Modulation of caspase-3 gene expression and protective effects of garlic and spirulina against CNS neurotoxicity induced by lead exposure in male rats

Neuroprotective Assessment of Betaine against Copper Oxide Nanoparticle-Induced Neurotoxicity in the Brains of Albino Rats: A Histopathological, Neurochemical, and Molecular Investigation

Copper oxide nanoparticles (CuO-NPs) are commonly used metal oxides. Betaine possesses antioxidant and neuroprotective activities. The current study aimed to investigate the neurotoxic effect of CuO-NPs on rats and the capability of betaine to mitigate neurotoxicity. Forty rats; 4 groups: group I a control, group II intraperitoneally CuO-NPs (0.5 mg/kg/day), group III orally betaine (250 mg/kg/day) and CuO-NPs, group IV orally betaine for 28 days. Rats were subjected to neurobehavioral assessments. Brain samples were processed for biochemical, molecular, histopathological, and immunohistochemical analyses. Behavioral performance of betaine demonstrated increasing locomotion and cognitive abilities. Group II exhibited significantly elevated malondialdehyde (MDA), overexpression of interleukin-1 beta (IL-1β), and tumor necrosis factor-alpha (TNF-α). Significant decrease in glutathione (GSH), and downregulation of acetylcholine esterase (AChE), nuclear factor erythroid 2-like protein 2 (Nrf-2), and superoxide dismutase (SOD). Histopathological alterations; neuronal degeneration, pericellular spaces, and neuropillar vacuolation. Immunohistochemically, an intense immunoreactivity is observed against IL-1β and glial fibrillary acidic protein (GFAP). Betaine partially neuroprotected against CuO-NPs associated alterations. A significant decrease at MDA, downregulation of IL-1β, and TNF-α, a significant increase at GSH, and upregulation of AChE, Nrf-2, and SOD. Histopathological alterations partially ameliorated. Immunohistochemical intensity of IL-1β and GFAP reduced. It is concluded that betaine neuroprotected against most of CuO-NP neurotoxic effects through antioxidant and cell redox system stimulating efficacy.

Antioxidant and anti-inflammatory potential of spirulina and thymoquinone mitigate the methotrexate-induced neurotoxicity

The objective of this study was to investigate whether the neurotoxic effects caused by methotrexate (MTX), a frequently used chemotherapy drug, could be improved by administering Spirulina platensis (SP) and/or thymoquinone (TQ). Seven groups of seven rats were assigned randomly for duration of 21 days. The groups consisted of a control group that was given saline only. The second group was given 500 mg/kg of SP orally; the third group was given 10 mg/kg of TQ orally. The fourth group was given a single IP dose of 20 mg/kg of MTX on the 15th day of the experiment. The fifth group was given both SP and MTX, the sixth group was given both TQ and MTX, and the seventh group was given SP, TQ, and MTX. After MTX exposure, the study found that AChE inhibition, depletion of glutathione, and increased levels of MDA occurred. MTX also decreased the activity of SOD and CAT, as well as the levels of inflammatory mediators such as IL-1, IL-6, and tumor necrosis factor-α. MTX induced apoptosis in brain tissue. However, when MTX was combined with either SP or TQ, the harmful effects on the body were significantly reduced. This combination treatment resulted in a faster return to normal levels of biochemical, oxidative markers, inflammatory responses, and cell death. In conclusion, supplementation with SP or TQ could potentially alleviate MTX-induced neuronal injury, likely due to their antioxidant, anti-inflammatory, and anti-apoptotic effects.

Role of Nitric Oxide, TNF-α and Caspase-3 in Lead Acetate-Exposed Rats Pretreated with Aqueous Rosmarinus officinalis Leaf Extract

Lead (Pb) toxicity is a worldwide significant public health challenge causing several neurological disorders. Reports indicate that plants rich in antioxidants, such as Rosmarinus officinalis (RO), can counteract Pb accumulation and its toxicity in the brain. Due to a dearth of literature evidence demonstrating the protective activity of RO against Pb toxicity, this study investigated such activity in Wistar rats. Thirty-six Wistar rats were allocated into six groups (n=6), namely I (control), II (lead acetate [Pb]; 100 mg/kg b.w.), III (100 mg/kg of RO and 100 mg/kg of Pb), IV (200 mg/kg of RO and 100 mg/kg of Pb), V (100 mg/kg b.w. of RO) and VI (200 mg/kg b.w. of RO). After 28 days, neurobehavioural, antioxidant, lipid peroxidation, apoptotic and inflammatory activities as well as the histology of the cerebellum were evaluated. Body weight, locomotion and exploration as well as antioxidant enzymes were significantly (p < 0.05) decreased in Pb-exposed rats when compared to control. Conversely, lipid peroxidation, nitric oxide, tumour necrosis factor-alpha and caspase-3 activities were significantly (p < 0.05) upregulated in the Pb-exposed rats when compared to control. These parameters were, however, significantly (p<0.05) attenuated in the RO-pretreated rats when compared to Pb-exposed rats. Cerebellar histology of the Pb-exposed rats showed severe degeneration of the Purkinje cells whereas the RO-pretreated rats showed better cerebellar architecture. These findings demonstrate that the neuroprotective activity of RO is facilitated via its effective antioxidant, anti-inflammatory and anti-apoptotic effects.

Possible role of selenium in ameliorating lead-induced neurotoxicity in the cerebrum of adult male rats: an experimental study

Chronic lead (Pb) poisoning is one of the greatest public health risks. The nervous system is the primary and most vulnerable target of Pb poisoning. Selenium (Se) has been shown to be a potential protection against heavy metal toxicity through anti-inflammatory and antioxidant properties. Therefore, the present study aimed to elucidate the possible protective role of Se in ameliorating the effects of Pb on rat cerebral structure by examining oxidative stress and markers of apoptosis. The rats were divided into 6 groups: control group, Se group, low Pb group, high Pb group, low Pb + Se group, high Pb + Se group. After the 4-week experiment period, cerebral samples were examined using biochemical and histological techniques. Pb ingestion especially when administered in high doses resulted in cerebral injury manifested by a significant increase in glial fibrillary acidic protein, malondialdehyde (MDA) marker of brain oxidation and DNA fragmentation. Moreover, Pb produced alteration of the normal cerebral structure and cellular degeneration with a significant reduction in the total number of neurons and thickness of the frontal cortex with separation of meninges from the cerebral surface. There was also a decrease in total antioxidant capacity. All these changes are greatly improved by adding Se especially in the low Pb + Se group. The cerebral structure showed a relatively normal histological appearance with normally attached pia and an improvement in neuronal structure. There was also a decrease in MDA and DNA fragmentation and an increase TAC. Selenium is suggested to reduce Pb-induced neurotoxicity due to its modulation of oxidative stress and apoptosis.

Screening and Identification of Probiotic Lactobacilli from the Infant Gut Microbiota to Alleviate Lead Toxicity

Lead (Pb2+) exposure cause a potential hazard to human health and the ecological environment; however, prevention and treatment of Pb2+ toxicity remain problems. The aim of this study is to isolate a novel probiotic lead (Pb2+)-resistant Lactobacillus strain from the infant gut microbiota and to determine whether they have the probiotic properties and investigate its preventive and therapeutic effects in the early-life Pb2+ exposure mouse model. In the present study, a total of 64 Pb2+-resistant colonies were isolated from the infant gut microbiota. Of these colonies, SYF-08, identified as Lacticaseibacillus casei, exhibited a Pb2+-binding capacity and Pb2+ tolerance. The in vivo study showed that SYF-08 treatment could effectively reduce Pb2+ levels in the blood, alleviate Pb2+ enrichment in bone and brain tissues, and recover the intestinal and brain damage in both dams and offspring. SYF-08 treatment also improved the antioxidant index in the liver and kidney tissues, while increasing the diversity of the intestinal microbiota of the offspring. The results of the in vitro and in vivo studies suggest that SYF-08, isolated from infant fecal samples, is a promising candidate probiotic against Pb2+ toxicity.

Assessment of the neuroprotective effect of selenium-loaded chitosan nanoparticles against silver nanoparticles-induced toxicity in rats

BACKGROUND

With the recent growth in the applications of silver nanoparticles (Ag-NPs), worries about their harmful effects are increasing. Selenium plays a vital role in the antioxidant defense system as well as free radical scavenging activity.

OBJECTIVES

This study aims to inspect the neuroprotective effect of selenium-loaded chitosan nanoparticles (CS-SeNPs) against the adverse impact of Ag-NPs on brain tissue in adult rats.

DESIGN

Rats were divided into four groups: group I (control) was administered distilled water (0.5 mL/kg), group II was administered Ag-NPs (100 mg/kg), group III was administered Ag-NPs (100 mg/kg) and CS- SeNPs (0.5 mg/kg) and group IV received only CS- SeNPs (0.5 mg/kg) daily by oral gavage. After 60 days, rats were subjected to behavioral assessment and then euthanized. Brain tissues were obtained for estimation of total antioxidant capacity (TAC), malondialdehyde (MDA), 8-hydroxy-2-deoxy Guanosine (8-OHdG), and Nuclear Factor Erythroid 2 Like Protein 2 (Nrf2). Also, histological examination of the brain and immunohistochemical detection of glial fibrillary acidic protein (GFAP) were investigated RESULTS: exposure to Ag-NPs induced marked neurotoxicity in the brain tissue of rats that was manifested by decreased levels of TAC and Nrf2 with increased levels of MDA and 8-OHdG. Also, various pathological lesions with an increase in the number of GFAP immunoreactive cells were detected. While brain tissue of rats received Ag-NPs plus CS-SeNPs group (III) revealed significantly fewer pathological changes.

CONCLUSION

Co-administration of CS-SeNPs significantly ameliorates most of the Ag-NPs-induced brain damage.

Zinc nanoparticles ameliorate oxidative stress and apoptosis induced by silver nanoparticles in the brain of male rats

The current study was conducted to investigate the possible ameliorative role of zinc nanoparticles (Zn NPs) against silver nanoparticles (Ag NPs)-induced oxidative and apoptotic brain damage in adult male rats. Twenty-four mature Wistar rats were randomly and equally divided into four groups: control group, Ag NPs group, Zn NPs group, and Ag NPs + Zn NPs group. Rats were exposed to Ag NPs (50 mg/kg) and/or Zn NPs (30 mg/kg) daily by oral gavage for 12 weeks. The results revealed that exposure to Ag NPs significantly increased malondialdehyde (MDA) content, decreased catalase and reduced glutathione (GSH) activities, downregulated the relative mRNA expression of antioxidant-related genes (Nrf-2 and SOD), and upregulated the relative mRNA expression of apoptosis-related genes (Bax, caspase 3 and caspase 9) in the brain tissue. Furthermore, severe neuropathological lesions with a substantial increase in the caspase 3 and glial fibrillary acidic protein (GFAP) immunoreactivity were observed in the cerebrum and cerebellum of Ag NPs-exposed rats. Conversely, co-administration of Zn NPs with Ag NPs significantly ameliorated most of these neurotoxic effects. Collectively, Zn NPs can be used as a potent prophylactic agent against Ag NPs-induced oxidative and apoptotic neural damage.

Effects of Aluminum Oxide Nanoparticles in the Cerebrum, Hippocampus, and Cerebellum of Male Wistar Rats and Potential Ameliorative Role of Melatonin

Aluminum oxide nanoparticles (Al₂O₃ NPs) have been widely used in vaccine manufacture, food additives, human care products, and cosmetics. However, they also have adverse effects on different organs, including the liver, kidneys, and testes. Melatonin is a potent antioxidant, particularly against metals by forming melatonin-metal complexes. The present study aimed to investigate the protective effects of melatonin against Al₂O₃ NP-induced toxicity in the rat brain. Forty adult male Wistar rats were allocated to four groups: the untreated control (received standard diet and distilled water), Al₂O₃ NP-treated (received 30 mg/kg body weight Al₂O₃ NPs), melatonin and Al₂O₃ NP-treated (received 30 mg/kg body weight Al₂O₃ NPs + 10 mg/kg body weight melatonin), and melatonin-treated (received 10 mg/kg body weight melatonin) groups. All treatments were by oral gavages and administered daily for 28 days. Afterward, the rats were sacrificed, and samples from various brain regions (cerebrum, cerebellum, and hippocampus) were subjected to biochemical, histopathological, and immunohistochemical analyses. Al₂O₃ NPs substantially increased malondialdehyde, β-amyloid 1-42 peptide, acetylcholinesterase, and β-secretase-1 expression, whereas they markedly decreased glutathione levels. Furthermore, Al₂O₃ NPs induced severe histopathological alterations, including vacuolation of the neuropil, enlarged pericellular and perivascular spaces, vascular congestion, neuronal degeneration, and pyknosis. Al₂O₃ NP treatment also resulted in an intense positive caspase-3 immunostaining. Conversely, the administration of melatonin alleviated the adverse effects induced by Al₂O₃ NPs. Therefore, melatonin can diminish the neurotoxic effects induced by Al₂O₃ NPs.

Sesamin: Insights into its protective effects against lead-induced learning and memory deficits in rats

BACKGROUND

Lead (Pb) is one of the most hazardous pollutants that induce a wide spectrum of neurological changes such as learning and memory deficits. Sesamin, a phytonutrient of the lignan class, exhibits anti-inflammatory, anti-apoptotic, and neuroprotective properties. The present study was designed to investigate the effects of sesamin against Pb-induced learning and memory deficits, disruption of hippocampal theta and gamma rhythms, inflammatory response, inhibition of blood δ-aminolevulinic acid dehydratase (δ-ALA-D) activity, Pb accumulation, and neuronal loss in rats.

METHODS

Sesamin treatment (30 mg/kg/day; P.O.) was started simultaneously with Pb acetate exposure (500 ppm in standard drinking water) in rats, and they continued for eight consecutive weeks.

RESULTS

The results showed that chronic exposure to Pb disrupted the learning and memory functions in both passive-avoidance and water-maze tests, which was accompanied by increase in spectral theta power and theta/gamma ratio, and a decrease in spectral gamma power in the hippocampus. Additionally, Pb exposure resulted in an enhanced tumor necrosis factor-alpha (TNF-α) content, decreased interleukin-10 (IL-10) production, inhibited blood δ-ALA-D activity, increased Pb accumulation, and neuronal loss of rats. In contrast, sesamin treatment improved all the above-mentioned Pb-induced pathological changes.

CONCLUSION

This data suggests that sesamin could improve Pb-induced learning and memory deficits, possibly through amelioration of hippocampal theta and gamma rhythms, modulation of inflammatory status, restoration of the blood δ-ALA-D activity, reduction of Pb accumulation in the blood and the brain tissues, and prevention of neuronal loss.

Taify Pomegranate Juice (TPJ) Abrogates Acrylamide-Induced Oxidative Stress Through the Regulation of Antioxidant Activity, Inflammation, and Apoptosis-Associated Genes

Acrylamide (ACR) has various effects on biological systems, including oxidative stress and its associated metabolic disorders. Previous research reports that plants growing at high altitude have a different profile of antioxidants. In the current report, the Taify pomegranate juice (TPJ) of the Taify pomegranate growing at the Taif region (high altitude), Saudi Arabia, was investigated for its protective activity from ACR-induced oxidative stress. Rats were treated with ACR, TPJ, or TPJ+ACR, and various assays, including blood chemistry, liver function biomarkers, gene expression of endogenous antioxidant enzymes, oxidative stress regulatory genes, inflammation biomarkers, and apoptosis, were estimated using biochemical, real-time PCR, histopathological, and immunohistochemical analysis. TPJ showed a protective function of ACR-induced alteration of AST, ALT, GGT, urea, total proteins, albumin, MDA, and NO. It also increased the level of the endogenous antioxidative enzymes, including SOD, catalase, and GSH. It showed anti-inflammatory activity by reduction the TNF-α, IL-6 secretion and the enhancing of IL-10 levels. At the gene expression level, TPJ upregulated the expression of endogenous antioxidant genes (SOD and catalase) and of antioxidant-regulating genes Nrf2 and HO-1; downregulated the expression of inflammatory genes TGF-β1, COX2, and the apoptotic gene caspase-3; and upregulated the expression of antiapoptotic gene Bcl2. At the histological level, TPJ showed a protective effect from the ACR-induced hepatic histological damage. Results of this study conclude that TPJ has a protective effect from ACR-induced oxidative stress and its associated metabolic alterations through its antioxidant and anti-inflammatory activities.

Curcumin Suppresses Lead-Induced Inflammation and Memory Loss in Mouse Model and In Silico Molecular Docking

This study examined the efficacy of curcumin (Cur) against lead (Pb)-induced oxidative damage, inflammation, and cholinergic dysfunction. Institute for Cancer Research (ICR) mice received Pb (II) acetate in drinking water (1%) with or without Cur via oral gavage. Blood and brain tissues were collected for investigation. Pb increased the inflammatory markers and oxidative parameters, which were ameliorated by Cur administration. Cur treatment also improved memory loss, learning deficit, and cholinergic dysfunction via elevating acetylcholinesterase (AChE) enzymatic activity and protein expression. In silico molecular docking supported the results; Cur had a potent binding affinity for AChE receptors, tumor necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2), phosphorylations of IκB kinase (IKK), extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (p38). According to the chemical absorption, distribution, metabolism, excretion, and toxicity (ADMET) profile, Cur could serve as a potential candidate for Pb detoxication substance via exerting antioxidant activity. Taken together, our results suggest that Cur is a natural compound that could be used for the treatment of neurodegenerative disorders via suppressing lead-induced neurotoxicity.

Carissa macrocarpa Leaves Polar Fraction Ameliorates Doxorubicin-Induced Neurotoxicity in Rats via Downregulating the Oxidative Stress and Inflammatory Markers

Chemotherapeutic-related toxicity exacerbates the increasing death rate among cancer patients, necessitating greater efforts to find a speedy solution. An in vivo assessment of the protective effect of the C. macrocarpa leaves polar fraction of hydromethanolic extract against doxorubicin (Dox)-induced neurotoxicity was performed. Intriguingly, this fraction ameliorated Dox-induced cognitive dysfunction; reduced serum ROS and brain TNF-α levels, upregulated the brain nerve growth factor (NGF) levels, markedly reduced caspase-3 immunoexpression, and restored the histological architecture of the brain hippocampus. The in vivo study results were corroborated with a UPLC-ESI-MS/MS profiling that revealed the presence of a high percentage of the plant polyphenolics. Molecular modeling of several identified molecules in this fraction demonstrated a strong binding affinity of flavan-3-ol derivatives with TACE enzymes, in agreement with the experimental in vivo neuroprotective activity. In conclusion, the C. macrocarpa leaves polar fraction possesses neuroprotective activity that could have a promising role in ameliorating chemotherapeutic-induced side effects.

Carissa macrocarpa Leaves Polar Fraction Ameliorates Doxorubicin-Induced Neurotoxicity in Rats via Downregulating the Oxidative Stress and Inflammatory Markers

Chemotherapeutic-related toxicity exacerbates the increasing death rate among cancer patients, necessitating greater efforts to find a speedy solution. An in vivo assessment of the protective effect of the C. macrocarpa leaves polar fraction of hydromethanolic extract against doxorubicin (Dox)-induced neurotoxicity was performed. Intriguingly, this fraction ameliorated Dox-induced cognitive dysfunction; reduced serum ROS and brain TNF-α levels, upregulated the brain nerve growth factor (NGF) levels, markedly reduced caspase-3 immunoexpression, and restored the histological architecture of the brain hippocampus. The in vivo study results were corroborated with a UPLC-ESI-MS/MS profiling that revealed the presence of a high percentage of the plant polyphenolics. Molecular modeling of several identified molecules in this fraction demonstrated a strong binding affinity of flavan-3-ol derivatives with TACE enzymes, in agreement with the experimental in vivo neuroprotective activity. In conclusion, the C. macrocarpa leaves polar fraction possesses neuroprotective activity that could have a promising role in ameliorating chemotherapeutic-induced side effects.

Carissa macrocarpa Leaves Polar Fraction Ameliorates Doxorubicin-Induced Neurotoxicity in Rats via Downregulating the Oxidative Stress and Inflammatory Markers

Chemotherapeutic-related toxicity exacerbates the increasing death rate among cancer patients, necessitating greater efforts to find a speedy solution. An in vivo assessment of the protective effect of the C. macrocarpa leaves polar fraction of hydromethanolic extract against doxorubicin (Dox)-induced neurotoxicity was performed. Intriguingly, this fraction ameliorated Dox-induced cognitive dysfunction; reduced serum ROS and brain TNF-α levels, upregulated the brain nerve growth factor (NGF) levels, markedly reduced caspase-3 immunoexpression, and restored the histological architecture of the brain hippocampus. The in vivo study results were corroborated with a UPLC-ESI-MS/MS profiling that revealed the presence of a high percentage of the plant polyphenolics. Molecular modeling of several identified molecules in this fraction demonstrated a strong binding affinity of flavan-3-ol derivatives with TACE enzymes, in agreement with the experimental in vivo neuroprotective activity. In conclusion, the C. macrocarpa leaves polar fraction possesses neuroprotective activity that could have a promising role in ameliorating chemotherapeutic-induced side effects.

The ameliorative effect of nanoselenium on histopathological and biochemical alterations induced by melamine toxicity on the brain of adult male albino rats

Melamine is a chemical substance used as a food adulterant because of its high nitrogen content; it is known to induce neurotoxicity, thereby adversely affecting the central nervous system. The biocompatibility, bioavailability, lower toxicity, and the large surface area of nanosized selenium relative to its other forms indicate that selenium nanoparticles (SeNPs) have a potential ameliorative effect against melamine-induced neurotoxicity. In this study, we tested this hypothesis using 40 adult male albino rats that were randomly assigned into four groups (n = 10 per group): group I rats served as the untreated negative controls and were fed with standard diet and distilled water; group II rats were orally treated with melamine (300 mg/kg body weight/d); group III rats orally received melamine (300 mg/kg body weight/d) and SeNPs (2 mg/kg body weight/d); and group IV rats received SeNPs only (2 mg/kg body weight/d) for 28 days. Blood and brain samples were collected from all rats and processed for biochemical, histopathological, and immunohistochemical investigations. SeNPs were encapsulated in starch as a natural stabilizer and a size-controlling agent (SeNP@starch). The prepared SeNPs were characterized using different techniques. Inductively coupled plasma-optical emission spectrometry (ICP-OES) indicated that the percentage of selenium loaded in starch was 1.888 %. Powder x-ray diffractometer (XRD) was used to investigate the crystalline structure of the Se-NP@starch, to be tubular and composed of amorphous starch as well as metallic selenium. Thermogravimetric analysis confirmed the thermal stability of the product and determined the interactions among the different components. Transmission electron microscope demonstrated the spherical shape of SeNPs and their dispersion into starch surface as well as evaluating their size in nanoscale (range 20-140 nm). Our results revealed that the melamine- exposed rats had significantly elevated in malondialdehyde levels, significantly reduced in total antioxidant capacity, down-regulated expression of the antioxidant related genes Nrf2 (nuclear factor erythroid 2-related factor 2) and GPx (glutathione peroxidase), as well as up-regulated expression of the apoptosis-related gene Bax (B-cell lymphoma 2-associated X protein), with down regulation of Bcl-2 (B-cell lymphoma 2). Histopathological examination exhibited several alterations in the cerebrum, cerebellum, and hippocampus of the treated rats compared with the controls. Neuronal degeneration, vacuolation of the neuropils, and pericellular and perivascular spaces were observed. In addition, the pyramidal and granular cell layers of the hippocampus and cerebellum, respectively, were found to have significantly reduced thickness. Furthermore, a significant decrease in the percentage area of the glial fibrillary acidic protein and a significant increase in the percentage area of caspase-3 were noted. On the other hand, co-treatment with SeNPs partially ameliorated these alterations. A significant reduction in malondialdehyde levels; a non- significant elevation in total antioxidant capacity; up-regulation, upregulation of Nrf2, GPx, and Bcl-2 and downregulation of Bax were recorded. Neuronal degeneration, vacuolation of neuropils, and pericellular spaces were reduced. The pyramidal and granular cell layers restored their normal thickness. The percentage area of the glial fibrillary acidic protein significantly increased, whereas that of caspase-3 significantly decreased. In conclusion, SeNPs have an ameliorative effect against melamine-induced neurotoxicity in albino rats.

Spirulina Microalgae and Brain Health: A Scoping Review of Experimental and Clinical Evidence

Spirulina microalgae contain a plethora of nutrient and non-nutrient molecules providing brain health benefits. Numerous in vivo evidence has provided support for the brain health potential of spirulina, highlighting antioxidant, anti-inflammatory, and neuroprotective mechanisms. Preliminary clinical studies have also suggested that spirulina can help to reduce mental fatigue, protect the vascular wall of brain vessels from endothelial damage and regulate internal pressure, thus contributing to the prevention and/or mitigating of cerebrovascular conditions. Furthermore, the use of spirulina in malnourished children appears to ameliorate motor, language, and cognitive skills, suggesting a reinforcing role in developmental mechanisms. Evidence of the central effect of spirulina on appetite regulation has also been shown. This review aims to understand the applicative potential of spirulina microalgae in the prevention and mitigation of brain disorders, highlighting the nutritional value of this "superfood", and providing the current knowledge on relevant molecular mechanisms in the brain associated with its dietary introduction.

MOLECULAR MECHANISMS OF LEAD NEUROTOXICITY

Lead (Pb2+) is a non-essential metal with numerous industrial applications that have led to ts ubiquity in the environment. Thus, not only occupational-exposed individuals' health is compromised, but also that of the general population and in particular children. Notably, although the central nervous system is particularly susceptible to Pb2+, other systems are affected as well. The present study focuses on molecular mechanisms that underlie the effects that arise from the presence of Pb2+ in situ in the brain, and the possible toxic effects that follows. As the brain barriers represent the first target of systemic Pb2+, mechanisms of Pb2+ entry into the brain are discussed, followed by a detailed discussion on neurotoxic mechanisms, with special emphasis on theories of ion mimicry, mitochondrial dysfunction, redox imbalance, and neuroinflammation. Most importantly, the confluence and crosstalk between these events is combined into a cogent mechanism of toxicity, by intertwining recent and old evidences from humans, in vitro cell culture and experimental animals. Finally, pharmacological interventions, including chelators, antioxidants substances, anti-inflammatory drugs, or their combination are reviewed as integrated approaches to ameliorate Pb2+ harmful effects in both developing or adult organisms.

Signal transduction associated with lead-induced neurological disorders: A review

Lead is a heavy metal pollutant that is widely present in the environment. It affects every organ system, yet the nervous system appears to be the most sensitive and primary target. Although many countries have made significant strides in controlling Pb pollution, Pb poisoning continuous to be a major public health concern. Exposure to Pb causes neurotoxicity that ranges from neurodevelopmental disorders to severe neurodegenerative lesions, leading to impairments in learning, memory, and cognitive function. Studies on the mechanisms of Pb-induced nervous system injury have convincingly shown that this metal can affect a plethora of cellular pathways affecting on cell survival, altering calcium dyshomeostasis, and inducing apoptosis, inflammation, energy metabolism disorders, oxidative stress, autophagy and glial stress. This review summarizes recent knowledge on multiple signaling pathways associated with Pb-induced neurological disorders in vivo and in vitro.

An Investigation of the Wild Rat Crown Incisor as an Indicator of Lead (Pb) Exposure Using Inductively Couple Plasma Mass Spectrometry (ICP-MS) and Laser Ablation ICP-MS

Lead (Pb) is a metal toxicant of great public health concern. The present study investigated the applicability of the rat incisor in Pb exposure screening. The levels of lead in teeth (Pb-T) in the crown and root of incisors in laboratory Pb-exposed Sprague Dawley rats were quantified using inductively coupled plasma mass spectrometry (ICP-MS). The crown accumulated much Pb-T than the root of the Sprague Dawley rat incisor. The levels of lead in blood (Pb-B) were positively correlated with the Pb-T in the crown and root incisors of the Sprague Dawley rats. As an application of the Pb-T crown results in experimental rats, we subsequently analyzed the Pb-T in the crown incisors of Pb-exposed wild rats (Rattus rattus) sampled from residential sites within varying distances from an abandoned lead-zinc mine. The Pb-T accumulation in the crown of incisors of R. rattus rats decreased with increased distance away from the Pb-Zn mine. Furthermore, the Pb-T was strongly correlated (r = 0.85) with the Pb levels in the blood. Laser ablation ICP-MS Pb-T mappings revealed a homogenous distribution of Pb in the incisor with an increased intensity of Pb-T localized in the tip of the incisor crown bearing an enamel surface in both Sprague Dawley and R. rattus rats. These findings suggest that Pb-T in the crown incisor may be reflective of the rat's environmental habitat, thus a possible indicator of Pb exposure.

Recent advances in environmentally benign hierarchical inorganic nano-adsorbents for the removal of poisonous metal ions in water: a review with mechanistic insight into toxicity and adsorption

Recent developments in nanoscience and technology have addressed many of the problems associated with water quality. Accordingly, using the technological outputs of the recent research on nanomaterials, the best solution for the purification of water is highlighted in this review. Herein, the main objective is to provide mechanistic insight into the synthesis of various inorganic nanoadsorbents and their adsorption chemistry for poisonous metal ions present in polluted water. Initially, the toxicity and carcinogenicity of As3+, Pb2+, Cr6+, Cd2+, and Hg2+ metal ions are highlighted. For the removal of these toxic ions, this review focuses on eco-friendly nanoadsorbents. The various preparation procedures utilized for the preparation of nanoadsorbents are briefly discussed. Generally, this is because of the adsorption capacity of nanoadsorbents depends on their morphology, shape, size, surface area, surface active sites, functional groups, and quantization effect. Also, due to the importance of their mechanism of action, the recent developments and challenges of novel nanoadsorbents such as metal oxides, core shell nanoparticles, magnetic nano ferrates, and functionalized core shell magnetic oxides and the processes for the treatment of water contaminated by toxic metal ions such as As3+, Pb2+, Cr6+, Cd2+, and Hg2+ are exclusively reviewed. Further, the adsorption efficiency of inorganic nanoadsorbents is also compared with that of activated carbon derived from various sources for all the above-mentioned metal ions.

Neuroprotective Potential of Allium sativum against Monosodium Glutamate-Induced Excitotoxicity: Impact on Short-Term Memory, Gliosis, and Oxidative Stress

This study evaluated the neuroprotective potential of Allium sativum against monosodium glutamate (MSG)-induced neurotoxicity with respect to its impact on short-term memory in rats. Forty male Wistar albino rats were assigned into four groups. The control group received distilled water. The second group was administered Allium sativum powder (200 mg/kg of body weight) orally for 7 successive days, then was left without treatment until the 30th day. The third group was injected intraperitoneally with MSG (4 g/kg of body weight) for 7 successive days, then left without treatment until the 30th day. The fourth group was injected with MSG in the same manner as the third group and was treated with Allium sativum powder in the same manner as the second group, simultaneously. Phytochemical analysis of Allium sativum powder identified the presence of diallyl disulphide, carvone, diallyl trisulfide, and allyl tetrasulfide. MSG-induced excitotoxicity and cognitive deficit were represented by decreased distance moved and taking a long time to start moving from the center in the open field, as well as lack of curiosity in investigating the novel object and novel arm. Moreover, MSG altered hippocampus structure and increased MDA concentration and protein expression of glial fibrillary acidic protein (GFAP), calretinin, and caspase-3, whereas it decreased superoxide dismutase (SOD) activity and protein expression of Ki-67 in brain tissue. However, Allium sativum powder prevented MSG-induced neurotoxicity and improved short-term memory through enhancing antioxidant activity and reducing lipid peroxidation. In addition, it decreased protein expression of GFAP, calretinin, and caspase-3 and increased protein expression of Ki-67 in brain tissues and retained brain tissue architecture. This study indicated that Allium sativum powder ameliorated MSG-induced neurotoxicity through preventing oxidative stress-induced gliosis and apoptosis of brain tissue in rats.

Plant Extracts and Isolated Compounds Reduce Parameters of Oxidative Stress Induced by Heavy Metals: An up-to-Date Review on Animal Studies

BACKGROUND

Heavy metals are elements that are naturally found in the earth. They are used in many modern-day applications in agriculture, medicine, and industry. Heavy metal poisoning occurs when the body's soft tissues absorb too much of a particular metal. The heavy metals of interest for this review paper were cadmium, arsenic, mercury, and lead since these are the most common metals that the human body can absorb in toxic amounts. Different plant species were investigated in recent years for their effect on oxidative stress parameters after intoxication with heavy metals.

OBJECTIVES

This review paper is focused on the current update to research on heavy metals induced oxidative stress in animal models and improvement of the oxidative stress parameters upon/co-/after treatment with different plant extracts and isolated compounds.

METHODS

The available literature was screened for the novel data regarding the influence of plant extracts and compounds on heavy metals induced oxidative stress. For that purposes Scopus database was used, looking for the publications in the last 5-10 years with the key terms: plant extracts, oxidative stress, in vivo, cadmium, lead, mercury and arcenic.

RESULTS

Various parameters of oxidative stress were investigated, and their improvement with plant extracts/ compounds was observed in the brain, lungs, kidneys, liver, uterus, testis, thymus, spleen, heart, skin and blood of experimental animals. Common parameters used to determine oxidative stress in animals were: superoxide dismutase; catalase; reduced glutathione; glutathione reductase; glutathione-S-transferase; glutathione peroxidase; lipid peroxidation; oxidized glutathione; malondialdehyde; xanthine oxidase; nonprotein-soluble thiol; thioredoxin reductase; total sulphydryl group; nitric oxide; γ-glutamyl cysteine synthetase.

CONCLUSION

The most investigated species for antioxidant effects upon intoxication with heavy metals seem to be Allium sp., Bacopa monniera, Camellia sinensis, Moringa oleifera, Vitis vinifera and Zingiber officinale. According to literature data, the most promising effect to alleviate symptoms of intoxication was achieved with proanthocyanidins obtained from Vitis vinifera.

Neuroprotective role of luteolin against lead acetate-induced cortical damage in rats

Luteolin (LUT) is a glycosylated flavonoid compound that has multiple beneficial pharmacological and biological impacts. The current investigation was undertaken to evaluate the putative neuroprotective potency of LUT against neuronal damage induced by lead acetate (PbAc). Twenty-eight rats were placed into four equal groups. Group 1: served as the control group, group 2: rats were supplemented orally with LUT (50 mg kg^-1), group 3: rats were intraperitoneally injected with PbAc (20 mg kg^-1), and group 4: rats were pretreated with LUT before PbAc injection with the same doses. All animals were treated for 7 days. The exposure to PbAc increased the concentration of lead in the cortical tissue, neuronal lipid peroxidation, and nitric oxide (NO) production and decreased the antioxidant enzymes. Additionally, PbAc enhanced a neuroinflammatory response in the cortical tissue through increasing the pro-inflammatory cytokines secretion and inducible NO synthase expression. Moreover, cortical cell death was recorded following PbAc intoxication as evidenced by the enhancement of the proapoptotic and inhibiting the antiapoptotic markers. Interestingly, LUT supplementation reversed the cortical adverse reactions induced by PbAc. Taken together, these findings may suggest that LUT may be useful for attenuating neuronal damage induced by PbAc through inhibiting the oxidative damage, neuroinflammation, and the cortical cell death.

Protective Effect of Spirulina platensis Extract against Dextran-Sulfate-Sodium-Induced Ulcerative Colitis in Rats

Inflammatory bowel disease is a multifactorial inflammatory condition. This study aimed to test the protective effects of Spirulina platensis against ulcerative colitis (UC). UC was induced in thirty-six male Wistar rats by adding dextran sulfate sodium (DSS) to their drinking water, while a control group received only drinking water. UC rats were equally-divided into six groups that received a single oral daily dose of vehicle (DSS), sulfasalazine (SSZ, 50 mg/kg/day), chloroform or the hydroalcoholic extracts of Spirulina platensis (100 or 200 mg/kg/day) for 15 days, and then blood and colon samples were harvested for determination of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), erythrocyte sedimentation rate (ESR), myeloperoxidase (MPO), and histopathology. At the end of the study, compared to time-matched controls, UC rats showed increased TNF-α (1.64-fold), IL-6 (5.73-fold), ESR (3.18-fold), and MPO (1.61-fold), along with loss of body weight (24.73%) and disease activity index (1.767 ± 0.216 vs. 0 ± 0), p < 0.001. These effects were prevented by SSZ treatment (p < 0.001 vs. DSS). The hydroalcoholic extract of Spirulina platensis dose-dependently modulated all DSS-induced inflammatory changes. However, the chloroform extract significantly lowered only IL-6 and ESR, but not TNF-α or MPO levels. The protective effects of the hydroalcoholic extract of Spirulina platensis against experimental UC involved mitigation of DSS-induced inflammation.