs e Scopus. Não houve restrição quanto ao ano de publicação. Resultados: foram identificados 37 artigos nas bases de dados pesquisados, 15 artigos foram excluídos por estarem duplicados, após aplicação do critério de inclusão e exclusão apenas 5 estudos tiveram relação ao tema, sendo 2 estudos abordando sobre melatonina e 3 pesquisas que analisaram o cortisol. Esta revisão mostrou que a melatonina está elevada em colostro de obesas e para este grupo ela possui potencial de restaurar atividade de fagócitos e de elevar a proliferação de linfócitos. Os estudos sobre o cortisol ilustraram que os níveis deste hormônio no leite materno não foram alterados pela obesidade materna. Conclusão: o aleitamento materno deve ser encorajado para todos os públicos, assim como mais pesquisas originais devem ser desenvolvidas para descrever os mecanismos protetores do colostro e leite materno

Attenuation of hemodynamic responses to laryngoscopy and intubation by pre-operative oral melatonin

Background: Laryngoscopy and endotracheal intubation are usually associated with tachycardia and hypertension. Pre-administration of melatonin has anxiolytic and sedative property which can reduce the tachycardia and hypertension during the surgical procedures. Aims and Objectives: The present study aimed to evaluate the melatonin effect on hemodynamic changes during laryngoscopy and intubation. Materials and Methods: This prospective study was done in the department of anesthesia, Sri Jayadeva Institute of Cardiovascular Sciences and Research, Bengaluru, Karnataka. Total 80 patients were included in the study based on the inclusion and exclusion criteria. Patients were divided into two groups. Group-A treated with placebo and Group-B treated with melatonin (6 mg) and demographic, clinical, and hemodynamic parameters were recorded. The data were analyzed with unpaired t-test with the use SPSS (20.0) version software. Results: Comparison of number and percentage of age, gender, and blood groups between the Group-I and Group-II not showed any significant difference. Group-I and Group-II mean age, height, and weight not showed any significant difference. Mean heart rate, systolic blood pressure, diastolic blood pressure, and mean arterial pressure were compared between the Group-I and Group-II at basal, during, after 1, 3, 5, and 10 min showed significant difference. Conclusion: Pre-administration melatonin showed significant reduction of hemodynamic changes compared to placebo group.

Immunohistochemical evidence of melatonin protection on lung tissue during chemotherapy / Evidencia inmunohistoquímica de la protección de la melatonina en el tejido pulmonar durante la quimioterapia

SUMMARY: The present study investigated the possible protective effects of melatonin on Bleomycin, Cisplatin and etoposide (BEP) chemotherapy regimens using immunohistochemistry. Forty male Wistar rats were divided into four groups of ten as; group 1 as untreated control; group 2 as BEP group which received the three cycles of 21 days' regimen each of 0.5¥ dose levels ofBEP (bleomycin 0.75 mg/kg, etoposide 7.5 mg/kg and cisplatin 1.5 mg/kg). Rats in the group 3 (MEL group) received 10 mg/kg/day melatonin once daily. Group 4 received the melatonin (30 min before the BEP injections) and BEP as in groups 2. Proliferating cell nuclear antigen (PCNA) staining was used to detect cell proliferation and caspase-3, caspase-9 and Caspase-8 were detected to investigate apoptosis. PCNA immunostaining in alveolar epithelium, alveolar macrophages and bronchus was weak to moderate in BEP group. However, diffuse and strong caspase immunoreactions for caspase-3, caspase 8- and caspase-9 were detected in the bronchioles epithelium, vascular endothelium, alveolar luminal macrophages in the BEP group. PCNA and caspase immunoreactivities in MEL and Mel + BEP groups were close to the control one. The surface are in the BEP group was significantly reduced as compared to the control one ((P0.05). It can be concluded that BEP regimen can affects negatively on lung tissue and melatonin inhibits lung tissue injuries during BEP chemotherapy.

El presente estudio investigó los posibles efectos protectores de la melatonina en los regímenes de quimioterapia con bleomicina, etopósido y cisplatino (BEP) mediante inmunohistoquímica. Cuarenta ratas Wistar macho se dividieron en cuatro grupos de diez: grupo 1, control sin tratar; grupo 2, quimioterapia con una dosis de 0,5x de BEP (0,75 mg/kg de bleomicina, 7,5 mg/ kg de etopósido y 1,5 mg/kg de cisplatino) con tres ciclos de 21 días cada uno. Las ratas del grupo 3 (grupo MEL) recibieron 10 mg/kg/día de melatonina una vez al día. El grupo 4 (Mel + BEP) recibió melatonina (30 minutos antes de las inyecciones de BEP) y BEP, como en los grupos 2. Se usó la tinción del antígeno nuclear de células en proliferación (PCNA) para detectar la proliferación celular y, caspasa- 3, caspasa-9 y caspasa-8 para investigar apoptosis. La inmunotinción de PCNA en el epitelio alveolar, los macrófagos alveolares y los bronquios varió de débil a moderada en el grupo BEP. Sin embargo, se detectaron inmunorreacciones difusas y fuertes para caspasa-3, caspasa 8- y caspasa-9 en el epitelio de los bronquiolos, endotelio vascular y macrófagos luminales alveolares. Las inmunorreactividades de PCNA y caspasa en los grupos MEL y Mel + BEP fueron similares a las del control. El área de superficie en el grupo BEP se redujo significativamente en comparación con el control (P0,05). Se puede concluir que la quimioterapia con BEP puede afectar negativamente al tejido pulmonar y la melatonina inhibe las lesiones durante la quimioterapia.

Time-dependent proregenerative effects of exogenous melatonin on the transected sciatic nerve / Efectos proregenerativos dependientes del tiempo de la melatonina exógena en el nervio ciático seccionado

SUMMARY: Microsurgical procedures are the treatment of choice of peripheral nerve injuries, but often fail to reach full functional recovery. Melatonin has neuroprotective actions and might be used as a possible proregenerative pharmacological support. Therefore, the aim of this study was to analyze the time-dependence of the neuroprotective effect of melatonin on the overall fascicular structures of both ends of the transected nerve. Sciatic nerve transection was performed in 34 adult male Wistar rats divided in four groups: two vehicle groups (N=7) treated intraperitoneally for 7 (V7) or 21 (V21) consecutive days with vehicle (5 % ethanol in Ringer solution) and two melatonin groups (N=10) administered intraperitoneally 30 mg/kg of melatonin for 7 (M7) or 21 (M21) consecutive days. At the end of the experiment, proximal stump neuroma and distal stump fibroma were excised and processed for qualitative and quantitative histological analysis. Intrafascicular neural structures were better preserved and the collagen deposition was reduced in the melatonin treated groups than in the vehicle groups. Myelin sheath regeneration observed through its thickness measurement was statistically significantly (p<0,05) more pronounced in the M21 (1,23±0,18 µm) vs. V21 group (0,98±0,13 µm). The mean volume density of the endoneurium was lower in both melatonin treated groups in comparison to the matching vehicle treated groups. Although not statistically different, the endoneural tube diameter was larger in both melatonin groups vs. vehicle groups, and the effect of melatonin was more pronounced after 21 days (24,97 % increase) vs. 7 days of melatonin treatment (18,8 % increase). Melatonin exerts a time-dependent proregenerative effect on nerve fibers in the proximal stump and an anti-scarring effect in both stumps.

Los procedimientos microquirúrgicos son el tratamiento de elección de las lesiones de los nervios periféricos, pero a menudo no logran una recuperación funcional completa. La melatonina tiene acciones neuroprotectoras y podría ser utilizada como un posible apoyo farmacológico proregenerativo. Por lo tanto, el objetivo de este estudio fue analizar la dependencia del tiempo del efecto neuroprotector de la melatonina sobre las estructuras fasciculares generales de ambos extremos del nervio seccionado. La sección del nervio ciático se realizó en 34 ratas Wistar macho adultas divididas en cuatro grupos: dos grupos de vehículo (N=7) tratados por vía intraperitoneal durante 7 (V7) o 21 (V21) días consecutivos con vehículo (5 % de etanol en solución Ringer) y dos grupos grupos de melatonina (N=10) a los que se les administró por vía intraperitoneal 30 mg/kg de melatonina durante 7 (M7) o 21 (M21) días consecutivos. Al final del experimento, se extirparon y procesaron el neuroma del muñón proximal y el fibroma del muñón distal del nervio para un análisis histológico cualitativo y cuantitativo. Las estructuras neurales intrafasciculares se conservaron mejor y el depósito de colágeno se redujo en los grupos tratados con melatonina respecto a los grupos con vehículo. La regeneración de la vaina de mielina observada a través de la medición de su espesor fue estadísticamente significativa (p<0,05) más pronunciada en el grupo M21 (1,23±0,18 µm) vs V21 (0,98±0,13 µm). La densidad de volumen media del endoneuro fue menor en ambos grupos tratados con melatonina en comparación con los grupos tratados con vehículo equivalente. Aunque no fue estadísticamente diferente, el diámetro del tubo endoneural fue mayor en ambos grupos de melatonina frente a los grupos de vehículo, y el efecto de la melatonina fue más pronunciado después de 21 días (aumento del 24,97 %) frente a los 7 días de tratamiento con melatonina (18,8 % de aumento). La melatonina ejerce un efecto proregenerativo dependiente del tiempo sobre las fibras nerviosas del muñón proximal y un efecto anticicatricial en ambos muñones.

Remote ischemic preconditioning-induced late cardioprotection: possible role of melatonin-mitoKATP-H2S signaling pathway

Purpose: Remote ischemic preconditioning (RIPC) confers cardioprotection against ischemia reperfusion (IR) injury. However, the precise mechanisms involved in RIPC-induced cardioprotection are not fully explored. The present study was aimed to identify the role of melatonin in RIPC-induced late cardioprotective effects in rats and to explore the role of H2 S, TNF-α and mitoKATP in melatoninmediated effects in RIPC. Methods: Wistar rats were subjected to RIPC in which hind limb was subjected to four alternate cycles of ischemia and reperfusion of 5 min duration by using a neonatal blood pressure cuff. After 24 h of RIPC or ramelteon-induced pharmacological preconditioning, hearts were isolated and subjected to IR injury on the Langendorff apparatus. Results: RIPC and ramelteon preconditioning protected the hearts from IR injury and it was assessed by a decrease in LDH-1, cTnT and increase in left ventricular developed pressure (LVDP). RIPC increased the melatonin levels (in plasma), H2 S (in heart) and decreased TNF-α levels. The effects of RIPC were abolished in the presence of melatonin receptor blocker (luzindole), ganglionic blocker (hexamethonium) and mitochondrial KATP blocker (5-hydroxydecanoic acid). Conclusion: RIPC produce delayed cardioprotection against IR injury through the activation of neuronal pathway, which may increase the plasma melatonin levels to activate the cardioprotective signaling pathway involving the opening of mitochondrial KATP channels, decrease in TNF-α production and increase in H2 S levels. Ramelteon-induced pharmacological preconditioning may also activate the cardioprotective signaling pathway involving the opening of mitochondrial KATP channels, decrease in TNF-α production and increase in H2 S levels.

Melatonin-Mediated Inhibitory Effect on Hyperimmune Status of Acquired Aplastic Anemia / 中国实验血液学杂志

OBJECTIVE@#To evaluate the expression level of melatonin and its effects on immune function in aplastic anemia (AA) patients.@*METHODS@#The enzyme-linked immunosorbent assay (ELISA) was used to detect the plasma levels of melatonin in AA patients, and the correlation between melatonin levels and laboratory indexs was analyzed. The activation, proliferation, and apoptosis of T cells from AA patients were analyzed by flow cytometry with or without melatonin in vitro.@*RESULTS@#The plasma levels of melatonin in AA patients were significantly lower compared with healthy controls (HC) (12.23 pg/ml vs 20.04 pg/ml, P < 0.01), while the plasma melatonin levels of AA patients in remission group after immunosuppressive therapy (IST) were significantly higher than those in non-remission group (29.16 pg/ml vs 11.73 pg/ml, P =0.04). Moreover, the melatonin levels were positively correlated with platelets (r =0.49), the absolute reticulocyte count (r =0.45), and the percentage of neutrophils (r =0.43). Meanwhile, there was a negative correlation between melatonin levels and the percentages of lymphocytes (r =-0.45). The expressions of CD25 and CD69 in both CD4+ and CD8+ T cells from AA patients were remarkably inhibited by melatonin in vitro (all P < 0.05). When cultured with melatonin, the proliferation rates of both CD4+ and CD8+ T cells from AA patients were markedly suppressed (P =0.01 andP < 0.01).@*CONCLUSION@#The plasma levels of melatonin were decreased in AA patients, which might play an important role in the mechanism of immunological abnormalities. The hyperimmune status of AA patients could be partially ameliorated by melatonin in vitro.

Research research on the use of melatonin in combination with therapeutic hypothermia for the treatment of neonatal hypoxic-ischemic encephalopathy / 中国当代儿科杂志

Neonatal hypoxic-ischemic encephalopathy (HIE) remains one of the leading causes of death and long-term neurodevelopmental disorders in full-term neonates, and there is currently no curative treatment. Therapeutic hypothermia is now a standard therapy for HIE in the neonatal intensive care unit, but its safety and efficacy in remote areas remains unclear. Melatonin is an indole endocrine hormone mainly produced by the pineal gland and it has the ability to easily penetrate the blood-brain barrier. Through receptor and non-receptor mechanisms, melatonin exerts anti-oxidative and anti-inflammatory effects and participates in the regulation of organelle function and the inhibition of cell death. Melatonin is considered one of the most promising drugs for the treatment of HIE based on its reliable safety profile and clinical/preclinical results. This article reviews the recent research on the use of melatonin in combination with therapeutic hypothermia for the treatment of neonatal HIE.

Melatonin promotes osteogenesis of bone marrow mesenchymal stem cells by improving the inflammatory state in ovariectomized rats / 中国修复重建外科杂志

OBJECTIVE@#To investigate the effects of melatonin (MT) on bone mass and serum inflammatory factors in rats received ovariectomy (OVX) and to investigate the effects of MT on the levels of inflammatory factors in culture medium and osteogenic ability of bone marrow mesenchymal stem cells (BMSCs) stimulated by lipopolysaccharide.@*METHODS@#Fifteen 12-week-old Sprague Dawley (SD) rats were randomly divided into 3 groups. The rats in Sham group only received bilateral lateral abdominal incision and suture, the rats in OVX group received bilateral OVX, and the rats in OVX+MT group received 100 mg/(kg·d) MT oral intervention after bilateral OVX. After 8 weeks, the levels of serum inflammatory factors [interleukin-1β (IL-1β), IL-6, and tumor necrosis factor α (TNF-α)] were detected using ELISA assay. Besides, the distal femurs were detected by Micro-CT to observe changes in bone mass and microstructure, and quantitatively measured bone volume fraction, trabecular thickness, and trabecular number. The BMSCs were extracted from the femurs of three 3-week-old SD rats using whole bone marrow culture method and passaged. The 3rd-5th passage BMSCs were cultured with different concentrations of MT (0, 1, 10, 100, 1 000 µmol/L), and the cell viability was then detected using cell counting kit 8 (CCK-8) to select the optimal concentration of MT for subsequent experiments. Cells were devided into osteogenic induction group (group A) and osteogenic induction+1/5/10 μg/mL lipopolysaccharide group (group B-D). The levels of inflammatory factors (IL-1β, IL-6 and TNF-α) in cell culture medium were detected using ELISA assay after corresponding intervention. According to the results of CCK-8 method and ELISA detection, the cells were intervened with the most significant concentration of lipopolysaccharide for stimulating inflammation and the optimal concentration of MT with osteogenic induction, defining as group E, and the cell culture medium was collected to detect the levels of inflammatory factors by ELISA assay. After that, alkaline phosphatase (ALP) staining and alizarin red staining were performed respectively in groups A, D, and E, and the expression levels of osteogenic related genes [collagen type Ⅰ alpha 1 chain (Col1a1) and RUNX family transcription factor 2 (Runx2)] were also detected by real time fluorescence quantitative PCR (RT-qPCR).@*RESULTS@#ELISA and Micro-CT assays showed that compared with Sham group, the bone mass of the rats in the OVX group significantly decreased, and the expression levels of serum inflammatory factors (IL-1β, IL-6, and TNF-α) in OVX group significantly increased (P<0.05). Significantly, the above indicators in OVX+MT group were all improved (P<0.05). Rat BMSCs were successfully extracted, and CCK-8 assay showed that 100 µmol/L was the maximum concentration of MT that did not cause a decrease in cell viability, and it was used in subsequent experiments. ELISA assays showed that compared with group A, the expression levels of inflammatory factors (IL-1β, IL-6, and TNF-α) in the cell culture medium of groups B-D were significantly increased after lipopolysaccharide stimulation (P<0.05), and in a concentration-dependent manner. Moreover, the expression levels of inflammatory factors in group D were significantly higher than those in groups B and C (P<0.05). After MT intervention, the expression levels of inflammatory factors in group E were significantly lower than those in group D (P<0.05). ALP staining, alizarin red staining, and RT-qPCR assays showed that compared with group A, the percentage of positive area of ALP and alizarin red and the relative mRNA expressions of Col1a1 and Runx2 in group D significantly decreased, while the above indicators in group E significantly improved after MT intervention (P<0.05).@*CONCLUSION@#MT may affect the bone mass of postmenopausal osteoporosis by reducing inflammation in rats; MT can reduce the inflammation of BMSCs stimulated by lipopolysaccharide and weaken its inhibition of osteogenic differentiation of BMSCs.

Melatonin attenuates bone resorption induced by acute sleep deprivation in growing rats / 中华内分泌代谢杂志

Objective:To explore the changes of bone turnover markers induced by sleep deprivation (SD) and the effect of melatonin supplementation on the bone turnover status.Methods:Six-week-old Wistar male rats were divided into SD, normal control (NC), and melatonin supplementation (SD+ MT) groups. Acute SD model was established using a modified multi-level bench method. The bone turnover markers, corticosterone, and melatonin in serum as well as Cathepsin K(CTSK) mRNA expression in bone tissue were tested.Results:Acute SD disrupted the balance between bone formation and bone absorption evidenced by rapid decreased serum procollagen type Ⅰ N-terminal propeptide (PⅠNP) levels and increased β cross-linked C-telopeptide of type Ⅰ collagen (β-CTX) levels ( P=0.003) from 24 h to 72 h. The exogenous melatonin treatment decreased β-CTX [(512.4±95.8) ng/mL vs (696.0±76.5) ng/mL, P=0.004] and the osteoclast-related gene CTSK mRNA level after 72 h SD. Conclusions:Acute SD accelerates bone resorption, which could be partially alleviated by melatonin supplementation.

Analysis of whole genome expression profile for the effect of melatonin on radiation-induced intestinal injury in mice / 中华放射医学与防护杂志

Objective:To elucidate the change of whole genome expression profile for the effect of melatonin on radiation-induced intestinal injury in mice.Methods:C57BL/6J male mice were administrated with melatonin at 10 mg/kg body weight by intraperitoneal injection once a day for five consecutive days before abdominal irradiation with 14 Gy of γ-rays. Small intestines were harvested 3 d after radiation. GO annotation and KEGG pathway of the differential genes involved in small intestine were explored by DNA microarray analysis.Results:Compared with the control group, 584 differential genes were up-regulated and 538 differential genes were down-regulated for administration group pre-irradiation. The overlapping differential genes were selected from the irradiated mice and the administrated mice pre-irradiation. There were 324 up-regulated genes and 246 down-regulated genes unique to the administrated mice pre-irradiation. GO annotation analysis of the differential genes indicated that the top 15 significantly enriched biological processes for the administrated mice pre-irradiation mainly included autophagosome assembly (GO: 0000045), autophagosome organization (GO: 1905037) and regulation of acute inflammatory response (GO: 0002673). The genes ATG12, ATG16L2 and AMBRA1 were involved in autophagosome assembly and autophagosome organization. The genes C3, CPN1, CD55, CFP, CNR1, C1QA, C2 and CREB3L3 were involved in the regulation of acute inflammation response. KEGG pathway analysis of the differential genes involved indicated that the top 15 significantly enriched pathways for the administrated mice pre-irradiation mainly included O-glycan biosynthesis (hsa00512), glycosphingolipid biosynthesis (hsa00603), ECM-receptor interaction (hsa04512) and biosynthesis of unsaturated fatty acids (hsa01040). qRT-PCR verification showed that the expressions of ATG12 and ATG16L2 genes involved in autophagy for the administrated mice pre-irradiation increased significantly compared with the irradiated mice ( t=2.40, 4.35, P<0.05). Conclusions:The differential genes related with the biological process of autophagy, acute inflammatory response and the pathway of unsaturated fatty acid biosynthesis might be involved in the effect of melatonin on radiation-induced intestinal injury.

Protective effect of remote ischemic preconditioning combined with melatonin against cerebral reperfusion injury in rats and the value of multimodal MRI in evaluating the efficacy / 中华放射学杂志

Objective:To explore the possible mechanisms of remote ischemic preconditioning (RIPC) combined with melatonin (MT) against cerebral ischemia-reperfusion injury and to evaluate the value of multimodal MRI.Methods:From December 2021 to December 2022, fifty SPF-grade male SD rats were selected and divided into sham surgery group ( n=10), middle cerebral artery occlusion model group ( n=10), melatonin (MT) group ( n=10), remote ischemic preconditioning (RIPC) group ( n=10) and MT+RIPC group ( n=10). Neurological function scoring and multimodal MRI examinations, including T 2 fluid-attenuated inversion recovery (FLAIR) imaging, diffusion-weighted imaging (DWI), and arterial spin labeling (ASL) imaging, were performed on rats after surgery. After the scans, the rats were euthanized. The brain tissues of 3 rats in each group were randomly selected for HE staining and immunohistochemical staining to observe the pathological morphology of brain tissues and to validate the expression of nuclear factor-E2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1). The remaining 6 rats were used for enzyme-linked immunosorbent assay to detect levels of interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in brain infarction tissues. ANOVA test or Kruskal-Wallis H test was performed to compare the differences between groups. Results:There were statistically significant differences in neurological function scores and brain infarct volumes among the five groups ( P<0.001). Compared with the sham surgery group, the rats′ neurological function scores and brain infarct volumes were increased in the model group, RIPC group, MT group, and MT+RIPC group ( P<0.05); While compared with the model group, the rats′ neurological function scores and brain infarct volumes were decreased in the RIPC group, MT group, and MT+RIPC group ( P<0.05). MRI showed that abnormal signals were observed on the lesion hemisphere on the right side in rats of the four groups except for the sham surgery group. The lesions showed high signal on T 2 FLAIR and DWI, low signal on apparent diffusion coefficient map, and low perfusion on cerebral blood flow map. Pathological examination showed neuronal nuclear shrinkage in the necrotic area of the brain tissue in the model group, with surrounding neurons exhibiting edema and degeneration. In the RIPC and MT groups, edema and degeneration of neural cells around the infarction area were reduced, while the MT+RIPC group showed primarily neuronal edema with overall structural preservation. The range of Nrf2 and HO-1 protein positivity was significantly increased in the MT+RIPC group compared with the model group. The overall differences in IL-1β, TNF-α and IL-6 levels of 5 groups were statistically significant ( P<0.05), in which IL-1β, TNF-α and IL-6 levels in the model group, RIPC group, MT group, and MT+RIPC group increased compared with the sham-operated group ( P<0.05), and IL-1β, TNF-α, and IL-6 levels decreased in the RIPC group, MT group, and MT+RIPC group compared with the model group ( P<0.05). Conclusion:RIPC+MT exerts antioxidant effects through Nrf2/HO-1 pathway and also exhibits anti-inflammatory properties by reducing levels of IL-1β, IL-6, and TNF-α, thereby alleviating brain edema and neuronal damage, reducing infarct volume and improving neurological deficits in rats with cerebral artery occlusion. The multimodal MRI evaluation demonstrates the value of RIPC+MT in protecting against cerebral ischemia-reperfusion injury.

The protective effects and mechanisms of melatonin on white matter damage in neonatal rats / 中国新生儿科杂志

Objective:To study the protective effects and mechanisms of melatonin (MTn) on lipopolysaccharide (LPS) and hypoxic-ischemic(HI) induced white matter damage (WMD) in neonatal rats.Methods:Seventy-two 3-day-old newborn Sprague-Dawley (SD) rats were randomly assigned into sham operation group (the sham group), model group (the HI group) and MTn intervention group (the HI+MTn group) ( n=24 for each group). For the sham group, only dissection of the right common carotid artery was performed without ligation. Animal models of WMD were established using LPS pretreatment and HI method in both the HI group and HI+MTn group. The HI+MTn group received MTn intraperitoneal injection (15 mg/kg, 1 h before LPS injection and then once daily). The HI group and the sham group received equal volume of normal saline containing 1% ethanol intraperitoneal injection. The rats were sacrificed on d7 of experiment and periventricular white matter (PVWM) was collected for hematoxylin-eosin (HE) and TUNEL staining to determine WMD and apoptosis. The distribution and morphology of microglial cells in the PVWM were studied using IBA1 immunofluorescence staining. Reactive oxygen species (ROS) kit was used to detect ROS. The expression of nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasomes, interleukin (IL)-1β, IL-18 and mitochondrial autophagy markers (pink1 and parkin) were determined using real-time quantitative PCR. Results:Compared with the sham group, the HI group showed WMD, cell degeneration and necrosis,increased cell apoptosis and increased expressions of NLRP3 inflammasomes and downstream inflammatory factors (IL-1β and IL-18) in PVWM. Compared with the HI group,the HI+MTn group showed reduced WMD, cell apoptosis, microglia infiltration and inflammatory factors expression. MTn increased pink1 and parkin expression and reduced ROS production in PVWM.Conclusions:MTn reduces ROS production by enhancing mitochondrial autophagy and inhibits NLRP3 inflammasomes hyperactivation to alleviate endotoxin- and HI-induced WMD in neonatal rats.

Breastfeeding and infant sleep:a review / 中国实用护理杂志

Sufficient and organized sleep is a key factor during the developmental process of infancy while disrupted sleep schedule and diseases might lead to sleeping disorders in infants. Breastfeeding is considered to be the most beneficial way to meet the nutritional needs of infants for optimal growth and development. The α-lactalbumin-tryptophan-melatonin axis, nucleotides, and other factors are breast milk components that may affect infant sleep. Meanwhile, diet, feeding schedule, tobacco smoking, alcohol intake, and caffeine consumption will affect the circadian rhythms which might lead to the fluctuations of sleep-influencing factors in breast milk. This study reviews literature of previous studies on this topic to summarize information that can be considered for both breastfeeding practice and future basic research on the establishment of organized sleep patterns in infants.

Mechanism of melatonin regulation of PI3K/Akt/mTOR signaling in hypothalamus delaying the initiation of puberty in female mice / 解剖学报

Objective To explore the effect of melatonin ( MLT) on the initiation of puberty in female mice and on the expression level of phosphatidylinositol-3-kinases ( PI3K)/protein kinase B ( Akt)/mammalian target of rapamycin (mTOR) signaling pathway in the frypothalamus. Methods Seventy-eight 20-day-old female KM mice were randomly divided into melatonin (MLT) group and normal saline (NS) group, with 39 mice in each group. Starting at 22 days of age, the MLT group was given a subcutaneous injection of 1 mg/kg melatonin and the NS group was given an equal volume of saline. Thirty-two days of age were selected as the sampling point before puberty initiation and 13 mice were executed in each of the two groups, while 37 and 42 days of age were selected as the sampling point after puberty initiation and 13 mice were executed in each of the two groups. Observation of vaginal opening time in mice, weighing of ovaries and uterus to calculate organ indices. HE staining to observe the number of ovarian corpora lutea. The levels of serum luteinizing hormone (LH)were determined by ELISA. The mRNA and protein expression levels of PI3K/Akt/mTOR pathway in frypothalamus were detected by Real-time PCR and Western blotting. Results Compared with the normal saline group, mice in the melatonin group had significantly delayed vaginal opening time ( P < 0. 05 ) , decreased significantly ovarian and uterine volume and index (P<0. 05) , decreased significantly serum LH levels (P<0. 05) , and decreased significantly mRNA and protein expression levels of the frypothalamic PI3K/Akt/mTOR pathway (P<0. 05). Conclusion Melatonin delays puberty initiation in mice by a mechanism that ma)' be related to inhibition of the hypothalamic PI3K/Akt/mTOR signalling pathway.