Subchronic exposure to arsenic induces apoptosis in the hippocampus of the mouse brains through the Bcl‐2/Bax pathway

Diosmin ameliorates inflammation, apoptosis and activates PI3K/AKT pathway in Alzheimer's disease rats

Alzheimer's disease (AD), a prevalent cognitive disorder among the elderly, is frequently linked to the abnormal accumulation of myloid-β (Aβ), which is mainly as a result of neuronal death and inflammation. Diosmin, a flavonoid, is considered a potential drug for the treatment of AD. Our study aimed to uncover the molecular mechanism of diosmin in AD therapy. Here, rats were randomly divided into three groups: control, Aβ25-35, and Aβ25-35 + diosmin groups. AD model rats were induced by Aβ25-35 intraventricular injection, meanwhile 50 mg/kg diosmin was orally administered for 6-week intervention. Morris water maze test assessed learning and memory abilities. Hippocampal neuronal damage was determined by HE, Nissl, and TUNEL staining. These assays indicate that diosmin improves cognitive dysfunction and reduces hippocampal neuronal loss and apoptosis. Western blot showed that diosmin reduced Bax (1.21 ± 0.12) and cleaved caspase-3 (1.27 ± 0.12) expression, and increased Bcl-2 (0.70 ± 0.06), p-PI3K (0.71 ± 0.08), and p-AKT (0.96 ± 0.10) in the hippocampus. ELISA indicated diosmin reduces IL-1β, IL-6, and TNF-α levels, suggesting anti-inflammation effect. These results suggest that diosmin inhibits neuronal apoptosis and neuroinflammatory responses to improve cognitive dysfunction in AD rats, possibly related to upregulation of the PI3K/AKT pathway, providing a scientific basis for its use in AD treatment.

Arsenic-Induced, Mitochondria-Mediated Apoptosis Is Associated with Decreased Peroxisome Proliferator-Activated Receptor γ Coactivator α in Rat Brains

Chronic exposure to arsenic in drinking water damages cognitive function, and nerve cell apoptosis is one of the primary characteristics. The damage to mitochondrial structure and/or function is one of the main characteristics of apoptosis. Peroxisome proliferator-activated receptor γ coactivator α (PGC-1α) is involved in the regulation of mitochondrial biogenesis, energy metabolism, and apoptosis. In this study, we aimed to study the role of PGC-1α in sodium arsenite (NaAsO₂)-induced mitochondrial apoptosis in rat hippocampal cells. We discovered that increased arsenic-induced apoptosis in rat hippocampus increased with NaAsO₂ (0, 2, 10, and 50 mg/L, orally via drinking water for 12 weeks) exposure by TUNEL assay, and the structure of mitochondria was incomplete and swollen and had increased lysosomes, lipofuscins, and nuclear membrane shrinkage observed via transmission electron microscopy. Furthermore, NaAsO₂ reduced the levels of Bcl-2 and PGC-1α and increased the levels of Bax and cytochrome C expression. Moreover, correlation analysis showed that brain arsenic content was negatively correlated with PGC-1α levels and brain ATP content; PGC-1α levels were negatively correlated with apoptosis rate; and brain ATP content was positively correlated with PGC-1α levels, but no significant correlation between ATP content and apoptosis has been observed in this study. Taken together, the results of this study indicate that NaAsO₂-induced mitochondrial pathway apoptosis is related to the reduction of PGC-1α, accompanied by ATP depletion.

The protective roles of allicin on type 1 diabetes mellitus through AMPK/mTOR mediated autophagy pathway

Background: Type 1 diabetes mellitus (T1DM) is one of the most common endocrine and metabolic diseases in children. Pancreatic β cells are thought to be critical cells involved in the progression of T1DM, and their injury would directly lead to impaired insulin secretion. Purpose: To investigate the protective effects of allicin on pancreatic β cell injury and elucidate the underlying mechanism. Methods: The streptozotocin (STZ)-induced mouse T1DM model in vivo and STZ-induced pancreatic β cell Min6 model in vitro were used to explore the effects of allicin on T1DM. The experiments include fasting blood glucose test, oral glucose tolerance detection, HE staining, immunohistochemistry, immunofluorescence, TUNEL staining, western blot, real-time quantitative PCR (RT-qPCR), and flow cytometry. Results: Allicin could significantly decrease blood glucose level, improve islet structure and insulin expression, and inhibit apoptosis to reduce STZ-induced pancreatic β cell injury and loss through activating AMPK/mTOR mediated autophagy pathway. Conclusion: Allicin treatment significantly reduced STZ-induced T1DM progression, suggesting that allicin may be a potential therapy option for T1DM patients.

Floralozone improves cognitive impairment in vascular dementia rats via regulation of TRPM2 and NMDAR signaling pathway

Vascular dementia (VD) is the second largest type of dementia after Alzheimer's disease. At present, the pathogenesis is complex and there is no effective treatment. Floralozone has been shown to reduce atherosclerosis in rats caused by a high-fat diet. However, whether it plays a role in VD remains elusive. In the present study, the protective activities and relevant mechanisms of Floralozone were evaluated in rats with cognitive impairment, which were induced by bilateral occlusion of the common carotid arteries (BCCAO) in rats. Cognitive function, pathological changes and oxidative stress condition in the brains of VD rats were assessed using Neurobehavioral tests, Morris water maze tests, hematoxylin-eosin staining, Neu N staining, TUNEL staining, Golgi staining, Western blot assay and antioxidant assays (MDA, SOD, GSH), respectively. The results indicated that VD model was established successfully and BCCAO caused a decline in spatial learning and memory and hippocampal histopathological abnormalities of rats. Floralozone (50, 100, 150 mg/kg) dose-dependently alleviated the pathological changes, decreased oxidative stress injury, which eventually reduced cognitive impairment in BCCAO rats. The same results were shown in further experiments with neurobehavioral tests. At the molecular biological level, Floralozone decreased the protein level of transient receptor potential melastatin-related 2 (TRPM2) in VD and normal rats, and increased the protein level of NR2B in hippocampus of N-methyl-D-aspartate receptor (NMDAR). Notably, Floralozone could markedly improved learning and memory function of BCCAO rats in Morris water maze (MWM) and improved neuronal cell loss, synaptic structural plasticity. In conclusion, Floralozone has therapeutic potential for VD, increased synaptic structural plasticity and alleviating neuronal cell apoptosis, which may be related to the TRPM2/NMDAR pathway.

Arsenic Induces Differential Neurotoxicity in Male, Female, and E2-Deficient Females: Comparative Effects on Hippocampal Neurons and Cognition in Adult Rats

We earlier reported that arsenic induced hippocampal neuronal loss, causing cognitive dysfunctions in male rats. This neuronal damage mechanism involved an altered bone morphogenetic protein (BMP2)/Smad and brain-derived neurotrophic factor (BDNF)/TrkB signaling. Susceptibility to toxicants is often sex-dependent, and hence we studied the comparative effects of arsenic in adult male and female rats. We observed that a lower dose of arsenic reduced learning-memory ability, examined through passive avoidance and Y-maze tests, in male but not female rats. Again, male rats exhibited greater learning-memory loss at a higher dose of arsenic. Supporting this, arsenic-treated male rats demonstrated larger reduction in the hippocampal NeuN and %-surviving neurons, together with increased apoptosis and altered BMP2/Smad and BDNF/TrkB pathways compared to their female counterparts. Since the primary female hormone, estrogen (E2), regulates normal brain functions, we next probed whether endogenous E2 levels in females offered resistance against arsenic-induced neurotoxicity. We used ovariectomized (OVX) rat as the model for E2 deficiency. We primarily identified that OVX itself induced hippocampal neuronal damage and cognitive decline, involving an increased BMP2/Smad and reduced BDNF/TrkB. Further, these effects appeared greater in arsenic + OVX compared to arsenic + sham (ovary intact) or OVX rats alone. The OVX-induced adverse effects were significantly reduced by E2 treatment. Overall, our study suggests that adult males could be more susceptible than females to arsenic-induced neurotoxicity. It also indicates that endogenous E2 regulates hippocampal BMP and BDNF signaling and restrains arsenic-induced neuronal dysfunctions in females, which may be inhibited in E2-deficient conditions, such as menopause or ovarian failure.

Arsenic causes mitochondrial biogenesis obstacles by inhibiting the AMPK/PGC-1α signaling pathway and also induces apoptosis and dysregulated mitophagy in the duck liver

Arsenic is a dangerous metalloid-material which is known to cause liver injury in many animals and humans. However, little is known about the underlying mechanism of arsenic-induced hepatotoxicity in poultry. This study was executed to systematically investigate the potential role of mitochondrial biogenesis, mitophagy and apoptosis in duck hepatotoxicity caused by arsenic. Results showed that the body weight and liver coefficient of duck had distinct changed after arsenic-exposure, and the arsenic content in serum and liver also increased significantly in a dose-dependent manner. Meanwhile, histopathological examination and metabolomics results showed that arsenic-exposure caused severe steatosis and metabolism disorder in liver tissues. Furthermore, arsenic-exposure significantly inhibited AMPK/PGC-1α-mediated mitochondrial biogenesis, determined by the ultrastructure observation and down-regulation of p-AMPKα/AMPKα, PGC-1α, NRF1, NRF2, TFAM, TFB1M, TFB2M and COX-Ⅳ expression levels. Besides, arsenic-treatment obviously increased the levels of mitophagy (PINK1, Parkin, LC3, P62) and pro-apoptotic (Caspase-3, Caspase-9, Cleaved Caspase-3, Cytc, Bax, P53) indexes, and simultaneously resulted in reductions in anti-apoptosis index (Bcl-2). Overall, our findings provided evidences that arsenic-induced duck hepatotoxicity may be caused by a combination of impaired mitochondrial biosynthesis, mitophagy, and mitochondrial-dependent apoptosis. To our knowledge, this is the first report to systematically investigate the potential mechanism of arsenic-induced hepatotoxicity in poultry.

Puerarin Alleviates Vascular Cognitive Impairment in Vascular Dementia Rats

Cerebral ischemia triggers vascular dementia (VD), which is characterized by memory loss, cognitive deficits, and vascular injury in the brain. Puerarin (Pur) represents the major isoflavone glycoside of Radix Puerariae, with verified neuroprotective activity and cardiovascular protective effects. However, whether Pur ameliorates cognitive impairment and vascular injury in rats with permanent occlusion of bilateral common carotid arteries (BCCAO) remains unknown. This work aimed to assess Pur's effects on BCCAO-induced VD and to dissect the underlying mechanisms, especially examining the function of transient receptor potential melastatin-related 2 (TRPM2) in alleviating cognitive deficits and vascular injuries. Rats with BCCAO developed VD. Pur (50, 100, and 150 mg/kg) dose-dependently attenuated the pathological changes, increased synaptic structural plasticity in the dorsal CA1 hippocampal region and decreased oxidative stress, which eventually reduced cognitive impairment and vascular injury in BCCAO rats. Notably, Pur-improved neuronal cell loss, synaptic structural plasticity, and endothelial vasorelaxation function might be mediated by the reactive oxygen species (ROS)-dependent TRPM2/NMDAR pathway, evidenced by decreased levels of ROS, malondialdehyde (MDA), Bax, Bax/Bcl2, and TRPM2, and increased levels of superoxide dismutase (SOD), Bcl2, and NR2A. In conclusion, Pur has therapeutic potential for VD, alleviating neuronal cell apoptosis and vascular injury, which may be related to the ROS-dependent TRPM2/NMDAR pathway.

Resveratrol protects against inorganic arsenic-induced oxidative damage and cytoarchitectural alterations in female mouse hippocampus

Prolonged inorganic arsenic (iAs) exposure is widely associated with brain damage particularly in the hippocampus via oxidative and apoptotic pathways. Resveratrol (RES) has gained considerable attention because of its benefits to human health. However, its neuroprotective potential against iAs-induced toxicity in CA1 region of hippocampus remains unexplored. Therefore, we investigated the neuroprotective efficacy of RES against arsenic trioxide (As₂O₃)-induced adverse effects on neuronal morphology, apoptotic markers and oxidative stress parameters in mouse CA1 region (hippocampus). Adult female Swiss albino mice of reproductive maturity were orally exposed to either As₂O₃ (2 and 4 mg/kg bw) alone or in combination with RES (40 mg/kg bw) for a period of 45 days. After animal sacrifice on day 46, the perfusion fixed brain samples were used for the observation of neuronal morphology and studying the morphometric features. While the freshly dissected hippocampi were processed for biochemical estimation of oxidative stress markers and western blotting of apoptosis-associated proteins. Chronic iAs exposure led to significant decrease in Stratum Pyramidale layer thickness along with reduction in cell density and area of Pyramidal neurons in contrast to the controls. Biochemical analysis showed reduced hippocampal GSH content but no change in total nitrite (NO) levels following iAs exposure. Western blotting showed apparent changes in the expression levels of Bax and Bcl-2 proteins following iAs exposure, however the change was statistically insignificant. Contrastingly, iAs +RES co-treatment exhibited substantial reversal in morphological and biochemical observations. Together, these findings provide preliminary evidence of neuroprotective role of RES on structural and biochemical alterations pertaining to mouse hippocampus following chronic iAs exposure.

Arsenic induces autophagy-dependent apoptosis via Akt inactivation and AMPK activation signaling pathways leading to neuronal cell death

Inorganic arsenic (As³⁺), a well-known worldwide industrial and environmental pollutant, has been linked to neurodegenerative disorders (NDs). Autophagy plays an important role in controlling neuronal cell survival/death. However, limited information is available regarding the toxicological mechanism at the interplay between autophagy and As³⁺-induced neurotoxicity. The present study found that As³⁺ exposure induced a concomitant activation of apoptosis and autophagy in Neuro-2a cells, which was accompanied with the increase of phosphatidylserine exposure on outer membrane leaflets and apoptotic cell population, and the activation of caspase-3, -7, and PARP as well as the elevation of protein expressions of LC3-II, Atg-5, and Beclin-1, and the accumulation of autophagosome. Pretreatment of cells with autophagy inhibitor 3-MA, but not that of Z-VAD-FMK (a pan-caspase inhibitor), effectively prevented the As³⁺-induced autophagic and apoptotic responses, indicating that As³⁺-triggered autophagy was contributing to neuronal cell apoptosis. Furthermore, As³⁺ exposure evoked the dephosphorylation of Akt. Pretreatment with SC79, an Akt activator, could significantly attenuated As³⁺-induced Akt inactivation as well as autophagic and apoptotic events. Expectedly, inhibition of Akt signaling with LY294002 obviously enhanced As³⁺-triggered autophagy and apoptosis. Exposure to As³⁺ also dramatically increased the phosphorylation level of AMPKα. Pretreatment of AMPK inhibitor (Compound C) could markedly abrogate the As³⁺-induced phosphorylated AMPKα expression, and autophagy and apoptosis activation. Taken together, these results indicated that As³⁺ exerted its cytotoxicity in neuronal cells via the Akt inactivation/AMPK activation downstream-regulated autophagy-dependent apoptosis pathways, which ultimately lead to cell death. Our findings suggest that the regulation of Akt/AMPK signals may be a promising intervention to against As³⁺-induced neurotoxicity and NDs.

Curcumin supplementation shows modulatory influence on functional and morphological features of hippocampus in mice subjected to arsenic trioxide exposure

Since, oxidative stress has been suggested as one of the mechanisms underlying arsenic-induced toxicity, the present study focused on the role of antioxidant (curcumin) supplementation on behavioral, biochemical, and morphological alterations with context to mice hippocampus (CA1) following arsenic trioxide (As₂O₃) administration. Healthy male Swiss albino mice were divided into control and experimental groups. As₂O₃ (2 mg/kg bw) alone or along with curcumin (100 mg/kg bw) was administered to experimental groups by oral route for 45 days whereas the control groups received either no treatment or vehicle for curcumin. Animals were subjected to behavioral study towards the end of the experimental period (day 33-45). On day 46, the brain samples were obtained and subjected either to immersion fixation (for morphometric observations) or used afresh for biochemical test. Behavioral tests (open field, elevated plus maze, and Morris water maze) revealed enhanced anxiety levels and impairment of cognitive functions in As₂O₃ alone treated groups whereas a trend of recovery was evident in mice simultaneously treated with As₂O₃ and curcumin. Morphological observations showed noticeable reduction in stratum pyramidale thickness (CA1), along with decrease in density and size of pyramidal neurons in As₂O₃ alone exposed group as compared to As₂O₃+Cu co-treated group. Hippocampal glutathione levels were found to be downregulated in animals receiving As₂O₃ as against the levels of controls and curcumin supplemented animals, thereby, suggestive of beneficial role of curcumin on As₂O₃ induced adverse effects.

In vivo evaluation of arsenic-associated behavioral and biochemical alterations in F0 and F1 mice

Groundwater contaminated with arsenic (As) is the biggest threat to public health in Bangladesh. The children of As-exposure parents are also exposing to As through drinking water. The effects of As on the children's health of As-exposure parents are poorly understood. An animal study was taken to evaluate the effects of As on behavioral and biochemical changes in F₁ mice. Swiss albino mice were separated into three groups: a) control, b) As-treated F₀ and c) As-treated F₁. Elevated plus maze and Morris water maze tests were used for evaluating anxiety, spatial memory and learning, respectively. We found that the effect of As on anxiety like behavior, spatial memory and learning impairment in As-treated F₁ mice was significantly higher than that of As-treated F₀ mice and control group. Additionally, we also evaluated the effects of As on biochemical parameters by measuring ALT, AST, ALP, BChE, SOD activities and the level of creatinine in As-induced mice, where we found that all of the blood parameters were significantly changed in F₁ generation. A significant portion of As accumulated in the brain, liver and kidney of F₁ mice than F₀ mice. Histological analysis revealed a significant change in tissue damage related to hepatic and renal dysfunctions that might be associated with As-induced biochemical alterations. In conclusion, arsenic plays an important role for the development of As-associated neurological disorders, hepatic toxicities, and renal dysfunctions in both F₀ and F₁ generations. Notably F₁ mice were much more vulnerable to As-exposure than F₀ mice.

Nano-curcumin versus curcumin in amelioration of deltamethrin-induced hippocampal damage

We aimed to prove that oxidative stress is the main mechanism responsible for hippocampal neurotoxicity induced by deltamethrin (DLM). The protective role of curcumin (CMN) and nano-curcumin (NCMN) over this toxicity was studied. The rats were categorized into four groups: control, DLM, CMN and NCMN. The study continued for 30 days. Hippocampus was processed for histological, biochemical and immunohistochemical studies. Caspase-3, glial fibrillar acidic protein (GFAP), acetylcholinesterase (AChE), malondialdehyde (MDA), glutathione (GSH), catalase (CAT) and superoxide dismutase (SOD) were measured for DLM-induced oxidative stress (increased MDA by 354%/decreased GSH by 61%, SOD by 61%, CAT 57%). Oxidative stress induced apoptosis of hippocampal neurons through increasing Nrf2, gamma-glutamyl cysteine synthetase heavy subunit (GCS-HS) and light subunit (GCS-LS) and decreasing AChE. It increases the activity of astrocytes through increasing GFAP. Finally, oxidative stress has a bad impaction on cognitive function. Improvement of oxidative stress was observed with use of CMN and NCMN (decrease of MDA/increase of GSH, SOD, CAT). The level of Nrf2, GCS-HS and GCS-LS decreased, while AChE, GFAP increased. Improvement of cognitive function was observed in both groups. In conclusion, oxidative stress is the common mechanism responsible for DLM-induced hippocampal neurotoxicity. It exerts apoptosis of hippocampal neurons through increasing Nrf2, HS-GCS, LS-GCS and decreasing AChE. In addition, it activates astrocytes through increasing expression of GFAP. The protective role of CMN and CMMN is related to their potent antioxidant effect. Much improvement has been detected with NCMN as compared to CMN.

Correlation Between Diabetic Cognitive Impairment and Diabetic Retinopathy in Patients With T2DM by 1H-MRS

Objective: To explore the correlation between diabetic cognitive impairment (DCI) and diabetic retinopathy (DR) through examining the cognitive function and the metabolism of the cerebrum in Type 2 diabetes mellitus (T2DM) by ¹H-MRS.

Methods: Fifty-three patients with T2DM were enrolled for this study. According to the fundus examination, the patients were divided into the DR group (n = 26) and the T2DM without DR group (T2DM group, n = 27). Thirty healthy adults were selected as a control group (HC group, n = 30). Cognitive function was measured by Montreal Cognitive Assessment (MoCA). The peak areas of N-acetylaspartate (NAA), Cho-line (Cho), Creatine (Cr), and Myo-inositol (mI) as well as their ratios were detected by proton magnetic resonance spectroscopy (¹H-MRS). The difference analysis between the three groups was performed by one-way ANOVA. When p < 0.05, LSD-t was applied. A partial correlation analysis (with age as a covariate) was used to analyze the correlation between metabolites in the DR group and MoCA scores. Among all T2DM patients, Chi-square test age, gender, education level, BMI, SBP, DBP, FPG, HbA1c, TC, TG, HDL-C, LDL-C, DR, and DCI correlation were measured. Differences were statistically significant while P < 0.05.

Results: 1. The scores of MoCA in the DR group or in the T2DM group were significantly less than those in the HC group (F = 3.54, P < 0.05), and the scores of MoCA in the DR group were significantly less than those in the other groups (F = 3.61, P < 0.05). 2. There were significant differences for NAA in the bilateral hippocampus in DR patients, T2DM patients, and healthy controls (P < 0.05). 3. The NAA/Cr was significantly positively correlated with the score of MoCA in DR patients' left hippocampus (r = 0.781, P < 0.01). 4. Chi-square analysis found that there was a correlation between DR and DCI (x² = 4.6, df = 1, p = 0.032, plt: 0.05). There was no correlation between other influencing factors and DCI (P > 0.05).

Conclusion: DCI is closely correlated with the DR in patients with T2DM. Hippocampal brain metabolism may have some changes in two sides of NAA in patients with DR, ¹H-MRS may provide effective imaging strategies and methods for the early diagnosis of brain damage and quantitative assessment cognitive function in T2DM.

Ginsenoside Rg1 attenuates cardiomyocyte apoptosis and inflammation via the TLR4/NF-kB/NLRP3 pathway

Sepsis-induced myocardial dysfunction (SIMD) causes high mortality in seriously ill patients. Ginsenoside Rg1 has been proven to have effective anti-inflammatory and antiapoptotic properties. However, the specific role of Rg1 in SIMD and the molecular mechanism remain unclear. Hence, we aimed to investigate the latent effects of ginsenoside Rg1 against SIMD and explore its underlying mechanisms. Male C57BL/6J mice and neonatal rat cardiomyocytes (NRCMs) were used as in vivo and in vitro models, respectively. Western blot analysis was used to detect the level of protein expression, and reverse transcription polymerase chain reaction was conducted to determine the messenger RNA expression of inflammatory factors. The terminal deoxynucleotidyl transferase-mediated nick end labeling assay and flow cytometry were used to determine the apoptosis rate. Echocardiography was performed to assess cardiac function. The results showed that Rg1 improved cardiac function and attenuated lipopolysaccharide (LPS)-induced apoptosis and inflammation in mice. In addition, in NRCMs, Rg1 downregulated the expression of LPS-induced inflammatory cytokines and reversed the increased expression of Toll-like receptor 4 (TLR4), nuclear factor-κB (NF-κB), and NOD-like receptor 3 (NLRP3). In addition, treatment with TLR4 small interfering RNA (siRNA), a p-NF-κB inhibitor, or NLRP3 siRNA suppressed LPS-induced apoptosis and inflammation. In conclusion, Rg1 can attenuate LPS-induced inflammation and apoptosis both in NRCMs and septic mice and restore impaired cardiac function. Moreover, Rg1 may exert its effect via blocking the TLR4/NF-κB/NLRP3 pathway.

MicroRNA-27a-3p Downregulation Inhibits Inflammatory Response and Hippocampal Neuronal Cell Apoptosis by Upregulating Mitogen-Activated Protein Kinase 4 (MAP2K4) Expression in Epilepsy: In Vivo and In Vitro Studies

BACKGROUND This study aimed to discover the effect and mechanism of microRNA-27a-3p (miR-27a-3p) in epilepsy. MATERIAL AND METHODS To perform our investigation, in vivo and in vitro models of epilepsy were induced using kainic acid (KA). Expression of miR-27a-3p in the hippocampus of epileptic rats or normal rats or neuronal cells was detected using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Racine score was used to assess seizures in epileptic rats. Cell viability and cell apoptosis were analyzed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay and flow cytometry. Enzyme-linked immunosorbent assay (ELISA) was performed to detect inflammatory factors expression. RESULTS Significantly higher expression of miR-27a-3p in the hippocampus of epileptic rats and in KA-induced neurons was observed. We found that miR-27a-3p inhibitor alleviated seizures in epileptic rats. miR-27a-3p inhibitor also inhibited apoptosis of hippocampal neurons in epileptic rats, promoted Bcl2 expression, and decreased Bax and Caspase3 expression. The results showed that miR-27a-3p inhibitor effectively reduced the expression levels of interleukin-1ß (IL-1ß), IL-6, and tumor necrosis factor-alpha (TNF-alpha) in hippocampal tissues of epileptic rats. Dual luciferase reporter assay showed that mitogen-activated protein kinase 4 (MAP2K4) was a direct target of miR-27a-3p. miR-27a-3p inhibitor significantly promoted the cell viability of KA-induced neurons, inhibited cell apoptosis, promoted the expression of Bcl-2, and decreased Bax and Caspase3 expression, and all these changes were abolished by MAP2K4-siRNA co-transfection. CONCLUSIONS Our preliminary findings indicated that miR-27a-3p inhibitor protected against epilepsy-induced inflammatory response and hippocampal neuronal apoptosis by targeting MAP2K4.

Aflatoxin B1 impairs leydig cells through inhibiting AMPK/mTOR-mediated autophagy flux pathway

Aflatoxin B1 (AFB1), a potential endocrine disrupter, has been shown to induce hepatotoxicity in animal models, but the effects of AFB1 on Leydig cell function are unclear. In this study, in vivo exposure to AFB1 at 15 and 150 μg/kg/day lowered serum testosterone (T), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) levels, reduced Leydig cell number, and down-regulated the expression of testosterone biosynthesis-related genes. In vitro study showed that AFB1 (10 μM) significantly increased ROS levels, and decreased T production in Leydig cells by suppressing certain T-biosynthesis gene expressions. Moreover, AFB1 induced Leydig cell apoptosis through lowering pAMPK/AMPK ratio and increasing pmTOR/mTOR ratio, and then further up-regulating autophagy and apoptosis proteins, LC3, BECLIN 1, and BAX, as well as down-regulating autophagy flux protein P62 and anti-apoptosis protein BCL-2. AFB1-induced toxicity in Leydig cells was characterized by inhibiting T-biosynthesis gene expression, reducing Leydig cell number, promoting ROS production, and inducing cell apoptosis via suppressing AMPK/mTOR-mediated autophagy flux pathway.

Retracted: Protection of miR-19b in hypoxia/reoxygenation-induced injury by targeting PTEN

OBJECTIVE

To study the role and mechanism of microRNA 19b (miR-19b) in hypoxia/reoxygenation (H/R)-induced injury by targeting PTEN.

METHODS

PC12 and BV2 cells induced by H/R were treated with miR-19b mimics/inhibitors or small interfering PTEN (si-PTEN), respectively. Lactate dehydrogenase (LDH) level, malondialdehyde (MDA), and superoxide dismutase (SOD) content was detected. Besides, cell viability and apoptosis were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, Hoechst33342 staining, and flow cytometry, whereas mitochondrial membrane potential (MMP) tested by JC-1 assay, and reactive oxygen species (ROS) evaluated by the dichloro-dihydro-fluorescein diacetate assay. The ischemia/reperfusion (I/R) rats model was used to investigate the effects of miR-19b in vivo test. The infarct area and apoptosis rates in brain tissues were detected by 2,3,5-triphenyltetrazolium chloride and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling staining, respectively. miR-19b and PTEN/PI3K/Akt pathway-related proteins were detected by quantitative reverse-transcription polymerase chain reaction and western blot analysis.

RESULTS

miR-19b mimics could reduce LDH, MDA, and ROS levels and decline cell apoptosis, but enhance the viability, MMP, and SOD activity with decreased PTEN and cleaved caspase, as well as increased p-Akt/Akt and Bcl-2/Bax ratios in H/R-induced PC12 and BV2 cells. However, miR-19b inhibitors led to completely opposite results to aggravate H/R-induced cell injury. Meanwhile, si-PTEN could reverse the effect of miR-19b inhibitors on H/R-induced injury. Moreover, treatment with miR-19b agomir after I/R in vivo sufficiently decreased infarct area and reduced apoptosis rates by targeting PTEN through the regulation of the PI3K/Akt pathway.

CONCLUSION

miR-19b could inhibit oxidative stress, enhance cell MMP, promote cell survival, and inhibit cell apoptosis by targeting PTEN via the regulation of the PI3K/Akt pathway, thus playing the neuronal protective effects.

Gestational Arsenic Trioxide Exposure Acts as a Developing Neuroendocrine-Disruptor by Downregulating Nrf2/PPARγ and Upregulating Caspase-3/NF-ĸB/Cox2/BAX/iNOS/ROS

The goal of this investigation was to evaluate the effects of gestational administrations of arsenic trioxide (ATO; As₂O₃) on fetal neuroendocrine development (the thyroid-cerebrum axis). Pregnant Wistar rats were orally administered ATO (5 or 10 mg/kg) from gestation day (GD) 1 to 20. Both doses of ATO diminished free thyroxine and free triiodothyronine levels and augmented thyrotropin level in both dams and fetuses at GD 20. Also, the maternofetal hypothyroidism in both groups caused a dose-dependent reduction in the fetal serum growth hormone, insulin growth factor-I (IGF-I), and IGF-II levels at embryonic day (ED) 20. These disorders perturbed the maternofetal body weight, fetal brain weight, and survival of pregnant and their fetuses. In addition, destructive degeneration, vacuolation, hyperplasia, and edema were observed in the fetal thyroid and cerebrum of both ATO groups at ED 20. These disruptions appear to depend on intensification in the values of lipid peroxidation, nitric oxide, and H₂O₂, suppression of messenger RNA (mRNA) expression of nuclear factor erythroid 2-related factor 2 and peroxisome proliferator-activated receptor gamma, and activation of mRNA expression of caspase-3, nuclear factor kappa-light-chain-enhancer of activated B cells, cyclooxygenase-2, Bcl-2–associated X protein, and inducible nitric oxide synthase in the fetal cerebrum. These data suggest that gestational ATO may disturb thyroid-cerebrum axis generating fetal neurodevelopmental toxicity.

Prevention of Deficit in Neuropsychiatric Disorders through Monitoring of Arsenic and Its Derivatives as Well as Through Bioinformatics and Cheminformatics

Neuropsychiatric disorders are induced by various risk factors, including direct exposure to environmental chemicals. Arsenic exposure induces neurodegeneration and severe psychiatric disorders, but the molecular mechanisms by which brain damage is induced are not yet elucidated. Our aim is to better understand the molecular mechanisms of arsenic toxicity in the brain and to elucidate possible ways to prevent arsenic neurotoxicity, by reviewing significant experimental, bioinformatics, and cheminformatics studies. Brain damage induced by arsenic exposure is discussed taking in account: the correlation between neuropsychiatric disorders and the presence of arsenic and its derivatives in the brain; possible molecular mechanisms by which arsenic induces disturbances of cognitive and behavioral human functions; and arsenic influence during psychiatric treatments. Additionally, we present bioinformatics and cheminformatics tools used for studying brain toxicity of arsenic and its derivatives, new nanoparticles used as arsenic delivery systems into the human body, and experimental ways to prevent arsenic contamination by its removal from water. The main aim of the present paper is to correlate bioinformatics, cheminformatics, and experimental information on the molecular mechanism of cerebral damage induced by exposure to arsenic, and to elucidate more efficient methods used to reduce its toxicity in real groundwater.

Gestational Exposure to Particulate Matter 2.5 (PM2.5) Leads to Spatial Memory Dysfunction and Neurodevelopmental Impairment in Hippocampus of Mice Offspring

Prenatal exposure to air pollutants has long-term impact on growth retardation of nervous system development and is related to central nervous system diseases in children. However, it is not well-characterized whether gestational exposure to air pollutants affects the development of nervous system in offspring. Here, we investigated the effects of gestational exposure to particulate matter 2.5 (PM_2.5) on hippocampus development in mice offspring, through neurobehavioral, ultrastructural, biochemical and molecular investigations. We found that spatial memory in mice offspring from PM_2.5 high-dosage group was impaired. Next, hippocampal ultrastructure of the mice offspring in puberty exhibited mitochondrial damage related to PM_2.5 exposure. Interestingly, EdU-positive cells in the subgranular zone (SGZ) of offspring from PM_2.5 high-dosage group decreased, with NeuN⁺/EdU⁺cells reduced significantly. Furthermore, the numbers of NeuN⁺/TUNEL⁺, GFAP⁺/TUNEL⁺, and Iba1⁺/TUNEL⁺ double-labeled cells increased with PM_2.5 exposure in a dosage-dependent manner. In addition, gestational exposure to PM_2.5 resulted in increased levels of both mRNAs and proteins involved in apoptosis, including caspase-3, -8, -9, p53, and c-Fos, and decreased Bcl-2/Bax ratios in the hippocampus of mice offspring. Moreover, gestational exposure to PM_2.5 was dosage-dependently associated with the increased secretions of inflammatory proteins, including NF-κB, TNF-α, and IL-1β. Collectively, our results suggest that gestational exposure to PM_2.5 leads to spatial memory dysfunction and neurodevelopmental impairment by exerting effects on apoptotic and neuroinflammatory events, as well as the neurogenesis in hippocampus of mice offspring.

Taurine Ameliorates Arsenic-Induced Apoptosis in the Hippocampus of Mice Through Intrinsic Pathway

Our group previously reported that arsenic (As) exposure induced apoptosis in hippocampus neurons. The aim of the present study was to clarify the protective capacity of taurine (Tau) on As-induced neuronal apoptosis and the related mechanism in mouse hippocampus. Mice were divided into: control group, Tau control group, As exposure group and Tau protective group, randomly. The apoptotic rate of mouse hippocampus was determined by TUNEL staining. The levels of Bcl-2 and Bax gene and protein were analyzed by real time RT-PCR and WB, respectively. Furthermore, cytochrome c (Cyt C) release, and the activity of caspase-8 and caspase-3 were also determined. The results showed that Tau treatment induced the decrease of TUNEL-positive cells, prohibited the disturbance of Bcl-2 and Bax expression, and inhibited Cyt C release and caspase-8 and caspase-3 activation significantly. The results indicated that Tau supplement markedly ameliorates As-induced apoptosis by mitochondria-related pathway in mouse hippocampus.

Toxic metal(loid)-based pollutants and their possible role in autism spectrum disorder

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social interaction, verbal and non-verbal communication, and stereotypic behaviors. Many studies support a significant relationship between many different environmental factors in ASD etiology. These factors include increased daily exposure to various toxic metal-based environmental pollutants, which represent a cause for concern in public health. This article reviews the most relevant toxic metals, commonly found, environmental pollutants, i.e., lead (Pb), mercury (Hg), aluminum (Al), and the metalloid arsenic (As). Additionally, it discusses how pollutants can be a possible pathogenetic cause of ASD through various mechanisms including neuroinflammation in different regions of the brain, fundamentally occurring through elevation of the proinflammatory profile of cytokines and aberrant expression of nuclear factor kappa B (NF-κB). Due to the worldwide increase in toxic environmental pollution, studies on the role of pollutants in neurodevelopmental disorders, including direct effects on the developing brain and the subjects' genetic susceptibility and polymorphism, are of utmost importance to achieve the best therapeutic approach and preventive strategies.

WITHDRAWN: Toxic effects of gestational arsenic trioxide on the neuroendocrine axis of developing rats

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Effects of microRNA-129 and its target gene c-Fos on proliferation and apoptosis of hippocampal neurons in rats with epilepsy via the MAPK signaling pathway

This study aims to investigate the effect of microRNA-129 (miR-129) on proliferation and apoptosis of hippocampal neurons in epilepsy rats by targeting c-Fos via the MAPK signaling pathway. Thirty rats were equally classified into a model group (successfully established as chronic epilepsy models) and a normal group. Expression of miR-129, c-Fos, bax, and MAPK was detected by RT-qPCR and Western blotting. Hippocampal neurons were assigned into normal, blank, negative control (NC), miR-129 mimic, miR-129 inhibitor, siRNA-c-Fos, miR-129 inhibitor+siRNA-c-Fos groups. The targeting relationship between miR-129 and c-Fos was predicted and verified by bioinformatics websites and dual-luciferase reporter gene assay. Cell proliferation after transfection was measured by MTT assay, and cell cycle and apoptosis by flow cytometry. c-Fos is a potential target gene of miR-129. Compared with the normal group, the other six groups showed a decreased miR-129 expression; increased expression of expression of c-Fos, Bax, and MAPK; decreased proliferation; accelerated apoptosis; more cells arrested in the G1 phase; and fewer cells arrested in the S phase. Compared with the blank and NC groups, the miR-129 mimic group and the siRNA-c-Fos group showed decreased expression of c-Fos, Bax, and MAPK, increased cells proliferation, and decreased cell apoptosis, fewer cells arrested in the G1 phase and more cells arrested in the S phase. However, the miR-129 inhibitor groups showed reverse consequences. This study suggests that miR-129 could inhibit the occurrence and development of epilepsy by repressing c-Fos expression through inhibiting the MAPK signaling pathway.

Maternal Exposure to PM2.5 during Pregnancy Induces Impaired Development of Cerebral Cortex in Mice Offspring

Air pollution is a serious environmental health problem closely related to the occurrence of central nervous system diseases. Exposure to particulate matter with an aerodynamic diameter less than or equal to 2.5 µm (PM_2.5) during pregnancy may affect the growth and development of infants. The present study was to investigate the effects of maternal exposure to PM_2.5 during pregnancy on brain development in mice offspring. Pregnant mice were randomly divided into experimental groups of low-, medium-, or high-dosages of PM_2.5, a mock-treated group which was treated with the same amount of phosphate buffer solution (PBS), and acontrol group which was untreated. The ethology of offspring mice on postnatal days 1, 7, 14, 21, and 30, along with neuronal development and apoptosis in the cerebral cortex were investigated. Compared with the control, neuronal mitochondrial cristae fracture, changed autophagy characteristics, significantly increased terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positive cell rate, and mRNA levels of apoptosis-related caspase-8 and caspase-9 were found in cerebral cortex of mice offspring from the treatment groups, with mRNA levels of Bcl-2 and ratio of Bcl-2 to Bax decreased. Treatment groups also demonstrated enhanced protein expressions of apoptosis-related cleaved caspase-3, cleaved caspase-8 and cleaved caspase-9, along with declined proliferating cell nuclear antigen (PCNA), Bcl-2, and ratio of Bcl-2 to Bax. Open field experiments and tail suspension experiments showed that exposure to high dosage of PM_2.5 resulted in decreased spontaneous activities but increased static accumulation time in mice offspring, indicating anxiety, depression, and social behavioral changes. Our results suggested that maternal exposure to PM_2.5 during pregnancy might interfere with cerebral cortex development in mice offspring by affecting cell apoptosis.

Low dosage of arsenic trioxide inhibits vasculogenic mimicry in hepatoblastoma without cell apoptosis

Hepatoblastoma (HB) is the most common type of pediatric liver malignancy, which predominantly occurs in young children (aged <5 years), and continues to be a therapeutic challenge in terms of metastasis and drug resistance. As a new pattern of tumor blood supply, vasculogenic mimicry (VM) is a channel structure lined by tumor cells rather than endothelial cells, which contribute to angiogenesis. VM occurs in a variety of solid tumor types, including liver cancer, such as hepatocellular carcinoma. The aim of the present study was to elucidate the effect of arsenic trioxide (As₂O₃) on VM. In vitro experiments identified that HB cell line HepG₂ cells form typical VM structures on Matrigel, and the structures were markedly damaged by As₂O₃ at a low concentration before the cell viability significantly decreased. The western blot results indicated that As₂O₃ downregulated the expression level of VM-associated proteins prior to the appearance of apoptotic proteins. In vivo, VM has been observed in xenografts of HB mouse models and identified by periodic acid-Schiff⁺/CD105⁻ channels lined by HepG₂ cells without necrotic cells. As₂O₃ (2 mg/kg) markedly depresses tumor growth without causing serious adverse reactions by decreasing the number of VM channels via inhibiting the expression level of VM-associated proteins. Thus, the present data strongly indicate that low dosage As₂O₃ reduces the formation of VM in HB cell line HepG₂ cells, independent of cell apoptosis in vivo and in vitro, and may represent as a candidate drug for HB targeting VM.

Euptox A Induces G1 Arrest and Autophagy via p38 MAPK- and PI3K/Akt/mTOR-Mediated Pathways in Mouse Splenocytes

Euptox A (9-oxo-10, 11-dehydroageraphorone), the main toxin isolated from Eupatorium adenophorum, is known to induce immunotoxicity in animals. However, the precise mechanism underlying the effects of Euptox A on splenocytes is unclear. Here, we aimed to investigate the molecular mechanisms underlying the effect of Euptox A in mouse spleens after its intragastric administration and found that Euptox A exhibits proautophagic effects in splenocytes. Euptox A markedly arrested the splenocytes in the G0/G1 phase, which was accompanied by inhibition of the expression of the positive regulators CDK4, CDK2, cyclin D1, PCNA, and E2F1, and promotion of the expression of the negative regulators p53, p21 Waf1/Cip1, p27 Kip1, and Chk1. We also found that Euptox A did not markedly induce splenocyte apoptosis, but induced autophagy while increasing the subcellular localization of punctate LC3, ratio of LC3-II/LC3-I, and Beclin 1 levels, and decreasing p62 levels. Euptox A also significantly inhibited p-PI3K, p-p38 MAPK, p-Akt, and p-mTOR expression, but increased PTEN and p-AMPK expression. These results indicated that Euptox A induced splenocyte autophagy by inhibiting the PI3K/Akt/mTOR pathway, suppressing p38 MAPK expression, and activating AMPK. These findings provide new insights into the mechanisms involved in spleen toxicity caused by Euptox A in mice.

Induction of mitochondria-mediated apoptosis and PI3K/Akt/ mTOR-mediated autophagy by aflatoxin B2 in hepatocytes of broilers

Aflatoxins have been shown to induce hepatotoxicity in animal models, but the effects of aflatoxin B2 (AFB2) on broiler hepatocytes is unclear. This study aimed to investigate the effects of AFB2 on apoptosis and autophagy to provide an experimental basis for understanding the mechanism of aflatoxin-induced hepatotoxicity. One hundred-twenty Cobb500 broilers were allocated to four groups and exposed to 0 mg/kg, 0.2 mg/kg, 0.4 mg/kg, and 0.8 mg/kg of AFB2 per day for 21 d. AFB2 exerted potent proapoptotic and proautophagic effects on hepatocytes, with increased numbers of apoptotic and autophagic hepatocytes.Poly ADP-ribose polymerase (PARP) was cleaved and caspase-3 was activated in experimental groups, showing that the apoptosis of hepatocytes was triggered by AFB2. Increased levels of the autophagy factors Beclin-1 and LC3-II/LC3-I, as well as down-regulation of p62, a marker of autophagic flux, provided additional evidence for AFB2-triggered autophagy. AFB2 induced mitochondria-mediated apoptosis via the production of reactive oxygen species (ROS) and promotion of the translocation of Bax and cytochrome c (cyt c) between mitochondria and the cytosol, triggering the formation of apoptosomes. AFB2 also inhibited the phosphoinositide 3-kinase/Akt/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway by activating PI3K, Akt, and mTOR and inhibiting their phosphorylation, contributing to the proautophagic activity of AFB2. These findings provide new insights into the mechanisms involved in AFB2-induced hepatotoxicity in broilers.

Hijacking microglial glutathione by inorganic arsenic impels bystander death of immature neurons through extracellular cystine/glutamate imbalance

Arsenic-induced altered microglial activity leads to neuronal death, but the causative mechanism remains unclear. The present study showed, arsenic-exposed (10 μM) microglial (N9) culture supernatant induced bystander death of neuro-2a (N2a), which was further validated with primary microglia and immature neuronal cultures. Results indicated that arsenic-induced GSH synthesis by N9 unfavorably modified the extracellular milieu for N2a by lowering cystine and increasing glutamate concentration. Similar result was observed in N9-N2a co-culture. Co-exposure of arsenic and 250 μM glutamate, less than the level (265 μM) detected in arsenic-exposed N9 culture supernatant, compromised N2a viability which was rescued by cystine supplementation. Therefore, microglia executes bystander N2a death by competitive inhibition of system Xc^- (xCT) through extracellular cystine/glutamate imbalance. We confirmed the role of xCT in mediating bystander N2a death by siRNA inhibition studies. Ex-vivo primary microglia culture supernatant from gestationally exposed mice measured to contain lower cystine and higher glutamate compared to control and N-acetyl cysteine co-treated group. Immunofluorescence staining of brain cryosections from treated group showed more dead immature neurons with no such effect on microglia. Collectively, we showed, in presence of arsenic microglia alters cystine/glutamate balance through xCT in extracellular milieu leading to bystander death of immature neurons.

Methane-rich saline attenuates ischemia/reperfusion injury of abdominal skin flaps in rats via regulating apoptosis level

Background

In plastic surgery, skin damage induced by ischemia/reperfusion (I/R) is a multifactorial process that often occurs. Methane gas has been reported to be a new therapeutic gas for attenuating I/R injury. In this study, we assessed the effects of methane-rich saline (MRS) in regulating apoptosis on skin flap I/R injury.

Methods

Male Sprague–Dawley rats, 6–8 weeks old, were divided randomly into three groups: one sham surgery group (SH) and two surgery groups. After undergoing 6 h of I/R management of an abdominal skin flap, surgery groups were treated with physiological saline (I/R-P) or methane-rich saline (I/R-M). On the 3rd postoperative day, a laser Doppler flowmeter was used to measure flap blood supply, and hematoxylin and eosin (H&E) staining was used to observe morphological changes. TdT-mediated dUTP-X nick end labeling (TUNEL) staining was also used to observe early apoptosis and is presented as the percentage of TUNEL-positive cells. Moreover, pASK-1, pJNK, Bcl-2 and Bax were detected by immunohistochemical technology. Caspase-3 activity was also measured to evaluate the effects of MRS.

Results

Compared to the I/R-P group, the flaps in the I/R-M group presented a larger survival area and better blood perfusion with less inflammatory infiltration and cell apoptosis, a higher expression of Bcl-2, a lower expression of pASK-1, pJNK and Bax, and a lower caspase-3 activity.

Conclusion

According to the results, MRS attenuated I/R injury by regulating apoptosis and has the potential to be applied as a new therapy for improving skin flap survival.