Preclinical efficacy of melatonin to reduce methotrexate-induced oxidative stress and small intestinal damage in rats

Melatonin and oral diseases: possible therapeutic roles based on cellular mechanisms

Oral diseases, including periodontal disorders, oral cancer, periodontitis, and mucositis are the major challenges for both patients and healthcare providers. These conditions often involve inflammation, oxidative stress, and impaired cellular processes, leading to symptoms ranging from discomfort to severe debilitation. Conventional treatments for such oral diseases exhibit constraints, prompting the investigation of innovative therapeutic approaches. Considering the anti-inflammatory, anti-oxidant, and anti-cancer effects of melatonin, this study was carried out to investigate the potential protective effects of melatonin in mitigating the severity of oral diseases. Studies indicate that melatonin influences the differentiation of periodontal stem cells, inhibits oral cancer progression, reduces inflammation associated with periodontitis, and alleviates the severity of oral mucositis. Melatonin has demonstrated potential efficacy in both preclinical and clinical investigations; however, findings are frequently heterogeneous and contingent upon contextual factors. This review provides a comprehensiveoverview of current state of knowledge in this domain, elucidating the multifaceted role that melatonin may assume in combatingoral diseases. Further research should be directed toward determining the most effective dosing, timing, and administration methods for melatonin-based therapies for oral diseases.

Vinpocetine mitigates methotrexate-induced duodenal intoxication by modulating NF-κB, JAK1/STAT-3, and RIPK1/RIPK3/MLKL signals

OBJECTIVES

Methotrexate (MTX) is an antimetabolite agent widely used to manage a variety of tumors and autoimmune diseases. Nonetheless, MTX-induced intestinal intoxication is a serious adverse effect limiting its clinical utility. Inflammation and oxidative stress are possible mechanisms for MTX-induced intestinal toxicity. Vinpocetine (VNP) is a derivative of the alkaloid vincamine with potent anti-inflammatory and antioxidant effects. The current study investigated the protective intestinal impact of VNP in attenuating MTX-induced intestinal intoxication in rats.

MATERIALS AND METHODS

VNP was administered orally in a dose of 20 mg/kg, while MTX was injected intraperitoneal in a dose of 20 mg/kg.

RESULTS

VNP administration attenuated drastic histological changes induced by MTX and preserved both normal villus and crypt histology. VNP significantly attenuated oxidative injury by upregulating intestinal Nrf2 and HO-1 expression. VNP attenuated inflammation by reducing MPO, NO2-, TNF-α, and IL-1β levels mediated by downregulating NF-κB, NDAPH-oxidase, IRF3, p-JAK-1, and p-STAT-3 expressions. Moreover, VNP potently counteracted intestinal necroptosis by effectively downregulating RIPK1, RIPK3, MLKL, and caspase-8 proteins.

CONCLUSION

Therefore, VNP may represent a promising approach that can attenuate intestinal toxicity in patients receiving MTX.

Melatonin reduced colon inflammation but had no effect on energy metabolism in ageing Mongolian gerbils (Meriones unguiculatus)

In photoperiod-sensitive wild animals, the secretion of melatonin (MT) is modulated by external photoperiod, and MT affects inflammation and the ageing process. The beneficial effects of MT in delaying the progress of ageing have been reported in laboratory mice and rats. However, little is known about MT in wild mammals. In the current study, we investigated energy metabolism, microbial community structure and colon homeostasis in ageing Mongolian gerbils (Meriones unguiculatus) through exogenous supplementation of MT to test the hypothesis that MT has beneficial effects on gut homeostasis in ageing gerbils. Exogenous MT supplementation had no effect on energy metabolism in Mongolian gerbils but reduced the levels of circulating tumor necrosis factor-α (TNF-α), immune globulin G (IgG) and corticosterone (CORT). The increase in the level of inflammation in ageing animals was related to changes in the structure and diversity of the gut microbiota. At the genus level, the relative abundance of Prevotella, Treponema, Corynebacterium, and Sphingomonas was increased in ageing animals and decreased significantly by the treatment of MT. Christensenella and Lactobacillus were attenuated in ageing animals, and tended to be enhanced by MT treatment. Functions related to glycosphingolipid biosynthesis-ganglio series and lipopolysaccharide biosynthesis (metabolisms of cofactors, vitamins and glycan) were increased in ageing animals and decreased significantly by the treatment of MT. Our data suggest that a supplement of MT could improve colon homeostasis through changing the composition of gut microbiota and reducing inflammation in ageing gerbils.

Assessment of Oxidative Stress-Induced Oral Epithelial Toxicity

Reactive oxygen species (ROS) are highly reactive molecules generated in living organisms and an excessive production of ROS culminates in oxidative stress and cellular damage. Notably, oxidative stress plays a critical role in the pathogenesis of a number of oral mucosal diseases, including oral mucositis, which remains one of cancer treatments' most common side effects. We have shown previously that oral keratinocytes are remarkably sensitive to oxidative stress, and this may hinder the development and reproducibility of epithelial cell-based models of oral disease. Here, we examined the oxidative stress signatures that parallel oral toxicity by reproducing the initial events taking place during cancer treatment-induced oral mucositis. We used three oral epithelial cell lines (an immortalized normal human oral keratinocyte cell line, OKF6, and malignant oral keratinocytes, H357 and H400), as well as a mouse model of mucositis. The cells were subjected to increasing oxidative stress by incubation with hydrogen peroxide (H2O2) at concentrations of 100 μM up to 1200 μM, for up to 24 h, and ROS production and real-time kinetics of oxidative stress were investigated using fluorescent dye-based probes. Cell viability was assessed using a trypan blue exclusion assay, a fluorescence-based live-dead assay, and a fluorometric cytotoxicity assay (FCA), while morphological changes were analyzed by means of a phase-contrast inverted microscope. Static and dynamic real-time detection of the redox changes in keratinocytes showed a time-dependent increase of ROS production during oxidative stress-induced epithelial injury. The survival rates of oral epithelial cells were significantly affected after exposure to oxidative stress in a dose- and cell line-dependent manner. Values of TC50 of 800 μM, 800 μM, and 400 μM were reported for H400 cells (54.21 ± 9.04, p < 0.01), H357 cells (53.48 ± 4.01, p < 0.01), and OKF6 cells (48.64 ± 3.09, p < 0.01), respectively. Oxidative stress markers (MPO and MDA) were also significantly increased in oral tissues in our dual mouse model of chemotherapy-induced mucositis. In summary, we characterized and validated an oxidative stress model in human oral keratinocytes and identified optimal experimental conditions for the study of oxidative stress-induced oral epithelial toxicity.

Integrative Hematology: State of the Art

Blood cancers are a group of diseases with thus far frequently poor prognosis. Although many new drugs, including target therapies, have been developed in recent years, there is still a need to expand our therapeutic armamentarium to better deal with these diseases. Integrative hematology was conceived as a discipline that enriches the patient's therapeutic possibilities with the use of supplements, vitamins and a nutritional approach aiming at improving the response to therapies and the clinical outcome. We will analyze the substances that have proved most useful in preclinical and clinical studies in some of the most frequent blood diseases or in those where these studies are more numerous; the importance of the nutritional approach and the role of the intestinal microbiota will also be emphasized.

Experimental Chemotherapy-Induced Mucositis: A Scoping Review Guiding the Design of Suitable Preclinical Models

Mucositis is a common and most debilitating complication associated with the cytotoxicity of chemotherapy. The condition affects the entire alimentary canal from the mouth to the anus and has a significant clinical and economic impact. Although oral and intestinal mucositis can occur concurrently in the same individual, these conditions are often studied independently using organ-specific models that do not mimic human disease. Hence, the purpose of this scoping review was to provide a comprehensive yet systematic overview of the animal models that are utilised in the study of chemotherapy-induced mucositis. A search of PubMed/MEDLINE and Scopus databases was conducted to identify all relevant studies. Multiple phases of filtering were conducted, including deduplication, title/abstract screening, full-text screening, and data extraction. Studies were reported according to the updated Preferred Reporting Items for Systematic reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) guidelines. An inter-rater reliability test was conducted using Cohen's Kappa score. After title, abstract, and full-text screening, 251 articles met the inclusion criteria. Seven articles investigated both chemotherapy-induced intestinal and oral mucositis, 198 articles investigated chemotherapy-induced intestinal mucositis, and 46 studies investigated chemotherapy-induced oral mucositis. Among a total of 205 articles on chemotherapy-induced intestinal mucositis, 103 utilised 5-fluorouracil, 34 irinotecan, 16 platinum-based drugs, 33 methotrexate, and 32 other chemotherapeutic agents. Thirteen articles reported the use of a combination of 5-fluorouracil, irinotecan, platinum-based drugs, or methotrexate to induce intestinal mucositis. Among a total of 53 articles on chemotherapy-induced oral mucositis, 50 utilised 5-fluorouracil, 2 irinotecan, 2 methotrexate, 1 topotecan and 1 with other chemotherapeutic drugs. Three articles used a combination of these drugs to induce oral mucositis. Various animal models such as mice, rats, hamsters, piglets, rabbits, and zebrafish were used. The chemotherapeutic agents were introduced at various dosages via three routes of administration. Animals were mainly mice and rats. Unlike intestinal mucositis, most oral mucositis models combined mechanical or chemical irritation with chemotherapy. In conclusion, this extensive assessment of the literature revealed that there was a large variation among studies that reproduce oral and intestinal mucositis in animals. To assist with the design of a suitable preclinical model of chemotherapy-induced alimentary tract mucositis, animal types, routes of administration, dosages, and types of drugs were reported in this study. Further research is required to define an optimal protocol that improves the translatability of findings to humans.

Modulation of Gut Microbiota by Magnesium Isoglycyrrhizinate Mediates Enhancement of Intestinal Barrier Function and Amelioration of Methotrexate-Induced Liver Injury

Background

The gut–liver axis plays a crucial role in various liver diseases. Therefore, targeting this crosstalk may provide a new treatment strategy for liver diseases. However, the exact mechanism underlying this crosstalk and its impact on drug-induced liver injury (DILI) requires clarification.

Aim

This study aimed to investigate the potential mechanism and therapeutic effect of MgIG on MTX-induced liver injury, which is associated with the gut–liver axis and gut microbiota.

Methods

An MTX-induced liver injury model was generated after 20-mg/kg/3d MTX application for 30 days. Meanwhile, the treatment group was treated with 40-mg/kg MgIG daily. Histological examination, aminotransferase, and aspartate aminotransferase enzyme levels were estimated to evaluate liver function. Immune cells infiltration and inflammatory cytokines were detected to indicate inflammation levels. Colon histological score, intestinal barrier leakage, and expression of tight junctions were employed to assess the intestinal injury. Bacterial translocation was observed using fluorescent in situ hybridisation, colony-forming unit counting, and lipopolysaccharide detection. Alterations in gut microbial composition were analysed using 16s rDNA sequencing and relative quantitative polymerase chain reaction. Short-chain-fatty-acids and lactic acid concentrations were then utilized to validate changes in metabolites of specific bacteria. Lactobacillus sp. supplement and fecal microbiota transplantation were used to evaluate gut microbiota contribution.

Results

MTX-induced intestinal and liver injuries were significantly alleviated using MgIG treatment. Bacterial translocation resulting from the intestinal barrier disruption was considered a crucial cause of MTX-induced liver injury and the therapeutic target of MgIG. Moreover, MgIG was speculated to have changed the gut microbial composition by up-regulating probiotic Lactobacillus and down-regulating Muribaculaceae, thereby remodelling the intestinal barrier and inhibiting bacterial translocation.

Conclusion

The MTX-induced intestinal barrier was protected owing to MgIG administration, which reshaped the gut microbial composition and inhibited bacterial translocation into the liver, thus attenuating MTX-related DILI.

The Intestinal Redox System and Its Significance in Chemotherapy-Induced Intestinal Mucositis

Chemotherapy-induced intestinal mucositis (CIM) is a significant dose-limiting adverse reaction brought on by the cancer treatment. Multiple studies reported that reactive oxygen species (ROS) is rapidly produced during the initial stages of chemotherapy, when the drugs elicit direct damage to intestinal mucosal cells, which, in turn, results in necrosis, mitochondrial dysfunction, and ROS production. However, the mechanism behind the intestinal redox system-based induction of intestinal mucosal injury and necrosis of CIM is still undetermined. In this article, we summarized relevant information regarding the intestinal redox system, including the composition and regulation of redox enzymes, ROS generation, and its regulation in the intestine. We innovatively proposed the intestinal redox “Tai Chi” theory and revealed its significance in the pathogenesis of CIM. We also conducted an extensive review of the English language-based literatures involving oxidative stress (OS) and its involvement in the pathological mechanisms of CIM. From the date of inception till July 31, 2021, 51 related articles were selected. Based on our analysis of these articles, only five chemotherapeutic drugs, namely, MTX, 5-FU, cisplatin, CPT-11, and oxaliplatin were shown to trigger the ROS-based pathological mechanisms of CIM. We also discussed the redox system-mediated modulation of CIM pathogenesis via elaboration of the relationship between chemotherapeutic drugs and the redox system. It is our belief that this overview of the intestinal redox system and its role in CIM pathogenesis will greatly enhance research direction and improve CIM management in the future.

Role of IL-6/STAT3 pathway in mediating the protective effect of agomelatine against methotrexate-induced lung/intestinal tissues damage in rats

BACKGROUND

Methotrexate (MTX), an anticancer drug, has been linked to multiple organ toxicity. The drug-induced acute toxic symptoms can negatively affect the patient's commitment to the course of treatment.

MATERIALS AND METHODS

This study aimed to investigate the mitigating action of agomelatine (Ago) against MTX-induced lung and intestinal toxicity. Forty eight male Wister rats were randomized into six experimental groups: Group 1: Control; Groups 2 and 3: received Ago L&H (20/40 mg/kg, respectively by gavage); Group 4: received MTX 10 mg/kg/day, i.p. on days 7-9; Group 5: received Ago L (20 mg/kg) + MTX; Group 6: received Ago H (40 mg/kg) +MTX. The duration of the study was 10 days. Lung/intestine oxidative markers were measured. Lung/intestinal tissues IL-6, STAT3, and HO-1 levels were evaluated by ELISA. Besides, lung/intestinal tissues were examined for Histological changes, collagen fibers detection using Massonꞌs trichome stain, and immunohistochemical study using HSP70 antibody.

RESULTS

MDA, NOx, IL-6, and STAT3 levels were significantly higher in the MTX group's lungs and intestines, indicating lung and intestinal toxicity. There were substantial decreases in GSH, SOD tissue levels, and HSP 70 immunoexpression, as well as histological changes suggesting significant lung and intestinal injury. All of the above parameters improved significantly by using Ago.

CONCLUSION

By reducing oxidative stress, inflammatory processes, and modulating the IL-6/STAT3 pathway, Ago has potent ameliorative effects against MTX-induced lung/intestinal toxicities.

Potential role of melatonin in prevention and treatment of leukaemia

Leukaemia is a haematological malignancy originated from the bone marrow. Studies have shown that shift work could disrupt the melatonin secretion and eventually increase leukaemia incidence risk. Melatonin, a pineal hormone, has shown promising oncostatic properties on a wide range of cancers, including leukaemia. We first reviewed the relationship between shift work and the incidence rate of leukaemia and then discussed the role of melatonin receptors (MT1 and MT2) and their functions in leukaemia. Moreover, the connection between inflammation and leukaemia, and melatonin-induced anti-leukaemia mechanisms including anti-proliferation, apoptosis induction and immunomodulation are comprehensively discussed. Apart from that, the synergistic effects of melatonin with other anticancer compounds are also included. In short, this review article has compiled the evidence of anti-leukaemia properties displayed by melatonin and discuss its potential to act as adjunct for anti-leukaemia treatment. This review may serve as a reference for future studies or experimental research to explore the possibility of melatonin serving as a novel therapeutic agent for leukaemia.

Opportunities and Challenges for Gut Microbiota in Acute Leukemia

Acute leukemia (AL) is a highly heterogeneous hematologic malignancy, and although great progress has been made in the treatment of AL with allogeneic hematopoietic stem cell transplantation (Allo-HSCT) and new targeted drugs, problems such as infection and GVHD in AL treatment are still serious. How to reduce the incidence of AL, improve its prognosis and reduce the side effects of treatment is a crucial issue. The gut microbiota plays an important role in regulating disease progression, pathogen colonization, and immune responses. This article reviews recent advances in the gut microbiota and AL pathogenesis, infection, treatment and its role in allo-HSCT.

Methotrexate Neurotoxicity Is Related to Epigenetic Modification of the Myelination Process

With the improvement of the survival rate of acute lymphoblastic leukemia (ALL) in children, some children ALL survivors reveal inferior intellectual and cognition outcome. Methotrexate (MTX), while serving as an essential component in ALL treatment, has been reported to be related to various neurologic sequelae. Using combined intrathecal (IT) and intraperitoneal (IP) MTX model, we had demonstrated impaired spatial memory function in developing rats, which can be rescued by melatonin treatment. To elucidate the impact of MTX treatment on the epigenetic modifications of the myelination process, we examined the change of neurotrophin and myelination-related transcriptomes in the present study and found combined IT and IP MTX treatment resulted in altered epigenetic modification on the myelination process, mainly in the hippocampus. Further, melatonin can restore the MTX effect through alterations of the epigenetic pathways.

Chemotherapeutics-Induced Intestinal Mucositis: Pathophysiology and Potential Treatment Strategies

The gastrointestinal tract is particularly vulnerable to off-target effects of antineoplastic drugs because intestinal epithelial cells proliferate rapidly and have a complex immunological interaction with gut microbiota. As a result, up to 40-100% of all cancer patients dosed with chemotherapeutics experience gut toxicity, called chemotherapeutics-induced intestinal mucositis (CIM). The condition is associated with histological changes and inflammation in the mucosa arising from stem-cell apoptosis and disturbed cellular renewal and maturation processes. In turn, this results in various pathologies, including ulceration, pain, nausea, diarrhea, and bacterial translocation sepsis. In addition to reducing patient quality-of-life, CIM often leads to dose-reduction and subsequent decrease of anticancer effect. Despite decades of experimental and clinical investigations CIM remains an unsolved clinical issue, and there is a strong consensus that effective strategies are needed for preventing and treating CIM. Recent progress in the understanding of the molecular and functional pathology of CIM had provided many new potential targets and opportunities for treatment. This review presents an overview of the functions and physiology of the healthy intestinal barrier followed by a summary of the pathophysiological mechanisms involved in the development of CIM. Finally, we highlight some pharmacological and microbial interventions that have shown potential. Conclusively, one must accept that to date no single treatment has substantially transformed the clinical management of CIM. We therefore believe that the best chance for success is to use combination treatments. An optimal combination treatment will likely include prophylactics (e.g., antibiotics/probiotics) and drugs that impact the acute phase (e.g., anti-oxidants, apoptosis inhibitors, and anti-inflammatory agents) as well as the recovery phase (e.g., stimulation of proliferation and adaptation).

Beneficial Effects of Melatonin and Atorvastatin on Retinopathy in Streptozocin-induced Diabetic Rats

Objective:

The present study was designed to evaluate the effects of Atorvastatin (ATO) plus Melatonin (MEL) on streptozocin-induced Diabetic Retinopathy (DR) in rats.

Methods:

Diabetes was induced in Wistar rats with an intraperitoneal injection of streptozocin (50 mg/kg). Animals were randomly assigned to one of the following groups (8 rats/group): Control group, Diabetic group, Diabetic + MEL group (20 mg/kg/day), Diabetic + ATO group (10 mg/kg/day), Diabetic + MEL + ATO group (as above). Treatments were started one week after induction of diabetes and continued for 7 weeks. At the end of the experiment, angiography was performed and the rats were killed and retinas were harvested for pathological and molecular examinations.

Results:

Administration of MEL reduced the fluorescein leakage, MDA and ROS levels compared to diabetic group. Treatment with ATO only reduced ROS levels compared to diabetic group. In addition, administration of ATO plus MEL decreased these indices compared to the diabetic and ATO groups. Histologically, retinal vascular congestion was not observed in the combined ATO and MEL group as compared to the diabetic, ATO, and MEL groups.

Conclusion:

These data provide evidence for the therapeutic value of MEL in combination with ATO in clinical practice for prevention of DR.

Protective effect of melatonin against methotrexate-induced testicular damage in the rat model: An experimental study

Background

Methotrexate (MTX) has been shown to affect the testes adversely, especially the seminiferous epithelium. As melatonin, an endocrine hormone, has been shown to normalize testicular function, its ability to prevent MTX-induced testicular damage should be considered.

Objective

Based on the antioxidant, anti-inflammatory, and antiapoptotic activities of melatonin, this study aimed to investigate its protective effect against testicular damage induced by MTX.

Materials and Methods

Forty adult male rats (200-230 g) were divided into five groups (n = 8/each). The rats in group I were injected with vehicle as a control. In group II, the rats were received intraperitoneal injections of melatonin (8 mg/kg) for 15 consecutive days. The rats in group III were intravenously injected with MTX (75 mg/kg) for 15 consecutive days. The remaining two groups received melatonin (8 mg/kgBW) for 15 (group IV) and 30 (group V) consecutive days, intraperitoneally, and then intravenously received MTX (75 mg/kgBW) on days 8 and 15 of the experimental period. Reproductive parameters, including epididymal sperm concentration, testicular tyrosine-phosphorylated protein expression, steroidogenic acute regulatory (StAR) protein expression, and caspase-3 and malondialdehyde levels, were examined.

Results

The sperm concentrations ( × 10 6 /ml) of groups IV (58.75 ± 1.28) and V (55.93 ± 2.57) were improved significantly (p = 0.032) compared with that of group II (32.92 ± 2.14). The seminiferous epithelium in groups IV and V also increased, while caspase-3 expression decreased. In the melatonin-treated groups, the expression of tyrosine-phosphorylated proteins at 32 kDa was decreased and that of proteins at 47 kDa was increased compared with the MTX group. StAR protein expression was not altered in any of the groups.

Conclusion

Our results indicate that melatonin improves the epididymal sperm concentration by decreasing the expression of caspase-3 and increasing that of tyrosine-phosphorylated proteins in MTX-treated testes.

Utilizing Melatonin to Alleviate Side Effects of Chemotherapy: A Potentially Good Partner for Treating Cancer with Ageing

Persistent senescence seems to exert detrimental effects fostering ageing and age-related disorders, such as cancer. Chemotherapy is one of the most valuable treatments for cancer, but its clinical application is limited due to adverse side effects. Melatonin is a potent antioxidant and antiageing molecule, is nontoxic, and enhances the efficacy and reduces the side effects of chemotherapy. In this review, we first summarize the mitochondrial protective role of melatonin in the context of chemotherapeutic drug-induced toxicity. Thereafter, we tabulate the protective actions of melatonin against ageing and the harmful roles induced by chemotherapy and chemotherapeutic agents, including anthracyclines, alkylating agents, platinum, antimetabolites, mitotic inhibitors, and molecular-targeted agents. Finally, we discuss several novel directions for future research in this area. The information compiled in this review will provide a comprehensive reference for the protective activities of melatonin in the context of chemotherapy drug-induced toxicity and will contribute to the design of future studies and increase the potential of melatonin as a therapeutic agent.

Melatonin alleviates oxidative stress in sleep deprived mice: Involvement of small intestinal mucosa injury

BACKGROUND

Previous research demonstrated that sleep deprivation (SD) resulted in intestinal homeostasis disorder in colon. The present study was further performed to clarify the role of melatonin in SD-induced small intestinal (SI) mucosal injury.

METHODS

We successfully established a multiplatform 72 h SD mouse model with or without melatonin supplementation to explore the improvement of melatonin in the destruction of SI induced by SD.

RESULTS

Melatonin supplementation suppressed an increase of corticosterone level and a decrease of melatonin level caused by SD. Meanwhile, we observed that melatonin supplementation in sleep deprived mice markedly reversed a decrease of the villi length/crypt depth (V/C) ratio and the number of goblet cells, PCNA positive cells, the expressions of MUC2 and tight junction proteins, as well as an upregulation of the expressions of autophagic proteins in the duodenum, jejunum and ileum. Furthermore, melatonin supplementation inverted the SD-induced the decline of antioxidant enzyme activities (T-AOC and CAT etc) and anti-inflammatory cytokines (IL-10 and IFN-γ) and the increase of oxidative product MDA, pro-inflammatory cytokines (IL-6 and TNF-α), p-P65 and p-IκB proteins in the SI.

CONCLUSIONS

These findings suggested that melatonin may be used as a probiotic agent to reverse SD-induced SI mucosa injury by suppressing oxidative stress and NF-κB pathway activation.

Role of melatonin in sleep deprivation-induced intestinal barrier dysfunction in mice

Intestinal diseases caused by sleep deprivation (SD) are severe public health threats worldwide. This study focuses on the effect of melatonin on intestinal mucosal injury and microbiota dysbiosis in sleep-deprived mice. Mice subjected to SD had significantly elevated norepinephrine levels and decreased melatonin content in plasma. Consistent with the decrease in melatonin levels, we observed a decrease of antioxidant ability, down-regulation of anti-inflammatory cytokines and up-regulation of pro-inflammatory cytokines in sleep-deprived mice, which resulted in colonic mucosal injury, including a reduced number of goblet cells, proliferating cell nuclear antigen-positive cells, expression of MUC2 and tight junction proteins and elevated expression of ATG5, Beclin1, p-P65 and p-IκB. High-throughput pyrosequencing of 16S rRNA demonstrated that the diversity and richness of the colonic microbiota were decreased in sleep-deprived mice, especially in probiotics, including Akkermansia, Bacteroides and Faecalibacterium. However, the pathogen Aeromonas was markedly increased. By contrast, supplementation with 20 and 40 mg/kg melatonin reversed these SD-induced changes and improved the mucosal injury and dysbiosis of the microbiota in the colon. Our results suggest that the effect of SD on intestinal barrier dysfunction might be an outcome of melatonin suppression rather than a loss of sleep per se. SD-induced intestinal barrier dysfunction involved the suppression of melatonin production and activation of the NF-κB pathway by oxidative stress.

Targeting miR-193a-AML1-ETO-β-catenin axis by melatonin suppresses the self-renewal of leukaemia stem cells in leukaemia with t (8;21) translocation

AML1‐ETO, the most common fusion oncoprotein by t (8;21) in acute myeloid leukaemia (AML), enhances hematopoietic self‐renewal and leukemogenesis. However, currently no specific therapies have been reported for t (8;21) AML patients as AML1‐ETO is still intractable as a pharmacological target. For this purpose, leukaemia cells and AML1‐ETO‐induced murine leukaemia model were used to investigate the degradation of AML1‐ETO by melatonin (MLT), synthesized and secreted by the pineal gland. MLT remarkedly decreased AML1‐ETO protein in leukemic cells. Meanwhile, MLT induced apoptosis, decreased proliferation and reduced colony formation. Furthermore, MLT reduced the expansion of human leukemic cells and extended the overall survival in U937T‐AML1‐ETO‐xenografted NSG mice. Most importantly, MLT reduced the infiltration of leukaemia blasts, decreased the frequency of leukaemia stem cells (LSCs) and prolonged the overall survival in AML1‐ETO‐induced murine leukaemia. Mechanistically, MLT increased the expression of miR‐193a, which inhibited AML1‐ETO expression via targeting its putative binding sites. Furthermore, MLT decreased the expression of β‐catenin, which is required for the self‐renewal of LSC and is the downstream of AML1‐ETO. Thus, MLT presents anti‐self‐renewal of LSC through miR‐193a‐AML1‐ETO‐β‐catenin axis. In conclusion, MLT might be a potential treatment for t (8;21) leukaemia by targeting AML1‐ETO oncoprotein.

Melatonin Alleviates Radiation-Induced Lung Injury via Regulation of miR-30e/NLRP3 Axis

Melatonin is a well-known anti-inflammatory and antioxidant molecule, which plays a crucial role in various physiological functions. In this study, mice received a single dose of 15 Gy radiation delivered to the lungs and daily intraperitoneal administration of melatonin. After 7 days, mice were processed to harvest either bronchoalveolar lavage fluid for cytokine assays or lungs for flow cytometry and histopathological studies. Herein, we showed that melatonin markedly alleviated the oxidative stress and injury, especially suppressing the infiltration of macrophages (CD11b+CD11c−) and neutrophils (CD11b+Ly6G+) to the irradiated lungs. Moreover, in the irradiated RAW 264.7 cells, melatonin blocked the NLRP3 inflammasome activation accompanied with the inhibition of the IL-1β release and caspase-1 activity. However, melatonin restored the downregulated miR-30e levels. Quantitative PCR analysis of miR-30e and NLRP3 indicated the negative correlation between them. Notably, immunofluorescence staining showed that overexpression of miR-30e dramatically diminished the increased NLRP3 expression. Luciferase reporter assay confirmed that NLRP3 was a target gene of miR-30e. Western blotting revealed that transfection with miR-30e mimics markedly reduced the expressions of NLRP3 and cleaved caspase-1, whereas this phenomenon was reversed by the miR-30e inhibitor. Consistent with this, the beneficial effect of melatonin under irradiated exposure was blunted in cells transfected with anti-miR-30e. Collectively, our results demonstrate that the NLRP3 inflammasome contributed to the pathogenesis of radiation-induced lung injury. Meanwhile, melatonin exerted its protective effect through negatively regulating the NLRP3 inflammasome in macrophages. The melatonin-mediated miR-30e/NLRP3 signaling may provide novel therapeutic targets for radiation-induced injury.

Induction and Amelioration of Methotrexate-Induced Gastrointestinal Toxicity are Related to Immune Response and Gut Microbiota

As a widely used anticancer and immunosuppressive agent, methotrexate (MTX) can induce multiple adverse drug reactions (ADRs), such as gastrointestinal toxicity, the mechanisms are poorly understood. Gut microbiota has been widely reported to be associated with the onset of multiple diseases as well as treatment outcomes of different drugs. In this study, mucosal injury was observed in MTX-treated mice, leading to significant changes in macrophages (i.e., M1/M2 ratio, P < 0.05) but not in dendritic cells. Moreover, the population, diversity and principal components of the gut microbiota in mice were dramatically altered after MTX treatment in a time-dependent manner, and Bacteroidales exhibited the most distinct variation among all the taxa (P < 0.05). Bacteroides fragilis was significantly decreased with MTX treatment (P < 0.01) and tended to decrease proportionately with increasing macrophage density. Gavage of mice with B. fragilis ameliorated MTX-induced inflammatory reactions and modulate macrophage polarization. In conclusion, our results delineate a strong impact of the gut microbiota on MTX-induced intestinal mucositis and provide a potential method for the prevention of such ADRs.

Melatonin protects against cisplatin-induced ovarian damage in mice via the MT1 receptor and antioxidant activity

This study evaluated the receptor- and/or antioxidant stress-mediated mechanisms by which melatonin prevents the ovarian toxicity of cisplatin treatment. The expression of the MT1 receptor in mouse ovaries was investigated by immunohistochemistry. Pretreatment with melatonin (5, 10, or 20 mg/kg body weight, i.p.) before cisplatin (5 mg/kg body weight, i.p.) was administered to mice once daily for 3 days (phase I). The pharmacological modulation via melatonin type 1 and/or 2 receptors was analyzed by administration of receptor antagonists (luzindole: nonselective MT1/MT2 antagonist; 5 mg/kg body weight or 4-phenyl-2-propionamidotetralin: selective MT2 antagonist; 4 mg/kg body weight) once daily for 3 days, 15 min before the treatment with melatonin and cisplatin (phase II). Thereafter, the ovaries were harvested and used for histological (morphology and activation), immunohistochemical (PCNA, activated caspase-3 and bcl-2 expression), terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling, and fluorescence (reactive oxygen species [ROS], glutathione [GSH], and active mitochondria levels) analyses. The expression of the MT1 protein in mouse ovaries was documented. Pretreatment with 20 mg/kg melatonin before cisplatin administration preserved the normal follicular morphology and cell proliferation rate, reduced apoptosis, ROS production, mitochondrial damage and increased GSH expression, as compared to the cisplatin treatment alone. Additionally, administration of the nonselective MT1/MT2 receptor antagonist inhibited the melatonin ovarian protection from the cytotoxic effects of cisplatin. However, administration of a selective MT2 antagonist did not modify the protective effects observed at 20 mg/kg melatonin. In conclusion, pretreatment with 20 mg/kg melatonin effectively protected the ovaries against cisplatin-induced damage. Moreover, the MT1 receptor and melatonin antioxidant effects mediated this cytoprotective activity.

Protective effect of melatonin in the diabetic rat retina

Diabetic retinopathy (DR) is one of the most common and serious microvascular complications of diabetes. The aim of this study was to evaluate the effects of melatonin (MEL) on retinal injury in diabetic rats. In this study, 21 rats were randomly divided into three groups: control, diabetic, and diabetic + MEL. Streptozotocin was used to induce diabetes at a dose of 50 mg/kg, i.p., and blood glucose was measured to choose the diabetic rats for the study. MEL (20 mg/kg) was given orally for 7 weeks in diabetic rats starting 1 week after induction of diabetes. After 8 weeks, the groups were compared in terms of mean scores of fluorescein leakage, using fluorescein angiography. Reactive oxygen species (ROS) and malondialdehyde (MDA) levels were estimated in retina using commercially available assays. Structural changes in retinas were evaluated by light microscopy. Results showed that diabetes significantly increased the mean scores of fluorescein leakage, and MDA and ROS levels compared to control group. Treatment of the diabetic rats with MEL for 7 weeks prevented the alterations induced by diabetes in comparison with the diabetic control group.Based on these findings, it can be concluded that MEL might have beneficial effects in prevention of DR.

Melatonin: does it have utility in the treatment of haematological neoplasms?

Melatonin, discovered in 1958 in the bovine pineal tissue, is an indoleamine that modulates circadian rhythms and has a wide variety of other functions. Haematological neoplasms are the leading cause of death in children and adolescents throughout the world. Research has demonstrated that melatonin is a low-toxicity protective molecule against experimental haematological neoplasms, but the mechanisms remain poorly defined. Here, we provide an introduction to haematological neoplasms and melatonin, especially as they relate to the actions of melatonin on haematological carcinogenesis. Secondly, we summarize what is known about the mechanisms of action of melatonin in the haematological system, including its pro-apoptotic, pro-oxidative, anti-proliferative and immunomodulatory actions. Thirdly, we discuss the advantages of melatonin in combination with other drugs against haematological malignancy, as well as its other benefits on the haematological system. Finally, we summarize the findings that are contrary to the suppressive effects of melatonin on cancers of haematological origin. We hope that this information will be helpful in the design of studies related to the therapeutic efficacy of melatonin in haematological neoplasms. LINKED ARTICLES: This article is part of a themed section on Recent Developments in Research of Melatonin and its Potential Therapeutic Applications. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.16/issuetoc.

Effects of nimesulide on the small intestine mucositis induced by methotrexate in rats

Intestinal mucositis is one of the major problems in the patients receiving cancer treatment. Nimesulide is a drug with antioxidant, antiinflammatory and antiulcer features. We aimed to investigate the effect of nimesulide on the small intestine mucositis induced by methotrexate (MTX) in rats. Experimental animals were divided into the control group, MTX group (MTXG) and nimesulide+MTX administered group (NMTXG) with eight rats per group. The control and MTXG groups were given distilled water by gavage and the NMTXG was given nimesulide 100 mg/kg orally. After one hour, the NMTXG and MTXG rat groups were administered oral MTX 5 mg/kg. This procedure was repeated once a day for 15 days and the rats were sacrificed. The duodenum and jejunum of each rat was removed for the assessment of biochemical markers and histopathological evaluation. Malondialdehyde (MDA) and myeloperoxidase (MPO) levels were significantly higher in the duodenal and jejunal tissues of the animals which received MTX, compared to the control and NMTXG (P<0.001). Also, the levels of total glutathione (tGSH), glutathione reductase (GSHRd), glutathione peroxidase (GSHPx), catalase (CAT) and superoxide dismutase (SOD) were significantly lower in the MTXG (P<0.001) compared to other groups. MTX led to villus and crypt epithelial damage and inflammation containing marked PMNL and eosinophils in the intestinal tissues histopathologically. Whereas, there was only mild irregularities in the villus structures of the NMTXG. Nimesulide protected the small intestines against damage by MTX. Intestinal mucositis caused by MTX may be preventable by co-administered nimesulide.

Rutin attenuates intestinal toxicity induced by Methotrexate linked with anti-oxidative and anti-inflammatory effects

BACKGROUND

Methotrexate (MTX) is recognized as an anti-metabolite in cancer chemotherapy and is associated with various toxicities assigned to inflammation and oxidative stress. Rutin has been reported to have significant anti-inflammatory, antioxidant along with antiulcer properties. The present study was undertaken to corroborate the effect of rutin against MTX induced intestinal toxicity in experimental animals.

METHOD

Six groups of rats (n = 6) were dosed with normal saline (3 ml/kg,i.p.); MTX (2.5 mg/kg,i.p.); rutin (50 and 100 mg/kg,i.p.); rutin + MTX (50 mg/kg + 2.5 mg/kg,i.p.); rutin + MTX (100 mg/kg + 2.5 mg/kg,i.p.) for seven consecutive days and sacrificed on eighth day. The intestinal contents were scrutinized physiologically (pH, total acidity, free acidity, CMDI), biochemically (TBARS, protein carbonyl, SOD, catalase and GSH) and for immunoregulatory cytokines (IL-2, IL-4 and IL-10).

RESULTS AND DISCUSSION

The administration of rutin demonstrated significant protection against intestinal lesions damaged by MTX. The treatment with rutin elicited noticeable inhibition of free acidity (26.20%), total acidity (22.05%) and CMDI (1.16%) in the experimental animals similar to control. In MTX treated toxic group, the levels of oxidative markers and immunoregulatory cytokines significantly increased in comparison to control, which was subsequently restored after rutin treatment. Rutin also demonstrated 75.63, 81.00 and 80.43% inhibition of cyclooxygenase-1 and 2, and 15-lipoxygenase respectively.

CONCLUSION

The positive modulation of MTX toxicity could be attributed to the free radical scavenging and anti-inflammatory (dual inhibition of arachidonic acid pathways) potential of rutin.

The effects of lycopene on intestinal injury due to methotrexate in rats

OBJECTIVE

The aim of this study was to investigate the effects of lycopene (Lyc) on methotrexate (Mtx)-induced intestinal damage in rats.

METHOD

Twenty-eight male Sprague Dawley rats were divided into four equal groups: control, Mtx, Lyc, and Mtx-L.

CONTROL GROUP

Rats were given only the vehicle. Lyc group: Rats were given Lyc (10 mg/kg) with corn oil by oral gavage for 10 days. Mtx group: Rats were injected intraperitoneally with a single dose of 20 mg/kg of Mtx and given corn oil by oral gavage. Mtx-L group: Rats were treated with Lyc (10 mg/kg) for 10 days after a single dose of Mtx (20 mg/kg). All of the rats were euthanized using terminal anesthesia, and the intestinal tissues were removed for histological examination and for pro-inflammatory cytokine measurement (tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β)), total oxidative status (TOS), total antioxidant capacity (TAC), and oxidative stress index (OSI).

RESULTS

Mtx administration increased histopathological damage and increased TNF-α, IL-1β, TOS, TAC, and OSI levels in the small intestine tissues. Lyc therapy applied to the Mtx-L group provided significant improvement in all parameters of histopathological damage to the small intestine and significantly reduced the levels of IL-1β, TOS, and OSI in the intestinal tissues.

CONCLUSIONS

The results of this study indicate that Lyc might be useful for protecting intestinal damage induced by Mtx in rats by reducing the increased oxidative stress and pro-inflammatory cytokine (IL-1β) levels.

Protective effect of vitamin E against ethanol-induced small intestine damage in rats

The role of oxidative stress and inflammatory reaction has been reported in various ethanol-induced complications. The purpose of this study was to evaluate the effect of ethanol-induced structural alteration, oxidative stress, and inflammatory reaction on the small intestine of rats, and plausible protective effect of vitamin E to determine whether it inhibits the abnormality induced by ethanol in the small intestine. Twenty-four male wistar rats were divided into three groups, namely: Control, ethanol, and vitamin E treated ethanol groups. After six weeks of treatment, the small intestine length, villus height, crypt depth and muscular layer thickness, oxidative stress, and inflammatory parameters showed significant changes in the ethanol treated group compared to the control group. Vitamin E consumption along with ethanol ameliorated structural alteration of the small intestine and reduced the elevated amount of oxidative stress and inflammatory markers such as protein carbonyl, OX-LDL, IL-6, Hcy, and TNF-α. Furthermore, their total antioxidant capacity was increased significantly compared to that of the ethanol group. These findings indicate that ethanol induces the small intestine abnormality by oxidative and inflammatory stress, and that these effects can be alleviated by using vitamin E as an antioxidant and anti-inflammatory molecule.

Mucoadhesive formulation of Bidens pilosa L. (Asteraceae) reduces intestinal injury from 5-fluorouracil-induced mucositis in mice

Gastrointestinal mucositis induced during cancer treatment is considered a serious dose-limiting side effect of chemotherapy and/or radiotherapy. Frequently, interruption of the cancer treatment due to this pathology leads to a reduction in cure rates, increase of treatment costs and decrease life quality of the patient. Natural products such as Bidens pilosa L. (Asteraceae), represent a potential alternative for the treatment of mucositis given its anti-inflammatory properties. In this study, B. pilosa glycolic extract was formulated (BPF) with poloxamer, a mucoadhesive copolymer, was used for treatment of 5-fluorouracil (5-FU)-induced mucositis in mice. As expected, animals only treated with 5-FU (200 mg/kg) presented marked weight loss, reduction of intestinal villi, crypts and muscular layer, which was associated with severe disruption of crypts, edema, inflammatory infiltrate and vacuolization in the intestinal tissue, as compared to the control group and healthy animals only treated with BPF. On the other hand, the treatment of intestinal mucositis-bearing mice with BPF (75, 100 or 125 mg/kg) managed to mitigate clinical and pathologic changes, noticeably at 100 mg/kg. This dose led to the restoration of intestinal proliferative activity through increasing Ki-67 levels; modulated the expression of Bax, Bcl2 and p53 apoptotic markers protecting intestinal cells from cell death. Moreover, this treatment regulated lipid peroxidation and inflammatory infiltration. No acute toxic effects were observed with this formulation. This work demonstrated that BPF was safe and effective against 5-FU-induced intestinal mucositis in mice. Additional studies are already in progress to further characterize the mechanisms involved in the protective effects of this technological formulation toward the development of a new medicine for the prevention and treatment of intestinal injury in patients undergoing chemotherapy/radiotherapy.

Protective effects of melatonin against oxidative damage induced by Egyptian cobra (Naja haje) crude venom in rats

Naja haje envenomation is one of the leading causes of death due to snakebite. Antiserum therapy sometimes fails to provide enough protection against venom toxicity. In this study, we investigated the protective effects of melatonin against N. haje venom in rats. The animals were injected with venom (0.25mg/kg) and/or melatonin (10mg/kg) and compared with vehicle-treated rats. There was oxidative/nitrosative damage and apoptosis in the liver, heart, and kidneys of venom-injected rats. Melatonin counteracted the increased lipoperoxidation and nitric oxide, prevented decreased glutathione peroxidase and reductase activity, reduced the glutathione disulfide/glutathione (GSSG/GSH) ratio, and maintained the GSH pool. Furthermore, melatonin administration was associated with a reduction of apoptosis, which was increased in venom-injected rats. Overall, these results suggest that melatonin mitigates oxidative/nitrosative stress in venom-induced cardio-hepato-renal injury in rats. Our results suggest that melatonin treatment may ameliorate some of the effects of N. haje envenomation.

Melatonin blunts the mitochondrial/NLRP3 connection and protects against radiation-induced oral mucositis

Mucositis is a common and distressing side effect of chemotherapy or radiotherapy that has potentially severe consequences, and no treatment is available. The purpose of this study was to analyze the molecular pathways involved in the development of oral mucositis and to evaluate whether melatonin can prevent this pathology. The tongue of male Wistar rats was subjected to irradiation (X-ray YXLON Y.Tu 320-D03 irradiator; the animals received a dose of 7.5 Gy/day for 5 days). Rats were treated with 45 mg/day melatonin or vehicle for 21 days postirradiation, either by local application into their mouths (melatonin gel) or by subcutaneous injection. A connection between reactive oxygen species, generating mitochondria and the NLRP3 (NLR-related protein 3 nucleotide-binding domain leucine-rich repeat containing receptor-related protein 3) inflammasome, has been reported in mucositis. Here, we show that mitochondrial oxidative stress, bioenergetic impairment and subsequent NLRP3 inflammasome activation are involved in the development of oral mucositis after irradiation and that melatonin synthesized in the rat tongue is depleted after irradiation. The application of melatonin gel restores physiological melatonin levels in the tongue and prevents mucosal disruption and ulcer formation. Melatonin gel protects the mitochondria from radiation damage and blunts the NF-κB/NLRP3 inflammasome signaling activation in the tongue. Our results suggest new molecular pathways involved in radiotherapy-induced mucositis that are inhibited by topical melatonin application, suggesting a potential preventive therapy for mucositis in patients with cancer.

Mitochondrial dysfunction and respiratory chain defects in a rodent model of methotrexate-induced enteritis

The efficacy of methotrexate (MTX), a widely used chemotherapeutic drug, is limited by its gastrointestinal toxicity and the mechanism of which is not clear. The present study investigates the possible role of mitochondrial damage in MTX-induced enteritis. Small intestinal injury was induced in Wistar rats by the administration of 7 mg kg(-1) body wt. MTX intraperitoneally for 3 consecutive days. MTX administration resulted in severe small intestinal injury and extensive damage to enterocyte mitochondria. Respiratory control ratio, the single most useful and reliable test of mitochondrial function, and 3-(4,5-dimethylthiazol-2-yll)-2,5-diphenyltetrazolium bromide reduction, a measure of cell viability were significantly reduced in all the fractions of MTX-treated rat enterocytes. A massive decrease (nearly 70%) in the activities of complexes II and IV was also observed. The results of the present study suggest that MTX-induced damage to enterocyte mitochondria may play a critical role in enteritis. MTX-induced alteration in mitochondrial structure may cause its dysfunction and decreases the activities of the electron chain complexes. MTX-induced mitochondrial damage can result in reduced adenosine triphosphate synthesis, thereby interfering with nutrient absorption and enterocyte renewal. This derangement may contribute to malabsorption of nutrients, diarrhea, and weight loss seen in patients on MTX chemotherapy.

Lutein protects against methotrexate-induced and reactive oxygen species-mediated apoptotic cell injury of IEC-6 cells

Purpose

High-dose chemotherapy using methotrexate (MTX) frequently induces side effects such as mucositis that leads to intestinal damage and diarrhea. Several natural compounds have been demonstrated of their effectiveness in protecting intestinal epithelial cells from these adverse effects. In this paper, we investigated the protection mechanism of lutein against MTX-induced damage in IEC-6 cells originating from the rat jejunum crypt.

Methods

The cell viability, induced-apoptosis, reactive oxygen species (ROS) generation, and mitochondrial membrane potential in IEC-6 cells under MTX treatment were examined in the presence or absence of lutein. Expression level of Bcl2, Bad and ROS scavenging enzymes (including SOD, catalase and Prdx1) were detected by quantitative RT-PCR.

Results

The cell viability of IEC-6 cells exposed to MTX was decreased in a dose- and time-dependent manner. MTX induces mitochondrial membrane potential loss, ROS generation and caspase 3 activation in IEC-6 cells. The cytotoxicity of MTX was reduced in IEC-6 cells by the 24 h pre-treatment of lutein. We found that pre-treatment of lutein significantly reduces MTX-induced ROS and apoptosis. The expression of SOD was up-regulated by the pre-treatment of lutein in the MTX-treated IEC-6 cells. These results indicated that lutein can protect IEC-6 cells from the chemo-drugs induced damage through increasing ROS scavenging ability.

Conclusion

The MTX-induced apoptosis of IEC-6 cells was shown to be repressed by the pre-treatment of lutein, which may represent a promising adjunct to conventional chemotherapy for preventing intestinal damages.