Ascorbic acid ameliorates lead-induced apoptosis in the cerebellar cortex of developing rats

From ferroptosis to cuproptosis, and calcicoptosis, to find more novel metals-mediated distinct form of regulated cell death

Regulated cell death (RCD), also known as programmed cell death (PCD), plays a critical role in various biological processes, such as tissue injury/repair, development, and homeostasis. Dysregulation of RCD pathways can lead to the development of many human diseases, such as cancer, neurodegenerative disorders, and cardiovascular diseases. Maintaining proper metal ion homeostasis is critical for human health. However, imbalances in metal levels within cells can result in cytotoxicity and cell death, leading to a variety of diseases and health problems. In recent years, new types of metal overload-induced cell death have been identified, including ferroptosis, cuproptosis, and calcicoptosis. This has prompted us to examine the three defined metal-dependent cell death types, and discuss other metals-induced ferroptosis, cuproptosis, and disrupted Ca2+ homeostasis, as well as the roles of Zn2+ in metals' homeostasis and related RCD. We have reviewed the connection between metals-induced RCD and various diseases, as well as the underlying mechanisms. We believe that further research in this area will lead to the discovery of novel types of metal-dependent RCD, a better understanding of the underlying mechanisms, and the development of new therapeutic strategies for human diseases.

Recent insights into autophagy and metals/nanoparticles exposure

Some anthropogenic pollutants, such as heavy metals and nanoparticles (NPs), are widely distributed and a major threat to environmental safety and public health. In particular, lead (Pb), cadmium (Cd), chromium (Cr), arsenic (As), and mercury (Hg) have systemic toxicity even at extremely low concentrations, so they are listed as priority metals in relation to their significant public health burden. Aluminum (Al) is also toxic to multiple organs and is linked to Alzheimer's disease. As the utilization of many metal nanoparticles (MNPs) gradually gain traction in industrial and medical applications, they are increasingly being investigated to address potential toxicity by impairing certain biological barriers. The dominant toxic mechanism of these metals and MNPs is the induction of oxidative stress, which subsequently triggers lipid peroxidation, protein modification, and DNA damage. Notably, a growing body of research has revealed the linkage between dysregulated autophagy and some diseases, including neurodegenerative diseases and cancers. Among them, some metals or metal mixtures can act as environmental stimuli and disturb basal autophagic activity, which has an underlying adverse health effect. Some studies also revealed that specific autophagy inhibitors or activators could modify the abnormal autophagic flux attributed to continuous exposure to metals. In this review, we have gathered recent data about the contribution of the autophagy/mitophagy mediated toxic effects and focused on the involvement of some key regulatory factors of autophagic signaling during exposure to selected metals, metal mixtures, as well as MNPs in the real world. Besides this, we summarized the potential significance of interactions between autophagy and excessive reactive oxygen species (ROS)-mediated oxidative damage in the regulation of cell survival response to metals/NPs. A critical view is given on the application of autophagy activators/inhibitors to modulate the systematic toxicity of various metals/MNPs.

The neuroprotective effect of ascorbic acid against imidacloprid-induced neurotoxicity and the role of HO-1 in mice

Imidacloprid (IMI) is not only a neurotoxic agricultural pesticide but also a possible food contaminant. The aims of this study were to (1) explore the relationship between recurrent IMI administration and neuronal toxicity in mice and (2) evaluate the potential neuroprotective effect of ascorbic acid (AA), a substance with significant free radical scavenger and having property to block the inflammatory pathways. Mice were categorized as naïve controls (administered vehicles for 28 days); the IMI-treatment animal group (administered po 45-mg/kg body weight of IMI per day for 28 days); and the IMI + AA treatment animal group (administered the same IMI dose + 200 mg/kg of AA orally for 28 days). On day 28, memory losses were assessed using the Y-maze and novel target identification behavioral tests. Mice were sacrificed 24 h after the final IMI treatments, as well as hippocampus tissues, were utilized to determine histological assessments, oxidative stress biomarkers, and Heme oxygenase-1 (HO-1) and nuclear factor erythroid 2-related factor 2 (Nrf2) gene expression levels. The findings demonstrated that IMI-treated mice had substantial impairment of spatial and non-spatial memory functions, as well as reduced antioxidant enzyme and acetylcholinesterase activity. The AA neuroprotective action was achieved through the suppression of the HO-1 expression as well as the stimulation of Nrf2 expression in hippocampal tissues. In summary, recurrent IMI exposure causes oxidative stress and neurotoxicity in mice, and the administration of AA significantly reduces the IMI toxicity possibly by the activation of the HO-1/Nrf2 pathway.

Regular combined training and vitamins modulated the apoptosis process in diabetic rats: Bioinformatics analysis of heart failure's differential genes expression network correlated with anti-apoptotic process

The apoptosis process could impose significantly by hyperglycemia. According to in silico language processing and high throughput raw data analysis, we recognized hub molecular mechanisms involved in the pathogenesis of diabetic hearts and suggested a new pharmaceutical approach for declining myocardial programed cell death. Fifty male Sprague-Dawley rats were classified into five groups: healthy rats as control, diabetic rats, diabetic combined resistance/endurance training, diabetic rats which consumed supplementation vitamins E and C, and the combined supplementation and training. Here, we calculated changes in gene expression based on artificial intelligence methods and evaluated gene expression in apoptotic influencing combined training and antioxidants vitamins consumption in heart injured models by streptozotocin via Real-Time PCR. Moreover, we assessed the binding affinity of the 3D structure of small molecules on macromolecule SIRT3 to a new compound pharmaceutical suggesting the decline in cell death program. The computational intelligence surveys revealed that the apoptosis process was a remarkable pathomechanism in the abnormality function of heart tissue in diabetic conditions. Furthermore, we showed that synchronizing antioxidant vitamin consumption and regular combined training could significantly decrease irreversible myocardial cell death in diabetic myocardiopathy. Hence, levels of antiapoptotic mRNA were modified in the combined training/vitamin consumption group compared with other classifications. We found that regular combined exercise and vitamin consumption could reverse the apoptosis process to enhance the survival of cardiac muscle cells in diabetes conditions. PRACTICAL APPLICATIONS: Machine learning and system biology indicated that the apoptosis process is a vital pathomechanism of hyperglycemia-induced heart failure. Sirt3/Fas/Bcl-2/Cycs and Bax, as a critical network of apoptosis, play an essential role in heart failure induced by hyperglycemia. Moreover, Type 2 diabetes and obesity increase the risk of heart failure by increasing high blood sugar levels. We calculated the binding power of the vitamins E and C on SIRT3 protein based on the drug software. In addition, this study assessed that regular combined training and vitamin consumption had an antiapoptotic effect. Also, our data might improve the hyperglycemia state.

Anthocyanin from purple sweet potato attenuates lead-induced reproductive toxicity mediated by JNK signaling pathway in male mice

The present work aimed to explore the protective effect of APSP on Pb-induced reproductive toxicity and possible mechanism. APSP (100 mg/kg) was administered to Pb-intoxicated (0.2% lead acetate) male Kunming mice once daily by oral gavage for 6 weeks. Our results showed that APSP exerted male reproductive protection effects as showed by attenuated Pb-induced testicular injury, improved sperm count and motility, and reduced sperm abnormality rate. APSP also restored Pb-induced decrease in both enzymatic and non-enzymatic antioxidants, and GSH/GSSG ratio, but inhibited lipid peroxidation in serum and testes. Moreover, APSP downregulated Pb-induced Bax mRNA and protein expressions, suppressed activation of caspase-3, upregulated Bcl-2 protein expression, and prevented Pb-induced DNA damage. APSP treatment also interfered with Pb-induced testicular JNK signaling through inhibition of JNK mRNA expression and phosphorylation, resulting in inhibition of c-Jun expression. These effects of APSP were abolished by Pb. In conclusion, APSP represents a potential therapeutic agent for preventing Pb-caused reproductive toxicity, which is attributed to its antioxidant and anti-apoptotic properties, as well as, modulation of JNK signaling pathway.

Cognitive Impairment Induced by Lead Exposure during Lifespan: Mechanisms of Lead Neurotoxicity

Lead (Pb) is considered a strong environmental toxin with human health repercussions. Due to its widespread use and the number of people potentially exposed to different sources of this heavy metal, Pb intoxication is recognized as a public health problem in many countries. Exposure to Pb can occur through ingestion, inhalation, dermal, and transplacental routes. The magnitude of its effects depends on several toxicity conditions: lead speciation, doses, time, and age of exposure, among others. It has been demonstrated that Pb exposure induces stronger effects during early life. The central nervous system is especially vulnerable to Pb toxicity; Pb exposure is linked to cognitive impairment, executive function alterations, abnormal social behavior, and fine motor control perturbations. This review aims to provide a general view of the cognitive consequences associated with Pb exposure during early life as well as during adulthood. Additionally, it describes the neurotoxic mechanisms associated with cognitive impairment induced by Pb, which include neurochemical, molecular, and morphological changes that jointly could have a synergic effect on the cognitive performance.

(Ascorb)ing Pb Neurotoxicity in the Developing Brain

Lead (Pb) neurotoxicity is a major concern, particularly in children. Developmental exposure to Pb can alter neurodevelopmental trajectory and has permanent neuropathological consequences, including an increased vulnerability to further stressors. Ascorbic acid is among most researched antioxidant nutrients and has a special role in maintaining redox homeostasis in physiological and physio-pathological brain states. Furthermore, because of its capacity to chelate metal ions, ascorbic acid may particularly serve as a potent therapeutic agent in Pb poisoning. The present review first discusses the major consequences of Pb exposure in children and then proceeds to present evidence from human and animal studies for ascorbic acid as an efficient ameliorative supplemental nutrient in Pb poisoning, with a particular focus on developmental Pb neurotoxicity. In doing so, it is hoped that there is a revitalization for further research on understanding the brain functions of this essential, safe, and readily available vitamin in physiological states, as well to justify and establish it as an effective neuroprotective and modulatory factor in the pathologies of the nervous system, including developmental neuropathologies.

Protective role of ascorbic acid on lead-induced damage to the thyroid gland in the rat

Lead exposure is known to affect the pituitary-thyroid axis. Likewise, ascorbic acid (AA) has a protective action against lead poisoning. We examine the protective role of AA in lead-induced damage to the thyroid gland. The Wistar rats were divided into three groups: control that received 0.2% AA in drinking water throughout the experiment (15 days), intoxicated with lead acetate (20 mg/kg) intraperitoneally every 48 h for 15 days, and the experimental group treated with lead acetate and 0.2% AA in drinking water throughout the experiment. Plasma thyroid-stimulating hormone, triiodothyronine, thyroxine, and lead were determined. The thyroid gland was weighed, then epithelial cell height and nuclear volume were measured on histological slides. The results show that AA reduced the thyroid atrophy caused by lead acetate, as well as the loss of weight of the gland. In addition, it prevented the decrease of the hormone triiodothyronine, although the thyroxine hormone remained lower than the control values ​​and the thyroid-stimulating hormone remains high. Our results indicated that AA could play a protective role in lead poisoning in the thyroid gland.

Developmental lead (Pb)-induced deficits in redox and bioenergetic status of cerebellar synapses are ameliorated by ascorbate supplementation

Neurotoxicity induced by exposure to heavy metal lead (Pb) is a concern of utmost importance particularly for countries with industrial-based economies. The developing brain is especially sensitive to exposure to even minute quantities of Pb which can alter neurodevelopmental trajectory with irreversible effects on motor, emotive-social and cognitive attributes even into later adulthood. Chemical synapses form the major pathway of inter-neuronal communications and are prime candidates for higher order brain (motor, memory and behavior) functions and determine the resistance/susceptibility for neurological disorders, including neuropsychopathologies. The synaptic pathways and mechanisms underlying Pb-mediated alterations in neuronal signaling and plasticity are not completely understood. Employing a biochemically isolated synaptosomal fraction which is enriched in synaptic terminals and synaptic mitochondria, this study aimed to analyze the alterations in bioenergetic and redox/antioxidant status of cerebellar synapses induced by developmental exposure to Pb (0.2 %). Moreover, we test the efficacy of vitamin C (ascorbate; 500 mg/kg body weight), a neuroprotective and neuromodulatory antioxidant, in mitigation of Pb-induced neuronal deficits. Our results implicate redox and bioenergetic disruptions as an underlying feature of the synaptic dysfunction observed in developmental Pb neurotoxicity, potentially contributing to consequent deficits in motor, behavioral and psychological attributes of the organisms. In addition, we establish ascorbate as a key ingredient for therapeutic approach against Pb induced neurotoxicity, particularly for early-life exposures.

Ginseng gintonin alleviates neurological symptoms in the G93A-SOD1 transgenic mouse model of amyotrophic lateral sclerosis through lysophosphatidic acid 1 receptor

Background

We recently showed that gintonin, an active ginseng ingredient, exhibits antibrain neurodegenerative disease effects including multiple target mechanisms such as antioxidative stress and antiinflammation via the lysophosphatidic acid (LPA) receptors. Amyotrophic lateral sclerosis (ALS) is a spinal disease characterized by neurodegenerative changes in motor neurons with subsequent skeletal muscle paralysis and death. However, pathophysiological mechanisms of ALS are still elusive, and therapeutic drugs have not yet been developed. We investigate the putative alleviating effects of gintonin in ALS.

Methods

The G93A-SOD1 transgenic mouse ALS model was used. Gintonin (50 or 100 mg/kg/day, p.o.) administration started from week seven. We performed histological analyses, immunoblot assays, and behavioral tests.

Results

Gintonin extended mouse survival and relieved motor dysfunctions. Histological analyses of spinal cords revealed that gintonin increased the survival of motor neurons, expression of brain-derived neurotrophic factors, choline acetyltransferase, NeuN, and Nissl bodies compared with the vehicle control. Gintonin attenuated elevated spinal NAD(P) quinone oxidoreductase 1 expression and decreased oxidative stress-related ferritin, ionized calcium-binding adapter molecule 1-immunoreactive microglia, S100β-immunoreactive astrocyte, and Olig2-immunoreactive oligodendrocytes compared with the control vehicle. Interestingly, we found that the spinal LPA1 receptor level was decreased, whereas gintonin treatment restored decreased LPA1 receptor expression levels in the G93A-SOD1 transgenic mouse, thereby attenuating neurological symptoms and histological deficits.

Conclusion

Gintonin-mediated symptomatic improvements of ALS might be associated with the attenuations of neuronal loss and oxidative stress via the spinal LPA1 receptor regulations. The present results suggest that the spinal LPA1 receptor is engaged in ALS, and gintonin may be useful for relieving ALS symptoms.

Effects of ascorbic acid treatment on developmental alterations in calcium-binding proteins and gamma-aminobutyric acid transporter 1 in the cerebellum of lead-exposed rats during pregnancy and lactation

In the present study, we investigated the effects of lead (Pb) and ascorbic acid co-administration on rat cerebellar development. Female rats were randomly divided into the following groups: control, Pb, and Pb plus ascorbic acid (PA) groups. From one week prior to mating, female rats were administered Pb (0.3% Pb acetate in drinking water) and ascorbic acid (100 mg/kg, oral intubation). The chemical administration was stopped on postnatal day 21 when the morphology of the offspring's cerebellum is similar to that of the adult brain. The blood Pb level was significantly increased following long-term Pb exposure. Ascorbic acid reduced Pb levels in the dams and offspring. Nissl staining demonstrated that the number of Purkinje cells was significantly reduced following Pb exposure, while ascorbic acid ameliorated this effect in the cerebellum of the offspring. Calcium-binding proteins, such as calbindin, calretinin, and parvalbumin were commonly expressed in Purkinje cells, and Pb exposure and ascorbic acid treatment resulted in similar patterns of change, namely Pb-induced impairment and ascorbic acid-mediated amelioration. The gamma-aminobutyric acid transporter 1 (GABAT1) is expressed in the pinceau structure where the somata of Purkinje cells are entwined in inhibitory synapses. The number of GABAT1-immunoreactive synapses was reduced following Pb exposure, and ascorbic acid co-treatment prevented this effect in the cerebellar cortex. Therefore, it can be concluded that ascorbic acid supplementation to mothers during gestation and lactation may have potential preventive effects against Pb-induced impairments in the developing cerebellum via protection of inhibitory neurons and synapses.

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.

Ginseng Gintonin Attenuates Lead-Induced Rat Cerebellar Impairments during Gestation and Lactation

Gintonin, a novel ginseng-derived lysophosphatidic acid receptor ligand, improves brain functions and protects neurons from oxidative stress. However, little is known about the effects of gintonin against Pb-induced brain maldevelopment. We investigated the protective effects of gintonin on the developing cerebellum after prenatal and postnatal Pb exposure. Pregnant female rats were randomly divided into three groups: control, Pb (0.3% Pb acetate in drinking water), and Pb plus gintonin (100 mg/kg, p.o.). Blood Pb was increased in dams and pups; gintonin treatment significantly decreased blood Pb. On postnatal day 21, the number of degenerating Purkinje cells was remarkably increased while the number of calbindin-, GAD67-, NMDAR1-, LPAR1-immunoreactive intact Purkinje cells, and GABA transporter 1-immunoreactive pinceau structures were significantly reduced in Pb-exposed offspring. Following Pb exposure, gintonin ameliorated cerebellar degenerative effects, restored increased pro-apoptotic Bax, and decreased anti-apoptotic Bcl2. Gintonin treatment attenuated Pb-induced accumulation of oxidative stress (Nrf2 and Mn-SOD) and inflammation (IL-1β and TNFα,), restoring the decreased cerebellar BDNF and Sirt1. Gintonin ameliorated Pb-induced impairment of myelin basic protein-immunoreactive myelinated fibers of Purkinje cells. Gintonin attenuated Pb-induced locomotor dysfunctions. The present study revealed the ameliorating effects of gintonin against Pb, suggesting the potential use of gintonin as a preventive agent in Pb poisoning during pregnancy and lactation.

Ascorbic Acid Supplementation Prevents the Detrimental Effects of Prenatal and Postnatal Lead Exposure on the Purkinje Cell and Related Proteins in the Cerebellum of Developing Rats

We investigated the effects of lead (Pb) and ascorbic acid co-administration on rat cerebellar development. Prior to mating, rats were randomly divided into control, Pb, and Pb plus ascorbic acid (PA) groups. Pregnant rats were administered Pb in drinking water (0.3% Pb acetate), and ascorbic acid (100 mg/kg) via oral intubation until the end of the experiment. Offspring were sacrificed at postnatal day 21, the age at which the morphology of the cerebellar cortex in developing pups is similar to that of the adult brain. In the cerebellum, Pb exposure significantly reduced Purkinje cells and ascorbic acid prevented their reduction. Along with the change of the Purkinje cells, long-term Pb exposure significantly reduced the expression of the synaptic marker (synaptophysin), γ-aminobutyric acid (GABA)-synthesizing enzyme (glutamic acid decarboxylase 67), and axonal myelin basic protein while ascorbic acid co-treatment attenuated Pb-mediated reduction of these proteins in the cerebellum of pups. However, glutamatergic N-methyl-D-aspartate receptor subtype 1 (NMDAR1), anchoring postsynaptic density protein 95 (PSD95), and antioxidant superoxide dismutases (SODs) were adversely changed; Pb exposure increased the expression of NMDAR1, PSD95, and SODs while ascorbic acid co-administration attenuated Pb-mediated induction. Although further studies are required about the neurotoxicity of the Pb exposure, the results presented here suggest that developmental Pb exposure disrupted normal development of Purkinje cells by increasing glutamatergic and oxidative stress in the cerebellum. Additionally, ascorbic acid co-treatment is beneficial in attenuating prenatal and postnatal Pb exposure-induced maldevelopment of Purkinje cells in the developing cerebellum.

Effects of Ascorbic Acid on Osteopontin Expression and Axonal Myelination in the Developing Cerebellum of Lead-Exposed Rat Pups

Osteopontin (OPN) is a multi-functional protein that binds to integrin and calcium-binding phosphoprotein. OPN is required for normal neuronal development and its axonal myelination. We studied the combined effect of lead (Pb) and ascorbic acid treatment on OPN expression in the developing cerebellum. We randomly divided pregnant female rats into three groups: control, Pb (lead acetate, 0.3%, drinking water), and Pb plus ascorbic acid (PA; ascorbic acid, 100 mg/kg, oral intubation) groups. The blood level of Pb was significantly increased, while ascorbic acid reduced Pb levels in the dams and pups. At postnatal day (PND) 21, results from Nissl staining and OPN immunohistochemistry demonstrated that OPN was detected in the Purkinje cell layer in the cerebellum. Ascorbic acid treatment mitigated Pb exposure-induced reduction in the number of intact Purkinje cells and OPN immunoreactive Purkinje cells in the cerebellum of pups. In addition, Pb-induced reduction in the number of oligodendrocytes and myelin-associated glycoprotein is associated with the malformation of the myelin sheath. Ascorbic acid provided protection from Pb-induced impairments. Pb-induced structural deficits in the cerebellum resulted in functional deterioration observed during locomotive tests (bar holding test and wire mesh ascending test), while ascorbic acid ameliorated these harmful effects. Present results suggest that the change of OPN is associated with myelination in the developing cerebellum. The results also demonstrated that exposure to Pb is harmful, while ascorbic acid treatment is beneficial.

Ascorbic Acid Attenuates Lead-Induced Alterations in the Synapses in the Developing Rat Cerebellum

We evaluated the effect of lead (Pb) and ascorbic acid treatment of pregnant female rats on cerebellar development in pups. Pb was administered in drinking water (0.2% Pb acetate), and ascorbic acid (100 mg/kg) was administered through oral intubation. Fifteen female rats were randomly classified into control, Pb, and Pb plus ascorbic acid (PA) groups. The treatment of Pb and ascorbic acid treatments were terminated after birth to evaluate the effects on the gestational development of the cerebellum. At postnatal day 21 (PND21), pups were sacrificed, and blood Pb level was analyzed. Blood Pb levels of pups and dams were highest in the Pb group and reduced in the PA group. Immunohistochemistry and immunoblot assays were conducted to study the cerebellar expression levels of synaptic proteins. Along with a significant reduction in Purkinje cells, the reduction in presynaptic (synaptophysin) and postsynaptic (postsynaptic density protein 95, N-methyl-D-aspartate receptor subtype 1) marker proteins was observed in Pb-exposed pups. Ascorbic acid treatment significantly prevented Pb-induced impairment in the cerebellar synaptic proteins. Hypothesizing that brain-derived neurotrophic factor (BDNF) might be affected by Pb exposure given its importance in the regulation of synaptogenesis, we observed a Pb-induced decrease and ascorbic acid-mediated increase of BDNF in the cerebellum. Luxol fast blue staining and myelin basic protein analysis suggest that ascorbic acid treatment ameliorated the Pb exposure-induced reduction in the axonal fibers in the developing cerebellum. Overall, we conclude that ascorbic acid treatment during pregnancy can prevent Pb-induced impairments in the cerebellar development in rats.