Dexamethasone enhances oxidative stress-induced cell death in murine neural stem cells

Prolonged exposure to the synthetic glucocorticoid dexamethasone induces brain damage via oxidative stress and apoptotic response in adult Daniorerio

Due to its extensive use as a painkiller, anti-inflammatory, and immune modulatory agent, as well as its effectiveness in treating severe COVID-19, dexamethasone, a synthetic glucocorticoid, has gained attention not only for its impact on public health but also for its environmental implications. Various studies have reported its presence in aquatic environments, including urban waters, surface samples, sediments, drinking water, and wastewater effluents. However, limited information is available regarding its toxic effects on nontarget aquatic organisms. Therefore, this study aimed to investigate the mechanism of toxicity underlying dexamethasone-induced brain damage in the bioindicator Danio rerio following long-term exposure. Adult zebrafish were treated with environmentally relevant concentrations of dexamethasone (20, 40, and 60 ng L-1) for 28 days. To elucidate the possible mechanisms involved in the toxicity of the pharmaceutical compound, we conducted a behavioral test battery (Novel Tank and Light and Dark tests), oxidative stress biomarkers, acetylcholinesterase enzyme activity quantification, histopathological analysis, and gene expression analysis using qRT-PCR (p53, bcl-2, bax, caspase-3, nrf1, and nrf2).The results revealed that the pharmaceutical compound could produce anxiety-like symptoms, increase the oxidative-induced stress response, decrease the activity of acetylcholinesterase enzyme, and cause histopathological alterations, including perineuronal vacuolization, granular and molecular layers deterioration, cell swallowing and intracellular spaces. The expression of genes involved in the apoptotic process (p53, bax, and casp-3) and antioxidant defense (nrf1 and nrf2) was upregulated in response to oxidative damage, while the expression of the anti-apoptotic gene bcl-2 was down-regulated indicating that the environmental presence of dexamethasone may pose a threat to wildlife and human health.

In vivo evaluation of efficacy and safety of Coagulansin-A in treating arthritis

The current study aimed to determine the safety and efficacy of Coag-A through in vivo analysis in CFA induced mice model. Treatment of CFA induced arthritis in mice with Coagulansin-A (10 mg/kg i.p. daily for 28 days), a withanolide obtained from Withania coagulans, as well as standard drug treatment with Dexamethasone (5 mg/kg i.p) was provided. The effect of Coag-A on body weight, relative organ weight, hematology, serum biochemistry, survival rate, oxidative stress markers, and antioxidant enzymes was evaluated. The liver and kidney histopathology were also assessed to ascertain its safety profile. Treatment of arthritic mice with Coag-A considerably improved body weight, relative organ weight of liver, kidney, and spleen, ameliorated hematology and serum biochemistry, and increased survival and antioxidant potential. Coag-A was found to be safer with fewer adverse effects showing hepato-protective, nephroprotective, and anti-inflammatory effect. It also significantly (p < 0.001) improved histopathology of CFA-induced mice when compared with Dexa. In conclusion, compared to dexamethasone, Coag-A has demonstrated a greater therapeutic benefit and fewer side effects in the treatment of arthritis against the CFA-induced model.

Recent Advances in Stem Cell Differentiation Control Using Drug Delivery Systems Based on Porous Functional Materials

The unique characteristics of stem cells, which include self-renewal and differentiation into specific cell types, have paved the way for the development of various biomedical applications such as stem cell therapy, disease modelling, and drug screening. The establishment of effective stem cell differentiation techniques is essential for the effective application of stem cells for various purposes. Ongoing research has sought to induce stem cell differentiation using diverse differentiation factors, including chemicals, proteins, and integrin expression. These differentiation factors play a pivotal role in a variety of applications. However, it is equally essential to acknowledge the potential hazards of uncontrolled differentiation. For example, uncontrolled differentiation can give rise to undesirable consequences, including cancerous mutations and stem cell death. Therefore, the development of innovative methods to control stem cell differentiation is crucial. In this review, we discuss recent research cases that have effectively utilised porous functional material-based drug delivery systems to regulate stem cell differentiation. Due to their unique substrate properties, drug delivery systems based on porous functional materials effectively induce stem cell differentiation through the steady release of differentiation factors. These ground-breaking techniques hold considerable promise for guiding and controlling the fate of stem cells for a wide range of biomedical applications, including stem cell therapy, disease modelling, and drug screening.

Protective potential of piroxicam on human peripheral blood mononuclear cells against the suppressive capacity of glioblastoma cell lines

Dexamethasone, a common medication used in the treatment regimen of glioblastoma, has broad inhibitory effects on the immune responses. Here, in an in vitro study, we examined the effects of piroxicam, a potent substitute for dexamethasone, on peripheral blood mononuclear cells (PBMCs) co-cultured with two glioblastoma cell lines, U-87 MG and A-172 cells. MTT assay was used to determine the proliferation of PBMCs treated with piroxicam, or dexamethasone. In addition, to evaluate the effects of drugs on the cell cycle distribution, DNA content per cell was analyzed in PBMCs and A-172 cell lines using flow cytometry. Oxidative parameters, including superoxide dismutase-3 (SOD3) activity and total anti-antioxidant capacity, lactate dehydrogenase (LDH) activity, as well as IFN-γ and TGF-β levels were measured in PBMCs alone or in the presence of cell lines using ELISA. Unlike dexamethasone, piroxicam showed a protective effect on PBMCs against both glioblastoma cell lines. Furthermore, while dexamethasone reduced the proliferation of PBMCs, piroxicam had no adverse effect on the proliferation. Cell cycle analysis showed a reduction in the G2/M phase in piroxicam-treated A-172 cells. Additionally, dexamethasone limited the cell cycle progression by increasing the fraction of PBMCs in G0/G1. Interestingly, after co-culturing piroxicam-treated PBMCs with cell lines, a remarkable rise in the LDH activity was observed. Although not significant, piroxicam partially decreased TGF-β levels in both cell lines. Our findings suggested a protective effect of piroxicam, but not dexamethasone, on PBMCs against inhibitory mechanisms of two glioblastoma cell lines, U-87 and A-172 cells.

RETRACTED: Environmental Risk Assessment of Dexamethasone Sodium Phosphate and Tocilizumab Mixture in Zebrafish Early Life Stage (Danio rerio)

Pharmaceuticals are widely regarded as a menace to the aquatic environment. The constant consumption of biologically active chemicals for human health has been matched by an increase in the leaking of these compounds in natural habitats over the last two decades. This study was aimed to evaluate the molecular pathway underling the developmental toxicity of exposure in the ecological environment. Zebrafish embryos were exposed at doses of dexamethasone sodium phosphate (DEX) 1 μmol/L, tocilizumab 442.1 μmol/L and dexamethasone + tocilizumab (1 μmol/L and 442.1 μmol/L, respectively) from 24 h post-fertilization (hpf) to 96 hpf. This study confirmed that DEX exposure in association with tocilizumab 442.1 μmol/L at 1 μmol/L (non-toxic concentration) affected the survival and hatching rate, morphology score, and body length. Additionally, it significantly disturbed the antioxidant defense system in zebrafish larvae. Furthermore, a DEX 1 μmol/L and tocilizumab 442.1 μmol/L association also increased the production of apoptosis-related proteins (caspase-3, bax, and bcl-2).

Brain damage induced by contaminants released in a hospital from Mexico: Evaluation of swimming behavior, oxidative stress, and acetylcholinesterase in zebrafish (Danio rerio)

Several studies have indicated that hospital effluents can produce genotoxic and mutagenic effects, cytotoxicity, hematological and histological alterations, embryotoxicity, and oxidative stress in diverse water organisms, but research on the neurotoxic effects hospital wastewater materials can generate in fish is still scarce. To fill the above-described knowledge gap, this study aimed to determine whether the exposure of adult zebrafish (Danio rerio) to several proportions (0.1%, 2.5%, 3.5%) of a hospital effluent can disrupt behavior or impair redox status and acetylcholinesterase content in the brain. After 96 h of exposure to the effluent, we observed a decrease in total distance traveled and an increase in frozen time compared to the control group. Moreover, we also observed a significant increase in the levels of reactive oxygen species in the brains of the fish, especially in hydroperoxide and protein carbonyl content, relative to the control group. Our results also demonstrated that hospital effluents significantly inhibited the activity of the AChE enzyme in the brains of the fish. Our Pearson correlation demonstrated that the response to acetylcholinesterase at the lowest proportions (0.1% and 2.5%) is positively related to the oxidative stress response and the behavioral changes observed. The cohort of our studies demonstrated that the exposure of adult zebrafish to a hospital effluent induced oxidative stress and decreased acetylcholinesterase activity in the brain of these freshwater organisms, which can lead to alterations in their behavior.

COVID-19: A Redox Disease-What a Stress Pandemic Can Teach Us About Resilience and What We May Learn from the Reactive Species Interactome About Its Treatment

Significance: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus causing coronavirus disease 2019 (COVID-19), affects every aspect of human life by challenging bodily, socioeconomic, and political systems at unprecedented levels. As vaccines become available, their distribution, safety, and efficacy against emerging variants remain uncertain, and specific treatments are lacking. Recent Advances: Initially affecting the lungs, COVID-19 is a complex multisystems disease that disturbs the whole-body redox balance and can be long-lasting (Long-COVID). Numerous risk factors have been identified, but the reasons for variations in susceptibility to infection, disease severity, and outcome are poorly understood. The reactive species interactome (RSI) was recently introduced as a framework to conceptualize how cells and whole organisms sense, integrate, and accommodate stress. Critical Issues: We here consider COVID-19 as a redox disease, offering a holistic perspective of its effects on the human body, considering the vulnerability of complex interconnected systems with multiorgan/multilevel interdependencies. Host/viral glycan interactions underpin SARS-CoV-2's extraordinary efficiency in gaining cellular access, crossing the epithelial/endothelial barrier to spread along the vascular/lymphatic endothelium, and evading antiviral/antioxidant defences. An inflammation-driven "oxidative storm" alters the redox landscape, eliciting epithelial, endothelial, mitochondrial, metabolic, and immune dysfunction, and coagulopathy. Concomitantly reduced nitric oxide availability renders the sulfur-based redox circuitry vulnerable to oxidation, with eventual catastrophic failure in redox communication/regulation. Host nutrient limitations are crucial determinants of resilience at the individual and population level. Future Directions: While inflicting considerable damage to health and well-being, COVID-19 may provide the ultimate testing ground to improve the diagnosis and treatment of redox-related stress diseases. "Redox phenotyping" of patients to characterize whole-body RSI status as the disease progresses may inform new therapeutic approaches to regain redox balance, reduce mortality in COVID-19 and other redox diseases, and provide opportunities to tackle Long-COVID. Antioxid. Redox Signal. 35, 1226-1268.

Grape skin extract modulates neuronal stem cell proliferation and improves spatial learning in senescence-accelerated prone 8 mice

In recent years, the number of patients with neurodegenerative illness such as Alzheimer’s disease (AD) has increased with the aging of the population. In this study, we evaluated the effect of Grape skin extract (GSE) on neurotypic SH-SY5Y cells as an in vitro AD model, murine neurospheres as an ex vivo neurogenesis model and SAMP8 mice as an in vivo AD model. Our in vitro result showed that pre-treatment of SH-SY5Y cells with GSE ameliorated Aβ-induced cytotoxicity. Moreover, GSE treatment significantly decreased the number of neurospheres, but increased their size suggesting reduced stem cell self-renewal but increased proliferation. Our in vivo Morris water maze test indicated that GSE improves learning and memory in SAMP8 mice. To detect proliferation and newborn neurons, we measured BrdU+ cells in the dentate gyrus (DG). GSE treatment increased the number of BrdU+ cells in the DG of SAMP8 mice. Finally, we showed that GSE induced a decrease in inflammatory cytokines and an increase in neurotransmitters in the cerebral cortex of SAMP8 mice. These results suggested that GSE increased neurogenic zone proliferation and memory but decreased oxidative stress associated with pro-inflammatory cytokines in aging, thus protecting neurons.

SENP3-Mediated PPARγ2 DeSUMOylation in BM-MSCs Potentiates Glucocorticoid-Induced Osteoporosis by Promoting Adipogenesis and Weakening Osteogenesis

Glucocorticoid-induced osteoporosis (GIOP) is the most common secondary osteoporosis and reduced bone formation was the main pathological change in GIOP. Our previous studies have shown that there was an imbalance between adipogenic and osteogenic differentiation in GIOP BM-MSCs and peroxisome proliferator-activated receptor γ2 (PPARγ2) played a vital role in this disorders. Here, we reported that there was an increase in ROS level and SENP3 expression in Dex-induced osteoporotic BM-MSCs, and enhanced adipogenesis and weakened osteogenesis in osteoporotic BM-MSCs might be caused by upregulated SENP3. Then we found that SENP3 de-SUMOylated PPARγ2 on K107 site to potentiate adipogenesis and weaken osteogenesis. These results may provide new strategy and target in the clinical diagnosis and treatment of GIOP.

In vivo biomarkers of structural and functional brain development and aging in humans

Brain aging is a major determinant of aging. Along with the aging population, prevalence of neurodegenerative diseases is increasing, therewith placing economic and social burden on individuals and society. Individual rates of brain aging are shaped by genetics, epigenetics, and prenatal environmental. Biomarkers of biological brain aging are needed to predict individual trajectories of aging and the risk for age-associated neurological impairments for developing early preventive and interventional measures. We review current advances of in vivo biomarkers predicting individual brain age. Telomere length and epigenetic clock, two important biomarkers that are closely related to the mechanistic aging process, have only poor deterministic and predictive accuracy regarding individual brain aging due to their high intra- and interindividual variability. Phenotype-related biomarkers of global cognitive function and brain structure provide a much closer correlation to age at the individual level. During fetal and perinatal life, autonomic activity is a unique functional marker of brain development. The cognitive and structural biomarkers also boast high diagnostic specificity for determining individual risks for neurodegenerative diseases.

Sirt7-p21 Signaling Pathway Mediates Glucocorticoid-Induced Inhibition of Mouse Neural Stem Cell Proliferation

Prenatal glucocorticoid (GC) overexposure impacts fetal hippocampal neural stem cells (NSCs) and increases the risk for relative cognitive and mood disorders in offspring. However, the precise underlying mechanisms remain elusive. Here, we treated mouse hippocampal NSCs with dexamethasone (DEX) in vitro and found that DEX inhibited cell proliferation and Sirt7 expression. In addition, prenatal mouse overexposure to DEX induced the suppression of Sirt7 in the hippocampus of offspring. Sirt7 knockdown significantly decreased the percentage of proliferating cells but did not further reduce the NSC proliferation rate in the presence of DEX, whereas Sirt7 overexpression rescued DEX-induced inhibition of hippocampal NSC proliferation. Moreover, DEX inhibited Sirt7 expression through the glucocorticoid receptor (GR), and p21 was found to mediate the functional effect of DEX-induced Sirt7 suppression. In conclusion, our data demonstrate for the first time the effect of DEX on the Sirt7-p21 pathway in hippocampal NSCs, identifying a new potential therapeutic target for prenatal GC overexposure-related neurodevelopmental disorders in offspring.

Thermo-Responsive PLGA-PEG-PLGA Hydrogels as Novel Injectable Platforms for Neuroprotective Combined Therapies in the Treatment of Retinal Degenerative Diseases

The present study aims to develop a thermo-responsive-injectable hydrogel (HyG) based on PLGA-PEG-PLGA (PLGA = poly-(DL-lactic acid co-glycolic acid); PEG = polyethylene glycol) to deliver neuroprotective agents to the retina over time. Two PLGA-PEG PLGA copolymers with different PEG:LA:GA ratios (1:1.54:23.1 and 1:2.25:22.5) for HyG-1 and HyG-2 development respectively were synthetized and characterized by different techniques (gel permeation chromatography (GPC), nuclear magnetic resonance (NMR), dynamic light scattering (DLS), critical micelle concentration (CMC), gelation and rheological behaviour). According to the physicochemical characterization, HyG-1 was selected for further studies and loaded with anti-inflammatory drugs: dexamethasone (0.2%), and ketorolac (0.5%), alone or in combination with the antioxidants idebenone (1 µM) and D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS) (0.002%). In vitro drug release and cytotoxicity studies were performed for the active substances and hydrogels (loaded and drug-free). A cellular model based on oxidative stress was optimized for anti-inflammatory and antioxidant screening of the formulations by using retinal-pigmented epithelial cell line hTERT (RPE-1). The copolymer 1, used to prepare thermo-responsive HyG-1, showed low polydispersity (PDI = 1.22) and a strong gel behaviour at 25% (w/v) in an isotonic buffer solution close to the vitreous temperature (31-34 °C). Sustained release of dexamethasone and ketorolac was achieved between 47 and 62 days, depending on the composition. HyG-1 was well tolerated (84.5 ± 3.2%) in retinal cells, with values near 100% when the anti-inflammatory and antioxidant agents were included. The combination of idebenone and dexamethasone promoted high oxidative protection in the cells exposed to H2O2, with viability values of 86.2 ± 14.7%. Ketorolac and dexamethasone-based formulations ameliorated the production of TNF-α, showing significant results (p ≤ 0.0001). The hydrogels developed in the present study entail a novel biodegradable tool to treat neurodegenerative processes of the retina overtime.

The effect of melatonin on testis histological changes and spermatogenesis indexes in mice following treatment with dexamethasone

Dexamethasone is a common medicine that is capable of causing malformation in the male reproductive system. The aim of this study was to investigate the effect of melatonin on testis histological changes and Spermatogenesis indexes in adult mice following treatment with dexamethasone. Adult male NMRI mice were divided randomly into four groups: control, dexamethasone (i.p injections, 7 mg/kg/day), dexamethasone + melatonin and melatonin (i.p injections, 20 mg/kg/day). After 7 days of treatment, the right testes were studied stereologically and the left testes were used to measure the daily sperm production (DSP). The serum levels of malondialdehyde (MDA), testosterone and total antioxidant capacity (TAC) were also measured. The left caudal epididymis was used to analyze sperm parameters. Data were analyzed using one way ANOVA and means were considered significantly different at p < 0.05. A significant decrease in the testis volume, seminiferous tubules volume, the number of spermatocytes, round and long spermatids, Spermatogenesis indexes, sperm parameters such as motility, count, viability, tail length and DSP, serum testosterone level, TAC and the body weight was found in the dexamethasone group compared to the control. Meanwhile a significant swelling of the interstitial tissue and a significant increase in the MDA level was found in the dexamethasone group compared to the control. The above parameters reached the control level in the dexamethasone + melatonin group. Melatonin can compensate for the adverse effects of dexamethasone on sperm parameters and the histology of the seminiferous tubules in mice.

Temporal expression of Toxoplasma stage-specific genes in brain tissue: coincidence with parasitological and histopathological findings in mice models

In the intermediate hosts, tachyzoites of T. gondii predominate in the acute stage while bradyzoites persist inside tissue cysts with the potential for reactivation. The two stages exhibit different metabolic and antigenic characters. The present study aimed to investigate temporal expression of Toxoplasma SAG1 and BAG1 genes in the brain tissue and the coincident parasitological and histopathological findings in mice models of toxoplasmosis. The study included group A: mice infected with RH strain and sacrificed 7 days post-infection (p.i.); group B: mice infected with RH strain and treated with sulfamethoxazole-trimethoprim (30 mg/kg/day and 150 mg/kg/day respectively) 24 h p.i. until sacrificed at days 5, 10, or 20 post-treatment; group C: mice infected with ME-49 strain and sacrificed at days 7, 27, 47, or 67 p.i; and group D: mice infected with ME-49 strain and received dexamethasone daily starting at day 68 p.i. and scarified at days 6 or 10 post-treatment. All mice were inspected daily for abnormal physical signs. Peritoneal exudate and brain homogenate were examined for detection of Toxoplasma stages. Brain sections were examined histopathologically. SAG1 and BAG1 gene expression was evaluated using reverse transcription real-time polymerase chain reaction and the ΔΔCt method. Results revealed that marked BAG1 upregulation is consistent with detection of Toxoplasma cysts and degenerative changes while predominance of tachyzoites and inflammatory infiltrate is compatible with SAG1 upregulation. The study sheds light on the potential for using stage-specific gene expression pattern as markers for evaluation of toxoplasmosis disease progression in clinical settings.

Berberine Protects C17.2 Neural Stem Cells From Oxidative Damage Followed by Inducing Neuronal Differentiation

Neurodegeneration is the loss of structure and/or function of neurons. Oxidative stress has been suggested as one of the common etiology in most of the neurodegenerative diseases. Previous studies have demonstrated the beneficial effects of berberine in various neurodegenerative and neuropsychiatric disorders. In this study, we hypothesized that berberine could protect C17.2 neural stem cells (NSCs) from 2,2′-Azobis(2-amidinopropane) dihydrochloride (AAPH)-induced oxidative damage then promote neuronal differentiation. AAPH was used to induce oxidative damage. After the damage, berberine protected C17.2 cells were kept cultured for another week in differentiation medium with/without berberine. Changes in cell morphology were detected by microscopy and cell viability was determined by MTT assay. Real-time PCR and western blot analysis were performed to confirm the associated pathways. Berberine was able to protect C17.2 NSCs from the oxidative damage. It lowered the cellular reactive oxygen species (ROS) level in C17.2 cells via Nuclear Factor Erythroid 2-Related Factor 1/2 (NRF1/2) – NAD(P)H Quinone Dehydrogenase 1 (NQO-1) – Heme Oxygenase 1 (HO-1) pathway. It also down-regulated the apoptotic factors-Caspase 3 and Bcl2 Associated X (Bax) and upregulated the anti-apoptotic factor-Bcl2 to reduce cell apoptosis. Besides, berberine increased C17.2 cell viability via up-regulating Extracellular-signal-Related Kinase (ERK) and phosphor-Extracellular-signal-Related Kinase (pERK) expression. Then, berberine promoted C17.2 cell to differentiate into neurons and the differentiation mechanism involved the activation of WNT/β-catenin pathway as well as the upregulation of expression levels of pro-neural factors Achaete-Scute Complex-Like 1 (ASCL1), Neurogenin 1 (NeuroG1), Neuronal Differentiation 2 (NeuroD2) and Doublecortin (DCX). In conclusion, berberine protected C17.2 NSCs from oxidative damage then induced them to differentiate into neurons.

Human Embryonic Stem Cell-Derived Neural Lineages as In Vitro Models for Screening the Neuroprotective Properties of Lignosus rhinocerus (Cooke) Ryvarden

In the biomedical field, there is growing interest in using human stem cell-derived neurons as in vitro models for pharmacological and toxicological screening of bioactive compounds extracted from natural products. Lignosus rhinocerus (Tiger Milk Mushroom) is used by indigenous communities in Malaysia as a traditional medicine to treat various diseases. The sclerotium of L. rhinocerus has been reported to have medicinal properties, including various bioactivities such as neuritogenic, anti-inflammatory, and anticancer effects. This study aims to investigate the neuroprotective activities of L. rhinocerus sclerotial extracts. Human embryonic stem cell (hESC)-derived neural lineages exposed to the synthetic glucocorticoid, dexamethasone (DEX), were used as the in vitro models. Excess glucocorticoids have been shown to adversely affect fetal brain development and impair differentiation of neural progenitor cells. Screening of different L. rhinocerus sclerotial extracts and DEX on the hESC-derived neural lineages was conducted using cell viability and neurite outgrowth assays. The neuroprotective effects of L. rhinocerus sclerotial extracts against DEX were further evaluated using apoptosis assays and Western blot analysis. Hot aqueous and methanol extracts of L. rhinocerus sclerotium promoted neurite outgrowth of hESC-derived neural stem cells (NSCs) with negligible cytotoxicity. Treatment with DEX decreased viability of NSCs by inducing apoptosis. Coincubation of L. rhinocerus methanol extract with DEX attenuated the DEX-induced apoptosis and reduction in phospho-Akt (pAkt) level in NSCs. These results suggest the involvement of Akt signaling in the neuroprotection of L. rhinocerus methanol extract against DEX-induced apoptosis in NSCs. Methanol extract of L. rhinocerus sclerotium exhibited potential neuroprotective activities against DEX-induced toxicity in hESC-derived NSCs. This study thus validates the use of human stem cell-derived neural lineages as potential in vitro models for screening of natural products with neuroprotective properties.

Vitamin C ameliorates the adverse effects of dexamethasone on sperm motility, testosterone level, and spermatogenesis indexes in mice

BACKGROUND:

Dexamethasone (DEX) is a common medicine that is capable of causing malformation in the male reproductive system. The aim of this study was to investigate the effect of vitamin C (Vit-C) on spermatogenesis indexes and daily sperm production (DSP) in adult mice treated with DEX.

METHODS:

Male Naval Medical Research Institute (NMRI) mice were divided into four groups: Control, DEX (7 mg/kg/day), Vit-C (100 mg/kg/day), and DEX +Vit-C and treated for 7 days with intraperitoneal injection.

RESULTS:

A significant increase in the mean levels of serum and tissue malondialdehyde (MDA) and apoptosis of Leydig cells was found in the DEX group compared to the control group. Sperm motility, DSP, tubular differentiation index, meiotic index, spermatogenesis index, the mean number of spermatocytes, round and long spermatids, and Leydig cells, and also serum testosterone level decreased in the DEX group compared to the control group. The results of this study indicate that Vit-C can significantly prevent the adverse effects of DEX on the mean number of spermatocyte, spermatid, and Leydig cells, tubular differentiation, meiotic and spermatogenesis index, DSP, sperm motility, and the mean levels of serum MDA.

CONCLUSION:

In conclusion, our results showed that coadministration of Vit-C and DEX prevents the adverse effects of DEX on the spermatogenesis indexes and DSP.

Non-genomic Effects of Glucocorticoids: An Updated View

Glucocorticoid (GC) anti-inflammatory effects generally require a prolonged onset of action and involve genomic processes. Because of the rapidity of some of the GC effects, however, the concept that non-genomic actions may contribute to GC mechanisms of action has arisen. While the mechanisms have not been completely elucidated, the non-genomic effects may play a role in the management of inflammatory diseases. For instance, we recently reported that GCs 'rapidly' enhanced the effects of bronchodilators, agents used in the treatment of allergic asthma. In this review article, we discuss (i) the non-genomic effects of GCs on pathways relevant to the pathogenesis of inflammatory diseases and (ii) the putative role of the membrane GC receptor. Since GC side effects are often considered to be generated through its genomic actions, understanding GC non-genomic effects will help design GCs with a better therapeutic index.

Prenatal Steroids and Metabolic Dysfunction: Lessons from Sheep

Prenatal exposure to excess steroids or steroid mimics can disrupt the normal developmental trajectory of organ systems, culminating in adult disease. The metabolic system is particularly susceptible to the deleterious effects of prenatal steroid excess. Studies in sheep demonstrate that prenatal exposure to excess native steroids or endocrine-disrupting chemicals with steroidogenic activity, such as bisphenol A, results in postnatal development of numerous cardiometabolic perturbations, including insulin resistance, increased adiposity, altered adipocyte size and distribution, and hypertension. The similarities in the phenotypic outcomes programmed by these different prenatal insults suggest that common mechanisms may be involved, and these may include hormonal imbalances (e.g., hyperandrogenism and hyperinsulinemia), oxidative stress, inflammation, lipotoxicity, and epigenetic alterations. Animal models, including the sheep, provide mechanistic insight into the metabolic repercussions associated with prenatal steroid exposure and represent valuable research tools in understanding human health and disease. Focusing on the sheep model, this review summarizes the cardiometabolic perturbations programmed by prenatal exposure to different native steroids and steroid mimics and discusses the potential mechanisms underlying the development of adverse outcomes.

Effect of dexamethasone intravitreal implant (Ozurdex®) on corneal endothelium in retinal vein occlusion patients : Corneal endothelium after dexamethasone implant injection

BACKGROUND

To assess corneal endothelial cell changes after intravitreal dexamethasone (DEX) implant (Ozurdex®) injection in patients with macular edema secondary to retinal vein occlusion (RVO).

METHODS

Twenty-two eyes of 22 patients were assessed prospectively after intravitreal 0.7 mg DEX implant injection. Twenty-two eyes of 22 healthy volunteers served as control group. Corneal endothelial cell parameters including endothelial cell density (ECD), coefficient of variation of cell size (CV), percentage of hexagonality (Hex) and central corneal thickness (CCT) were analyzed before and 1 and 3 months after injection by specular microscopy. The results of the study were compared statistically.

RESULTS

There were 17 (77.3%) patients with branch RVO and 5 (22.7%) patients with central RVO. Mean intraocular pressure (IOP) was 14.73 mmHg before injection, 17.05 mmHg at 1 month and 17.15 mmHg at 3 months after injection. Mean IOP at 1 and 3 months were significantly higher than pre-injection value (p = 0.002 and p = 0.003, respectively). There was a statistically significant reduction in mean ECD at 3 months after injection compared to pre-injection and 1 month (p = 0.013, p = 0.009, respectively) in the injected eyes. Mean ECD showed no significant difference in the uninjected fellow eyes during the follow up (p>0.05). Mean CV and Hex did not reveal a statistically significant difference in injected and uninjected fellow eyes (p > 0.05). No significant change was observed in mean CCT values during the follow up (p = 0.8).

CONCLUSION

Intravitreal dexamethasone implant may cause a transient reduction in corneal endothelial cell density in short term without changing cell morphology.

Sonic Hedgehog Agonist Protects Against Complex Neonatal Cerebellar Injury

The cerebellum undergoes rapid growth during the third trimester and is vulnerable to injury and deficient growth in infants born prematurely. Factors associated with preterm cerebellar hypoplasia include chronic lung disease and postnatal glucocorticoid administration. We modeled chronic hypoxemia and glucocorticoid administration in neonatal mice to study whole cerebellar and cell type-specific effects of dual exposure. Chronic neonatal hypoxia resulted in permanent cerebellar hypoplasia. This was compounded by administration of prednisolone as shown by greater volume loss and Purkinje cell death. In the setting of hypoxia and prednisolone, administration of a small molecule Smoothened-Hedgehog agonist (SAG) preserved cerebellar volume and protected against Purkinje cell death. Such protective effects were observed even when SAG was given as a one-time dose after dual insult. To model complex injury and determine cell type-specific roles for the hypoxia inducible factor (HIF) pathway, we performed conditional knockout of von Hippel Lindau (VHL) to hyperactivate HIF1α in cerebellar granule neuron precursors (CGNP) or Purkinje cells. Surprisingly, HIF activation in either cell type resulted in no cerebellar deficit. However, in mice administered prednisolone, HIF overactivation in CGNPs resulted in significant cerebellar hypoplasia, whereas HIF overactivation in Purkinje cells caused cell death. Together, these findings indicate that HIF primes both cell types for injury via glucocorticoids, and that hypoxia/HIF + postnatal glucocorticoid administration act on distinct cellular pathways to cause cerebellar injury. They further suggest that SAG is neuroprotective in the setting of complex neonatal cerebellar injury.

[Effect of corticosterone on lissencephaly 1 expression in developing cerebral cortical neurons of fetal rats cultured in vitro]

OBJECTIVE

To investigate the effect of corticosterone on the expression of the neuronal migration protein lissencephaly 1 (LIS1) in developing cerebral cortical neurons of fetal rats.

METHODS

The primary cultured cerebral cortical neurons of fetal Wistar rats were divided into control group, low-dose group, and high-dose group. The neurons were exposed to the medium containing different concentrations of corticosterone (0 μmol/L for the control group, 0.1 μmol/L for the low-dose group, and 1.0 μmol/L for the high-dose group). The neurons were collected at 1, 4, and 7 days after intervention. Western blot and immunocytochemical staining were used to observe the change in LIS1 expression in neurons.

RESULTS

Western blot showed that at 7 days after intervention, the low- and high-dose groups had significantly higher expression of LIS1 in the cytoplasm and nucleus of cerebral cortical neurons than the control group (P<0.05), and the high-dose group had significantly lower expression of LIS1 in the cytoplasm of cerebral cortical neurons than the low-dose group (P<0.05). Immunocytochemical staining showed that at 1, 4, and 7 days after corticosterone intervention, the high-dose group had a significantly lower mean optical density of LIS1 than the control group and the low-dose group (P<0.05). At 7 days after intervention, the low-dose group had a significantly lower mean optical density of LIS1 than the control group (P<0.05).

CONCLUSIONS

Corticosterone downregulates the expression of the neuronal migration protein LIS1 in developing cerebral cortical neurons of fetal rats cultured in vitro, and such effect depends on the concentration of corticosterone and duration of corticosterone intervention.

Sex-dependent mental illnesses and mitochondria

The prevalence of some mental illnesses, including major depression, anxiety-, trauma-, and stress-related disorders, some substance use disorders, and later onset of schizophrenia, is higher in women than men. While the higher prevalence in women could simply be explained by socioeconomic determinants, such as income, social status, or cultural background, extensive studies show sex differences in biological, pharmacokinetic, and pharmacological factors contribute to females' vulnerability to these mental illnesses. In this review, we focus on estrogens, chronic stress, and neurotoxicity from behavioral, pharmacological, biological, and molecular perspectives to delineate the sex differences in these mental illnesses. Particularly, we investigate a possible role of mitochondrial function, including biosynthesis, bioenergetics, and signaling, on mediating the sex differences in psychiatric disorders.

Compared antioxidant activity among corticosteroids on cultured retinal pigment epithelial cells

PURPOSE

The aim of this study is to determine if dexamethasone, prednisolone and triamcinolone acetonide (TA), three anti-inflammatory drugs commonly used for ocular treatments, could affect the oxidative status of cultured human cells of the retinal pigment epithelium (RPE) and protect them against oxidative injury.

METHODS

ARPE-19 cells were used as an in vitro model of RPE. Glutathione (GSH) levels were assessed to evaluate the effects of dexamethasone, prednisolone and triamcinolone on cellular antioxidant status. Oxidative stress was induced in ARPE-19 cells by treatment with the oxidizing agent menadione, and the effects of dexamethasone, prednisolone and triamcinolone were evaluated. Release of lactate dehydrogenase (LDH) in the culture medium was used to measure cytotoxicity.

RESULTS

Incubation with triamcinolone or prednisolone was not able to revert menadione-induced cytotoxicity and GSH depletion; furthermore, it significantly decreased GSH levels in ARPE-19 cells (nmol of GSH/mg cellular protein: 99.7 ± 0.1 in untreated controls vs. 52.6 ± 5.2 with triamcinolone vs. 77.6 ± 5.2 with prednisolone; p < 0.001). Treatment with dexamethasone protected ARPE-19 cells from cytotoxicity and oxidative damage: lactate dehydrogenase release and GSH depletion were significantly decreased after incubation with this compound (LDHout/LDHtot: 0.221 ± 0.038 with menadione vs. 0.041 ± 0.007 with menadione + dexamethasone; p < 0.001; nmol of GSH/mg cellular protein: 5.7 ± 4.2 with menadione vs. 53.2 ± 6.1 with menadione + dexamethasone, respectively; p < 0.001) and did not induce GSH depletion (nmol of GSH/mg cellular protein: 99.7 ± 0.1 vs. 86.5 ± 8.1 nmol/min/mg prot with dexamethasone; p > 0.05).

CONCLUSIONS

Dexamethasone, besides suppressing intraocular inflammation, may protect human RPE cells from oxidative stress and decrease the oxidation rate of GSH. Triamcinolone and prednisolone, inducing GSH depletion, may contribute to reduce antioxidant capacity of ARPE-19 cells.

Melatonin prevents cytosolic calcium overload, mitochondrial damage and cell death due to toxically high doses of dexamethasone-induced oxidative stress in human neuroblastoma SH-SY5Y cells

Stressor exposure activates the hypothalamic-pituitary-adrenal (HPA) axis and causes elevations in the levels of glucocorticoids (GC) from the adrenal glands. Increasing evidence has demonstrated that prolonged exposure to high GC levels can lead to oxidative stress, calcium deregulation, mitochondrial dysfunction and apoptosis in a number of cell types. However, melatonin, via its antioxidant activity, exhibits a neuroprotective effect against oxidative stress-induced cell death. Therefore, in the present study, we explored the protective effect of melatonin in GC-induced toxicity in human neuroblastoma SH-SY5Y cells. Cellular treatment with the toxically high doses of the synthetic GC receptor agonist, dexamethasone (DEX) elicited marked decreases in the levels of glutathione and increases in ROS production, lipid peroxidation and cell death. DEX toxicity also induced increases in the levels of cytosolic calcium and mitochondrial fusion proteins (Mfn1 and Opa1) but decreases in the levels of mitochondrial fission proteins (Fis1 and Drp1). Mitochondrial damage was observed in large proportions of the DEX-treated cells. Pretreatment of the cells with melatonin substantially prevented the DEX-induced toxicity. These results suggest that melatonin might exert protective effects against oxidative stress, cytosolic calcium overload and mitochondrial damage in DEX-induced neurotoxicity.

Dexamethasone acts as a radiosensitizer in three astrocytoma cell lines via oxidative stress

Glucocorticoids (GCs), which act on stress pathways, are well-established in the co-treatment of different kinds of tumors; however, the underlying mechanisms by which GCs act are not yet well elucidated. As such, this work investigates the role of glucocorticoids, specifically dexamethasone (DEXA), in the processes referred to as DNA damage and DNA damage response (DDR), establishing a new approach in three astrocytomas cell lines (CT2A, APP.PS1 L.1 and APP.PS1 L.3). The results show that DEXA administration increased the basal levels of gamma-H2AX foci, keeping them higher 4 h after irradiation (IR) of the cells, compared to untreated cells. This means that DEXA might cause increased radiosensitivity in these cell lines. On the other hand, DEXA did not have an apparent effect on the formation and disappearance of the 53BP1 foci. Furthermore, it was found that DEXA administered 2 h before IR led to a radical change in DNA repair kinetics, even DEXA does not affect cell cycle. It is important to highlight that DEXA produced cell death in these cell lines compared to untreated cells. Finally and most important, the high levels of gamma-H2AX could be reversed by administration of ascorbic acid, a potent blocker of reactive oxygen species, suggesting that DEXA acts by causing DNA damage via oxidative stress. These exiting findings suggest that DEXA might promote radiosensitivity in brain tumors, specifically in astrocytoma-like tumors.

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Dexamethasone causes DNA damage by increasing gamma-H2AX levels in three astrocytoma cell lines (CT2A, APP.PS1 L.1 and APP.PS1 L.3)

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Dexamethasone affects DNA repair kinetics and produces cell death in three astrocytoma cell lines (CT2A, APP.PS1 L.1 and APP.PS1 L.3) even dexamethasone does not affect any cell cycle arrest in any cell line studied.

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Oxidative stress appears to be one of the mechanisms of dexamethasone action in DNA damage as their effect is reversed with ascorbic acid addition.

Mitochondria in the center of human eosinophil apoptosis and survival

Eosinophils are abundantly present in most phenotypes of asthma and they contribute to the maintenance and exacerbations of the disease. Regulators of eosinophil longevity play critical roles in determining whether eosinophils accumulate into the airways of asthmatics. Several cytokines enhance eosinophil survival promoting eosinophilic airway inflammation while for example glucocorticoids, the most important anti-inflammatory drugs used to treat asthma, promote the intrinsic pathway of eosinophil apoptosis and by this mechanism contribute to the resolution of eosinophilic airway inflammation. Mitochondria seem to play central roles in both intrinsic mitochondrion-centered and extrinsic receptor-mediated pathways of apoptosis in eosinophils. Mitochondria may also be important for survival signalling. In addition to glucocorticoids, another important agent that regulates human eosinophil longevity via mitochondrial route is nitric oxide, which is present in increased amounts in the airways of asthmatics. Nitric oxide seems to be able to trigger both survival and apoptosis in eosinophils. This review discusses the current evidence of the mechanisms of induced eosinophil apoptosis and survival focusing on the role of mitochondria and clinically relevant stimulants, such as glucocorticoids and nitric oxide.

Accelerated aging of reproductive capacity in male rat offspring of protein-restricted mothers is associated with increased testicular and sperm oxidative stress

Maternal protein restriction (MPR) in pregnancy causes life course organ dysfunction, but few studies link the developmental origins of disease hypothesis to early aging. Suboptimal developmental nutrition increases oxidative stress (OS) and male infertility, damaging sperm function. We hypothesized that MPR in pregnancy accelerates age-related changes in testicular and sperm function related to both maternal diet and increased testicular OS in rat offspring. We studied male rats whose pregnant mothers ate either control (C, 20 % casein) or restricted (R, 10 % casein) isocaloric diet. After birth, mothers and offspring ate C diet. Testes were retrieved at 19 days gestation and across the life course (postnatal day (PND) 21, 36, 110, and 850) to measure OS markers, antioxidant enzymes, serum FSH, LH, and testosterone, and PND 110 sperm OS and quality. Fertility rate was evaluated at PND 110, 450, and 850. Offspring showed age- and MPR-related changes in testosterone, testicular OS markers and antioxidant enzymes and fertility, and maternal diet-related OS and sperm antioxidant enzyme changes. Developmental programming is considered a key factor in predisposing to chronic disease. Our data show that programming also plays an important role in aging trajectory. This interaction is a little studied area in aging biology that merits more investigation.

D-Arginine as a neuroprotective amino acid: promising outcomes for neurological diseases

In humans, as in other mammals, endogenous glucocorticoids (GCs) are essential for adapting to physiological life stress. They are also crucial for the healthy development of the fetus. However, when the physiological concentrations of GCs increase over a long period of time, the central nervous system (CNS) is predisposed to the development of psychiatric disorders and neurological diseases. Here, I discuss the strong influence of GCs on the nitric oxide (NO) pathway and the generation of reactive oxygen species (ROS). I also highlight supporting evidence for the neuroprotective actions of d-arginine (d-Arg) against neurotoxicity induced by high levels of GCs in the CNS. Given that d-Arg does not interfere with the immunosuppressive and anti-inflammatory effects of GCs, this might be a novel way of neutralizing the neurotoxic effects of GCs in the CNS without compromising their positive peripheral actions.

Melatonin attenuates dexamethasone toxicity-induced oxidative stress, calpain and caspase activation in human neuroblastoma SH-SY5Y cells

Glucocorticoids (GCs) have a significant role in the adaptive response of the brain to stress. Increasing evidence has demonstrated that an increase of GC levels may induce neuronal cell death via apoptotic pathways. There is a correlation between over-production of reactive oxygen species (ROS) and an elevation in cytosolic calcium that causes a subsequent increase in the calcium-dependent death-process activation in GC-induced toxicity. Consequently, melatonin, via its antioxidant activity, exhibits a neuroprotective effect against apoptosis induced by intracellular calcium overload. Therefore, in the present study, we explored the protective effect of melatonin in GC-induced toxicity in dopaminergic SH-SY5Y cells. Cellular treatment with the synthetic GCs, dexamethasone (DEX), resulted in a marked decrease in cell viability and in the level of the calpain-inhibitor protein, calpastatin. DEX-induced toxicity also caused an increase in ROS production and the activation of the calcium-dependent cysteine protease, calpain, along with an increase in caspase-3 activation. Pretreatment of the cells with melatonin substantially prevented the decrease in cell viability, over-production of ROS and the activation of calpain and caspase-3, and reversed the depletion in calpastatin levels. These results suggest that melatonin may exert its protective effects against the calpain- and caspase-dependent death process in DEX-induced neurotoxicity.

Dexamethasone induces apoptosis of progenitor cells in the subventricular zone and dentate gyrus of developing rat brain

The use of dexamethasone in premature infants to prevent and/or treat bronchopulmonary dysplasia adversely affects neurocognitive development and is associated with cerebral palsy. The underlying mechanisms of these effects are multifactorial and likely include apoptosis. The objective of this study was to confirm whether dexamethasone causes apoptosis in different regions of the developing rat brain. On postnatal day 2, pups in each litter were randomly divided into the dexamethasone-treated (n = 91) or vehicle-treated (n = 92) groups. Rat pups in the dexamethasone group received tapering doses of dexamethasone on postnatal days 3-6 (0.5, 0.25, 0.125, and 0.06 mg/kg/day, respectively). Dexamethasone treatment significantly decreased the gain of body and brain weight and increased brain caspase-3 activity, DNA fragments, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling, and cleaved caspse-3-positive cells at 24 hr after treatment. Dexamethasone increased cleaved caspse-3-positive cells in the cortex, thalamus, hippocampus, cerebellum, dentate gyrus, and subventricular zone. Double-immunofluorescence studies show that progenitor cells in the subventricular zone and dentate gyrus preferentially undergo apoptosis following dexamethasone exposure. These results indicate that dexamethasone-induced apoptosis in immature cells in developing brain is one of the mechanisms of its neurodegenerative effects in newborn rats.

Sox2 protects neural stem cells from apoptosis via up-regulating survivin expression

The transcription factor Sox2 [SRY (sex-determining region Y)-box 2] is essential for the regulation of self-renewal and homoeostasis of NSCs (neural stem cells) during brain development. However, the downstream targets of Sox2 and its underlying molecular mechanism are largely unknown. In the present study, we found that Sox2 directly up-regulates the expression of survivin, which inhibits the mitochondria-dependent apoptotic pathway in NSCs. Although overexpression of Sox2 elevates survivin expression, knockdown of Sox2 results in a decrease in survivin expression, thereby initiating the mitochondria-dependent apoptosis related to caspase 9 activation. Furthermore, cell apoptosis owing to knockdown of Sox2 can be rescued by ectopically expressing survivin in NSCs as well as in the mouse brain, as demonstrated by an in utero-injection approach. In short, we have found a novel Sox2/survivin pathway that regulates NSC survival and homoeostasis, thus revealing a new mechanism of brain development, neurological degeneration and such aging-related disorders.

Role of the hypothalamic-pituitary-adrenal axis in developmental programming of health and disease

Adverse environments during the fetal and neonatal development period may permanently program physiology and metabolism, and lead to increased risk of diseases in later life. Programming of the hypothalamic-pituitary-adrenal (HPA) axis is one of the key mechanisms that contribute to altered metabolism and response to stress. Programming of the HPA axis often involves epigenetic modification of the glucocorticoid receptor (GR) gene promoter, which influences tissue-specific GR expression patterns and response to stimuli. This review summarizes the current state of research on the HPA axis and programming of health and disease in the adult, focusing on the epigenetic regulation of GR gene expression patterns in response to fetal and neonatal stress. Aberrant GR gene expression patterns in the developing brain may have a significant negative impact on protection of the immature brain against hypoxic-ischemic encephalopathy in the critical period of development during and immediately after birth.

The developing, aging neocortex: how genetics and epigenetics influence early developmental patterning and age-related change

A hallmark of mammalian development is the generation of functional subdivisions within the nervous system. In humans, this regionalization creates a complex system that regulates behavior, cognition, memory, and emotion. During development, specification of neocortical tissue that leads to functional sensory and motor regions results from an interplay between cortically intrinsic, molecular processes, such as gene expression, and extrinsic processes regulated by sensory input. Cortical specification in mice occurs pre- and perinatally, when gene expression is robust and various anatomical distinctions are observed alongside an emergence of physiological function. After patterning, gene expression continues to shift and axonal connections mature into an adult form. The function of adult cortical gene expression may be to maintain neocortical subdivisions that were established during early patterning. As some changes in neocortical gene expression have been observed past early development into late adulthood, gene expression may also play a role in the altered neocortical function observed in age-related cognitive decline and brain dysfunction. This review provides a discussion of how neocortical gene expression and specific patterns of neocortical sensori-motor axonal connections develop and change throughout the lifespan of the animal. We posit that a role of neocortical gene expression in neocortex is to regulate plasticity mechanisms that impact critical periods for sensory and motor plasticity in aging. We describe results from several studies in aging brain that detail changes in gene expression that may relate to microstructural changes observed in brain anatomy. We discuss the role of altered glucocorticoid signaling in age-related cognitive and functional decline, as well as how aging in the brain may result from immune system activation. We describe how caloric restriction or reduction of oxidative stress may ameliorate effects of aging on the brain.