Neurobehavioral, biochemical and histological assessment of the effects of resveratrol on cuprizone-induced demyelination in mice: role of autophagy modulation

Resveratrol is known to exhibit neuroprotective effects in many neurological disorders via autophagy modulation. However, controversial results have been reported about the therapeutic potential of resveratrol and the implication of autophagy in demyelinating diseases. This study aimed to evaluate the autophagic changes in cuprizone-intoxicated C57Bl/6 mice and explore the effect of autophagy activation by resveratrol on the demyelination and remyelination processes. Mice were fed with chow containing 0.2% cuprizone for 5 weeks, followed by a cuprizone-free diet for 2 weeks. Resveratrol (250 mg/kg/day) and/or chloroquine (an autophagy inhibitor; 10 mg/kg/day) were given for 5 weeks starting from the third week. At the end of the experiment, animals were tested on rotarod and then sacrificed for biochemical assessment, luxol fast blue (LFB) staining, and transmission electron microscopy (TEM) imaging of the corpus callosum. We observed that cuprizone-induced demyelination was associated with impaired degradation of autophagic cargo, induction of apoptosis, and manifest neurobehavioral disturbances. Oral treatment with resveratrol promoted motor coordination and improved remyelination with regular compacted myelin in most axons without a significant impact on myelin basic protein (MBP) mRNA expression. These effects are mediated, at least in part, via activating autophagic pathways that may involve SIRT1/FoxO1 activation. This study verified that resveratrol dampens cuprizone-induced demyelination, and partially enhances myelin repair through modulation of the autophagic flux, since interruption of the autophagic machinery by chloroquine reversed the therapeutic potential of resveratrol. (AU)

Neurobehavioral, biochemical and histological assessment of the effects of resveratrol on cuprizone-induced demyelination in mice: role of autophagy modulation.

Resveratrol is known to exhibit neuroprotective effects in many neurological disorders via autophagy modulation. However, controversial results have been reported about the therapeutic potential of resveratrol and the implication of autophagy in demyelinating diseases. This study aimed to evaluate the autophagic changes in cuprizone-intoxicated C57Bl/6 mice and explore the effect of autophagy activation by resveratrol on the demyelination and remyelination processes. Mice were fed with chow containing 0.2% cuprizone for 5 weeks, followed by a cuprizone-free diet for 2 weeks. Resveratrol (250 mg/kg/day) and/or chloroquine (an autophagy inhibitor; 10 mg/kg/day) were given for 5 weeks starting from the third week. At the end of the experiment, animals were tested on rotarod and then sacrificed for biochemical assessment, luxol fast blue (LFB) staining, and transmission electron microscopy (TEM) imaging of the corpus callosum. We observed that cuprizone-induced demyelination was associated with impaired degradation of autophagic cargo, induction of apoptosis, and manifest neurobehavioral disturbances. Oral treatment with resveratrol promoted motor coordination and improved remyelination with regular compacted myelin in most axons without a significant impact on myelin basic protein (MBP) mRNA expression. These effects are mediated, at least in part, via activating autophagic pathways that may involve SIRT1/FoxO1 activation. This study verified that resveratrol dampens cuprizone-induced demyelination, and partially enhances myelin repair through modulation of the autophagic flux, since interruption of the autophagic machinery by chloroquine reversed the therapeutic potential of resveratrol.

Carnosic Acid Mitigates Depression-Like Behavior in Ovariectomized Mice via Activation of Nrf2/HO-1 Pathway.

The peri- and post-menopausal periods have been described as the "window of vulnerability" for the development of depressive symptoms that impair women activities and quality of life. The etiopathogenesis of these symptoms is multifactorial and may confer resistance to traditional antidepressants. Attention is now directed toward phytochemicals for their pleiotropic functions and safer profiles. This study investigated the possible perturbation of the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathways as an underlying mechanism of post-ovariectomy depression and highlighted the potential benefits of carnosic acid (CA) on the associated behavioral, biochemical, and histopathological alterations. Female Balb/c mice were randomly assigned to be sham-operated or ovariectomized (OVX). After 3 weeks, OVX mice received either a vehicle, CA (20 mg/kg/day), or tin protoporphyrin IX (SnPP-IX; a heme oxygenase-1 (HO-1) inhibitor; 50 µmol/kg/day) for 3 weeks. Our findings revealed that OVX mice had depressive but not anxiety-like behavior. Suppressed Nrf2 and its downstream signaling, and augmented proinflammatory markers were observed in both the hippocampus and prefrontal cortex. CA treatment alleviated depressive behavior, induced the expression of Nrf2, HO-1, thioredoxin-1, and brain-derived neurotrophic factor, and enhanced serotonin levels. CA also suppressed oxidative stress, reduced TNF-α, IL-1ß, and iNOS mRNA expression, and ameliorated OVX-induced histopathological changes. SnPP-IX aggravated post-OVX behavioral, neurobiochemical, and histological deteriorations, and reduced CA-protective effects. In conclusion, Nrf2/HO-1 signaling suppression and the associated proinflammatory state are key mechanisms in post-OVX depression. CA exerts multifaceted neuroprotection in OVX mice and represents a promising candidate for clinical evaluation as an antidepressant.

Improved oral nutraceutical-based intervention for the management of obesity: pterostilbene-loaded chitosan nanoparticles.

Aim: To formulate and assess the oral anti-obesity effect of polymeric-based pterostilbene (PS)-loaded nanoparticles. Methods: Pterostilbene-hydroxypropyl ß-cyclodextrin inclusion complex loaded in chitosan nanoparticles (PS/HPßCD-NPs) were prepared and characterized in vitro. Cytotoxicity, pharmacokinetics and anti-obesity effects were assessed on Caco-2 cell line and high-fat-diet-induced obesity rat model, respectively. In vivo assessment included histological examination, protein and gene expression of obesity biomarkers in adipose tissues. Results: Safe PS/HPßCD-NPs were successfully prepared with improved bioavailability compared with free PS. PS/HPßCD-NPs showed an improved anti-obesity effect, as supported by histological examination, lipid profile, UCP1 gene expression and protein expression of SIRT1, COX2, IL-6 and leptin. Conclusion: Orally administered PS nanoparticles represent a new and promising anti-obesity strategy owing to the sustainable weight loss and minimal side effects; this may be of great socio-economic impact.

Weight gain or obesity represents a major health risk and leads to diseases including cancer and heart disease. Most anti-obesity medications have significant side effects, and there are notable challenges concerning their availability in the body to produce an effect. Pterostilbene is a herbal drug with beneficial anti-obesity effects. However, it has problems such as poor solubility which restrict its use. The aim of the study was to formulate pterostilbene in a nano-based delivery system and fully characterize its anti-obesity effect when given orally. We evaluated the safety and anti-obesity effects of pterostilbene nanoparticles in cells and in obese rats fed on a high-fat diet. We also looked at how the body absorbs, distributes and gets rid of these nanoparticles. The prepared nanoparticles were nontoxic, with an improved anti-obesity effect; they decreased cholesterol levels and helped in changing white fat (which stores fat) to brown fat (which burns calories). We conclude that the developed pterostilbene nanoparticles, given orally, are a new and promising anti-obesity strategy given their long-lasting effect on weight loss and the minimal side effects. This may be of great economic and societal impact.

In vitro differentiation of human bone marrow stromal cells into neural precursor cells using small molecules.

BACKGROUND: Neurogenic differentiation of human marrow stromal stem cells (hMSCs) into neural precursor cells (NPCs) offers new hope in many neurological diseases. Stromal cells can be differentiated into NPCs using small molecules acting as chemical inducers. The aim of this study is to formulate an efficient, direct, fast and safe protocol to differentiate hMSCs into NPCs using different inducers: b-mercaptoethanol (BME), triiodothyronine (T3), and curcumin (CUR). NEW METHOD: hMSCs were subjected to either 1 mM BME, 0.5 µM T3, or 5 µM CUR. Neurogenic differentiation was determined by assessing the protein expression of PAX6, SOX2, DLX2, and GAP-43 with flow cytometry and immunofluorescence, along with Nissl staining of differentiated cells. RESULTS AND COMPARISON WITH EXISTING METHOD: It was revealed that T3 and CUR are 70-80% better than BME in terms of efficiency and safety, and surprisingly BME was a good promoting factor for cell preconditioning with limited effects on neural trans-differentiation related to its toxic effects on cell viability. CONCLUSION: Reprogramming of bone marrow stromal cells into neural cells gives hope for treating different neurological disorders. Our study shows that T3 and CUR were effective in generation of NPCs from hMSCs with preservation of cell viability. BME was a good promoting factor for cell preconditioning with limited effects on neural transdifferentiation related to its toxic effects on cell viability.

Crosstalk of hypothalamic chemerin, histamine, and AMPK in diet-and olanzapine-induced obesity in rats.

AIM: Contradiction overwhelms chemerin link to feeding behavior. Neither the chemerin central role on appetite regulation nor its relation to hypothalamic histamine and AMPK is verified. MAIN METHODS: Food intake, body weight and hypothalamic biochemical changes were assessed after a single intra-cerebroventricular or intraperitoneal injection (ip) (1 µg/kg or 16 µg/kg, respectively) or chronic ip administration (8 µg/kg/day) of chemerin for 14 or 28 days. Hypothalamic neurobiochemical changes in chemerin/histamine/AMPK induced by either 8-week high fat diet (HFD) or food restriction were also investigated. To confirm chemerin-histamine crosstalk, these neurobiochemical changes were assessed under settings of H1-receptor agonism and/or antagonism by betahistine and/or olanzapine, respectively for 3 weeks. KEY FINDINGS: Chemerin-injected rats exhibited anorexigenic behavior in both acute and chronic studies that was associated with a decreased AMPK activity in the arcuate nucleus (ARC). However, with long-term administration, chemerin anorexigenic effect gradually ceased. Contrarily to food restriction, 8-week HFD increased ARC expression of chemerin and its receptor CMKLR1, reducing food intake via an interplay of H1-receptors and AMPK activity. Blockage of H1-receptors by olanzapine disrupted chemerin signaling pathway with an increased AMPK activity, augmenting food intake. These changes were reversed to normal by betahistine coadministration. SIGNIFICANCE: Chemerin is an anorexigenic adipokine, whose dysregulation is implicated in diet, and olanzapine-induced obesity through a histamine/AMPK axis in the ARC. Hypothalamic chemerin/CMKLR1 expression is a dynamic time-dependent response to changes in body weight and/or food intake. Targeting chemerin as a novel therapeutic approach against antipsychotic- or diet-induced obesity is worth to be further delineated.

Cortical tau burden and behavioural dysfunctions in mice exposed to monosodium glutamate in early life.

Although monosodium glutamate (MSG)-induced neurotoxicity has been recognized for decades, the potential similarities of the MSG model to Alzheimer's disease (AD)-type neuropathology have only recently been investigated. MSG-treated mice were examined behaviourally and histologically in relation to some features of AD. Four-week old mice received 5 subcutaneous MSG (2 g/kg) injections on alternate days, or saline. At age 10-12 weeks, they were given a battery of behavioural tests for species-typical behaviours and working memory. The mice were killed at 12 weeks and the brains excised. Accumulation of hyperphosphorylated tau protein was assessed in cortical and hippocampal neurons by immunohistochemistry, and in cerebral cortical homogenates. A 78% increase in cortical concentrations of phosphorylated tau protein was observed in the MSG mice. Intracellular hyperphosphorylated tau immunostaining was observed diffusely in the cortex and hippocampus, together with cortical atrophic neurons, extensive vacuolation and dysmorphic neuropil suggestive of spongiform neurodegeneration. Nest-building was significantly impaired, and spontaneous T-maze alternation was reduced, suggesting defective short-term working memory. Subcutaneous MSG treatment also induced a 56% reduction in exploratory head dips in a holeboard (P = 0.009), and a non-significant tendency for decreased burrowing behaviour (P = 0.085). These effects occurred in the absence of MSG-induced obesity or gross locomotor deficits. The findings point to subcutaneous MSG administration in early life as a cause of tau pathology and compromised species-typical behaviour in rodents. Determining whether MSG can be useful in modelling AD requires further studies of longer duration and full behavioural characterization.

Irisin vs. Treadmill Exercise in Post Myocardial Infarction Cardiac Rehabilitation in Rats.

BACKGROUND: Irisin is an exercise-induced myokine that could play a role in post-myocardial infarction (MI) cardiac rehabilitation. AIM OF THE STUDY: We investigated the ability of dihydromyricetin to mimic the effects of exercise on raising serum irisin and on enhancing cardiac function and remodeling following MI in rats. METHODS: MI was induced in albino rats by subcutaneous injection of isoproterenol (85 mg/kg) for 2 consecutive days at an interval of 24 h. One week post-MI, rats either underwent physical exercise by running on a motor-driven treadmill at 25 m/min, 30 min/d, 5 d/week or received orally dihydromyricetin 100 mg/kg/d, for 8 weeks. RESULTS: Exercise and dihydromyricetin raised serum irisin 1.8 and 1.9 folds as compared to sedentary rats (p <0.001) with no difference between both regimens (p = 0.992). There was an improvement of cardiac remodeling where ß-myosin heavy chain level was not different in exercise and dihydromyricetin groups from normal group (p = 0.695, p = 0.470). The heart rate variability domains increased back to normal. However, exercise was superior to dihydromyricetin in improving cardiac contractility by increasing carotid blood flow, stroke volume and cardiac output to be insignificant from normal rats (p = 0.899, p = 0.850, p = 0.912). Meanwhile, treatment with dihydromyricetin showed reduction by 29% of carotid blood flow, 24% of stroke volume and 25% of cardiac output compared to normal rats (p <0.001). CONCLUSIONS: DHM could mimic the effect of exercise in stimulating irisin secretion but it is not as effective as exercise in improving myocardial contractility.

Cardioprotective effect of cerium oxide nanoparticles in monocrotaline rat model of pulmonary hypertension: A possible implication of endothelin-1.

AIMS: Cerium oxide nanoparticles (CeO2NPs) have been recently introduced into the medical field for their antioxidant properties. The ability of CeO2NPs alone or in combination with spironolactone (SP) to attenuate monocrotaline (MCT)-induced pulmonary hypertension and associated right ventricular hypertrophy was studied in rats. A special emphasis was given to endothelin-1 pathway. MATERIALS AND METHODS: Pulmonary hypertension was induced in albino rats by a single subcutaneous injection of MCT (60 mg/kg). Rats received either single CeO2NPs therapy or combined therapy with SP for 2 weeks. KEY FINDINGS: CeO2NPs improved pulmonary function tests with concomitant decrease in serum endothelin-1 and pulmonary expression of endothelin-1 and its receptor ETAR. Besides, CeO2NPs diminished MCT-induced right ventricular hypertrophy and reduced cardiac oxidative stress and apoptosis. SIGNIFICANCE: CeO2NPs could improve pulmonary hypertension and associated right ventricular hypertrophy with no additive value for SP. Besides being an antioxidant, CeO2NPs work through endothelin-1 pathway to improve pulmonary hypertension.