Anti-Inflammatory Effects of Melatonin in Rats with Induced Type 2 Diabetes Mellitus

Modulation of neural circuits by melatonin in neurodegenerative and neuropsychiatric disorders

Neurodegenerative and neuropsychiatric disorders are two broad categories of neurological disorders characterized by progressive impairments in movement and cognitive functions within the central and peripheral nervous systems, and have emerged as a significant cause of mortality. Oxidative stress, neuroinflammation, and neurotransmitter imbalances are recognized as prominent pathogenic factors contributing to cognitive deficits and neurobehavioral anomalies. Consequently, preventing neurodegenerative and neuropsychiatric diseases has surfaced as a pivotal challenge in contemporary public health. This review explores the investigation of neurodegenerative and neuropsychiatric disorders using both synthetic and natural bioactive compounds. A central focus lies on melatonin, a neuroregulatory hormone secreted by the pineal gland in response to light-dark cycles. Melatonin, an amphiphilic molecule, assumes multifaceted roles, including scavenging free radicals, modulating energy metabolism, and synchronizing circadian rhythms. Noteworthy for its robust antioxidant and antiapoptotic properties, melatonin exhibits diverse neuroprotective effects. The inherent attributes of melatonin position it as a potential key player in the pathophysiology of neurological disorders. Preclinical and clinical studies have demonstrated melatonin's efficacy in alleviating neuropathological symptoms across neurodegenerative and neuropsychiatric conditions (depression, schizophrenia, bipolar disorder, and autism spectrum disorder). The documented neuroprotective prowess of melatonin introduces novel therapeutic avenues for addressing neurodegenerative and psychiatric disorders. This comprehensive review encompasses many of melatonin's applications in treating diverse brain disorders. Despite the strides made, realizing melatonin's full neuroprotective potential necessitates further rigorous clinical investigations. By unravelling the extended neuroprotective benefits of melatonin, future studies promise to deepen our understanding and augment the therapeutic implications against neurological deficits.

Unraveling the complex roles of macrophages in obese adipose tissue: an overview

Macrophages, a heterogeneous population of innate immune cells, exhibit remarkable plasticity and play pivotal roles in coordinating immune responses and maintaining tissue homeostasis within the context of metabolic diseases. The activation of inflammatory macrophages in obese adipose tissue leads to detrimental effects, inducing insulin resistance through increased inflammation, impaired thermogenesis, and adipose tissue fibrosis. Meanwhile, adipose tissue macrophages also play a beneficial role in maintaining adipose tissue homeostasis by regulating angiogenesis, facilitating the clearance of dead adipocytes, and promoting mitochondrial transfer. Exploring the heterogeneity of macrophages in obese adipose tissue is crucial for unraveling the pathogenesis of obesity and holds significant potential for targeted therapeutic interventions. Recently, the dual effects and some potential regulatory mechanisms of macrophages in adipose tissue have been elucidated using single-cell technology. In this review, we present a comprehensive overview of the intricate activation mechanisms and diverse functions of macrophages in adipose tissue during obesity, as well as explore the potential of drug delivery systems targeting macrophages, aiming to enhance the understanding of current regulatory mechanisms that may be potentially targeted for treating obesity or metabolic diseases.

Effects of melatonin against experimentally induced apical periodontitis in rats

Apical periodontitis is an inflammatory condition resulting from microbial invasion in the root canal system, causing periapical tissue destruction and bone resorption. This study investigated melatonin's effects, known for its antioxidant and anti-inflammatory properties, on experimentally induced apical periodontitis in rats. Three groups of rats were studied: control, apical periodontitis and apical periodontitis with melatonin treatment. Proinflammatory cytokines and enzyme levels in blood serum were measured, and micro-CT analysis assessed bone resorption. Results showed significantly elevated cytokines and enzyme levels in the apical periodontitis group compared to the control. However, in the melatonin-treated group, these levels were significantly reduced (p < 0.01-0.001). Micro-CT analysis indicated decreased periapical resorption cavity volume and surface area with melatonin treatment. This suggests that systemic melatonin administration can mitigate inflammation and reduce bone resorption in experimentally induced apical periodontitis in rats, potentially holding promise for human endodontic disease treatment pending further research.

Chronodisruption and Gut Microbiota: Triggering Glycemic Imbalance in People with Type 2 Diabetes

The desynchronization of physiological and behavioral mechanisms influences the gut microbiota and eating behavior in mammals, as shown in both rodents and humans, leading to the development of pathologies such as Type 2 diabetes (T2D), obesity, and metabolic syndrome. Recent studies propose resynchronization as a key input controlling metabolic cycles and contributing to reducing the risk of suffering some chronic diseases such as diabetes, obesity, or metabolic syndrome. In this analytical review, we present an overview of how desynchronization and its implications for the gut microbiome make people vulnerable to intestinal dysbiosis and consequent chronic diseases. In particular, we explore the eubiosis-dysbiosis phenomenon and, finally, propose some topics aimed at addressing chronotherapy as a key strategy in the prevention of chronic diseases.

Clinacanthus nutans leaf extract reduces pancreatic β-cell apoptosis by inhibiting JNK activation and modulating oxidative stress and inflammation in streptozotocin-induced diabetic rats

Background

Controlling apoptosis induced by oxidative stress in pancreatic β-cells provides promising strategies for preventing and treating diabetes. Clinacanthus nutans leaves possess bioactive constituents with potential antioxidant and anti-diabetic properties.

Aim

This study aimed to investigate the molecular mechanisms by which C. nutans extract protects pancreatic β-cells from apoptotic damage in streptozotocin (STZ)-induced diabetic rats.

Methods

Diabetes was induced in male Wistar rats by intraperitoneal injection of 45 mg/kg STZ, followed by 28 days of treatment with C. nutans leaf extract and Glibenclamide as the standard drug. At the end of the study, blood samples were collected to measure glucose levels, oxidative stress markers, and inflammation. Pancreatic tissue was stained immunohistochemically to detect c-Jun N-terminal kinase (JNK) and Caspase-3 expression.

Results

The administration of C. nutans leaf extract to diabetic rats significantly reduced fasting blood glucose, malondialdehyde, and tumor necrosis factor-α levels, while concurrently enhancing the activity of superoxide dismutase. The immunohistochemical studies revealed a decrease in the expression of JNK and caspase-3 in the pancreatic islets of diabetic rats.

Conclusion

Clinacanthus nutans exhibits the potential to protect pancreatic β-cells from apoptosis by suppressing oxidative stress and inflammation.

Clinacanthus nutans L Extracts Reduce the Serum Tumor Necrosis Factor-α, Malondialdehyde, and Interleukin-6 Levels and Improve the Langerhans Islet Area in Diabetic Rat Models

Background

Diabetes mellitus-induced hyperglycemia increases oxidative stress and inflammatory cytokine production, which play a significant role in the damage and apoptosis of pancreatic β cells. Therefore, the administration of medications that can reduce oxidative stress and inflammation plays an important role in diabetes treatment.

Objective

To probe the Clinacanthus nutans leaf extract effect on oxidative stress and inflammatory markers and the Langerhans islet area in diabetic rat models.

Design

An experimental laboratory in the animal model.

Methods

Twenty-five diabetic rat models were randomly assigned into 5 clusters. Clusters 1, 2, and 3 were administered with C. nutans leaf extract in aqueous suspension with vehicle 1% Na-CMC at 75 mg/kg body weight (BW), 150 mg/kg BW, and 300 mg/kg BW, respectively. Cluster 4 was diabetic control rats administered with metformin at a 21 mg/rat dose. Cluster 5 was a control diabetic rat only administered with 1% Na-CMC suspension. Treatment was administered orally for 14 days. On the 15th day, the rats were sacrificed to obtain blood samples and pancreatic tissues. Serum interleukin (IL)-6, malondialdehyde (MDA), and tumor necrosis factor (TNF-α) were measured using the enzyme-linked immunosorbent assay (ELISA) method. Histopathological examination was performed by counting the Langerhans islet areas.

Results

The average IL-6, MDA, and TNF-α levels declined in the cluster receiving C. nutans extract and were significantly different from the untreated cluster (P < .05). Histopathological examination revealed a significant upsurge in the Langerhans islets area in diabetic rats receiving C. nutans extract at doses of 75 and 150 mg/kg (P < .05).

Conclusion

C. nutans leaf extract reduced the serum MDA, TNF-α, and IL-6 levels, and increased the Langerhans islets area in a diabetic rat model.

Artemisinin attenuates type 2 diabetic cardiomyopathy in rats through modulation of AGE-RAGE/HMGB-1 signaling pathway

Diabetes mellitus is a common metabolic disorder. About two-thirds of diabetic patients develop diabetic cardiomyopathy (DCM), which becomes a challenging issue as it severely threatens the patient's life. Hyperglycemia and the resulting advanced glycated end products (AGE) and their receptor (RAGE)/High Mobility Group Box-1 (HMGB-1) molecular pathway are thought to be key players. Recently, artemisinin (ART) has gained more attention owing to its potent biological activities beyond its antimalarial effect. Herein, we aim to evaluate the effect of ART on DCM and the possible underlying mechanisms. Twenty-four male Sprague-Dawley rats were divided into: control, ART, type 2 diabetic and type 2 diabetic treated with ART groups. At the end of the research, the ECG was recorded, then the heart weight to body weight (HW/BW) ratio, fasting blood glucose, serum insulin and HOMA-IR were evaluated. Cardiac biomarkers (CK-MB and LDH), oxidative stress markers, IL-1β, AGE, RAGE and HMGB-1 expression were also measured. The heart specimens were stained for H&E as well as Masson's trichrome. DCM induced disturbances in all studied parameters; contrary to this, ART improved these insults. Our study concluded that ART could improve DCM through modulation of the AGE-RAGE/HMGB-1 signaling pathway, with subsequent impacts on oxidative stress, inflammation and fibrosis. ART could therefore be a promising therapy for the management of DCM.

The effect of melatonin on glycoprotein levels and oxidative liver injury in experimental diabetes

In this present study, the duration of melatonin (Mel) administered to diabetic rats was prolonged so as to examine its effects on the biochemical liver parameters of diabetic rats. In the experiment, Male Sprague Dawley rats were divided randomly into five groups; the control, diabetic + Mel, diabetic, diabetic + insulin, and diabetic + Mel + insulin. Diabetes mellitus was induced by administration of a single dose of streptozotocin (60 mg/kg) intraperitoneally and rats were given vehicle as a solvent for Mel every day for 12 weeks. In the diabetic + Mel group, diabetic rats were administered Mel (10 mg/kg/day) for 12 weeks to treat diabetes. The diabetic + insulin group were diabetic rats given insulin (6 U/kg) subcutaneously for 12 weeks. The diabetic + Mel + insulin rats received insulin and Mel at the same dose and time. At the end of the experiment, the animals were decapitated and liver tissues were taken. The protective effect of Mel on liver tissue of diabetic rats was investigated, total antioxidant status, total oxidant status, reactive oxygen species, oxidative stress index, adenosine deaminase, xanthine oxidase, paraoxonase 1, sodium/potassium ATPase, myeloperoxidase, γ-glutamyl transferase, sorbitol dehydrogenase, tumor necrosis factor-alpha, homocysteine, nitric oxide, glucose-6-phosphate dehydrogenase, and glycoprotein levels were determined in liver tissues. Treatment with Mel and/or insulin has been found to have a protective effect on biochemical parameters. The results showed that administration of Mel to diabetic rats prevented the distortion of the studied biochemical parameters of liver tissues.

Neurotoxicity of Bisphenol A and the Impact of Melatonin Administration on Oxidative Stress, ERK/NF-kB Signaling Pathway, and Behavior in Rats

Bisphenol A (BPA) exposure can be associated with neurodevelopmental disorders due to impairment of cell proliferation and synaptic development. Our study evaluated the effects of melatonin (MEL) on ambulatory activity, lipid peroxidation, cytokines, ERK/NF-kB signaling pathway in the hippocampus and frontal lobe, and histopathological changes in the hippocampus of the BPA-treated rats. The animals were divided into 4 groups: control, BPA, BPA + MEL I, and BPA + MEL II. MEL I (20 mg/kg b.w.) and MEL II (40 mg/kg b.w.) were orally administered for 28 days. On the 29th day, BPA (1 mg/kg b.w.) was intraperitoneally administered, and, after 24 h, an open field test (OFT) and an elevated plus maze (EPM) were conducted. The results showed that the MEL II group made significantly more entries in the open arms of EPM, traveled significantly greater distance, and spent more time in the central part of OFT. Malondialdehyde levels were diminished by MEL II in the hippocampus and by MEL I in the frontal lobe. In the hippocampus, the MAPK level was significantly lowered by both doses of MEL (p < 0.05) while in the frontal lobe, only MEL II reduced the MAPK activation. MEL I and II significantly decreased the γH2AX and upregulated the NFkB and pNFkB expressions in the hippocampus while MEL II downregulated the MCP1 expression. Both doses of MEL attenuated the BPA-evoked histopathological alterations in the hippocampus. These data indicate that MEL can mediate the neuroprotection against BPA-induced neurotoxicity and improves behavioral changes suggesting a real potential as a protective agent in brain toxicity.