Apelin-13 attenuates spatial memory impairment by anti-oxidative, anti-apoptosis, and anti-inflammatory mechanism against ethanol neurotoxicity in the neonatal rat hippocampus

Amelioration of Chronic Ethanol Administration-Induced Learning and Memory Impairments by High-Intensity Interval Training (HIIT) and Ritalin

OBJECTIVES

The current study aimed to investigate the impacts of 8-week high-intensity interval training (HIIT) and Ritalin (RIT), alone and in combination, on cognitive functions and hippocampal oxidative parameters following chronic ethanol consumption in male rats.

METHODS

A total of 56 adult male rats were divided into 8 groups and received one of the following treatments: ethanol 20% (ET) (3 mL/kg/day, orally, 5 consecutive days/week in weeks 1-4, and 3 consecutive days/week in weeks 4-8), RIT (10 mg/kg, intraperitoneally, three consecutive times/week for 8 weeks), HIIT + SAL (five consecutive times/week for 8 weeks + saline injection), or saline (1 mL/day, intraperitoneally, three consecutive times/week for 8 weeks). Cognitive performance was assessed using the Morris water maze (MWM) and passive avoidance tasks. Oxidative stress markers, including malondialdehyde (MDA), glutathione peroxidase (GPx), and total antioxidant capacity (TAC), were measured in the hippocampus using thiobarbituric acid reactive substances (TBARS) and ferric reduction antioxidant power (FRAP). Nitric oxide (NO) level in the hippocampus was determined using an NO Assay Kit (Natrix, Arman Biotech, Iran).

RESULTS

Chronic ethanol administration impaired cognitive functions. However, RIT, HIIT, and their combination significantly improved these impairments. Furthermore, RIT increased ethanol-induced oxidative stress, whereas HIIT reduced it, even in the combination group.

CONCLUSION

Chronic ethanol consumption caused learning and memory deficits and disrupted oxidant/antioxidant balance in the hippocampus of rats. HIIT potentially improved memory impairments by restoring this balance, whereas RIT ameliorated cognitive dysfunction through a mechanism that requires further investigation.

Erythropoietin improves spatial and nonspatial memory defects by suppressing oxidative damage, inflammation and apoptosis against ethanol neurotoxicity in the developing male rat hippocampus

Excessive prenatal exposure to ethanol leads to a condition called fetal alcohol spectrum disorder (FASD). The neurotoxicity of alcohol causes changes in the hippocampus of animals during this time, resulting in impaired hippocampus-related functions, including memory/learning and cognition.The liver and kidneys produce erythropoietin (EPO). The synthesis of EPO by immature neurons also plays a decisive role in the embryonic stage. Also, exogenous EPO exerts its neurocognitive effects in the developing brain under pathophysiological conditions. The aim of this study was to investigate the protective effects of EPO administration after ethanol-induced increased neurodevelopmental toxicity. Male Wistar rat pups were intubated with a dose of 5/27 g/kg/day ethanol from postnatal day 2-10, similar to the last trimester of gestation in humans. Immediately thereafter, EPO (1000 /2000 U/kg, s.c.) were injected. Spatial memory was tested with the Morris water maze (days 36-40) and non-spatial recognition memory with the novel object task (days 39-40). Concentrations of antioxidant enzymes and TNF-α (ELISA) and caspase-3 (immunohistochemical staining) was then performed. The current study shows that EPO administration significantly attenuates spatial and nonspatial memory impairment (P < 0.001). EPO dramatically decreased the amount of caspase 3 positive cells in the CA1 area of the hippocampus (P < 0.01). EPO increased total superoxide dismutase activity (P < 0.05), glutathione concentrations (P < 0.05) and catalase levels (P < 0.001). EPO also attenuated the production of TNF-α and malondialdehyde (P < 0.05). Given EPO's protective effect against ethanol-induced increased neurotoxicity, it is a viable treatment option for FASD, although more research is needed.

Effects of apelin on neonatal brain neurogenesis in L-NAME-induced maternal preeclampsia

The aim of this study was to investigate the possible protective effects of apelin, which is known to have antioxidant and anti-inflammatory effects, on changes in neurogenesis in newborns of pregnant rats with L-NAME-induced preeclampsia. Wistar albino female rats were divided into four experimental groups: Control, Apelin, Preeclampsia and Preeclampsia + Apelin. Blood pressure was measured on the 5th, 11th and 17th days of gestation, urine protein was analyzed from urine samples collected for 24 h on the 6th, 12th and 18th days and serum creatinine was analyzed from serum samples. Maternal kidney and placenta tissues were obtained to establish the preeclampsia model, and neonatal brain tissues including the cortex, hippocampus and cerebellum regions were obtained to investigate neurogenesis and examined by histological and immunohistochemical methods. The number of newborns, body weight and brain weight of the newborns were measured. eNOS, IL-10, nNOS and NO levels in the brain analyzed via ELISA. Mean arterial pressure, urine protein and serum creatinine increased in the preeclampsia. Newborn weight decreased in the Preeclampsia group, the values in the Preeclampsia + Apelin group were closer to the Control and Apelin groups. In the Preeclampsia group, edema and dilatation in the proximal and distal tubules of kidneys, perivillous fibrin deposition and increase in syncytial nodules of placenta were observed. VEGF immunoreactivity decreased and iNOS immunoreactivity increased in both kidney and placenta. In neonatal brain tissue examinations, cytotoxic edema accompanied by thinning of cortex, delayed migration and lower cell counts in the hippocampus, and increase in intercellular spaces and EGL thickening in the cerebellum were observed in the preeclampsia. Expression of NeuN, GFAP, MBP, IL-10, eNOS, nNOS and NO levels decreased, whereas expression of Iba-1 increased in the preeclampsia. In the Preeclampsia + Apelin group, these findings were similar to the Control and Apelin groups. Apelin administration was found to be beneficial for preventing the adverse consequences of preeclampsia, but further experimental and clinical studies are needed to better understand these effects.

Potential Involvement of Apelin/APJ System in Addiction and Neuroprotection Against Drugs of Abuse

Addiction, characterized by compulsive drug-seeking behavior and impaired self-control, remains a significant public health concern. Understanding the neurobiology of addiction is crucial for identifying novel therapeutic targets and further developing effective treatments. Recently, the apelin/APJ system, an emerging signaling pathway, has attracted attention for its involvement in various neuropsychiatric disorders. The cross-talk between the apelin/APJ system and hypothalamic mu opioid signaling, as well as its heterodimerization with kappa opioid receptors (KORs), supports the potential relevance of this system to addiction. Moreover, several protective effects of apelin against various addictive substances, including methamphetamine, morphine, and alcohol, underscore the need for further investigation into its role in substance use disorder. Understanding the contribution of the apelin/APJ system in addiction may offer valuable insights into the underlying neurobiology and pave the way for novel therapeutic interventions in substance use disorders. This review provides a concise overview of the apelin/APJ system, emphasizing its physiological roles and highlighting its relevance to addiction research.

The Fetal Alcohol Spectrum Disorders-An Overview of Experimental Models, Therapeutic Strategies, and Future Research Directions

Since the establishment of a clear link between maternal alcohol consumption during pregnancy and certain birth defects, the research into the treatment of FASD has become increasingly sophisticated. The field has begun to explore the possibility of intervening at different levels, and animal studies have provided valuable insights into the pathophysiology of the disease, forming the basis for implementing potential therapies with increasingly precise mechanisms. The recent reports suggest that compounds that reduce the severity of neurodevelopmental deficits, including glial cell function and myelination, and/or target oxidative stress and inflammation may be effective in treating FASD. Our goal in writing this article was to analyze and synthesize current experimental therapeutic interventions for FASD, elucidating their potential mechanisms of action, translational relevance, and implications for clinical application. This review exclusively focuses on animal models and the interventions used in these models to outline the current direction of research. We conclude that given the complexity of the underlying mechanisms, a multifactorial approach combining nutritional supplementation, pharmacotherapy, and behavioral techniques tailored to the stage and severity of the disease may be a promising avenue for further research in humans.

Disorders of the central nervous system: Insights from Notch and Nrf2 signaling

The functional complexity of the central nervous system (CNS) is unparalleled in living organisms. It arises from neural crest-derived cells that migrate by the exact route, leading to the formation of a complex network of neurons and glial cells. Recent studies have shown that novel crosstalk exists between the Notch1 and Nrf2 pathways and is associated with many neurological diseases. The Notch1-Nrf2 axis may act on nervous system development, and the molecular mechanism has recently been reported. In this review, we summarize the essential structure and function of the CNS. The significance of interactions between signaling pathways and between developmental processes like proliferation, apoptosis and migration in ensuring the correct development of the CNS is also presented. We primarily focus on research concerning possible mechanism of interaction between Notch1 and Nrf2 and the functions of Notch1-Nrf2 in neurons. There may be a direct interaction between Notch1 and NRF2, which is closely related to the crosstalk that occurs between them. The significance and potential applications of the Notch1-Nrf2 axis in abnormal development of the nervous system are been highlighten. We also discuss the molecular mechanisms by which the Notch1-Nrf2 axis controls the apoptosis, antioxidant pathway and differentiation of neurons to modulate the development of the nervous system. This information will lead to a better understanding of Notch1-Nrf2 axis signaling pathways in the nervous system and may facilitate the development of new therapeutic strategies.

Apelin receptor antagonist (ML221) treatment has a stimulatory effect on the testicular proliferation, antioxidants system and steroidogenesis in adult mice

The expression of apelin and its receptor (APJ) has been shown in the hypothalamus-pituitary-testicular axis. It has also been suggested apelin and APJ are neuropeptide factors. The presence of apelin and APJ in the seminiferous tubules and interstitium might be predicted to act as a local regulator of testicular activity, although the function is not well known in the mice testis. In the present study, we have investigated the effects of APJ, antagonist, ML221 on the gonadotropin levels, testicular steroidogenesis, proliferation, apoptosis and antioxidant system. Our results showed that inhibition of APJ by ML221 increased the sperm concentration, circulating testosterone, FSH, LH levels and intra-testicular testosterone concentration. Furthermore, ML221 treatment stimulates the germ cell proliferation and antioxidant system in the testis. The expression of BCL2, AR was up-regulated whereas, the expression of BAX and active caspase3 was down-regulated after ML221 treatment. Immunohistocehmical analysis of AR also showed increase abundance in the spermatogonia, primary spermatocytes and Leydig cells of 150 μg/kg dose group. These findings suggest that in adult testis, the apelin system might have an inhibitory role in germ cell proliferation and a stimulatory role in apoptosis. It might also be suggested that the apelin system could be involved in the disposal mechanism for damaged germ cells during spermatogenesis via the down-regulation of AR.

Alcohol induces apoptosis and autophagy in microglia BV-2 cells

Alcohol (ethanol) has proven to be toxic to nearly all organs, with the brain being one of the principal targets. As one of the important components of the brain's blood-brain barrier (BBB) and central nervous system, the state of microglia may be associated with some symptoms of alcohol intoxication. In the present study, microglia BV-2 cells were exposed to various concentrations of alcohol for 3 or 12 h, imitating different stages of drunkenness after alcohol use, respectively. From the perspective of the autophagy-phagocytosis axis, our findings show that alcohol alters autophagy levels or promotes apoptosis in BV-2 cells. The current study adds to the understanding of the action mechanisms of alcohol neurotoxicity. We anticipate that this study will increase public awareness of alcohol's negative effects and contribute to the creation of novel alcoholism treatment approaches.

Several neuropeptides involved in parkinsonian neuroprotection modulate the firing properties of nigral dopaminergic neurons

Parkinson's disease is characterized by progressive degeneration of dopaminergic neurons in the substantia nigra pars compacta. The surviving nigral dopaminergic neurons display altered spontaneous firing activity in Parkinson's disease. The firing rate of nigral dopaminergic neurons decreases long before complete neuronal death and the appearance of parkinsonian symptoms. A mild stimulation could rescue dopaminergic neurons from death and in turn play neuroprotective effects. Several neuropeptides, including cholecystokinin (CCK), ghrelin, neurotensin, orexin, tachykinins and apelin, within the substantia nigra pars compacta play important roles in the modulation of spontaneous firing activity of dopaminergic neurons and therefore involve motor control and motor disorders. Here, we review neuropeptide-induced modulation of the firing properties of nigral dopaminergic neurons. This review may provide a background to guide further investigations into the involvement of neuropeptides in movement control by modulating firing activity of nigral dopaminergic neurons in Parkinson's disease.

Irisin attenuates ethanol-induced behavioral deficits in mice through activation of Nrf2 and inhibition of NF-κB pathways

This study aims to investigate the effect of irisin on ethanol-induced behavioral deficits and explore the underlying mechanisms. A mouse model of ethanol addiction/withdrawal was constructed through chronic ethanol administration. Depressive-like behaviors were evaluated by the tail suspension test and forced swimming test, and anxiety-like behaviors were evaluated by the marble-burying test and elevated plus maze test. The expression of Nrf2 was measured by western blotting. Levels of inflammatory mediators (NF-κB, TNF-α, IL-1β and IL-6) and oxidative stress factors (ROS, MDA, GSH and SOD) were detected by ELISA. The ethanol-induced PC12/BV2 cell injury model was used to elucidate whether the effect of irisin on ethanol-induced neurological injury was related to anti-inflammatory and antioxidant mechanisms. Ethanol-induced ethanol preference and emotional deficits were improved by chronic irisin treatment; however, these improvements were partly reversed by cotreatment with the Nrf2 inhibitor ML385. Further results implied that the improvement effect of irisin on behavioral abnormalities may be related to its anti-inflammatory and antioxidant effects. In detail, irisin inhibited ethanol-induced abnormal expression of ROS and MDA and upregulated the expression of GSH and SOD. Meanwhile, irisin treatment inhibited ethanol-induced overexpression of NF-κB, TNF-α, IL-1β and IL-6 in the hippocampus and cerebral cortex. The regulation of oxidative stress factors by irisin was reversed after ML385 treatment. In the in vitro study, overexpression of oxidative stress factors in ethanol-treated PC12 cells was inhibited by irisin treatment; however, the prevention was reversed after the knockdown of Nrf2 siRNA. Moreover, ethanol-induced overexpression of inflammatory mediators in BV2 cells was also inhibited by irisin treatment. Irisin improved depressive and anxiety-like behaviors induced by ethanol addiction/withdrawal in mice, and this protection was greatly associated with the NF-κB-mediated anti-inflammatory signaling pathway and Nrf2-mediated antioxidative stress signaling pathway.

The Yin and Yang Effect of the Apelinergic System in Oxidative Stress

Apelin is an endogenous ligand for the G protein-coupled receptor APJ and has multiple biological activities in human tissues and organs, including the heart, blood vessels, adipose tissue, central nervous system, lungs, kidneys, and liver. This article reviews the crucial role of apelin in regulating oxidative stress-related processes by promoting prooxidant or antioxidant mechanisms. Following the binding of APJ to different active apelin isoforms and the interaction with several G proteins according to cell types, the apelin/APJ system is able to modulate different intracellular signaling pathways and biological functions, such as vascular tone, platelet aggregation and leukocytes adhesion, myocardial activity, ischemia/reperfusion injury, insulin resistance, inflammation, and cell proliferation and invasion. As a consequence of these multifaceted properties, the role of the apelinergic axis in the pathogenesis of degenerative and proliferative conditions (e.g., Alzheimer's and Parkinson's diseases, osteoporosis, and cancer) is currently investigated. In this view, the dual effect of the apelin/APJ system in the regulation of oxidative stress needs to be more extensively clarified, in order to identify new potential strategies and tools able to selectively modulate this axis according to the tissue-specific profile.

Reactive Oxygen Species/Reactive Nitrogen Species as Messengers in the Gut: Impact on Physiology and Metabolic Disorders

Significance: The role of reactive oxygen/nitrogen species as "friend" or "foe" messengers in the whole body is well characterized. Depending on the concentration in the tissue considered, these molecular actors exert beneficial or deleterious impacts leading to a pathological state, as observed in metabolic disorders such as type 2 diabetes and obesity. Recent Advances: Among the tissues impacted by oxidation and inflammation in this pathological state, the intestine is a site of dysfunction that can establish diabetic symptoms, such as alterations in the intestinal barrier, gut motility, microbiota composition, and gut/brain axis communication. In the intestine, reactive oxygen/nitrogen species (from the host and/or microbiota) are key factors that modulate the transition from physiological to pathological signaling. Critical Issues: Controlling the levels of intestinal reactive oxygen/nitrogen species is a complicated balance between positive and negative impacts that is in constant equilibrium. Here, we describe the synthesis and degradation of intestinal reactive oxygen/nitrogen species and their interactions with the host. The development of novel redox-based therapeutics that alter these processes could restore intestinal health in patients with metabolic disorders. Future Directions: Deciphering the mode of action of reactive oxygen/nitrogen species in the gut of obese/diabetic patients could result in a future therapeutic strategy that combines nutritional and pharmacological approaches. Consequently, preventive and curative treatments must take into account one of the first sites of oxidative and inflammatory dysfunctions in the body, that is, the intestine. Antioxid. Redox Signal. 37, 394-415.

Neuroprotective Effects of Crocin Against Ethanol Neurotoxicity in the Animal Model of Fetal Alcohol Spectrum Disorders

Several experimental and clinical findings suggest that ethanol consumption during pregnancy activates an oxidative-inflammatory cascade followed by wide apoptotic neurodegeneration within several brain areas, including the hippocampus. Crocin can protect neurons because of its antioxidant, anti-inflammatory, and antiapoptotic effects. This study evaluated the crocin protective impact on ethanol-related neuroinflammation and neuronal apoptosis in the hippocampus of rat pups exposed to alcohol over postnatal days. Ethanol (5.25 g/kg) was administrated in milk solution (27.8 ml/kg) by intragastric intubation 2-10 days after birth. The animals received crocin (15, 30, and 45 mg/kg) 2-10 days after birth. The hippocampus-dependent memory and spatial learning were evaluated 36 days after birth using the Morris water maze task. Further, the concentrations of TNF-α and antioxidant enzymes were determined using ELISA assay to examine the antioxidant and anti-inflammatory activities. Also, immunohistochemical staining was performed to evaluate the glial fibrillary acidic protein (GFAP), Ionized calcium binding adaptor molecule 1(Iba-1), and caspase-3 expression. The administration of crocin significantly attenuated spatial memory impairment (P < 0.01) after ethanol neurotoxicity. Also, crocin led to a significant enhancement in SOD (P < 0.05) and GSH-PX (P < 0.01), whereas it caused a reduction in the TNF-α and MDA concentrations compared to the ethanol group (P < 0.01). Moreover, the hippocampal level of caspase-3 (P < 0.01) and the number of GFAP and Iba-1-positive cells decreased in the crocin group (P < 0.001). Crocin suppresses apoptotic signaling mediated by the oxidative-inflammatory cascade in rat pups exposed to ethanol after birth.