Reduced mitochondrial complex II activity enhances cell death via intracellular reactive oxygen species in STHdhQ111 striatal neurons with mutant huntingtin.

Huntington's disease (HD) is an inherited neurodegenerative disorder caused by CAG repeat expansion in the huntingtin (HTT) gene. Here, we examined the effects of antioxidants on 3-nitropropionic acid (3-NP; a mitochondrial complex II inhibitor)-induced mitochondrial dysfunction and cell death in STHdhQ111 striatal cells carrying homozygous mutant HTT with extended CAG repeats compared with those in STHdhQ7 striatal cells. 3-NP reduced cell viability and increased cell death both in STHdhQ111 and STHdhQ7, and the cytotoxicity was markedly attenuated by antioxidants (N-acetyl-l-cysteine and edaravone). Furthermore, 3-NP increased intracellular reactive oxygen species (ROS) production in both cell lines, and this increase was inhibited by antioxidants. Mitochondrial ROS was also increased by 3-NP in STHdhQ111 but not in STHdhQ7, and this increase was significantly inhibited by edaravone. Mitochondrial membrane potential (MMP) was lower in STHdhQ111 than that in STHdhQ7, and antioxidants prevented 3-NP-induced MMP decrease in STHdhQ111.3-NP enhanced oligomerization of dynamin-related protein 1 (Drp1), a protein that promotes mitochondrial fission in both cells, and both antioxidants prevented the increase in oligomerization. These results suggest that reduced mitochondrial complex II activity enhances cell death via intracellular ROS production and Drp1 oligomerization in striatal cells with mutant HTT and antioxidants may reduce striatal cell death.

Predicting the combinatorial effects of water activity, pH and organic acids on Listeria growth in media and complex food matrices.

The aim of this study was to develop a model to predict growth of Listeria in complex food matrices as a function of pH, water activity and undissociated acetic and propionic acid concentration i.e. common food hurdles. Experimental growth curves of Listeria in food products and broth media were collected from ComBase, the literature and industry sources from which a bespoke secondary gamma model was constructed. Model performance was evaluated by comparing predictions to measured growth rates in growth media (BHI broth) and two adjusted food matrices (zucchini purée and béarnaise sauce). In general, observed growth rates were higher in broth than in the food matrices which resulted in the model over-estimating growth in the adjusted food matrices. In addition, model outputs were more accurate for conditions without acids, indicating that the organic acid component of the model was a source of inaccuracy. In summary, a new predictive growth model for innovating or renovating food products that rely on multi-hurdle technology was created. This study is the first to report on modelling of propionic acid as an inhibitor of Listeria in combination with other hurdles. Our findings provide valuable insights into predictive model design and performance and highlight the importance of experimental validation of models in real food matrices rather than laboratory media alone.

Pomegranate seed oil: Effect on 3-nitropropionic acid-induced neurotoxicity in PC12 cells and elucidation of unsaturated fatty acids composition.

BACKGROUND: Seed oils are used as cosmetics or topical treatment for wounds, allergy, dandruff, and other purposes. Natural antioxidants from plants were recently reported to delay the onset or progress of various neurodegenerative conditions. Over one thousand cultivars of Punica granatum (Punicaceae) are known and some are traditionally used to treat various ailments. AIM: The effect of pomegranate oil on 3-nitropropionic acid- (3-NP) induced cytotoxicity in rat pheochromocytoma (PC12) neuronal cells was analyzed in this study. Furthermore, the analysis of unsaturated fatty acid composition of the seed oil of pomegranate by gas chromatography-electron impact mass spectrometry (GC-MS) was done. RESULTS: GC-MS study showed the presence of 6,9-octadecadiynoic acid (C18:2(6,9)) as a major component (60%) as 4,4-dimethyloxazoline derivative. The total extractable oil with light petroleum ether by Soxhlet from the dry seed of P. granatum was 4-6%. The oil analyzed for 48.90 ±â€Š1.50 mg gallic acid equivalents/g of oil, and demonstrated radical-scavenging-linked antioxidant activities in various in vitro assays like the DPPH (2,2-diphenyl-l-picrylhydrazyl, % IP = 35.2 ± 0.9%), ABTS (2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid), % IP 2.2 ± 0.1%), and ß-carotene bleaching assay (% IP = 26 ± 3%), respectively, which could be due the possible role of one methylene interrupted diynoic acid system for its radical-scavenging/antioxidant properties of oil. The oil also reduced lipid peroxidation, suppressed reactive oxygen species, extracellular nitric oxide, lactate/pyruvate ratio, and lactase dehydrogenase generated by 3-NP- (100 mM) induced neurotoxicity in PC12 cells, and enhanced the levels of enzymatic and non-enzymatic antioxidants at 40 µg of gallic acid equivalents. CONCLUSION: The protective effect of pomegranate seed oil might be due to the ability of an oil to neutralize ROS or enhance the expression of antioxidant gene and the exact mechanism of action yet to be elucidated.

Effect of rutin against a mitochondrial toxin, 3-nitropropionicacid induced biochemical, behavioral and histological alterations-a pilot study on Huntington's disease model in rats.

Dietary compounds like flavonoids may offer protection against neurodegeneration. Huntington's disease (HD) is a neurodegenerative disorder characterized by symptoms like chorea and dementia. 3-Nitropropionic acid (3-NP), a Succinate dehydrogenase (SDH) inhibitor produces behavioral, biochemical and histological changes in the striatum, mimics HD in animals and humans. The present study was designed to examine the protective activity of Rutin (RT), a primary flavonoid from citrus fruits, green tea on 3-NP induced experimental model of HD in rats. Rats were pretreated with Rutin, a potent antioxidant (25 and 50 mg/kg b.w.) orally prior to the intraperitoneally (i.p.) administration of 3-NP (10 mg/kg b.w.) for 14 days. Behavioral assessments were carried out on 5th, 10th and 15th day after 3-NP treatment. Body weight, biochemical and histological studies were analyzed on 15th day. Systemic administration of 3-NP significantly reduced the body weight, locomotor activities (Rota rod, Open field test), memory (Morris water maze) and antioxidants such as Glutathione (GSH) levels, activities of Superoxide dismutase (SOD), Catalase (CAT), Glutathione peroxidase (GPx), Glutathione-S-transferase (GST), Glutathione reductase (GR). 3-NP also produces striatal damage by increased the levels of lipid peroxides, nitrite, Glial Fibrillary Acidic Protein (GFAP) and activity of Acetylcholine esterase (AchE). Thus, Rutin treatment of 25 and 50 mg/kg b.w. has significantly restored all the biochemical, behavioral and histological alterations caused by the 3-NP through its antioxidant activity. The findings of our study indicates that Rutin may have an important role in protecting the striatum from oxidative/nitrosative insults caused by 3-NP. These results suggest that RT might be a drug of choice to treat HD.

c-Jun-dependent sulfiredoxin induction mediates BDNF protection against mitochondrial inhibition in rat cortical neurons.

In current study, we tested the hypothesis that c-Jun-dependent sulfiredoxin expression mediates protective effects of brain-derived neurotrophic factor (BDNF) against neurotoxicity induced by 3-nitropropionic acid (3-NP), a mitochondrial complex II inhibitor, in primary rat cortical cultures. We found that BDNF-dependent c-Jun expression and nuclear translocation required prior phosphorylation of extracellular signal-regulated kinase (ERK)1/2, but not Akt. BDNF also transiently activated the expression of sulfiredoxin, an ATP-dependent antioxidant enzyme, at both mRNA and protein levels. Furthermore, both c-Jun siRNA and ERK1/2 inhibitor PD98059 suppressed BDNF-induced sulfiredoxin expression. Finally, PD98059, c-Jun siRNA, and sulfiredoxin siRNA all abrogated BDNF-mediated 3-NP resistance. Together, these results established a signaling cascade of "BDNF → ERK1/2-Pi → c-Jun → sulfiredoxin → 3-NP resistance". We therefore conclude that c-Jun-induced sulfiredoxin mediates the BDNF-dependent neuroprotective effects against 3-NP toxicity in primary rat cortical neurons, at least in part.

Harmine prevents 3-nitropropionic acid-induced neurotoxicity in rats via enhancing NRF2-mediated signaling: Involvement of p21 and AMPK.

Oxidative stress induced neurotoxicity is increasingly perceived as an important neuropathologic mechanism underlying the motor and behavioral phenotypes associated with Huntington's disease (HD). Repeated exposure to 3-nitropropionic acid (3-NP) induces neurotoxic changes which closely simulate the neuropathological and behavioral characteristics of HD. This study aimed at evaluating the prophylactic effects of the dual-specificity tyrosine phosphorylation regulated kinase 1A (DYRK1A) inhibitor "harmine" against 3-NP-indued neurotoxicity and HD-like symptoms. The potential prophylactic effect of harmine (10 mg/kg/day; intraperitoneal) was investigated on 3-NP-induced motor and cognitive HD-like deficits, nuclear factor erythroid 2 like 2 (NRF2), AMP kinase (AMPK) and p21 protein levels and the gene expression of haem oxygenase-1 (Ho-1), NAD(P)H: quinone oxidoreductase-1 (Nqo-1) and p62 in addition to redox imbalance and histological neurotoxic changes in the striatum, prefrontal cortex, and hippocampus of male Wistar rats. Harmine successfully increased the protein levels of NRF2, AMPK and p21 and the gene expression of Ho-1, Nqo-1 and p62, restored redox homeostasis, and reduced CASPASE-3 level. This was reflected in attenuation of 3-NP-induced neurodegenerative changes and improvement of rats' motor and cognitive performance. This study draws attention to the protective role of harmine against 3-NP-induced motor and cognitive dysfunction that could be mediated via enhancing NRF2-mediated signaling with subsequent amelioration of oxidative stress injury via NRF2 activators, p21 and AMPK, in the striatum, prefrontal cortex, and hippocampus which could offer a promising therapeutic tool to slow the progression of HD.

Neuroprotective effects of creatine.

There is a substantial body of literature, which has demonstrated that creatine has neuroprotective effects both in vitro and in vivo. Creatine can protect against excitotoxicity as well as against ß-amyloid toxicity in vitro. We carried out studies examining the efficacy of creatine as a neuroprotective agent in vivo. We demonstrated that creatine can protect against excitotoxic lesions produced by N-methyl-D: -aspartate. We also showed that creatine is neuroprotective against lesions produced by the toxins malonate and 3-nitropropionic acid (3-NP) which are reversible and irreversible inhibitors of succinate dehydrogenase, respectively. Creatine produced dose-dependent neuroprotective effects against MPTP toxicity reducing the loss of dopamine within the striatum and the loss of dopaminergic neurons in the substantia nigra. We carried out a number of studies of the neuroprotective effects of creatine in transgenic mouse models of neurodegenerative diseases. We demonstrated that creatine produced an extension of survival, improved motor performance, and a reduction in loss of motor neurons in a transgenic mouse model of amyotrophic lateral sclerosis (ALS). Creatine produced an extension of survival, as well as improved motor function, and a reduction in striatal atrophy in the R6/2 and the N-171-82Q transgenic mouse models of Huntington's disease (HD), even when its administration was delayed until the onset of disease symptoms. We recently examined the neuroprotective effects of a combination of coenzyme Q10 (CoQ10) with creatine against both MPTP and 3-NP toxicity. We found that the combination of CoQ and creatine together produced additive neuroprotective effects in a chronic MPTP model, and it blocked the development of alpha-synuclein aggregates. In the 3-NP model of HD, CoQ and creatine produced additive neuroprotective effects against the size of the striatal lesions. In the R6/2 transgenic mouse model of HD, the combination of CoQ and creatine produced additive effects on improving survival. Creatine may stabilize mitochondrial creatine kinase, and prevent activation of the mitochondrial permeability transition. Creatine, however, was still neuroprotective in mice, which were deficient in mitochondrial creatine kinase. Administration of creatine increases the brain levels of creatine and phosphocreatine. Due to its neuroprotective effects, creatine is now in clinical trials for the treatment of Parkinson's disease (PD) and HD. A phase 2 futility trial in PD showed approximately a 50% improvement in Unified Parkinson's Disease Rating Scale at one year, and the compound was judged to be non futile. Creatine is now in a phase III clinical trial being carried out by the NET PD consortium. Creatine reduced plasma levels of 8-hydroxy-2-deoxyguanosine in HD patients phase II trial and was well-tolerated. Creatine is now being studied in a phase III clinical trial in HD, the CREST trial. Creatine, therefore, shows great promise in the treatment of a variety of neurodegenerative diseases.

Neuroprotective effects of the CTK 01512-2 toxin against neurotoxicity induced by 3-nitropropionic acid in rats.

The mitochondrial inhibitor 3-nitropropionic acid (3-NP) induces excitotoxicity. The authors hypothesized that CTK 01512-2, a recombinant peptide calcium channel N-type blocker, and the TRPA1 antagonist, could show neuroprotective effects. The male Wistar rats received 3-NP [25 mg/kg (i.p.) for 7 days], and a treatment of CTK 01512-2 was delivered intrathecally (i.t.), thrice a week. The neuroprotective effects were evaluated by [18F]FDG MicroPET analysis. The CTK 01512-2 toxin was able to reestablish similar glucose uptakes on the control animals. To detect the neurobehavioral effects from 3-NP, three protocols (6.25, 12.5, 18.75 mg/kg of 3-NP (i.p.), for 3, 4, and 6 days, respectively) were evaluated by performance tests (open field test, walk footprint, elevated plus-maze, Y-maze, and the object recognition test). Important disabilities in the gait of the rats were seen, as well as memory deficits, and anxious behavior in the animals that were treated with all 3-NP protocols. The dose of 18.75 mg/kg (for 3 days) showed the most pronounced behavioral effects and lethality, while the rats treated with 12.5 mg/kg (for 4 days) showed behavioral effects similar to the 6.25 mg/kg dose (for 6 days). The third protocol was then repeated and the rats were treated with the CTK 01512-2 toxin to be evaluated behaviorally again. The recombinant peptide prevented all of the gait-evaluated parameters that were induced by 3-NP at a 6.25 mg/kg dose, which displayed an improvement in the exploratory activities. Overall, these results have reinforced the positive effects of CTK 01512-2 against the behavioral changes that were induced by the mitochondrial inhibitor 3-NP.

Erythropoietin and sonic hedgehog mediate the neuroprotective effects of brain-derived neurotrophic factor against mitochondrial inhibition.

Brain-derived neurotrophic factor (BDNF) deficiency and mitochondrial dysfunction have been implicated in the pathogenesis of Huntington's disease (HD). 3-Nitropropionic acid (3-NP) is a mitochondrial inhibitor commonly used as a pharmacological model mimicking HD. We have recently reported that preconditioning of primary rat cortical cultures with BDNF induces sonic hedgehog (SHH), which contributes to the protective effects of BDNF against 3-NP neurotoxicity. Because carbamylated erythropoietin (EPO) may induce SHH, we investigated whether BDNF-dependent SHH expression and 3-NP resistance require prior induction of EPO. We found that BDNF induced EPO expression at both mRNA and protein levels. BDNF-mediated SHH induction and 3-NP resistance were abolished by the soluble EPO receptor (sEPO-R), an EPO inhibitor. Recombinant rat EPO (rEPO) induced SHH and attenuated 3-NP neurotoxicity. The rEPO-dependent neuroprotection was suppressed by the SHH inhibitor cyclopamine (CPM); however, sEPO-R failed to affect SHH neuroprotection. Furthermore, the rEPO-dependent neuroprotection was not suppressed by the BDNF neutralizing antibody, which completely abolished BDNF-mediated 3-NP resistance at the same dosage. Overall, our results demonstrate that BDNF-dependent SHH expression and 3-NP resistance require prior induction of EPO, thus establishing a signaling cascade of "BDNF-->EPO-->SHH-->3-NP resistance" in rat cortical neurons.

Folic acid increases levels of GHS in brain of rats with oxidative stress induced with 3-nitropropionic acid.

Aim: This study tested the hypothesis that folic acid (FA) modulates biogenic amines and protects the brain against oxidative stress induced by 3-nitropropionic acid (3NPA).Methods: Male Wistar rats received (groups of six) for 5 d: FA (50 mg/kg); 3NPA (10 mg/kg); or FA +3NPA. At last day, rats were sacrificed, and their brain was obtained to measure the levels of dopamine, 5-hydroxiindol acetic acid (5-HIAA). Reduced glutathione (GSH), total ATPase, H2O2 and lipid peroxidation were measured.Results: GSH increased significantly in cortex of rats treated with FA. ATPase increased significantly in cerebellum/medulla oblongata and decreased in cortex of animal treated with 3NPA. 5-HIAA increased in striatum of rats that received 3NPA alone or combined with FA.Conclusion: 3NPA generates free radicals such effect can be counteracted with FA administration since this folate increases antioxidant capacity and modulates biogenic amines.

GW9508 ameliorates cognitive impairment via the cAMP-CREB and JNK pathways in APPswe/PS1dE9 mouse model of Alzheimer's disease.

GPR40 was utilized as the drug target to the treatment of diabetes, but the function and mechanisms ameliorating the Alzheimer's disease (AD) remain unknown. In present study, the typical APP/PS1 mouse model was applied to explore the function and mechanism of GPR40 in AD. GPR40 agonist GW9508 and antagonist GW1100 were respectively given by i.c.v. injection to activate/inhibit the GPR40 in the brain of APP/PS1 mice which illustrated the function and mechanism of GPR40 in ameliorating AD symptoms. Morris water maze test, step-through test, Y-maze spontaneous alternation test, open field test and new object recognition test were used to test the cognitive function and memory ability of mice, while molecular biology experiments such as Western blot, immunofluorescence, JC-1 were used to detect the corresponding changes of signal pathways. The results revealed that treatment with GW9508 could significantly ameliorate cognitive deficits of APP/PS1 mice, upregulate the expression levels of cAMP, p-CREB and neurotrophic factors in vivo, while GW9508 also ameliorate Aß1-42-induced neuron damage and downregulate the expression levels of pathological protein such as p-JNK, JNK and apoptosis-related proteins such as IL-6, IL-1ß, TNF-α and caspase-3 in vitro. Meanwhile, high-content screening also showed that GW9508 promoted the cellular differentiation of SH-SY5Y cells, while GW1100 reversed the effects of GW9508. These results suggested that GPR40 was an underlying therapeutic target for the treatment of AD and GPR40 agonist could be explored as the emerging AD therapeutic drug.

Sonic hedgehog mediates BDNF-induced neuroprotection against mitochondrial inhibitor 3-nitropropionic acid.

Sonic hedgehog (SHH), a morphogen critical for embryogenesis, has also been shown to be neuroprotective. We have recently reported that pretreatment of rat cortical neurons for 8 h with brain-derived neurotrophic factor (BDNF; 100 ng/ml) affords protection against neurotoxicity of 3-nitropropionic acid (3-NP; 2.5 mM for 24 h), a mitochondrial complex II inhibitor. However, whether SHH is involved in BDNF-mediated neuroprotection remains unknown. Herein we tested whether BDNF induces SHH expression and if so, whether BDNF induction of SHH contributes to the observed neuroprotective effects. We found BDNF (100 ng/ml) increased SHH expression at both mRNA and protein levels. BDNF protection against 3-NP was abolished by cyclopamine (CPM; 5 microM), the SHH pathway inhibitor. Preconditioning of cortical neurons with N-terminal fragment of SHH (SHH-N; 0.1-1 ng/ml) was sufficient to confer resistance. These results indicate that BDNF induces SHH expression, which contributes to neuroprotection against 3-NP toxicity in rat cortical neurons.

In vitro antioxidant activity of Valeriana officinalis against different neurotoxic agents.

Valeriana officinalis L. (Valerian) is widely used as a traditional medicine to improve the quality of sleep. Although V. officinalis have been well documented as promising pharmacological agent; the exact mechanisms by which this plant act is still unknown. Limited literature data have indicated that V. officinalis extracts can exhibit antioxidant properties against iron in hippocampal neurons in vitro. However, there is no data available about the possible antioxidant effect of V. officinalis against other pro-oxidants in brain. In the present study, the protective effect of V. officinalis on lipid peroxidation (LPO) induced by different pro-oxidant agents with neuropathological importance was examined. Ethanolic extract of valerian (0-60 microg/ml) was tested against quinolinic acid (QA); 3-nitropropionic acid; sodium nitroprusside; iron sulfate (FeSO4) and Fe2+/EDTA induced LPO in rat brain homogenates. The effect of V. officinalis in deoxyribose degradation and reactive oxygen species (ROS) production was also investigated. In brain homogenates, V. officinalis inhibited thiobarbituric acid reactive substances induced by all pro-oxidants tested in a concentration dependent manner. Similarly, V. officinalis caused a significant decrease on the LPO in cerebral cortex and in deoxyribose degradation. QA-induced ROS production in cortical slices was also significantly reduced by V. officinalis. Our results suggest that V. officinalis extract was effective in modulating LPO induced by different pro-oxidant agents. These data may imply that V. officinalis extract, functioning as antioxidant agent, can be beneficial for reducing insomnia complications linked to oxidative stress.

Early nerve ending rescue from oxidative damage and energy failure by L: -carnitine as post-treatment in two neurotoxic models in rat: recovery of antioxidant and reductive capacities.

Cell rescue is a primary need during acute and chronic insults to the central nervous system. Functional preservation during the early stages of toxicity in a given degenerative event may represent a significant amelioration of detrimental processes linked to neuronal cell loss. Excitotoxicity and depleted cellular energy are toxic events leading to cell death in several neurodegenerative disorders. In this work, the effects of the well-known antioxidant and energy precursor, L: -carnitine (L: -CAR), were tested as a post-treatment in two neurotoxic models under in vitro and in vivo conditions. The experimental models tested included: (1) a typical excitotoxic and pro-oxidant inducer, quinolinic acid (QUIN); and (2) a mitochondrial energy inhibitor, 3-nitropropionic acid (3-NP). For in vitro studies, increasing concentrations of L: -CAR (10-1,000 microM) were added to the isolated brain synaptosomes at different times (1, 3 and 6 h) after the incubation with toxins (100 microM QUIN and 1 mM 3-NP), and 30 min later, lipid peroxidation (LP) and mitochondrial dysfunction (MD) were evaluated. For in vivo purposes, L: -CAR (100 mg/kg, i.p.) was given to rats either as a single administration 120 min after the intrastriatal infusion of QUIN (240 nmol/microl) or 3-NP (500 nmol/microl), or for 7 consecutive days (starting 120 min post-lesion). LP and MD were evaluated 4 h and 7 days post-lesions in isolated striatal synaptosomes. Our results show that, despite some variations depending on the toxic model tested, the time of exposure, or the biomarker evaluated, nerve ending protection can be mostly achieved by L: -CAR within the first hours after the toxic insults started, suggesting that targeting the ongoing oxidative damage and/or energy depletion during the first stages of neurotoxic events is essential to rescue nerve endings.

The natural xanthone alpha-mangostin reduces oxidative damage in rat brain tissue.

The antiperoxidative properties of alpha-mangostin, a xanthone isolated from mangosteen fruit, were tested for the first time in nerve tissue exposed to different toxic insults. Two reliable biological preparations (rat brain homogenates and synaptosomal P2 fractions) were exposed to the toxic actions of a free radical generator (ferrous sulfate), an excitotoxic agent (quinolinate), and a mitochondrial toxin (3-nitropropionate). alpha-Mangostin decreased the lipoperoxidative action of FeSO(4) in both preparations in a concentration-dependent manner, and completely abolished the peroxidative effects of quinolinate, 3-nitropropionate and FeSO(4) + quinolinate at all concentrations tested. Interestingly, when tested alone in brain homogenates, alpha-mangostin significantly decreased the lipoperoxidation even below basal levels. alpha-Mangostin also prevented the decreased reductant capacity of mitochondria in synaptosomal fractions. Our results suggest that alpha-mangostin exerts a robust antiperoxidative effect in brain tissue preparations probably through its properties as a free radical scavenger. In light of these findings, this antioxidant should be tested in other neurotoxic models involving oxidative stress.

Melatonin protects against Fenoxaprop-ethyl exposure-induced meiotic defects in mouse oocytes.

Prolonged exposure of Fenoxaprop-ethyl (FE), a post-emergence herbicide, can cause serious damage to animals through food chain. Melatonin is synthesized by the pineal gland in mammals and believed to protect cells from oxidative stress damage. In this study, we aimed to investigate the effects of FE on mouse oocyte meiosis maturation and the protective roles of melatonin on FE-exposed oocytes by in vitro maturation model. FE exposure significantly caused defects of the first polar body extrusion, which could be protected by co-culture with melatonin. Furthermore, we examined the meiotic maturation details by performing the sperm binding, actin and tubulin immunofluorescence, ROS and apoptosis detection, and histone methylation assay. Our data showed that FE exposure to oocytes led to disrupted actin filament dynamics, mis-organized spindle, and reduced the sperm binding capacity. In addition, FE-exposure increased oxidative stress level and induced oocyte apoptosis. We also found that FE exposure resulted in histone methylation changes. Treatment with melatonin could significantly improve these phenotypes in oocytes exposed to FE. In conclusion, FE exposure can cause meiotic defects by disrupting the cytoskeletal integrality and inducing excessive ROS accumulation to initiate apoptosis in oocytes, while melatonin can reduce all these damages, suggesting that melatonin has protective effects on oocytes exposed to FE during meiotic maturation.

Protective effect of minocycline, a semi-synthetic second-generation tetracycline against 3-nitropropionic acid (3-NP)-induced neurotoxicity.

3-Nitropropionic acid (3-NP) is an irreversible inhibitor of the electron transport enzyme succinate dehydrogenase, a mitochondrial Complex II enzyme. Minocycline is a semi-synthetic second-generation tetracycline with neuroprotective activity and has the capability to effectively cross the blood-brain barrier. We investigated the effects of minocycline on behavioral, biochemical, inflammation related and neurochemical alterations induced by the sub-chronic administration of 3-nitropropionic acid to rats. Chronic pre-administration of minocycline (50 and 100mg/kg) dose dependently prevented 3-NP-induced dysfunction behavioral (hypoactivity, memory retention, locomotor and rota-rod activity). In addition, 3-NP produced a marked increase in lipid peroxidation levels whereas decreased the activities of catalase and succinate dehydrogenase. In contrast, pretreatment of 3-NP injected rats with minocycline resulted in the attenuation of all these alterations. A marked increase in an inflammatory cytokine TNF-alpha by 3-NP was also decreased by minocycline treatment. Neurochemically, the administration of 3-NP significantly decreased the levels of catecholamines in the brain homogenates (dopamine, norepinephrine and serotonin) which were reversed by pretreatment of minocycline. The present finding explains the neuroprotective effect of minocycline against 3-NP toxicity by virtue of its antioxidant and anti-inflammatory activity.

3-Nitropropionic acid depresses spinal reflexes involving GABAergic and glycinergic transmission in neonatal rat spinal cord in vitro.

AIMS: 3-Nitropropionic acid (3-NPA) is a naturally occurring fungal toxin that leads to ATP-depletion by inhibiting mitochondrial succinate dehydrogenase and produces chemical anoxia. The present study was conducted to identify the involvement of inhibitory system in 3-NPA-induced depression of spinal reflexes. METHODS: The monosynaptic (MSR) and polysynaptic reflex (PSR) potentials were recorded at ventral root by stimulating the corresponding dorsal root in hemisected (sagitally) spinal cord from 4-8 day old rats. Effect of 3-NPA in the absence and presence of antagonists was evaluated on the reflexes. KEY FINDINGS: Superfusion of 3-NPA (3.4 mM) depressed the reflexes in a time-dependent manner abolishing them by 35 min. The T-50 values were around 18 and 16 min for MSR and PSR, respectively. An NMDA receptor antagonist, DL-2-amino-5-phosphonovaleric acid (10 microM) failed to block the 3-NPA (3.4 mM)-induced depression of reflexes. Superfusion of bicuculline (GABAA receptor antagonist; 1 microM), or strychnine (glycineA receptor antagonist; 1 microM) antagonized the 3-NPA-induced depression of reflexes significantly. The T-50 values were 26 and 30 min in bicuculline and strychnine pretreated groups, respectively and were significantly greater than 3-NPA only group. SIGNIFICANCE: The results indicate that 3-NPA-induced depression of spinal reflexes is partially mediated by GABAergic and glycinergic inhibitory transmission.

Mechanism of 3-nitropropionic acid-induced membrane permeability transition of isolated mitochondria and its suppression by L-carnitine.

3-Nitropropionic acid (3NP) functions as an irreversible inhibitor of succinic acid dehydrogenase (complex II) and induces neuronal disorders in rats similar to those in patients with Huntington's disease. It is well known that L-carnitine (LC), a carrier of long chain fatty acid into the mitochondrial matrix, attenuates the neuronal degeneration in 3NP-treated rats. From these findings it has been suggested that 3NP induces certain neuronal cell death through mitochondrial dysfunction and that LC preserves the neurons against the dysfunction of mitochondria caused by 3NP. However, the detailed mechanism of cell death by 3NP and the protective actions of LC against the mitochondrial dysfunction have not been fully elucidated yet. Thus, we studied the molecular mechanism of the effects of 3NP and LC on isolated rat liver mitochondria. 3NP inhibited succinate respiration and the decreased respiratory control ratio of isolated mitochondria without affecting oxidative phosphorylation. 3NP induced a membrane permeability transition (MPT), which plays an important role in the mechanism of apoptotic cell death. 3NP stimulated Ca2+ release from mitochondria, decreased membrane potential, induced mitochondrial swelling, and stimulated cytochrome c release from mitochondria. 3NP-induced swelling was suppressed by bovine serum albumin, inhibitors of phospholipase A(2) and by an inhibitor of classic MPT, cyclosporin A. Furthermore, LC suppressed the changes brought about by 3NP in mitochondrial functions in the presence of ATP. These results suggest that MPT underlies the mechanism of 3NP-induced cell death, and that LC attenuates mitochondrial MPT by decreasing long chain fatty acids generated by phospholipase A(2).

Prolonged pretreatment with carvedilol prevents 3-nitropropionic acid-induced behavioral alterations and oxidative stress in rats.

3-nitropropionic acid (3-NP)-induced neurotoxicity causes a cellular energy deficit and oxidative stress via an irreversible inhibition of the mitochondrial enzyme succinate dehydrogenase (SDH). Systemic administration of 3-NP causes motor and cognitive deficits, particularly those associated with excessive free radical generation. Recently, carvedilol has been implicated as a neuroprotectant in the treatment of various neurological disorders. The present study was designed to investigate the neuroprotective effects of carvedilol against 3-NP-induced cognitive impairment and oxidative damage in rats. Intraperitoneal administration of 3-NP (20 mg/kg for 4 days) caused significant body weight reduction, impaired motor function (locomotor activity, movement pattern), induced vacuous chewing movements, led to poor retention of memory in the Morris water maze, and elevated plus maze task paradigms. Chronic treatment with carvedilol (1 and 2 mg/kg, po), once daily for a period of 8 days beginning 4 days before 3-NP administration, significantly reversed 3-NP-induced motor impairment and cognitive deficits. However, carvedilol (1 and 2 mg/kg, po) treatment significantly attenuated oxidative damage (reduced lipid peroxidation and nitrite levels, and restored depleted reduced glutathione and succinate dehydrogenase enzyme activity) in the rat brain. The results of the present study suggest that carvedilol has a neuroprotective effect against 3-NP-induced behavioral alterations and oxidative damage.