Changes in the brain antioxidant profile after chronic vanadium administration in mice

Mitochondria-associated endoplasmic reticulum membrane as a mediator of vanadium-induced endoplasmic reticulum quality control in duck brains

Vanadium (V) plays a crucial role in normal cells, but excess V causes multi-organ toxicity, including neurotoxicity. Mitochondria-associated endoplasmic reticulum membrane (MAM) is a dynamic structure between endoplasmic reticulum (ER) and mitochondria that mediates ER quality control (ERQC). To explore the effects of excess V on MAM and ERQC in the brain, 72 ducks were randomly divided into two groups: the control group (basal diet) and the V group (30 mg V/kg basal diet). On days 22 and 44, brain tissues were collected for histomorphological observation and determination of trace element contents. In addition, the mRNA and protein levels of MAM and ERQC-related factors in the brain were analyzed. Results show that excessive V causes the imbalance of trace elements, the integrity disruption of MAM, rupture of ER and autophagosomes formation. Moreover, it inhibits IP3R and VDAC1 co-localization, down-regulates the expression levels of MAM-related factors, but up-regulates the expression levels of ERQC and autophagy related factors. Together, results indicate that V exposure causes disruption of MAM and activates ERQC, which is further causing autophagy.

The mediating role of accelerated biological aging in the association between blood metals and cognitive function

Aging is a key risk factor in cognitive diseases. Recently, metal exposures were found associated with both biological aging and cognitive function. Here, we aim to evaluate the associations of blood metals with cognitive function and the mediated effect of biological aging. Fourteen metals were detected and biological age was calculated through Klemera and Doubal method among 514 adults in Beijing, China. The generalized linear models indicated that the copper (Cu), molybdenum (Mo), and strontium (Sr) were positively associated with biological aging [βCu (95% CI): 12.76 (9.26, 16.27); βMo (95% CI): 1.50 (0.15, 2.85)], and βSr (95% CI): 1.86 (0.68, 3.03)], while vanadium (V) was inversely related to biological aging [βV (95% CI): -0.76 (-1.48, -0.05)]. Subsequently, Cu, lead (Pb), selenium (Se), and biological aging were associated with cognitive function and further mediation analyses confirmed that biological aging partially mediated (33.98%, P = 0.019) the association of Cu and cognitive function. Additionally, we constructed a lifestyle index that implied the modifiable healthy lifestyle could slow aging to attenuate the detrimental effect of metals on cognition. Our findings provide insights into the potential pathways linking multiple metals exposure to aging and cognition and underscore the importance of adopting healthy lifestyles.

Neuropathological profile of the African Giant Rat brain (Cricetomys gambianus) after natural exposure to heavy metal environmental pollution in the Nigerian Niger Delta

Pollution by heavy metals is a threat to public health because of the adverse effects on multiple organ systems including the brain. Here, we used the African giant rat (AGR) as a novel sentinel host to assess the effect of heavy metal accumulation and consequential neuropathology upon the brain. For this study, AGR were collected from distinct geographical regions of Nigeria: the rain forest region of south-west Nigeria (Ibadan), the central north of Nigeria (Abuja), and in oil-polluted areas of south Nigeria (Port-Harcourt). We found that zinc, copper, and iron were the major heavy metals that accumulated in the brain and serum of sentinel AGR, with the level of iron highest in animals from Port-Harcourt and least in animals from Abuja. Brain pathology, determined by immunohistochemistry markers of inflammation and oxidative stress, was most severe in animals from Port Harcourt followed by those from Abuja and those from Ibadan were the least affected. The brain pathologies were characterized by elevated brain advanced oxidation protein product (AOPP) levels, neuronal depletion in the prefrontal cortex, severe reactive astrogliosis in the hippocampus and cerebellar white matter, demyelination in the subcortical white matter and cerebellar white matter, and tauopathies. Selective vulnerabilities of different brain regions to heavy metal pollution in the AGR collected from the different regions of the country were evident. In conclusion, we propose that neuropathologies associated with redox dyshomeostasis because of environmental pollution may be localized and contextual, even in a heavily polluted environment. This novel study also highlights African giant rats as suitable epidemiological sentinels for use in ecotoxicological studies.

Vanadium improves memory and spatial learning and protects the pyramidal cells of the hippocampus in juvenile hydrocephalic mice

Background

Hydrocephalus is a neurological condition known to cause learning and memory disabilities due to its damaging effect on the hippocampal neurons, especially pyramidal neurons. Vanadium at low doses has been observed to improve learning and memory abilities in neurological disorders but it is uncertain whether such protection will be provided in hydrocephalus. We investigated the morphology of hippocampal pyramidal neurons and neurobehavior in vanadium-treated and control juvenile hydrocephalic mice.

Methods

Hydrocephalus was induced by intra-cisternal injection of sterile-kaolin into juvenile mice which were then allocated into 4 groups of 10 pups each, with one group serving as an untreated hydrocephalic control while others were treated with 0.15, 0.3 and 3 mg/kg i.p of vanadium compound respectively, starting 7 days post-induction for 28 days. Non-hydrocephalic sham controls (n = 10) were sham operated without any treatment. Mice were weighed before dosing and sacrifice. Y-maze, Morris Water Maze and Novel Object Recognition tests were carried out before the sacrifice, the brains harvested, and processed for Cresyl Violet and immunohistochemistry for neurons (NeuN) and astrocytes (GFAP). The pyramidal neurons of the CA1 and CA3 regions of the hippocampus were assessed qualitatively and quantitatively. Data were analyzed using GraphPad prism 8.

Results

Escape latencies of vanadium-treated groups were significantly shorter (45.30 ± 26.30 s, 46.50 ± 26.35 s, 42.99 ± 18.44 s) than untreated group (62.06 ± 24.02 s) suggesting improvements in learning abilities. Time spent in the correct quadrant was significantly shorter in the untreated group (21.19 ± 4.15 s) compared to control (34.15 ± 9.44 s) and 3 mg/kg vanadium-treated group (34.35 ± 9.74 s). Recognition index and mean % alternation were lowest in untreated group (p = 0.0431, p=0.0158) suggesting memory impairments, with insignificant improvements in vanadium-treated groups. NeuN immuno-stained CA1 revealed loss of apical dendrites of the pyramidal cells in untreated hydrocephalus group relative to control and a gradual reversal attempt in the vanadium-treated groups. Astrocytic activation (GFAP stain) in the untreated hydrocephalus group were attenuated in the vanadium-treated groups under the GFAP stain. Pyknotic index in CA1 pyramidal layer of untreated (18.82 ± 2.59) and 0.15mg/kg vanadium-treated groups (18.14 ± 5.92) were significantly higher than control (11.11 ± 0.93; p = 0.0205, p = 0.0373) while there was no significant difference in CA3 pyknotic index across all groups.

Conclusion

Our results suggest that vanadium has a dose-dependent protective effect on the pyramidal cells of the hippocampus and on memory and spatial learning functions in juvenile hydrocephalic mice.

Naringin ameliorates motor dysfunction and exerts neuroprotective role against vanadium-induced neurotoxicity

Exposure to vanadium has been known to lead to a progressive neurodegenerative disorder like Parkinson's disease. Naringin is a known flavonoid glycoside that is mostly seen in the flesh of grapefruit and orange and is believed to have protective effects for the treatment of neurodegenerative disorders. This study sought to investigate the role of Naringin in the treatment of vanadium-induced neurotoxicity. Vanadium (10 mg/kg BW) was injected intraperitoneally to induce motor dysfunction, followed by treatment with Naringin (30 mg/kg BW) intraperitoneally for 14 days. Oxidative stress imbalance was monitored by checking Glutathione Peroxidase (GPX) and Catalase levels. Histological and immunohistochemical alterations were observed using RBFOX3 polyclonal antibody to determine neuronal cell distribution and NLRP3 inflammasome antibody as a marker of inflammation. Exposure to vanadium induces neurotoxicity by significantly increasing the Catalase and Glutathione Peroxidase (GPX) levels. Vanadium administration also led to increased inflammatory cells and a significant reduction of the viable neuronal cells in the SNc and CPu. Treatment with Naringin showed a neuroprotective role by dependently restoring the Catalase and Glutathione Peroxidase (GPX) levels, inflammasome activation, and neuronal damage in the SNc and CPu. Naringin demonstrated anti-oxidative, and anti-inflammatory responses by inhibiting oxidative stress, and inflammation and exerts neuroprotective effects by inhibiting apoptosis following vanadium-induced neurotoxicity in adult Wistar rats.

Neuroecotoxicology: Effects of environmental heavy metal exposure on the brain of African giant rats and the contribution of vanadium to the neuropathology

Increased exploitation of minerals has led to pollution of confined environments as documented in Nigeria Niger Delta. Information on the effects on brain of such exposure is limited. Due to its exploratory activities, the African giant rat (Cricetomys gambianus) (AGR) provides a unique model for neuroecotoxicological research to determine levels of animal and human exposure to different pollutants. This study aims to unravel neuropathological features of AGR sampled from three agro-ecological zones of Nigeria. Fifteen AGR were sampled according to previously determined data on heavy metal exposure: high vanadium, high lead, and low metals. Eighteen AGR were collected from low metal zone and divided into two groups. Control group received vehicle while SMV exposed group received 3 mg/kg sodium metavanadate (SMV) intraperitoneally for 14days. Brain immunohistochemical analyses were conducted, and ultrastructural changes were studied in experimentally exposed group. Results showed significant loss of tyrosin hydroxylase, parvalbumin, orexin-A and melanin concentration hormone containing neuronal populations in brains obtained from high vanadium and high lead zones and in experimentally intoxicated SMV groups. Similarly, significant decrease numbers of dendritic arborations; extracellular matrix density, perineuronal nets; astrocytes and microglia activations are documented in same groups. Ultrastructural studies revealed mass denudation, cilia loss, disintegration of ependymal layer and intense destructions of myelin sheaths in SMV exposed group. These are the first "neuroecotoxicological" findings in distinct neuronal cells. The implications of these findings are highly relevant for human population living in these areas, not only in Nigeria but also in similarly polluted areas elsewhere in the world.

Tramadol and Codeine Stacking/Boosting Dose Exposure Induced Neurotoxic Behaviors, Oxidative Stress, Mitochondrial Dysfunction, and Neurotoxic Genes in Adolescent Mice

In spite of the increasing epidemic of pharmaceutical opioids (codeine and tramadol) misuse and abuse among the adolescents, little is known about the neurotoxic consequences of the widespread practice of tramadol and codeine abuse involving increasing multiple doses across days, referred to as stacking and boosting. Hence, in this study, we replicated stacking and boosting doses of tramadol, codeine alone, or in combination on spontaneous motor activity and cognitive function in adolescent mice and adduced a plausible mechanism of possible neurotoxicity. Ninety-six adolescent mice were randomly distributed into 4 groups (n = 24 per group) and treated thrice daily for 9 days with vehicle, tramadol (20, 40, or 80 mg/kg), codeine (40, 80, or 160 mg/kg), or their combinations. Exposure of mice to tramadol induced hyperactivity and stereotypic behavior while codeine exposure caused hypoactivity and nootropic effect but tramadol-codeine cocktail led to marked reduction in spontaneous motor activity and cognitive function. In addition, tramadol, codeine, and their cocktail caused marked induction of nitroso-oxidative stress and inhibition of mitochondrial complex I activity in the prefrontal cortex (PFC) and midbrain (MB). Real-time PCR expression profiling of genes encoding neurotoxicity (RT) showed that tramadol exposure upregulate 57 and downregulate 16 neurotoxic genes, codeine upregulate 45 and downregulate 25 neurotoxic genes while tramadol-codeine cocktail upregulate 52 and downregulate 20 neurotoxic genes in the PFC. Findings from this study demonstrate that the exposure of adolescents mice to multiple and increasing doses of tramadol, codeine, or their cocktail lead to spontaneous motor coordination deficits indicative of neurotoxicity through induction of oxidative stress, inhibition of mitochondrial complex I activity and upregulation of neurotoxicity encoding genes in mice.

Effects of Sodium Pyruvate on Vanadyl Sulphate-Induced Reactive Species Generation and Mitochondrial Destabilisation in CHO-K1 Cells

Vanadium is ranked as one of the world’s critical metals considered important for economic growth with wide use in the steel industry. However, its production, applications, and emissions related to the combustion of vanadium-containing fuels are known to cause harm to the environment and human health. Pyruvate, i.e., a glucose metabolite, has been postulated as a compound with multiple cytoprotective properties, including antioxidant and anti-inflammatory effects. The aim of the present study was to examine the antioxidant potential of sodium pyruvate (4.5 mM) in vanadyl sulphate (VOSO₄)-exposed CHO-K1 cells. Dichloro-dihydro-fluorescein diacetate and dihydrorhodamine 123 staining were performed to measure total and mitochondrial generation of reactive oxygen species (ROS), respectively. Furthermore, mitochondrial damage was investigated using MitoTell orange and JC-10 staining assays. We demonstrated that VOSO₄ alone induced a significant rise in ROS starting from 1 h to 3 h after the treatment. Additionally, after 24 and 48 h of exposure, VOSO₄ elicited both extensive hyperpolarisation and depolarisation of the mitochondrial membrane potential (MMP). The two-way ANOVA analysis of the results showed that, through antagonistic interaction, pyruvate prevented VOSO₄-induced total ROS generation, which could be observed at the 3 h time point. In addition, through the independent action and antagonistic interaction with VOSO₄, pyruvate provided a pronounced protective effect against VOSO₄-mediated mitochondrial toxicity at 24-h exposure, i.e., prevention of VOSO₄-induced hyperpolarisation and depolarisation of MMP. In conclusion, we found that pyruvate exerted cytoprotective effects against vanadium-induced toxicity at least in part by decreasing ROS generation and preserving mitochondrial functions

Vanadium Induces Oxidative Stress and Mitochondrial Quality Control Disorder in the Heart of Ducks

Vanadium (V) is an ultra-trace element presenting in humans and animals, but excessive V can cause toxic effects. Mitochondrial quality control (MQC) is an essential process for maintaining mitochondrial functions, but the relationship between V toxicity and MQC is unclear. To investigate the effects of excessive V on oxidative stress and MQC in duck hearts, 72 ducks were randomly divided into two groups, including the control group and the V group (30 mg of V/kg dry matter). The cardiac tissues were collected for the histomorphology observation and oxidative stress status evaluation at 22 and 44 days. In addition, the mRNA and protein levels of MQC-related factors were also analyzed. The results showed that excessive V could trigger vacuolar degeneration, granular degeneration, as well as mitochondrial vacuolization and swelling in myocardial cells. In addition, CAT activity was elevated in two time points, while T-SOD activity was increased in 22 days but decreased in 44 days after V treatment. Meanwhile, excessive V intake could also increase the number of Drp1 puncta, the mRNA levels of mitochondrial fission–related factors (Drp1and MFF), and protein (MFF) level, but decrease the number of Parkin puncta and the mitochondrial biogenesis (PGC-1α, NRF-1, and TFAM), mitochondrial fusion (OPA1, Mfn1, and Mfn2), and mitophagy (Parkin, PINK1, P62, and LC3B) related mRNA levels and protein (PGC-1α, Mfn1, Mfn2, PINK1) levels. Collectively, our results suggested that excessive V could induce oxidative stress and MQC disorder in the heart of ducks.

Study on the Pharmacological Character of an Insulin-Mimetic Small Molecular Compound of Vanadyl Trehalose

To investigate the effect of vanadyl trehalose (VT) on oxidative stress and reduced glutathione/glutathione-S-transferase (GSH/GSTs) pathway gene expression in mouse gastrointestinal tract, as well as the protective effects of vitamin C (VC) and reduced glutathione (GSH). Thirty male Kunming mice were randomly divided into five groups: control group (group A), VT group (group B), VC + VT group (group C), GSH + VT group (group D) and VC + GSH + VT group (group E). The content of reduced glutathione (GSH) and glutathione peroxidase (GSH-Px) activity and the expressions of glutamate-cysteine ligase catalytic subunit (GCLC), glutathione synthetase (GSS), regulated through glutathione reductase (GSR) and glutathione-S-transferase pi (GSTpi) in stomach and duodenum in vanadyl trehalose treated group were lower than those in group A (P<0.05). The C, D, E group can significantly improve the above indicators, but those only in the stomach in E group reached the level of the control group. Vanadyl trehalose (VT) was able to cause oxidative stress damage to the gastrointestinal tract of mice, which affects GSH content and GSH-Px activity and interferes with the normal expression of GSH/GSTs pathway. Exogenous vitamin C, reduced glutathione and the combination of the two could play a specific role in antioxidant protection and reduce the toxicity of vanadyl trehalose.

Novel NMDA-receptor antagonists ameliorate vanadium neurotoxicity

Various NMDA-receptor antagonists have been investigated for their therapeutic potential in Alzheimer's disease with memantine shown to be safe and with relative efficacy. There is, however, need to develop novel drugs to counter tolerance and with better efficacy in ameliorating neurodegeneration. We have shown neurodegeneration in different models of vanadium-exposed mice. This study was designed to evaluate and ascertain the potency of three novel NMDA-receptor antagonists (Compounds A, B and C) to ameliorate neurodegeneration in vanadium-exposed mice. One-month-old mice (n = 6) received sterile water (control) and another group (n = 6) was treated with vanadium (3 mg/kg sodium metavanadate) intraperitoneally for 1 month. Three other groups (n = 6) received vanadium and compounds A, B and C (4.35 mg/kg, 30 mg/kg and 100 mg/kg, respectively) simultaneously for the same period. Assessment of pathologies and neurodegeneration in different brain regions was done to test the ameliorative effects of the 3 antagonists using different immunohistochemical markers. Vanadium exposure resulted in reduced calbindin expression and pyknosis of Purkinje cells, cell loss and destruction of apical dendrites with greater percentage of cytoplasmic vacuolations, morphological alterations characterized by cell clustering and multiple layering patterns in the Purkinje cell layer. In addition, the observed degeneration included demyelination, increased GFAP-immunoreactive cells and microgliosis. Simultaneous administration of the compounds to vanadium-exposed mice resulted in the preservation of cellular integrity in the same anatomical regions and restoration of the cells' vitality with reduced astroglial and microglial activation.

In vitro effect of vanadyl sulfate on cultured primary astrocytes: cell viability and oxidative stress markers

Exposure to vanadium has been associated with deleterious effects on the central nervous system in animals and humans. Although vanadium-derived pro-oxidant species were reported to be involved in vanadium-mediated neurotoxicity, the ability of this metal to induce oxidative stress markers in glial cells remains to be elucidated. In this study, we investigated the cytotoxicity and the generation of reactive oxygen species (ROS) and nitric oxide (NO) by mouse primary astrocytes after treatment with vanadyl sulfate (VOSO₄ ) at concentrations of 20, 50, 100, 200, and 500 μM. The resazurin assay revealed that treatment with VOSO₄ for 24 and 48 h at concentrations of 50 and 100 μM, respectively, or higher substantially induced astrocytic cytotoxicity. Intracellular ROS increased after 6-h exposure to the lowest concentration tested (20 μM VOSO₄ ) and tended to intensify after 24- and 48-h treatments reaching significant values for 20 and 500 μM VOSO₄ . In turn, NO production in the examined cells was elevated after exposure to all concentrations at the 6-, 24-, and 48-h incubation periods. Our study demonstrated the ability of VOSO₄ to induce H₂ O₂ generation in cell-free DMEM/F12 medium. The H₂ O₂ levels were in the micromolar range (up to 5 μM) and were detected mostly during the first few minutes after VOSO₄ addition, suggesting that the generated H₂ O₂ could not induce toxic effects on the cells. Taken together, these results show VOSO₄ induced cytotoxicity in primary astrocyte cells, which may have resulted from vanadyl-stimulated intracellular ROS and NO generation in these cells.

Vanadium and Oxidative Stress Markers - In Vivo Model: A Review

This review article is an attempt to summarize the current state of knowledge of the impact of Vanadium (V) on Oxidative Stress (OS) markers in vivo. It shows the results of our studies and studies conducted by other researchers on the influence of different V compounds on the level of selected Reactive Oxygen Species (ROS)/Free Radicals (FRs), markers of Lipid peroxidation (LPO), as well as enzymatic and non-enzymatic antioxidants. It also presents the impact of ROS/peroxides on the activity of antioxidant enzymes modulated by V and illustrates the mechanisms of the inactivation thereof caused by this metal and reactive oxygen metabolites. It also focuses on the mechanisms of interaction of V with some nonenzymatic compounds of the antioxidative system. Furthermore, we review the routes of generation of oxygen-derived FRs and non-radical oxygen derivatives (in which V is involved) as well as the consequences of FR-mediated LPO (induced by this metal) together with the negative/ positive effects of LPO products. A brief description of the localization and function of some antioxidant enzymes and low-molecular-weight antioxidants, which are able to form complexes with V and play a crucial role in the metabolism of this element, is presented as well. The report also shows the OS historical background and OS markers (determined in animals under V treatment) on a timeline, collects data on interactions of V with one of the elements with antioxidant potential, and highlights the necessity and desirability of conducting studies of mutual interactions between V and antioxidant elements.

Trends in vanadium neurotoxicity

Vanadium, atomic number 23, is a transition metal widely distributed in nature. It is a major contaminant of fossil fuels and is widely used in industry as catalysts, in welding, and making steel alloys. Over the years, vanadium compounds have been generating interests due to their use as therapeutic agents in the control of diabetes, tuberculosis, and some neoplasms. However, the toxicity of vanadium compounds is well documented in literature with occupational exposure of workers in vanadium allied industries, environmental pollution from combustion of fossil fuels and industrial exhausts receiving concerns as major sources of toxicity and a likely predisposing factor in the aetiopathogenesis of neurodegenerative diseases. A lot has been done to understand the neurotoxic effects of vanadium, its mechanisms of action and possible antidotes. Sequel to our review of the subject in 2011, this present review is to detail the recent insights gained in vanadium neurotoxicity.

Notes on the Recent History of Neuroscience in Africa

Neuroscience began with neuroanatomy and neurosurgery in Egypt more than 5000 years ago. Knowledge grew over time and specialized neurosurgery centers were established in north Africa in the eleventh century. However, it was not until the twentieth century that neuroscience research became established in sub-Saharan Africa. In most African countries, clinical research focused on understanding the rationale and improving treatment of epilepsy, infections, nutritional neuropathies, stroke and tumors. Significant advances were made. In the twenty-first century, African knowledge expanded to include all branches of neuroscience, contributing to genetic, biochemical and inflammatory determinants of brain disorders. A major focus of basic neuroscience research has been, and is, investigation of plant extracts, drugs and stress in animal models, providing insight and identifying potential novel therapies. A significant event in the history of African neuroscience was the founding of the Society of Neuroscientists of Africa (SONA) in 1993. The International Brain Research Organization (IBRO) supported SONA conferences, as well as workshops and neuroscience training schools in Africa. Thanks to their investment, as well as that of funding agencies, such as the National Institutes of Health (NIH), International Society for Neurochemistry (ISN), World Federation of Neurosurgical Societies (WFNS), World Federation of Neurology (WFN) and the International League Against Epilepsy (ILAE), neuroscience research is well-established in Africa today. However, in order to continue to develop, African neuroscience needs continued international support and African neuroscientists need to engage in policy and decision-making to persuade governments to fund studies that address the unique regional needs in Africa.