Effects of selenium and topiramate on cytosolic Ca(2+) influx and oxidative stress in neuronal PC12 cells

Antioxidant Capacity and Protective Effects on H2O2-Induced Oxidative Damage in PC12 Cells of the Active Fraction of Brassica rapa L

Brassica rapa L. (BR), a traditional biennial herb belonging to the Brassica species of Brassicaceae, has been widely used for functions of anti-inflammatory, antitumor, antioxidation, antiaging, and regulation of immunity. In this study, antioxidant activity and protective effects on H2O2-induced oxidative damage in PC12 cells of the active fractions of BR were investigated in vitro. Among all active fractions, the ethyl acetate fraction of ethanol extract from BR (BREE-Ea) showed the strongest antioxidant activity. Additionally, it was noted that BREE-Ea and n-butyl alcohol fraction of ethanol extract from BR (BREE-Ba) both have protective effects in oxidatively damaged PC12 cells, while BREE-Ea displayed the best protective effect in all determined experimental doses. Furthermore, flow cytometry (DCFH-DA staining) analysis indicated that BREE-Ea could reduce the H2O2-induced apoptosis in PC12 cells by reducing the production of intracellular reactive oxygen species (ROS) and increasing enzymatic activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Moreover, BREE-Ea could decrease the malondialdehyde (MDA) content and reduce the release of extracellular lactic dehydrogenase (LDH) from H2O2-induced PC12 cells. All these results demonstrate that BREE-Ea has a good antioxidant capacity and protective effect on PC12 cells against apoptosis induced by H2O2 and that it can be used as a good edible antioxidant to improve the body's endogenous antioxidant defense.

Parvalbumin in the metabolic pathway of glutamate and γ-aminobutyric acid: Influence on expression of GAD65 and GAD67

Parvalbumin-expressing neurons are a type of inhibitory intermediate neuron that play an important role in terminating seizures. The aim of the present study was to use lentiviral construction and packaging technology to overexpress and silence the parvalbumin gene in pheochromocytoma (PC12) cells, and to evaluate how parvalbumin influences the metabolic pathway involving glutamate and γ-aminobutyric acid (GABA). In this work, Immunofluorescence staining was used to verify the differentiation of PC12 cells into neurons after adding nerve growth factor (NGF). Western blotting and real-time quantitative polymerase chain reaction (qRT-PCR) were used to confirm lentivirus-mediated knockdown or overexpression of parvalbumin. Expression of parvalbumin, the 65-kDa GAD isoform (GAD65), and the 67-kDa GAD isoform (GAD67) in neuronal cells was examined at the mRNA and protein levels using qRT-PCR, western blotting and immunofluorescence staining, while intracellular glutamate and GABA levels were determined by high performance liquid chromatography (HPLC). We demonstrate that the expression of parvalbumin is associated with GAD65 and GAD67. Interestingly, overexpression of parvalbumin up-regulated GAD65 and GAD67, increased GABA concentration, and decreased glutamate concentration. Silencing of parvalbumin led to the opposite effects. Altogether, parvalbumin affected the expression of GAD65 and GAD67, thereby influencing the metabolic pathway involving glutamate and GABA.

The protective effects of topiramate and spirulina against doxorubicin-induced cardiotoxicity in rats

Doxorubicin (DOX) is a widely used chemotherapy drug that can cause significant cardiotoxicity, limiting its clinical application. This study aimed to investigate the potential protective effects of topiramate (TPM) and spirulina (SP), either alone or in combination, in preventing DOX-induced cardiotoxicity. Adult Sprague Dawley rats were divided into five groups, including a normal control group and groups receiving DOX alone, DOX with TPM, DOX with SP, or DOX with a combination of TPM and SP. Cardiotoxicity was induced by administering DOX intraperitoneally at a cumulative dose of 16 mg/kg over 4 weeks. TPM and/or SP administration started 1 week before DOX treatment and continued for 35 days. Body weight, serum markers of cardiac damage, oxidative stress and inflammatory parameters were assessed. Histopathological and immunohistochemical examinations were performed on cardiac tissues. Results showed that TPM and SP monotherapy led to significant improvements in serum levels of cardiac markers, decreased oxidative stress, reduced fibrosis-related growth factor levels, increased antioxidant levels, and improved histopathological features. SP demonstrated more prominent effects in comparison to TPM, and the combination of TPM and SP exhibited even more pronounced effects. In conclusion, TPM and SP, either alone or in combination, hold promise as therapeutic interventions for mitigating DOX-induced cardiotoxicity.

Selenium prevents interferon-gamma induced activation of TRPM2 channel and inhibits inflammation, mitochondrial oxidative stress, and apoptosis in microglia

Microglia as the primary immune cells of brain act protective effects against injuries and infections in the central nervous system. Inflammation via excessive Ca²⁺ influx and oxygen radical species (ROS) generation is a known factor in many neurodegenerative disorders. Importantly, the Ca²⁺ permeable TRPM2 channel is activated by oxidative stress. Thus, TRPM2 could provide the excessive Ca²⁺ influx in the microglia. Although TRPM2 expression level is high in inflammatory cells, the interplay between mouse microglia and TRPM2 channel during inflammation is not fully identified. Thus, it is important to understand the mechanisms and factors involved in order to enhance neuronal regeneration and repair. The data presented here indicate that TRPM2 channels were activated in microglia cells by interferon-gamma (IFNγ). The IFNγ treatment further increased apoptosis (early and late) and cytokine productions (TNF-α, IL-1β, and IL-6) which were due to increased lipid peroxidation and ROS generations as well as increased activations of caspase -3 (Casp-3) and - 9 (Casp-9). However, selenium treatment diminished activations of TRPM2, cytokine, Casp-3, and Casp-9, and levels of lipid peroxidation and mitochondrial ROS production in the microglia that were treated with IFNγ. Moreover, addition of either PARP1 inhibitors (PJ34 or DPQ) or TRPM2 blockers (2-APB or ACA) potentiated the modulator effects of selenium. These results clearly suggest that IFNγ leads to TRPM2 activation in microglia cells; whereas, selenium prevents IFNγ-mediated TRPM2 activation and cytokine generation. Together the interplay between IFNγ released from microglia cells is importance in brain inflammation and may affect oxidative cytotoxicity in the microglia. Graphical abstract Summary of pathways involved in IFNγ-induced TRPM2 activation and microglia death through excessive reactive oxygen species (ROS): Modulator role of selenium (Se). The IFNγ causes the microglia activation. Nudix box domain of TRPM2 is sensitive to ROS. The ROS induces DNA damage and ADPR-ribose (ADPR) production in the nucleus via PARP1 enzyme activation. ADPR and ROS-induced TRPM2 activation stimulates excessive Ca²⁺ influx. ROS are produced in the mitochondria through the increase of free cytosolic Ca²⁺ (via TRPM2 activation) by the IFNγ treatment, although they are diminished by the TRPM2 channel blocker (ACA and 2-APB) and PARP1 inhibitor treatments. The main mechanism in the cell death and inflammatory effects of IFNγ is mediated by stimulation of ROS-mediated caspase (caspase -3 and - 9) activations and cytokine production (TNF-α, IL-1β, and IL-6) via TRPM2 activation, respectively. The apoptotic, inflammatory, and oxidant actions of IFNγ are modulated through TRPM2 inhibition by the Se treatment.

Hydroxy-α-sanshool Possesses Protective Potentials on H2O2-Stimulated PC12 Cells by Suppression of Oxidative Stress-Induced Apoptosis through Regulation of PI3K/Akt Signal Pathway

Zanthoxylum bungeanum pericarp is a commonly used herbal medicine in China with effects of anti-inflammatory and analgesic, improving learning and memory ability, while hydroxy-α-sanshool (HAS) is the most important active ingredient of Z. bungeanum pericarps. The purpose of this study was to investigate the neuroprotective effect of HAS and its related possible mechanisms using a H₂O₂-stimulated PC12 cell model. CCK-8 assay results showed that HAS had a significant protective effect on H₂O₂-stimulated PC12 cells without obvious cytotoxicity on normal PC12 cells. Flow cytometry and fluorescence microscope (DAPI staining and DCFH-DA staining) indicated that HAS could reduce the H₂O₂-induced apoptosis in PC12 cells via reduction of intracellular ROS and increase of mitochondrial membrane potential (MMP). Subsequently, results of malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) determination suggested that HAS could increase the enzyme activities of SOD, CAT, and GSH-Px whereas it could decrease the MDA contents in H₂O₂-stimulated PC12 cells. Furthermore, the western blotting assays showed that HAS could upregulate the expressions of p-PI3k, Akt, p-Akt, and Bcl-2, while it could downregulate the expressions of cleaved caspase-3 and Bax in H₂O₂-stimulated PC12 cells. Collectively, it could be concluded according to our results that HAS possesses protective potentials on H₂O₂-stimulated PC12 cells through suppression of oxidative stress-induced apoptosis via regulation of PI3K/Akt signal pathway.

Topiramate: A novel protective agent against ischemia reperfusion-induced oxidative injury after testicular torsion/detorsion

Testicular torsion is a common urologic emergency and one of the causes of genital injury in males. Hence, early diagnosis and treatment are necessary to prevent testicular damage and infertility. It has been proved that topiramate (TPM) a medication used to treat epilepsy and prevent migraines has anti-inflammatory and anti-oxidative effects. Therefore, this study was designed to determine the influence of TPM on ischemia/reperfusion injury following testicular torsion/detorsion (T/D). Thirty-six male Wistar rats were divided into three groups (n = 12 for each group) including sham operated, T/D + vehicle, T/D + TPM(100 mg/kg, 30 min before detorsion). Testicular torsion was induced for 1 h by rotating right testis 720⁰ in the clockwise direction. After 5 h of reperfusion the testis was removed and histological changes and biochemical markers such as superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and levels of malondialdehyde (MDA) and reduced glutathione (GSH) were evaluated. MDA level significantly increased and GSH level significantly decreased after T/D compared to the sham group (p < 0.001). Moreover, after inducing testicular T/D, GPx, CAT and SOD activity were decreased, whereas administration of TPM significantly increased GSH level and GPx, CAT and SOD activities and decreased MDA level in testis tissue as compared to T/D group. After induction of T/D, histopathological evaluations also revealed severe testicular damages which were improved by TPM administration. Our results indicate that TPM had an ameliorating impact on ischemia/reperfusion injury in the rat model of testicular T/D. This protective effect was most likely induced by anti-oxidative properties of this drug.

Assessing the Efficacy of Dietary Selenomethionine Supplementation in the Setting of Cardiac Ischemia/Reperfusion Injury

Oxidative stress is a major hallmark of cardiac ischemia/reperfusion (I/R) injury. This partly arises from the presence of activated phagocytes releasing myeloperoxidase (MPO) and its production of hypochlorous acid (HOCl). The dietary supplement selenomethionine (SeMet) has been shown to bolster endogenous antioxidant processes as well as readily react with MPO-derived oxidants. The aim of this study was to assess whether supplementation with SeMet could modulate the extent of cellular damage observed in an in vitro cardiac myocyte model exposed to (patho)-physiological levels of HOCl and an in vivo rat model of cardiac I/R injury. Exposure of the H9c2 cardiac myoblast cell line to HOCl resulted in a dose-dependent increase in necrotic cell death, which could be prevented by SeMet supplementation and was attributed to SeMet preventing the HOCl-induced loss of mitochondrial inner trans-membrane potential, and the associated cytosolic calcium accumulation. This protection was credited primarily to the direct oxidant scavenging ability of SeMet, with a minor contribution arising from the ability of SeMet to bolster cardiac myoblast glutathione peroxidase (GPx) activity. In vivo, a significant increase in selenium levels in the plasma and heart tissue were seen in male Wistar rats fed a diet supplemented with 2 mg kg⁻¹ SeMet compared to controls. However, SeMet-supplementation demonstrated only limited improvement in heart function and did not result in better heart remodelling following I/R injury. These data indicate that SeMet supplementation is of potential benefit within pathological settings where excessive HOCl is known to be generated but has limited efficacy as a therapeutic agent for the treatment of heart attack.

Antiepileptic Effects of Protein-Rich Extract from Bombyx batryticatus on Mice and Its Protective Effects against H2O2-Induced Oxidative Damage in PC12 Cells via Regulating PI3K/Akt Signaling Pathways

Bombyx batryticatus is a known traditional Chinese medicine (TCM) utilized to treat convulsions, epilepsy, cough, asthma, headaches, and purpura in China for thousands of years. This study is aimed at investigating the antiepileptic effects of protein-rich extracts from Bombyx batryticatus (BBPs) on seizure in mice and exploring the protective effects of BBPs against H₂O₂-induced oxidative stress in PC12 cells and their underlying mechanisms. Maximal electroshock-induced seizure (MES) and pentylenetetrazole- (PTZ-) induced seizure in mice and the histological analysis were carried out to evaluate the antiepileptic effects of BBPs. The cell viability of PC12 cells stimulated by H₂O₂ was determined by MTT assay. The apoptosis and ROS levels of H₂O₂-stimulated PC12 cells were determined by flow cytometry analysis. Furthermore, the levels of malondialdehyde (MDA), superoxide dismutase (SOD), lactate dehydrogenase (LDH), and glutathione (GSH) in PC12 cells were assayed by ELISA and expressions of caspase-3, caspase-9, Bax, Bcl-2, PI3K, Akt, and p-Akt were evaluated by Western blotting and quantitative real-time polymerase chain reaction (RT-qPCR) assays. The results revealed that BBPs exerted significant antiepileptic effects on mice. In addition, BBPs increased the cell viability of H₂O₂-stimulated PC12 cells and reduced apoptotic cells and ROS levels in H₂O₂-stimulated PC12 cells. By BBPs treatments, the levels of MDA and LDH were reduced and the levels of SOD and GSH-Px were increased in H₂O₂-stimulated PC12 cells. Moreover, BBPs upregulated the expressions of PI3K, Akt, p-Akt, and Bcl-2, whereas they downregulated the expressions of caspase-9, caspase-3, and Bax in H₂O₂-stimulated PC12 cells. These findings suggested that BBPs possessed potential antiepileptic effects on MES and PTZ-induced seizure in mice and protective effects on H₂O₂-induced oxidative stress in PC12 cells by exerting antioxidative and antiapoptotic effects via PI3K/Akt signaling pathways.

Selenium maintains Ca2+ homeostasis in sheep lymphocytes challenged by oxidative stress

Selenium (Se) is an essential element in human and animal diets, based upon a widespread range of beneficial effects that are primarily due to its antioxidant properties. While Se can be associated to anti-cancer and anti-diabetic activities, reproductive efficiency, and enhancement of the immune system, the mechanistic details of the corresponding biological processes are still largely elusive. To avoid deficiencies and increase bioavailability, Se it is generally supplied to livestock through Se-supplemented feeds or forage plants fertilized with inorganic Se. While the relationship between Ca²⁺ and ROS (reactive oxygen species) is well known, only a few studies have addressed the possible involvement of Se in the control of cytosolic Ca²⁺ in oxidative stress. The results on Ca²⁺ homeostasis were obtained adding exogenous Se in the form of SeO₄^2- to sheep lymphomonocytes cultured in vitro. In particular, Se strongly attenuated 1mM H₂O₂-induced alteration of intracellular [Ca²⁺]_C as well as the entry of extracellular Ca²⁺ into the cells with comparable EC50 values for sodium selenate accounting to 1.72 and 2.28 mM, respectively. In an ex vivo trial, it was observed that Ca²⁺ homeostasis can effectively be rescued in sheep lymphomonocytes exposed in vivo to a Se concentration of approximately 1.9 mM, that was achieved by feeding sheep with olive leaves previously sprayed with 500 mg/plant Na-selenate. Thus the results obtained suggest that the mode of action of selenium markedly influenced Ca²⁺-related signaling events. Furthermore, results clearly reveal that the protective effect of Se on Ca²⁺ homeostasis under oxidative challenge can be clearly and effectively achieved through an appropriate dietary regimen obtained also in a circular economy logic using pruning of olive trees treated to reduce tree drought stress.

Topiramate Reduces Aortic Cross-Clamping-Induced Lung Injury in Male Rats

BACKGROUND

Topiramate (TPM) decreases cytokine release and generation of reactive oxygen species (ROS). Cytokine and endothelin-1 (ET-1) secretion and ROS formation play an important role in ischemia-reperfusion (I/R) injury. We aimed to evaluate whether TPM prevents damage occurring in lung tissue during I/R.

MATERIALS AND METHODS

A total of 27 Wistar albino rats were divided into three groups of nine. To the I/R group, two hours of ischemia via infrarenal abdominal aorta cross-ligation and then two hours of reperfusion process were applied. TPM (100 mg/kg/day) orally for seven days was administered in the TPM treatment group. After the last dose of TPM treatment, respectively, two hours of ischemia and two hours of reperfusion were applied in this group.

RESULTS

Tumor necrosis factor-alpha (TNF-α) (p < 0.05), malondialdehyde (MDA) (p < 0.05), myeloperoxidase (MPO) (p < 0.05) and ET-1 (p < 0.05) levels of TPM treatment group's lung tissue were significantly lower than for the I/R group. Caspase-3 and histopathological damage were rather lower than that of the I/R group.

CONCLUSIONS

During I/R, lung damage occurs due to excessive TNF-α and ET-1 release and ROS generation. TPM could well reduce development of lung damage by decreasing cytokine and ET-1 release and levels of ROS produced.

Topiramate Improves Neuroblast Differentiation of Hippocampal Dentate Gyrus in the D-Galactose-Induced Aging Mice via Its Antioxidant Effects

Some anticonvulsant drugs are associated with cognitive ability in patients; Topiramate (TPM) is well known as an effective anticonvulsant agent applied in clinical settings. However, the effect of TPM on the cognitive function is rarely studied. In this study, we aimed to observe the effects of TPM on cell proliferation and neuronal differentiation in the dentate gyrus (DG) of the D-galactose-induced aging mice by Ki-67 and doublecortin (DCX) immunohistochemistry. The study is divided into four groups including control, D-galactose-treated group, 25 and 50 mg/kg TPM-treated plus D-galactose-treated groups. We found, 50 mg/kg (not 25 mg/kg) TPM treatment significantly increased the numbers of Ki-67+ cells and DCX immunoreactivity, and improved neuroblast injury induced by D-galactose treatment. In addition, we also found that decreased immunoreactivities and protein levels of antioxidants including superoxide dismutase and catalase induced by D-galactose treatment were significantly recovered by 50 mg/kg TPM treatment in the mice hippocampal DG (P < 0.05). In conclusion, our present results indicate that TPM can ameliorate neuroblast damage and promote cell proliferation and neuroblast differentiation in the hippocampal DG via increasing SODs and catalase levels in the D-galactose mice.

Selenium Deficiency Induces Autophagy in Immune Organs of Chickens

The aim of the present study was to investigate the effects of selenium (Se) deficiency on autophagy-related genes and on ultrastructural changes in the spleen, bursa of Fabricius, and thymus of chickens. The Se deficiency group was fed a basal diet containing Se at 0.033 mg/kg and the control group was fed the same basal diet containing Se at 0.15 mg/kg. The messenger RNA (mRNA) levels of the autophagy genes microtubule-associated protein 1 light chain 3 (LC3)-I, LC3-II, Beclin 1, dynein, autophagy associated gene 5 (ATG5), and target of rapamycin complex 1 (TORC1) were assessed using real-time qPCR. The protein levels of LC3-II, Beclin 1, and dynein were investigated using western blot analysis. Furthermore, the ultrastructure was observed using an electron microscope. The results indicated that spleen mRNA levels of LC3-I, LC3-II, Beclin 1, dynein, ATG5, and TORC1 and the protein levels of LC3-II, Beclin 1, and dynein were increased in the Se deficiency group compared with the control group. In the bursa of Fabricius, the mRNA levels of LC3-I, LC3-II, Beclin 1, dynein, ATG5, and TORC1 and the protein levels of Beclin 1 and dynein were increased; furthermore, the protein level of LC3-II was decreased in the Se deficiency group compared to the control group. In the thymus, the mRNA levels of LC3-I, Beclin 1, and ATG5 increased; the levels of LC3-II, dynein, and TORC1 were decreased; the protein level of Beclin 1 increased; and the levels of LC3-II and dynein decreased in the Se deficiency group compared to those in the control group. Further cellular morphological changes, such as autophagy vacuoles, autolysosomes, and lysosomal degradation, were observed in the spleen, bursa of Fabricius, and thymus of the Se-deficiency group. In summary, Se deficiency caused changes in autophagy-related genes, which increased the autophagic process and also caused structural damages to the immune organs of chickens.

Topiramate Confers Neuroprotection Against Methylphenidate-Induced Neurodegeneration in Dentate Gyrus and CA1 Regions of Hippocampus via CREB/BDNF Pathway in Rats

Methylphenidate (MPH) abuse can cause serious neurological damages. The neuroprotective effects of topiramate (TPM) have been reported already, but its mechanism of action still remains unclear. The current study evaluates in vivo role of CREB/BDNF in TPM protection of the rat hippocampal cells from methylphenidate-induced apoptosis, oxidative stress, and inflammation. A total of 60 adult male rats were divided into six groups. Groups 1 and 2 received normal saline (0.7 ml/rat) and MPH (10 mg/kg) respectively for 14 days. Groups 3 and 4 were concurrently treated with MPH (10 mg/kg) and TPM 50 and 100 mg/kg respectively for 14 days. Groups 5 and 6 were treated with 50 and 100 mg/kg TPM only respectively. After drug administration, open field test (OFT) was used to investigate motor activity. The hippocampus was then isolated and the apoptotic, antiapoptotic, oxidative, antioxidant, and inflammatory factors were measured. Expression of the total and phosphorylated CREB and BDNF in gene and protein levels, and gene expression of Ak1, CaMK4, MAPK3, PKA, and c-Fos levels were also measured. MPH significantly decreased motor activity in OFT. TPM (50 and 100 mg/kg) decreased MPH-induced motor activity disturbance. Additionally, MPH significantly increased Bax protein level, CaMK4 gene expression, lipid peroxidation, catalase activity, mitochondrial GSH, IL-1β, and TNF-α levels in isolated hippocampal cells. Also CREB, in total and phosphorylated forms, BDNF and Bcl-2 protein levels, Ak1, MAPK3, PKA and c-Fos gene expression, superoxide dismutase, glutathione peroxidase, and glutathione reductase activities decreased significantly by MPH. TPM (50 and 100 mg/kg), both in the presence and absence of MPH, attenuated the effects of MPH. Immunohistochemistry data showed that TPM increased localization of the total and phosphorylated forms of CREB in dentate gyrus (DG) and CA1 areas of the hippocampus. It seems that TPM can be used as a neuroprotective agent against apoptosis, oxidative stress, and neuroinflammation induced by frequent use of MPH. This might be probably mediated by the CREB/BDNF and their upstream signaling pathways.

Neuroprotective effects of various doses of topiramate against methylphenidate induced oxidative stress and inflammation in rat isolated hippocampus

Methylphenidate (MPH) abuse causes neurodegeneration. The neuroprotective effects of topiramate (TPM) have been reported but its putative mechanism remains unclear. The current study evaluates the role of various doses of TPM on protection of rat hippocampal cells from MPH-induced oxidative stress and inflammation in vivo. Seventy adult male rats were divided into six groups. Group 1 received normal saline (0.7 mL/rat) and group 2 was injected with MPH (10 mg/kg) for 21 days. Groups 3, 4, 5, 6 and 7 concurrently were treated by MPH (10 mg/kg) and TPM (10, 30, 50, 70 and 100 mg/kg, intraperitoneally (i.p.)), respectively for 21 days. After drug administration, the open field test (OFT) was used to investigate motor activity. Oxidative, antioxidant and inflammatory factors were measured in isolated hippocampus. Also, the brain-derived neurotrophic factor (BDNF) level was measured by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. Cresyl violet staining of Dentate Gyrus (DG) and CA1 cell layers of the hippocampus were also performed. MPH significantly disturbs motor activity in OFT and TPM (70 and 100 mg/kg) decreased this disturbance. Also MPH significantly increased lipid peroxidation, mitochondrial reduced state of glutathione (GSH) level, interleukin (IL)-1β and tumour necrosis factor (TNF)-α and BDNF level in isolated hippocampal cells. Also superoxide dismutase, glutathione peroxidase and glutathione reductase activity significantly decreased. Various doses of TPM attenuated these effects and significantly decreased MPH-induced oxidative damage, inflammation and hippocampal cell loss and increased BDNF level. This study suggests that TPM has the potential to be used as a neuroprotective agent against oxidative stress and neuroinflammation induced by frequent use of MPH.

Neuroprotective effects of various doses of topiramate against methylphenidate-induced oxidative stress and inflammation in isolated rat amygdala: the possible role of CREB/BDNF signaling pathway

Methylphenidate (MPH) abuse damages brain cells. The neuroprotective effects of topiramate (TPM) have been reported previously, but its exact mechanism of action still remains unclear. This study investigated the in vivo role of various doses of TPM in the protection of rat amygdala cells against methylphenidate-induced oxidative stress and inflammation. Seventy adult male rats were divided into seven groups. Groups 1 and 2 received normal saline (0.7 ml/rat) and MPH (10 mg/kg), respectively, for 21 days. Groups 3, 4, 5, 6, and 7 were concurrently treated with MPH (10 mg/kg) and TPM (10, 30, 50, 70, and 100 mg/kg), respectively, for 21 days. elevated plus maze (EPM) was used to assess motor activity disturbances. In addition, oxidative, antioxidantand inflammatory factors and CREB, Ak1, CAMK4, MAPK3, PKA, BDNF, and c FOS gene levels were measured by RT-PCR, and also, CREB and BDNF protein levels were measured by WB in isolated amygdalae. MPH significantly disturbed motor activity and TPM (70 and 100 mg/kg) neutralized its effects. MPH significantly increased lipid peroxidation, mitochondrial GSSG levels and IL-1β and TNF-α level and CAMK4 gene expression in isolated amygdala cells. In contrast, superoxide dismutase, glutathione peroxidase, and glutathione reductase activities and CREB, BDNF Ak1, MAPK3, PKA, BDNF, and c FOS expression significantly decreased. The various doses of TPM attenuated these effects of MPH. It seems that TPM can be used as a neuroprotective agent and is a good candidate against MPH-induced neurodegeneration.

TRPV1 Channel: A Potential Drug Target for Treating Epilepsy

Epilepsy has 2-3% incidence worldwide. However, present antiepileptic drugs provide only partial control of seizures. Calcium ion accumulation in hippocampal neurons has long been known as a major contributor to the etiology of epilepsy. TRPV1 is a calcium-permeable channel and mediator of epilepsy in the hippocampus. TRPV1 is expressed in epileptic brain areas such as CA1 area and dentate gyrus of the hippocampus. Here the author reviews the patent literature on novel molecules targeting TRPV1 that are currently being investigated in the laboratory and are candidates for future clinical evaluation in the management of epilepsy. A limited number of recent reports have implicated TRPV1 in the induction or treatment of epilepsy suggesting that this may be new area for potential drugs targeting this debilitating disease. Thus activation of TRPV1 by oxidative stress, resiniferatoxin, cannabinoid receptor (CB1) activators (i.e. anandamide) or capsaicin induced epileptic effects, and these effects could be reduced by appropriate inhibitors, including capsazepine (CPZ), 5'-iodoresiniferatoxin (IRTX), resolvins, and CB1 antagonists. It has been also reported that CPZ and IRTX reduced spontaneous excitatory synaptic transmission through modulation of glutaminergic systems and desensitization of TRPV1 channels in the hippocampus of rats. Immunocytochemical studies indicated that TRPV1 channel expression increased in the hippocampus of mice and patients with temporal lobe epilepsy. Taken together, findings in the current literature support a role for calcium ion accumulation through TRPV1 channels in the etiology of epileptic seizures, indicating that inhibition of TRPV1 in the hippocampus may possibly be a novel target for prevention of epileptic seizures.

Involvement of AMPA/kainate and GABAA receptors in topiramate neuroprotective effects against methylphenidate abuse sequels involving oxidative stress and inflammation in rat isolated hippocampus

Abuses of methylphenidate (MPH) as psychostimulant cause neural damage of brain cells. Neuroprotective properties of topiramate (TPM) have been indicated in several studies but its exact mechanism of action remains unclear. The current study evaluates protective role of various doses of TPM and its mechanism of action in MPH induced oxidative stress and inflammation. The neuroprotective effects of various doses of TPM against MPH induced oxidative stress and inflammation were evaluated and then the action of TPM was studied in presence of domoic acid (DOM), as AMPA/kainate receptor agonist and bicuculline (BIC) as GABAA receptor antagonist, in isolated rat hippocampus. Open Field Test (OFT) was used to investigate motor activity changes. Oxidative, antioxidant and inflammatory factors were measured in isolated hippocampus. TPM (70 and 100mg/kg) decreased MPH induced motor activity disturbances and inhibit MPH induced oxidative stress and inflammation. On the other hand pretreatment of animals with DOM or BIC, inhibit this effect of TPM and potentiate MPH induced motor activity disturbances and increased lipid peroxidation, mitochondrial oxidized form of glutathione (GSSG) level, interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in isolated hippocampal cells and decreased reduced form of glutathione (GSH) level, superoxide dismutase, glutathione peroxidase and glutathione reductase activity. It seems that TPM can protect cells of hippocampus from oxidative stress and neuroinflammation and it could be partly by activation of GABAA receptor and inhibition of AMPA/kainite receptor.

Selenoproteins and heat shock proteins play important roles in immunosuppression in the bursa of Fabricius of chickens with selenium deficiency

Selenium (Se) is necessary for the immune system in chicken and mediates its physiological functions through selenoproteins. Heat shock proteins (Hsps) are indispensable for maintaining normal cell function and for directing the immune response. The aim of the present study was to investigate the effects of Se deficiency on the messenger ribonucleic acid (mRNA) expression levels of selenoproteins and Hsps as well as immune functions in the chicken bursa of Fabricius. Two groups of chickens, namely the control and Se-deficient (L group) groups, were reared for 55 days. The chickens were offered a basal diet, which contained 0.15 mg Se/kg in the diet fed to the control group and 0.033 mg Se/kg in the diet fed to the L group. We performed real-time quantitative polymerase chain reaction to detect the mRNA expression levels of selenoproteins and Hsps on days 15, 25, 35, 45 and 55. Western blotting was used to determine the protein expression levels of Hsps on days 35, 45 and 55, and immune functions were assessed through an enzyme-linked immunosorbent assay on days 15, 35, and 55. The data showed that the mRNA expression levels of selenoproteins, such as Txnrd1, Txnrd2, Txnrd3, Dio1, Dio2, Dio3, GPx1, GPx2, GPx3 GPx4, Sepp1, Selo, Sel-15, Sepx1, Sels, Seli, Selu, Selh, and SPS2, were significantly lower (P < 0.05) in the L group compared with the control group. Additionally, the mRNA and protein expression levels of Hsps (Hsp27, Hsp40, Hsp60, Hsp70, and Hsp90) were also significantly higher (P < 0.05) in the L group. The expression levels of IL-2, IL-6, IL-8, IL-10, IL-17, IL-1β, IFN-α, IFN-β, and IFN-γ were significantly lower (P < 0.05) and TNF-α was significantly higher (P < 0.05) in the L group compared with the control group. Our results show that immunosuppression was accompanied by a downregulation of mRNA expression levels of selenoproteins and an upregulation of the Hsp mRNA expression levels. Thus, Se deficiency causes defects in the chicken bursa of Fabricius, and selenoproteins and Hsps play important roles in immunosuppression in the bursa of Fabricius of chickens with Se deficiency.

Protective effects of riboflavin and selenium on brain microsomal Ca2+-ATPase and oxidative damage caused by glyceryl trinitrate in a rat headache model

Migraine headaches are considered to be associated with increased mitochondrial energy metabolism. Mitochondrial oxidative stress is also important in migraine headache pathophysiology although riboflavin and selenium (Se) induced a modulator role on mitochondrial oxidative stress in the brain. The current study aimed to determine the effects of Se with/without riboflavin on the microsomal membrane Ca(2+)-ATPase (MMCA), lipid peroxidation, antioxidant, and electroencephalography (EEG) values in glyceryl trinitrate (GTN)-induced brain injury rats. Thirty-two rats were randomly divided into four groups. The first group was used as the control, and the second group was the GTN group. Se and Se plus oral riboflavin were administered to rats constituting the third and fourth groups for 10 days prior to GTN administration. The second, third, and fourth groups received GTN to induce headache. Ten hours after the administration of GTN, the EEG records and brain cortex samples were obtained for all groups. Brain cortex microsomes were obtained from the brain samples. The brain and microsomal lipid peroxidation levels were higher in the GTN group compared to the control group, whereas they were decreased by selenium and selenium + riboflavin treatments. Vitamin A, vitamin C, vitamin E, and reduced glutathione (GSH) concentrations of the brain and MMCA, GSH and glutathione peroxidase values of microsomes were decreased by the GTN administration, although the values and β-carotene concentrations were increased by Se and Se + riboflavin treatments. There was no significant change in EEG records of the four groups. In conclusion, Se with/without riboflavin administration protected against GTN-induced brain oxidative toxicity by inhibiting free radicals and the modulation of MMCA activity and supporting the antioxidant redox system.

Prediction of selenoprotein T structure and its response to selenium deficiency in chicken immune organs

Selenoprotein T (SelT) is associated with the regulation of calcium homeostasis and neuroendocrine secretion. SelT can also change cell adhesion and is involved in redox regulation and cell fixation. However, the structure and function of chicken SelT and its response to selenium (Se) remains unclear. In the present study, 150 1-day-old chickens were randomly divided into a low Se group (L group, fed a Se-deficient diet containing 0.020 mg/kg Se) and a control group (C group, fed a diet containing sodium selenite at 0.2 mg/kg Se). The immune organs (spleen, thymus, and bursa of Fabricius) were collected at 15, 25, 35, 45, and 55 days of age. We performed a sequence analysis and predicted the structure and function of SelT. We also investigated the effects of Se deficiency on the expression of SelT, selenophosphate synthetase-1 (SPS1), and selenocysteine synthase (SecS) using RT-PCR and the oxidative stress in the chicken immune organs. The data showed that the coding sequence (CDS) and deduced amino acid sequence of SelT were highly similar to those of 17 other animals. Se deficiency induced lower (P < 0.05) levels of SelT, SPS1, and SecS, reduced the catalase (CAT) activity, and increased the levels of hydrogen peroxide (H2O2) and hydroxyl radical (-OH) in immune organs. In conclusion, the CDS and deduced amino acid sequence of chicken SelT are highly homologous to those of various mammals. The redox function and response to the Se deficiency of chicken SelT may be conserved. A Se-deficient diet led to a decrease in SelT, SecS, and SPS1 and induced oxidative stress in the chicken immune organs. To our knowledge, this is the first report of predictions of chicken SelT structure and function. The present study demonstrated the relationship between the selenoprotein synthases (SPS1, SecS) and SelT expression in the chicken immune organs and further confirmed oxidative stress caused by Se deficiency. Thus, the information presented in this study is helpful to understand chicken SelT structure and function. Meanwhile, the present research also confirmed the negative effects of Se deficiency on chicken immune organs.

Role and mechanism of Twist1 in modulating the chemosensitivity of FaDu cells

Multidrug resistance (MDR) is one of the most important obstacles affecting the efficacy of chemotherapy treatments for numerous types of cancer. In the present study, we have demonstrated the possible function of Twist1 in the chemosensitivity of head and neck squamous cell carcinoma (HNSCC) and have identified that its mechanism maybe associated with MDR1/P-gp regulation. To investigate this, the hypopharyngeal cancer cell line, FaDu, and its MDR cell line induced by taxol, FaDu/T, were employed. Stable transfectants targeted to Twist1 overexpression and Twist1 silencing based on FaDu were also conducted. Morphological observation, flow cytometry, reverse transcription-polymerase chain reaction (RT-PCR), western blotting and laser scanning confocal microscope detection were utilized to detect the associations between Twist1 and the chemosensitivity of FaDu cells. Our results demonstrated that Twist1 and MDR1/P-gp were upregulated in FaDu/T cells in a MDR dose-dependent manner. The anti-apoptotic capabilities of FaDu/T cells were enhanced during MDR progression, with apoptosis-related proteins (Bcl-2, Bax, activated caspase-3 and caspase-9) changing to resist apoptosis. Twist1 overexpression decreased the sensitivity of cells to taxol as revealed by a significant increase in MDR1/P-gp and IC₅₀ (P<0.05). This overexpression also enhanced the resistance to apoptosis, with apoptotic proteins changing to resist cell death, and inhibited Ca²⁺ release induced by taxol (P<0.05). Detections in Twist1 silencing cells also confirmed this result. This study provided evidence that alterations of Twist1 expression modulates the chemosensitivity of FaDu cells to taxol. Therefore, Twist1 knockdown may be a promising treatment regimen for advanced hypopharyngeal carcinoma patients with MDR.

Trace element, oxidant, and antioxidant enzyme values in blood of children with refractory epilepsy

PURPOSE

The aim of this study is to evaluate the serum levels of some trace elements, oxidants, and antioxidants in children with intractable epilepsy compared to healthy children.

PATIENTS AND METHODS

In a case-control study, 40 children (24 males and 16 females) suffering from refractory generalized epileptic seizures were compared with 40 sex- and age-matched healthy children serve as a control group. Serum selenium (Se), zinc (Zn), copper (Cu), and plasma malondialdehyde (MDA) as well as erythrocyte glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) values were measured in the patients and controls.

RESULTS

Plasma MDA values of the patient group were significantly ( p < 0.001) higher than those in control. Serum Zn, Se, and erythrocyte GSH-Px values of the patient group are significantly ( p < 0.001) lower than those in control, although there is no statistical difference in Cu and SOD values.

CONCLUSION

Plasma MDA, erythrocyte GSH-Px, and trace elements Zn and Se may play an important role in the pathogenesis of intractable epilepsy in children.

Prostate epithelium-specific deletion of the selenocysteine tRNA gene Trsp leads to early onset intraepithelial neoplasia

Although various lines of evidence suggest that oxidative stress plays a role in human prostate cancer initiation and progression, there is a paucity of direct evidence for its role in tumor initiation. To begin to address this issue, we developed a novel tumorigenesis model by reducing the expression of multiple selenoproteins (SPs) in mouse prostatic epithelium. This was accomplished via the prostate-specific deletion of Trsp, a gene that encodes a transfer RNA (Sec tRNA) required for the insertion of selenocysteine residues into SPs during their translation. By 6 weeks of age, Trsp-deficient mice exhibited widespread prostatic intraepithelial neoplasia lesions in all prostatic lobes, which then progressed to high-grade dysplasia and microinvasive carcinoma by 24 weeks. In contrast to other murine prostate cancer models, Trsp-deficient mice required neither the deletion of a tumor suppressor nor the transgenic introduction of an oncogene for prostatic intraepithelial neoplasia lesion development. In keeping with the antioxidant functions of several SPs, we found increases in lipid peroxidation markers in Trsp-deficient epithelial cells. This novel model of prostate neoplasia provides evidence for the existence of a selenoprotein or selenoproteins capable of acting as a tumor suppressor in the murine prostate.

Selenium attenuates adriamycin-induced cardiac dysfunction via restoring expression of ATP-sensitive potassium channels in rats

The possible mechanism of adriamycin (ADR) and/or selenium (Se) deficiency-induced cardiac dysfunction, and cardioprotective effects of Se against ADR-induced cardiac toxicity were investigated in this study. Cardiac function was evaluated by plasma brain natriuretic peptide level and echocardiographic and hemodynamic parameters. Cardiac glutathione peroxidase (GPx) activity was assessed spectrophotometrically. Expression of ATP-sensitive potassium channels (KATP) subunits-SUR2A and Kir6.2-were examined by real-time PCR and Western blotting. The results showed that cardiac function and cardiac GPx activity decreased remarkably after administration of ADR or Se deficiency; more dramatic impairment of cardiac function and cardiac GPx activity were observed after co-administration of ADR and Se deficiency. Mechanically, it is novel for us to find down-regulation of KATP subunits gene expression in cardiac tissue after administration of ADR or Se deficiency, and more significant inhibition of cardiac KATP gene expression was identified after co-administration of ADR and Se deficiency. Furthermore, cardiac toxicity of ADR was found alleviated by Se supplementation, accompanied by restoring of cardiac GPx activity and cardiac KATP gene expression. These results indicate that decreased expression of cardiac KATP is involved in adriamycin and/or Se deficiency-induced cardiac dysfunction; Se deficiency exacerbates adriamycin-induced cardiac dysfunction by future inhibition of KATP expression; Se supplementation seems to protect against adriamycin-induced cardiac dysfunction via restoring KATP expression, showing potential clinical application in cancer chemotherapy.

Oxidative stress and paraoxonase activity in experimental selenosis: effects of betaine administration

The present study was undertaken on male rats to elucidate the selenosis induced by sodium selenite and the role played by betaine in alleviating selenium toxicity. Rats were treated with sodium selenite (6 mg/kg body weight/day) with or without betaine (240 mg/kg body weight/day). Selenotoxicosis was evident from the elevated plasma levels of total bilirubin, transaminases, and alkaline phosphatase activities. Moreover, the total protein levels decreased, and this decrease associated with a decreased albumin level, whereas the globulin level increased in selenium-intoxicated rats. The development of selenosis corresponded well with the induction of oxidative stress evident from decrease of total thiol level and glutathione content. Furthermore, activities of glutathione reductase, glucose-6-phosphate dehydrogenase, catalase, and paraoxonase-1 were decreased in selenium-treated rats. In contrast, superoxide dismutase and glutathione peroxidase activities were increased by excess selenium administration compared with control animals. As well, malondialdehyde and protein carbonyl were elevated in rats treated with selenium. Supplementation of betaine simultaneously with selenium caused less marked alteration in the investigated parameters. Betaine attenuated the selenotoxicosis by restoring thiol levels that preserve enzymatic antioxidants activity and attenuate the oxidation of lipids and proteins.

Selenium and topiramate attenuates blood oxidative toxicity in patients with epilepsy: a clinical pilot study

It is well known that oxidative stress plays an important role in the etiology of epilepsy. We investigated effects of selenium (Se) and topiramate (TPM) combination supplementation on antioxidant and oxidant values in control and patients with epilepsy and refractory epilepsy. For the aim, we used control (n = 19), epilepsy + TPM (n = 19), epilepsy + TPM + Se (n = 15) groups. We also used control (n = 15), refractory epilepsy (n = 15), and refractory epilepsy + Se (n = 8) groups. TPM (0.2 mg/daily) and Se, as sodium selenite (twice daily with 0.1 mg doses), were orally supplemented to the patients for 45 days. Erythrocyte lipid peroxidation levels were higher in refractory epilepsy groups than in control although its level and seizure numbers were decreased in TPM and TPM + Se supplemented groups of the patients. The erythrocyte reduced glutathione (GSH), glutathione peroxidase (GSH-Px), plasma total antioxidant status (TAS), and vitamin E concentration in refractory epilepsy group were lower than in control. However, the erythrocyte and plasma TAS, erythrocyte GSH and GSH-Px, and plasma vitamins A and C values were increased either by Se or Se + TPM in epilepsy and refractory epilepsy groups. There were no effects of TPM and Se on plasma β-carotene values in the groups. In conclusion, TPM and selenium caused protective effects on the epilepsy and refractory epilepsy-induced oxidative injury by inhibiting free radical production and supporting antioxidant redox system.

Effects of selenium and zinc status in biological samples of hepatitis C patient after herbal and pharmaceutical supplements

The use of natural remedies and pharmacological mineral supplements for liver disease treatment has a long history. In present study, the levels of selenium (Se) and zinc (Zn) were determined in biological samples (serum and whole blood) of female hepatitis C patients (n = 132), age ranged 30-45 years, before and after 30 days treatment with herbal/pharmaceutical supplements. For comparative study, 128 age-matched female subjects, residing in the same residential areas and have socioeconomic status, were selected as referents. The Se and Zn in supplements, blood, and sera were determined by atomic absorption spectrometry. It was observed that Zn and Se in blood and serum samples of viral hepatitis C (HCV) patients were reduced in the range of 28.6-39 % and 24-36 %, respectively, as compared to those of referents. After herbal/pharmaceutical supplementations, 20.6-25.0 and 9.15-13.2 % of Zn and 10.6-12.1 and 19.6-21.4 % of Se were enhanced in sera and blood samples of HCV patients, respectively. The resulted data indicated that the levels of Se and Zn in addition to some biochemical parameters were improved in HCV patients after herbal/pharmaceutical supplementation. The effects of both supplements were not significantly different (p > 0.05).