Cyclooxygenase inhibition attenuates 3-nitropropionic acid-induced neurotoxicity in rats: possible antioxidant mechanisms

Quercetin's Restorative Properties in Male Mice with 3-Nitropropionic Acid-induced Huntington-like Symptoms: Molecular Docking, Behavioral, and Biochemical Assessment

The neurotoxicity of 3-Nitropropionic acid (3-NP) is well known. Herein, the prophylactic versus therapeutic effects of quercetin (QCT) were investigated against 3-NP-induced behavioral anomalies and oxidative neural damage. Thirty male mice were assigned into five groups; the negative control group, the QCT group (25 mg/kg/day, p.o. for 21 days), the 3-NP group (17 days), the prophylactic group (QCT administration for 14 consecutive days, and then 3-NP was administrated), the therapeutic group (3-NP was administrated and then QCT for 21 days). At the end of the animal treatment, behavioral studies were assessed. Subsequently, the brain sample tissues were assessed for oxidative stress-related parameters and histological evaluation. Moreover, the potential interaction between 3-NP and tumor necrosis factor-alpha (TNF-α) was evaluated by using a molecular docking study. 3-NP markedly led to neurotoxicity which was indicated by behavioral deficits (motor behavior, depression-like behavior, memory dysfunction, and passive avoidance) and oxidative damage. Blind and targeted molecular docking results showed good interaction between 3-NP and TNF-α. However, the prophylactic effects of QCT were superior to the therapeutic effects for attenuating 3-NP-induced neurobehavioral and oxidative neural changes in experimental mice, which histological changes of the brain's striatum region approved our findings. Taken together, the antioxidant activity of QCT remarkably could attenuate 3-NP-induced neurobehavioral deficits and mitochondrial dysfunctions in mice.

Neuroprotective effects of silymarin in 3-nitropropionic acid-induced neurotoxicity in male mice: improving behavioral deficits by attenuating oxidative stress and neuroinflammation

3-Nitropropionic acid (3-NP) is strongly believed to be an irreversible inhibitor of mitochondrial complex II, leading to neural damage. This study aimed to investigate the neuroprotective effects of silymarin against 3-NP-induced neurotoxicity in male mice. Six-week-old mice received subacute doses of 3-NP intraperitoneally for 17 days. Mice were given silymarin (70 mg/kg/day, P.O.) for 2 weeks before 3-NP administration or for 4 weeks after 3-NP administration. At the end of the treatment schedule, animals were evaluated for behavioral alterations. Subsequently, neuronal damage in the hippocampus region of the brain tissues, oxidative stress-related parameters (lipid peroxidation, nitric oxide, superoxide dismutase, glutathione, and total antioxidant capacity), and pro-inflammatory cytokine (TNF-α, IL-17, and IL-1β) levels were evaluated. Our results indicated that 3-NP treatment significantly (p < 0.05) tended to reduce motor coordination, memory, and neuronal antioxidant status while increasing pro-inflammatory cytokine levels. However, silymarin in both treatment and pretreatment protocols markedly (p < 0.05) attenuated the behavioral deficits, oxidative stress status, and neuroinflammation. The results of the current study suggest that the neuroprotective effect of silymarin against 3-NP-induced neurotoxicity might be due to the mitigation of oxidative stress status and provide insight into the therapeutic potential of silymarin.

A clinical study and future prospects for bioactive compounds and semi-synthetic molecules in the therapies for Huntington's disease

A neurodegenerative disorder (ND) refers to Huntington's disease (HD) which affects memory loss, weight loss, and movement dysfunctions such as chorea and dystonia. In the striatum and brain, HD most typically impacts medium-spiny neurons. Molecular genetics, excitotoxicity, oxidative stress (OS), mitochondrial, and metabolic dysfunction are a few of the theories advanced to explicit the pathophysiology of neuronal damage and cell death. Numerous in-depth studies of the literature have supported the therapeutic advantages of natural products in HD experimental models and other treatment approaches. This article briefly discusses the neuroprotective impacts of natural compounds against HD models. The ability of the discovered natural compounds to suppress HD was tested using either in vitro or in vivo models. Many bioactive compounds considerably lessened the memory loss and motor coordination brought on by 3-nitropropionic acid (3-NP). Reduced lipid peroxidation, increased endogenous enzymatic antioxidants, reduced acetylcholinesterase activity, and enhanced mitochondrial energy generation have profoundly decreased the biochemical change. It is significant since histology showed that therapy with particular natural compounds lessened damage to the striatum caused by 3-NP. Moreover, natural products displayed varying degrees of neuroprotection in preclinical HD studies because of their antioxidant and anti-inflammatory properties, maintenance of mitochondrial function, activation of autophagy, and inhibition of apoptosis. This study highlighted about the importance of bioactive compounds and their semi-synthetic molecules in the treatment and prevention of HD.

Protective Effect of Fustin against Huntington's Disease in 3-Nitropropionic Treated Rats via Downregulation of Oxidative Stress and Alteration in Neurotransmitters and Brain-Derived Neurotrophic Factor Activity

Researchers have revealed that Rhus verniciflua heartwood, which contains fustin as an important component, possesses antioxidant-mediated, anti-mutagenic, and anti-rheumatoid arthritis characteristics. Additionally, out of the numerous plant-derived secondary metabolites, there are various research papers concentrating on flavonoids for potential advantages in neurological illnesses. The current study aims to assess the neuroprotective potential of fustin in rodents over 3-nitropropionic acid (3-NPA)-induced Huntington's disease (HD)-like consequences. The efficacy of fustin 50 and 100 mg/kg was studied with multiple-dose administrations of 3-NPA, which experimentally induced HD-like symptoms in rats for 22 days. At the end of the study, several behavioral tests were performed including a beam walk, rotarod, and grip strength tests. Similarly, some biochemical parameters were assessed to support oxidative stress (reduced glutathione-GSH, superoxide dismutase-SOD, catalase-CAT, and malondialdehyde-MDA), alteration in neurotransmitters (gamma-aminobutyric acid-GABA-and glutamate), alteration in brain-derived neurotrophic factor activity, and nitrite levels. Additionally, pro-inflammatory parameters were carried out to evaluate the neuroinflammatory responses associated with streptozotocin such as TNF-α, IL-1β, and COX in the perfused brain. The fustin-treated group exhibited a significant restoration of memory function via modulation in behavioral activities. Moreover, 3-NPA altered biochemical, neurotransmitters, brain protein levels, and neuroinflammatory measures, which fustin efficiently restored. This is the first report demonstrating the efficacy of novel phytoconstituent fustin as a potential future candidate for the treatment of HD via offering neuroprotection by subsiding the oxidative and enzymatic activity in the 3-NPA experimental animal paradigm.

Berberine Ameliorate Haloperidol and 3-Nitropropionic Acid-Induced Neurotoxicity in Rats

Berberine due to its antioxidant properties, has been used around the globe significantly to treat several brain disorders. Also, oxidative stress is a pathological hallmark in neurodegenerative diseases like Huntington's disease (HD) and Tardive dyskinesia (TD). Berberine an alkaloid from plants has been reported to have neuroprotective potential in several animal models of neurodegenerative diseases. Hence, this study aims to evaluate the neuroprotective effect of berberine in the animal model of 3-nitropropionic acid (3-NP) induced HD and haloperidol induced tardive dyskinesia with special emphasis on its antioxidant property. The study protocol was divided into 2 phases, first phase involved the administration of 3-NP and berberine at the dose of (25, 50, and 100 mg/kg) intraperitoneally (i.p) and orally (p.o.) respectively for 21 days, and the following parameters (rotarod, narrow beam walk and photoactometer) as a measure of motor activity and striatal and cortical levels of (LPO, GSH, SOD, catalase, and nitrate) evaluated as a measure of oxidative stress were assessed for HD. Similarly in the second phase, TD was induced by using haloperidol, for 21 days and berberine at the dose of (25, 50, and 100 mg/kg) was administered, and both physical and biochemical parameters were assessed as mentioned for the HD study. The resultant data indicated that berberine attenuate 3-NP and haloperidol-induced behavioral changes and improved the antioxidant capcity in rodents. Hence berberine might be a novel therapeutic candidate to manage TD & HD.

The Role of Cyclooxygenase 2 in the Cognitive Impairment Induced by Alcohol or Stress in Rats

Background:

Cognitive impairment is an unpleasant and progressive mental disorder characterized by learning and memory disabilities. Stress and alcohol are two known environmental factors that increase cognitive impairment. This study was designed to evaluate the relative role of cyclooxygenase 2 in alcohol or stress-induced cognitive impairment.

Materials and Methods:

Male Wistar rats were randomly divided into groups with six rats in each. The groups included sham, control, alcohol (15% ethanol in drinking water), and restraint stress (restraint 6 h per day). Three separated groups received celecoxib at a dose of 20 mg/kg in addition to those listed above. The treatments continued daily for 28 days. The object recognition task (ORT) and Morris water maze (MWM) are used to evaluate the learning and memory.

Results:

Alcohol or restrain stress significantly increased the time and distance needed to find the hidden platform in MWM. Furthermore, they decreased the recognition index in ORT compared to the control group. Administration of celecoxib significantly decreased the required time and traveled distance to reach the platform in alcohol-treated animals but not in the stress-exposed rats. Celecoxib also significantly increased the recognition index both in alcohol- or restraint stress-exposed animals.

Conclusion:

We found that either alcohol or restraint stress impairs memory in rats. In MWM, celecoxib improved the alcohol-induced memory impairment but could not show a reduction in memory deterioration due to restraint stress. In ORT, celecoxib reversed memory impairment due to both alcohol and restraint stress.

Anti-Huntington's Effect of Butin in 3-Nitropropionic Acid-Treated Rats: Possible Mechanism of Action

Butin has a strong antioxidant plus anti-inflammatory action and it is reported to be protective in oxidative stress-induced mitochondrial dysfunction. Butin has been shown to protect the mouse hippocampus HT22 cells from glutamate-induced neurotoxicity. The current investigation was planned to assess anti-Huntington's effect of butin in 3-nitropropionic acid-treated rats. A total of 32 Wistar rats (200-240 g) were equally segregated into four groups. Groups I and II were treated with vehicle (0.3 ml/100 g) and groups III and IV received butin 25 and 50 mg/kg for 15 days. Daily 1 h post above oral treatments, 3 ml/kg of normal saline was injected (i.p.) to group I animals and 10 mg/kg of 3-NP was injected (i.p.) to II and IV groups for 15 days. During the experimental schedule, behavioral tests were conducted for animals. On day 15, after behavioral parameters, animals were sacrificed and brains were removed for biochemical tests. Systemic administration of 3-NP induced neurobehavioral deficits which resulted in reduced spontaneous locomotor activity, motor incoordination, learning ability, and memory in the animals. Moreover, 3-NP depleted endogenous antioxidants (GSH, catalase, and SOD), mitochondrial complexes activities (I, II, IV, and MTT assay), elevated LDH, MDA, nitrite, and AchE. Administration of butin significantly improved neurobehavioral impairments, nitrative and oxidative stress, activities of mitochondrial enzyme complex, and reduced AchE levels in rat brain.

Nano-ivabradine averts behavioral anomalies in Huntington's disease rat model via modulating Rhes/m-tor pathway

Huntington's disease (HD) is characterized by abnormal involuntary movements together with cognitive impairment and disrupted mood changes. 3-nitropropionic acid (3-NP) is one of the chemo-toxic models used to address the striatal neurotoxicity pattern encountered in HD. This study aims to explain the neuroprotective effect of nano-formulated ivabradine (nano IVA) in enhancing behavioral changes related to 3-NP model and to identify the involvement of ras homolog enriched striatum (Rhes)/mammalian target of rapamycin (m-Tor) mediated autophagy pathway. Rats were divided into 6 groups, the first 3 groups received saline (control), ivabradine (IVA), nano IVA respectively, the fourth received a daily dose of 3-NP (20 mg/kg, s.c) for 2 weeks, the fifth received 3-NP + IVA (1 mg/kg, into the tail vein, every other day for 1 week) and the last group received 3-NP + nano IVA (1 mg/kg, i.v, every other day for 1 week). Interestingly, nano IVA reversed motor disabilities, improved memory function and overcame the psychiatric changes. It boosted expression of autophagy markers combined with down regulation of Rhes, m-Tor and b-cell lymphoma 2 protein levels. Also, it restored the normal level of neurotransmitters and myocardial function related-proteins. Histopathological examination revealed a preserved striatal structure with decreased number of darkly-degenerated neurons. In conclusion, the outcomes of this study provide a well-recognized clue for the promising neuroprotective effect of IVA and the implication of autophagy and Rhes/m-Tor pathways in the 3-NP induced HD and highlight the fact that nano formulations of IVA would be an auspicious approach in HD therapy.

Resveratrol (RV): A pharmacological review and call for further research

Resveratrol (RV) is a well-known polyphenolic compound in various plants, including grape, peanut, and berry fruits, which is quite famous for its association with several health benefits such as anti-obesity, cardioprotective neuroprotective, antitumor, antidiabetic, antioxidants, anti-age effects, and glucose metabolism. Significantly, promising therapeutic properties have been reported in various cancer, neurodegeneration, and atherosclerosis and are regulated by several synergistic pathways that control oxidative stress, cell death, and inflammation. Similarly, RV possesses a strong anti-adipogenic effect by inhibiting fat accumulation processes and activating oxidative and lipolytic pathways, exhibiting their cardioprotective effects by inhibiting platelet aggregation. The RV also shows significant antibacterial effects against various food-borne pathogens (Listeria, Campylobacter, Staphylococcus aureus, and E. coli) by inhibiting an electron transport chain (ETC) and F0F1-ATPase, which decreases the production of cellular energy that leads to the spread of pathogens. After collecting and analyzing scientific literature, it may be concluded that RV is well tolerated and favorably affects cardiovascular, neurological, and diabetic disorders. As such, it is possible that RV can be considered the best nutritional additive and a complementary drug, especially a therapeutic candidate. Therefore, this review would increase knowledge about the blend of RV as well as inspire researchers around the world to consider RV as a pharmaceutical drug to combat future health crises against various inhumane diseases. In the future, this article will be aware of discoveries about the potential of this promising natural compound as the best nutraceuticals and therapeutic drugs in medicine.

The neuroprotective attribution of Ocimum basilicum: a review on the prevention and management of neurodegenerative disorders

Background

Bioactive principles from various natural resources including medicinal herbs have always played a crucial role in healthcare settings and increasingly became key players in drug discovery and development for many biopharmaceutical applications. Additionally, natural products (NPs) have immense arrangement of distinctive chemical structures with diverse functional groups that motivated numerous investigators including synthetic chemists to discover new therapeutic entities. Numerous pre-clinical investigations involving the animal models have evident the usefulness of these NPs against various human diseases including neurodegenerative disorders (NDs).

Main text

Ocimum basilicum Linn (O. basilicum L.), also known as sweet basil, is well practiced in traditional healthcare systems and has been used to treat various human illnesses, which include malaria, skin disease, diarrhea, bronchitis, dysentery, arthritis, eye diseases, and insect bites and emphasize the significance of the ethno-botanical approach as a potential source of novel drug leads With the growing interest in advanced techniques, herbal medicine and medicinal plants explorations are still considered to be a novel resource for new pharmacotherapeutic discovery and development. O. basilicum L and its bioactive principles including apigenin, eugenol, myretenal, β-sitosterol, luteolin, rosmarinic acid, carnosic acid, essential oil (EO)-rich phenolic compounds, and others like anthocyanins and flavones could be of therapeutic values in NDs by exhibiting their neuro-protective efficacy on various signaling pathways. The present comprehensive review collected various related information using the following searching engines such as PubMed, Science Direct, Google Scholar, etc. and focused mainly the English written documents. The search period comprised of last two decades until present.

Conclusion

Although these efficacious plant genera of prime importance and has potential medical and socioeconomic importance, yet the pivotal evidence for its neuroprotective potential in novel clinical trials remains lacking. However, with the available wealth of obtainable literature on this medicinal plant, which supports this review and concludes that O. basilicum L may function as a promising therapeutics for the treatment of NDs.

Incorporation of a Biocompatible Nanozyme in Cellular Antioxidant Enzyme Cascade Reverses Huntington's Like Disorder in Preclinical Model

The potentiality of nano-enzymes in therapeutic use has directed contemporary research to develop a substitute for natural enzymes, which are suffering from several disadvantages including low stability, high cost, and difficulty in storage. However, inherent toxicity, inefficiency in the physiological milieu, and incompatibility to function in cellular enzyme networks limit the therapeutic use of nanozymes in living systems. Here, it is shown that citrate functionalized manganese-based biocompatible nanoscale material (C-Mn₃ O₄ NP) efficiently mimics glutathione peroxidase (GPx) enzyme in the physiological milieu and easily incorporates into the cellular multienzyme cascade for H₂ O₂ scavenging. A detailed computational study reveals the mechanism of the nanozyme action. The in vivo therapeutic efficacy of C-Mn₃ O₄ nanozyme is further established in a preclinical animal model of Huntington's disease (HD), a prevalent progressive neurodegenerative disorder, which has no effective medication to date. Management of HD in preclinical animal trial using a biocompatible (non-toxic) nanozyme as a part of the metabolic network may uncover a new paradigm in nanozyme based therapeutic strategy.

Prostaglandins as the Agents That Modulate the Course of Brain Disorders

Neurologic and neuropsychiatric diseases are associated with great morbidity and mortality. Prostaglandins (PGs) are formed by sequential oxygenation of arachidonic acid in physiologic and pathologic conditions. For the production of PGs cyclooxygenase is a necessary enzyme that has two isoforms, that are named COX-1 and COX-2. COX-1 produces type 1 prostaglandins and on the other hand, COX-2 produces type 2 prostaglandins. Recent studies suggest PGs abnormalities are present in a variety of neurologic and psychiatric disorders. In a disease state, type 2 prostaglandins are mostly responsible and type 1 PGs are not so important in the disease state. In this review, the importance of prostaglandins especially type 2 in brain diseases has been discussed and their possible role in the initiation and outcome of brain diseases has been assessed. Overall the studies suggest prostaglandins are the agents that modulate the course of brain diseases in a positive or negative manner. Here in this review article, the various aspects of PGs in the disease state have discussed. It appears more studies must be done to understand the exact role of these agents in the pathophysiology of brain diseases. However, the suppression of prostaglandin production may confer the alleviation of some brain diseases.

Adenylate cyclase activator forskolin alleviates intracerebroventricular propionic acid-induced mitochondrial dysfunction of autistic rats

Neuronal mitochondrial dysfunction increases inflammatory mediators and leads to free radical generation and anti-oxidant enzymatic alterations, which are major neuropathological hallmarks responsible for autism. Mitochondrial dysfunction in autism is associated with decreased ATP levels due to reduced levels of cyclic adenosine monophosphate. Rat models of autism were established by intracerebroventricular injection of propionic acid. These rat models had memory dysfunction, decreased muscle coordination and gait imbalance. Biochemical estimation of propionic acid-treated rats showed changes in enzyme activity in neuronal mitochondrial electron transport chain complexes and increases in pro-inflammatory cytokines, oxidative stress and lipid biomarkers. Oral administration of 10, 20 and 30 mg/kg adenylate cyclase activator forskolin for 15 days reversed these changes in a dose-dependent manner. These findings suggest that forskolin can alleviate neuronal mitochondrial dysfunction and improve neurological symptoms of rats with autism. This study was approved by the RITS/IAEC, SIRSA, HARYANA on March 3, 2014 (approval No. RITS/IAEC/2014/03/03).

Neuroprotective effect of solanesol against 3-nitropropionic acid-induced Huntington's disease-like behavioral, biochemical, and cellular alterations: Restoration of coenzyme-Q10-mediated mitochondrial dysfunction

OBJECTIVE

The aim of the present study was to evaluate the solanesol (SNL)-mediated coenzyme-Q10 restoration to ameliorate 3-nitropropionic (3-NP)-induced behavioral, biochemical, and histological changes which resemble Huntington's disease (HD)-like symptoms in men.

MATERIALS AND METHODS

Various behavioral and biochemical parameters were carried out to evaluate the activity of SNL on 3-NP-treated rats. To determine the therapeutic significance of SNL on HD, different behavioral tests such as memory task, locomotor activity, grip strength, and beam cross and some biochemical test along with histopathological findings were done.

RESULTS

Chronic 3-NP, 10 mg/kg i.p., caused physical and mental abnormalities in animals, including memory impairment, weak grip strength, abnormal posture, and cognitive deficit. Biochemical analysis of brain homogenate in 3-NP-treated rats showed altered mitochondrial complexes, oxidative stress, and elevated lipid biomarkers. Neurohistological alterations of hippocampus, basal ganglia, and cerebral cortex of 3-NP-treated rats exhibit severe neuronal space, irregular damaged cells, and dense pyknotic nuclei-associated marked focal diffused gliosis. SNL administered for 15 days significantly improved motor performance and cognitive behavior task and restored the histopathological changes. Further, SNL treatment significantly improved mitochondrial complexes such as coenzyme-Q10 enzyme activity and attenuated inflammatory and oxidative damage of rat brain.

CONCLUSION

In the present research work, SNL (5, 10, and 15 mg/kg p.o.) provided notable neuroprotective effect, which was confirmed by behavioral paradigms and biochemical test. It restored the behavioral and biochemical alteration caused by 3-NP and confirmed the strong neuroprotective mechanism of SNL in 3-NP-intoxicated memory and cognitive abnormalities.

Neuroprotective Strategies for Neurological Disorders by Natural Products: An update

Nature has bestowed mankind with surplus resources (natural products) on land and water. Natural products have a significant role in the prevention of disease and boosting of health in humans and animals. These natural products have been experimentally documented to possess various biological properties such as antioxidant, anti-inflammatory and anti-apoptotic activities. In vitro and in vivo studies have further established the usefulness of natural products in various preclinical models of neurodegenerative disorders. Natural products include phytoconstituents, like polyphenolic antioxidants, found in herbs, fruits, nuts, vegetables and also in marine and freshwater flora. These phytoconstituents may potentially suppress neurodegeneration and improve memory as well as cognitive functions of the brain. Also, they are known to play a pivotal role in the prevention and cure of different neurodegenerative diseases, such as Alzheimer's disease, epilepsy, Parkinson's disease and other neuronal disorders. The large-scale neuro-pharmacological activities of natural products have been documented due to the result of either the inhibition of inflammatory processes, or the up-regulation of various cell survival proteins or a combination of both. Due to the scarcity of human studies on neuroprotective effects of natural products, this review focuses on the various established activities of natural products in in vitro and in vivo preclinical models, and their potential neuro-therapeutic applications using the available knowledge in the literature.

Nicotinamide reverses behavioral impairments and provides neuroprotection in 3-nitropropionic acid induced animal model ofHuntington's disease: implication of oxidative stress- poly(ADP- ribose) polymerase pathway

Huntington's disease (HD) is characterized by cognitive and psychiatric impairment caused by neuronal degeneration in the brain. Several studies have supported the hypothesis that oxidative stress is the main pathogenic factor in HD. The current study aims to determine the possible neuroprotective effects of nicotinamide on 3-nitropropionic acid (3-NP) induced HD. Male Wistar albino rats were divided into six groups. Group I was the vehicle-treated control, group II received 3-NP (20 mg/kg, intraperitoneally (i.p.) for 4 days, group III received nicotinamide (500 mg/kg, i.p.). The remaining groups received a combination of 3-NP plus nicotinamide 100, 300 or 500 mg/kg, i.p. respectively for 8 days. Afterward, the motor function and hind paw activity in the limb withdrawal were tested; rats were then euthanized for biochemical and histopathological analyses. Treatment of rats with 3-NP altered the motor function, elevated oxidative stress and caused significant histopathological changes in the brain. The treatment of rats with nicotinamide (100, 300 and 500 mg/kg) improved the motor function tested by locomotor activity test, movement analysis, and limb withdrawal test, which was associated with decreased oxidative stress markers (malondialdehyde, nitrites) and increased antioxidant enzyme (glutathione) levels. In addition, nicotinamide treatment decreased lactate dehydrogenase and prevented neuronal death in the striatal region. Our study, therefore, concludes that antioxidant drugs like nicotinamide might slow progression of clinical HD and may improve the motor functions in HD patients. To the best of our knowledge, this study is the first to explore the neuroprotective effects of nicotinamide on 3-NP-induced HD.

Thymoquinone loaded solid lipid nanoparticles counteracts 3-Nitropropionic acid induced motor impairments and neuroinflammation in rat model of Huntington's disease

Defect in gene transcription, excitotoxicity, neuroinflammation and oxidative stress are the dominant disease process that causes striatal cell loss with motor abnormalities in Huntington's disease (HD). Homogeneous pathological reminiscent of HD was extrapolated in the present study using a potent mitochondrial toxin, 3-Nitropropionic acid (3-NP). Administration of 3-NP for 14 days in the present study portends glial cell activation, N-methyl-D-aspartate (NMDA) receptor stimulation, neuroinflammation and motor deficits. The therapeutic strategy in the present study was improvised by formulating thymoquinone, a biologically active compound into a colloidal carrier namely solid lipid nanoparticles. Treatment with 10 and 20 mg/kg b.w of thymoquinone loaded solid lipid nanoparticles (TQ-SLNs) and 80 mg/kg b.w of thymoquinone suspension (TQ-S) showed a significant (P < 0.01) improvement in ATPases function in 3-NP induced animals than TQ-S (40 mg/kg b.w) treated group. TQ-SLNs (10 and 20 mg/kg) treatment also attenuated the overexpression of glial fibrillary acidic protein (GFAP), pro-inflammatory cytokines and p-p65 NFκB nuclear translocation in 3-NP exposed animals. Further, TQ-SLNs treatment desensitizes NR2B-subtype NMDA receptor, improves tyrosine hydroxylase (TH) immune reactive neurons and ameliorated the motor abnormalities in 3-NP intoxicated animals than TQ-S treated group. Hence, the study signifies that the treatment with lower doses of nanoformulated thymoquinone than thymoquinone suspension can efficiently culminate 3-NP induced HD progression in the striatum of male wistar rats.

Bacterial communities related to 3-nitro-1-propionic acid degradation in the rumen of grazing ruminants in the Qinghai-Tibetan Plateau

The objectives of this current study were to characterize the overall rumen bacterial community in grazing yak and two sheep species (Tibetan and Small Tail Han sheep) reared in the unique environmental conditions of the Qinghai-Tibetan Plateau, as well as the bacterial community associated with the detoxification of a phytotoxin, 3-nitro-1-propionic acid (NPA), during in vitro culture with 4.2 mM NPA. Using 16S rRNA gene high-throughput sequencing, it was found that the yak rumen harbored populations showing a higher bacterial diversity compared to Tibetan sheep. The rumen bacterial community in the three ruminant species differed from each other. PICRUSt analysis identified that the pathway involved in nitrogen metabolism was enriched in Tibetan sheep while that related to fatty acid biosynthesis was over-represented in the yak. The methane metabolism pathway was dominant in bacterial populations from the Small Tail Han sheep. Comparisons between freshly collected rumen fluid and populations subjected to consecutive 72 h batch cultures revealed substantial decreases in alpha diversity in populations cultured with NPA. Moreover, the relative abundances of some bacterial taxa changed significantly, with increased abundance of Proteobacteria and Actinobacteria. In addition, the overall community structure of the bacterial population in the freshly collected ruminal fluid was clearly different than that within populations observed in the 72 h batch cultures likely due to the impact of NPA treatments and the more restrictive growth conditions of the culture medium. In regard to PICRUSt analysis, the methane metabolism pathway became scarce in Tibetan and Small Tail Han sheep, whereas the energy and carbohydrate metabolic pathways such as nitrogen metabolism, ABC transporters and glycolysis/gluconeogenesis were found to be maintained across all populations. Results from the present study provide new information on the bacterial and functional composition within ruminal populations adapted to three economically important grazing ruminant species prominent on the Qinghai-Tibetan Plateau. The results further reveal that effects of NPA treatment on community structure can have an impact not only the metabolism of NPA but on other digestive functions as well.

Integrated communications between cyclooxygenase-2 and Alzheimer's disease

Elevated levels of cyclooxygenase-2 (COX-2) and prostaglandins (PGs) are involved in the pathogenesis of Alzheimer's disease (AD), which is characterized by the accumulation of β-amyloid protein (Aβ) and tau hyperphosphorylation. However, the gaps in our knowledge of the roles of COX-2 and PGs in AD have not been filled. Here, we summarized the literature showing that COX-2 dysregulation obviously influences abnormal cleavage of β-amyloid precursor protein, aggregation and deposition of Aβ in β-amyloid plaques and the inclusion of phosphorylated tau in neurofibrillary tangles. Neuroinflammation, oxidative stress, synaptic plasticity, neurotoxicity, autophagy, and apoptosis have been assessed to elucidate the mechanisms of COX-2 regulation of AD. Notably, an imbalance of these factors ultimately produces cognitive decline. The current review substantiates our understanding of the mechanisms of COX-2-induced AD and establishes foundations for the design of feasible therapeutic strategies to treat AD.-Guan, P.-P., Wang, P. Integrated communications between cyclooxygenase-2 and Alzheimer's disease.

Selective A2A receptor antagonist SCH 58261 modulates striatal oxidative stress and alleviates toxicity induced by 3-Nitropropionic acid in male Wistar rats

The aim of the present study was to investigate the effects of SCH58261, a selective adenosine A_2A receptor antagonist, on striatal toxicity induced by 3-nitropropionic acid (3-NP) in rats. The experimental protocol consisted of 10 administrations (once a day) of SCH58261 (0.01 or 0.05 mg/kg/day, intraperitoneal, i.p.). From 7th to 10th day, 3-NP (20 mg/kg/day, i.p.) was injected 1 h after SCH58261 administration. Twenty-four hours after the last 3-NP injection, the body weight gain, locomotor activity (open-field test), motor coordination (rotarod test), striatal succinate dehydrogenase (SDH) activity and parameters linked to striatal oxidative status were evaluated in rats. The marked body weight loss resulting from 3-NP injections in rats was partially protected by SCH 58261 at both doses. SCH 58261 at the highest dose was effective against impairments on motor coordination and locomotor activity induced by 3-NP. SCH 58261 was unable to restore the inhibition of SDH activity caused by 3-NP. In addition, the increase in striatal reactive species (RS) levels, depletion of reduced glutathione (GSH) content and stimulation of glutathione reductase (GR) activity provoked by 3-NP injections were alleviated by both doses of SCH 58261. The highest dose of SCH 58261 was also effective in attenuating the increase of protein carbonyl levels as well as the inhibition of glutathione peroxidase (GPx) activity in rats exposed to 3-NP. Our results revealed that reduction of oxidative stress in rat striatum by adenosine A_2A receptor antagonism contributes for alleviating 3-NP-induced toxicity.

Participation of COX-1 and COX-2 in the contractile effect of phenylephrine in prepubescent and old rats

Vascular reactivity can be influenced by the vascular region, animal age, and pathologies present. Prostaglandins (produced by COX-1 and COX-2) play an important role in the contractile response to phenylephrine in the abdominal aorta of young rats. Although these COXs are found in many tissues, their distribution and role in vascular reactivity are not clear. At a vascular level, they take part in the homeostasis functions involved in many physiological and pathologic processes (e.g., arterial pressure and inflammatory processes). The aim of this study was to analyze changes in the contractile response to phenylephrine of thoracic/abdominal aorta and the coronary artery during aging in rats. Three groups of rats were formed and sacrificed at three distinct ages: prepubescent, young and old adult. The results suggest that there is a higher participation of prostanoids in the contractile effect of phenylephrine in pre-pubescent rats, and a lower participation of the same in old rats. Contrarily, there seems to be a higher participation of prostanoids in the contractile response of the coronary artery of older than pre-pubescent rats. Considering that the changes in the expression of COX-2 were similar for the three age groups and the two tissues tested, and that expression of COX-1 is apparently greater in older rats, COX-1 and COX-2 may lose functionality in relation to their corresponding receptors during aging in rats.

Adenyl cyclase activator forskolin protects against Huntington's disease-like neurodegenerative disorders

Long term suppression of succinate dehydrogenase by selective inhibitor 3-nitropropionic acid has been used in rodents to model Huntington's disease where mitochondrial dysfunction and oxidative damages are primary pathological hallmarks for neuronal damage. Improvements in learning and memory abilities, recovery of energy levels, and reduction of excitotoxicity damage can be achieved through activation of Adenyl cyclase enzyme by a specific phytochemical forskolin. In this study, intraperitoneal administration of 10 mg/kg 3-nitropropionic acid for 15 days in rats notably reduced body weight, worsened motor cocordination (grip strength, beam crossing task, locomotor activity), resulted in learning and memory deficits, greatly increased acetylcholinesterase, lactate dehydrogenase, nitrite, and malondialdehyde levels, obviously decreased adenosine triphosphate, succinate dehydrogenase, superoxide dismutase, catalase, and reduced glutathione levels in the striatum, cortex and hippocampus. Intragastric administration of forskolin at 10, 20, 30 mg/kg dose-dependently reversed these behavioral, biochemical and pathological changes caused by 3-nitropropionic acid. These results suggest that forskolin exhibits neuroprotective effects on 3-nitropropionic acid-induced Huntington's disease-like neurodegeneration.

Genistein improves sensorimotor gating: Mechanisms related to its neuroprotective effects on the striatum

Huntington's disease (HD) is a neurodegenerative disorder, characterized by selective atrophy in the striatum, particularly the medium spiny GABAergic efferent neurons. This results in striatal sensorimotor gating deficits. Systemic administration of 3-nitropropionic acid (3-NPA) produces selective lesions mimicking those of HD. Males were found to be more susceptible to 3-NPA-induced neurotoxicity than females, suggesting neuroprotective effects of estrogens. Phytoestrogens, including genistein, are good estrogenic alternatives that keep their beneficial effects on non-reproductive organs and lack the potential hazardous side effects. The current study was designed to investigate the potential beneficial effects of genistein in 3-NPA-induced HD in ovariectomized rats. Results showed that 3-NPA (20 mg/kg) administration caused significant disruption of the rats' locomotor activity and prepulse inhibition. In addition, it decreased striatal ATP levels and increased oxidative stress, inflammatory and apoptotic markers with striatal focal hemorrhage and gliosis. Pretreatment with 17β-estradiol (2.5 mg/kg) or genistein (20 mg/kg) led to a significant improvement of behavioral parameters, increased ATP production, decreased oxidative stress, attenuated inflammation and apoptosis. Therefore, this study suggests potential neuroprotective effects of genistein in ovariectomized rats challenged with 3-NPA.

A novel therapeutic application of solid lipid nanoparticles encapsulated thymoquinone (TQ-SLNs) on 3-nitroproponic acid induced Huntington's disease-like symptoms in wistar rats

Huntington's disease (HD), a devastating neurodegenerative disease causing a remarkable pathogenesis involves mitochondrial dysfunction and bioenergetics failure. 3-Nitropropionic acid (3-NP) is a unique toxin model of HD that are mainly confined to mitochondrial complex-II inhibition and free radical generation. Recently, several nanoparticle formulations were developed to treat against various neurodegenerative diseases including HD. One among them is solid lipid nanoparticles (SLNs), a colloidal carrier designed to enhance the brain drug delivery and to prolong the bio-availability of drugs in the system. Hence, the present study was framed to evaluate solid lipid nanoparticles encapsulated thymoquinone (TQ-SLNs) in comparison with thymoquinone suspension (TQ-S) against 3-NP induced behavioral despair, oxidative injury and striatal pathology. This study reports that theTQ-SLNs (10 and 20 mg/kg) and TQ-S (80 mg/kg) treated animals showed a significant (P < 0.01) improvement in the muscle strength, rigidity, movement and memory performances on 7th and 14th day behavioral analysis than TQ-S (40 mg/kg) treated group. Similarly, TQ-SLNs highly attenuated the levels of oxidative stress markers such as LPO, NO and protein carbonylsin 3-NP induced animals. Further, TQ-SLNs significantly restored the antioxidant defense system, controls the mitochondrial SDH inhibition and alleviates anti-cholinergic effect upon 3-NP induction. In addition, TQ-SLNs efficiently protected the striatal structural microelements against 3-NP toxicity, which was confirmed by light microscopic studies. Thus, the present investigation, collectively suggests that the low dose of TQ-SLNs supplementation is highly sufficient to attain the effect of TQ-S (80 mg/kg) to attenuate behavioral, biochemical and histological modifications in 3-NP exposed HD model.

Resveratrol: A Focus on Several Neurodegenerative Diseases

Molecules of the plant world are proving their effectiveness in countering, slowing down, and regressing many diseases. The resveratrol for its intrinsic properties related to its stilbene structure has been proven to be a universal panacea, especially for a wide range of neurodegenerative diseases. This paper evaluates (in vivo and in vitro) the various molecular targets of this peculiar polyphenol and its ability to effectively counter several neurodegenerative disorders such as Parkinson's, Alzheimer's, and Huntington's diseases and amyotrophic lateral sclerosis. What emerges is that, in the deep heterogeneity of the pathologies evaluated, resveratrol through a convergence on the protein targets is able to give therapeutic responses in neuronal cells deeply diversified not only in morphological structure but especially in their function performed in the anatomical district to which they belong.

Protective effect of Convolvulus pluricaulis standardized extract and its fractions against 3-nitropropionic acid-induced neurotoxicity in rats

CONTEXT

Convolvulus pluricaulis Chois. (Convolvulaceae), a well-known Ayurvedic "Medhya Rasayana" (nervine tonic), is extensively used for different central nervous system (CNS) disorders.

OBJECTIVE

The objective of this study was to evaluate the protective effect of standardized hydro-methanol extract of C. pluricaulis (CPE) and its fractions, namely ethyl acetate (EAE), butanol (BE), and aqueous (AE), against 3-nitropropionic acid (3-NP) induced neurotoxicity in rats.

MATERIALS AND METHODS

The extract of the whole plant was standardized on the basis of scopoletin content (0.014%) using thin layer chromatography densitometric analysis. CPE (100 and 200 mg/kg) and its fractions, namely EAE (15 and 30 mg/kg), BE (25 and 50 mg/kg), and AE (50 and 100 mg/kg) were administered orally for 20 d. Their protective effect against 3-NP (10 mg/kg, i.p. for 14 d) was assessed by the effect on various behavioral parameters, namely body weight, locomotor activity, grip strength, gait pattern, and the effect on cognitive dysfunction. Biochemical parameters for oxidative damage were also assessed in the striatum and cortex regions of the brain.

RESULTS

Administration of 3-NP induced HD-like symptoms that were indicated by reduced body weight, locomotor activity, memory, grip strength, and oxidative defense. CPE (200 mg/kg), EAE (30 mg/kg), and BE (50 mg/kg) significantly (p < 0.001) attenuated 3-NP induced reduction in locomotor activity, grip strength, memory, body weight, and oxidative defense in comparison with 3-NP-treated animals on 10 and 15 d.

CONCLUSION

The present study suggested that CPE has a protective action against 3-NP-induced neurotoxicity and can be further explored for its efficacy against Huntington's disease.

Ebselen protects against behavioral and biochemical toxicities induced by 3-nitropropionic acid in rats: correlations between motor coordination, reactive species levels, and succinate dehydrogenase activity

The protective effect of ebselen was investigated against 3-nitropropionic acid (3-NP)-induced behavioral and biochemical toxicities in rats. Ebselen (10 or 25 mg/kg, intragastrically) was administered to rats 30 min before 3-NP (20 mg/kg, intraperitoneally) once a day for a period of 4 days. Locomotor activity, motor coordination, and body weight gain were determined. The striatal content of reactive oxygen species (ROS), reduced glutathione (GSH), ascorbic acid (AA), and protein carbonyl as well as catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione-S-transferase (GST) activities was determined 24 h after the last dose of 3-NP. Na(+)/ K(+)-ATPase, succinate dehydrogenase (SDH), and δ-aminolevulinic dehydratase (δ-ALA-D) activities were also determined. The results demonstrated that ebselen at a dose of 25 mg/kg, but not at 10 mg/kg, protected against (1) a decrease in locomotor activity, motor coordination impairment, and body weight loss; (2) striatal oxidative damage, which was characterized by an increase in ROS levels, protein carbonyl content, and GR activity, an inhibition of CAT and GPx activities, and a decrease in GSH levels; and (3) an inhibition of SDH and Na(+)/K(+)-ATPase activities, induced by 3-NP. GST activity and AA levels were not modified by ebselen or 3-NP. Ebselen was not effective against the inhibition of δ-ALA-D activity induced by 3-NP. The results revealed a significant correlation between SDH activity and ROS levels, and SDH activity and latency to fall (rotarod test). The present study highlighted the protective effect of ebselen against 3-NP-induced toxicity in rats.

Plants and phytochemicals for Huntington's disease

Huntington's disease (HD) is a neurodegenerative disorder characterized by progressive motor dysfunction, including chorea and dystonia, emotional disturbances, memory, and weight loss. The medium spiny neurons of striatum and cortex are mainly effected in HD. Various hypotheses, including molecular genetics, oxidative stress, excitotoxicity, metabolic dysfunction, and mitochondrial impairment have been proposed to explain the pathogenesis of neuronal dysfunction and cell death. Despite no treatment is available to fully stop the progression of the disease, there are treatments available to help control the chorea. The present review deals with brief pathophysiology of the disease, plants and phytochemicals that have shown beneficial effects against HD like symptoms. The literature for the current review was collected using various databases such as Science direct, Pubmed, Scopus, Sci-finder, Google Scholar, and Cochrane database with a defined search strategy.

Development, characterization and nasal delivery of rosmarinic acid-loaded solid lipid nanoparticles for the effective management of Huntington's disease

OBJECTIVE

The objective of the present study was to investigate the potential use of solid lipid nanoparticles (SLNs) as a drug delivery system to enhance the brain-targeting efficiency of rosmarinic acid (RA) following intranasal (i.n.) administration.

MATERIALS AND METHODS

The RA-loaded SLNs was prepared by the hot homogenization technique, in which glycerol monostearate (GMS) as lipid, tween 80 and soya lecithin were used as surfactant along with hydrogenated soya phosphatidyl choline (HSPC) as a stabilizer, and were characterized for particle size, zeta potential (ZP), in vitro study. Nasal delivery of the developed formulation followed by the study of behavioral (locomotor, narrow beam, body weight) and biochemical parameters (glutathione, lipid peroxidation, catalase and nitrite) in wistar rat was carried out.

RESULTS

Optimized RA-loaded SLNs using tween 80 (SLNPRT) have the mean size of (149.2 ± 3.2 nm), ZP (-38.27 mV) entrapment efficiency (61.9 ± 2.2%). 3-NP-treated rat significantly increased behavioral alterations, oxidative damage as compared with the control group. SLNPRT treatment significantly improved behavioral abnormalities and attenuated the oxidative stress in 3NP-treated rats. However, the nasal delivery of SLNPRT produced significant therapeutic action as compared to intravenous application. In the organ distribution study, brain drug concentration was found to be 5.69 µg, in pharmacokinetic study Cmax, tmax, t1/2, AUC values were found to be 0.284 µg/ml, 1.5 h, 3.17 h, and 1.505 µg/ml/h, respectively.

CONCLUSION

The encouraging results confirmed the developed optimized RA-loaded SLNs formulation following the non-invasive nose-to-brain drug delivery that is a promising therapeutic approach for the effective management in Huntington disease.

Characterization of bovine ruminal and equine cecal microbial populations enriched for enhanced nitro-toxin metabolizing activity

The nitrotoxins 3-nitro-1-propionic acid (NPA) and 3-nitro-1-propanol (NPOH) are produced by a wide variety of leguminous plants, including over 150 different species and varieties of Astragalus potentially grazed by livestock. These toxins are known to be detoxified by at least one ruminal bacterium but detoxification by bacteria from other gut habitats is not known. In the present study, mixed populations of bovine ruminal and equine cecal microbes were enriched for NPA-metabolizing bacteria via consecutive 24-72 h culture in a basal minimal rumen fluid-based medium supplemented with 4.2 mM NPA and H₂ as the energy source. Rates of NPA metabolism by the respective populations increased from 58.4 ± 4.8 and 8.6 ± 11.6 nmol NPA/mL per h during initial culture to 88.9 ± 30.6 and 50.2 ± 30.9 nmol NPA/mL per h following enrichment. Results from 3-tube most probable number tests indicated that numbers of NPA-degrading microbes increased 2.1 and 1.8 log₁₀ units during enrichment from numbers measured pre-enrichment (3.9 × 10³ and 4.3 × 10¹ cells/mL for ruminal and equine cecal populations, respectively). Hydrogen, formate, and to a lesser extent, DL-lactic acid, served as electron donors to the enriched populations and CO₂ or formate were needed to maintain high rates of NPA-metabolism. The NPA-enriched populations were able to metabolize nitrate which, being a preferred electron acceptor, was antagonistic to NPA metabolism. Supplemental NPA was inhibitory to methanogenesis. Fermentation balance estimates indicated that only 47.6% of carbon available in potential substrates was recovered in headspace CO₂, volatile fatty acids or unmetabolized NPA after 72 h incubation of NPA-enriched populations that had metabolized 98% of 8.4 mM added NPA. Overall, these results reveal low level carriage of NPA-metabolizing, CO₂ or formate-requiring bacterial populations in the equine cecum yet support the concept that Denitrobacterium detoxificans-like organisms may well be the functional agents of NPA and NPOH detoxification in the populations studied here.

Protective effect of HMG CoA reductase inhibitors against running wheel activity induced fatigue, anxiety like behavior, oxidative stress and mitochondrial dysfunction in mice

BACKGROUND

Chronic fatigue stress (CFS) is an important health problem with unknown causes and unsatisfactory prevention strategies, often characterized by long-lasting and debilitating fatigue, myalgia, impairment of neuro-cognitive functions along with other common symptoms. The present study has been designed to explore the protective effect of statins against running wheel activity induced fatigue anxiety.

METHODS

Male albino Laca mice (20-30 g) were subjected to swim stress induced fatigue in a running wheel activity apparatus. Atorvastatin (10, 20 mg/kg, po) and fluvastatin (5, 10 mg/kg, po) were administered daily for 21 days, one hour prior to the animals being subjected to running wheel activity test session of 6 min. Various behavioral tests (running wheel activity, locomotor activity and elevated plus maze test), biochemical parameters (lipid peroxidation, nitrite concentration, glutathione levels and catalase activity) and mitochondrial complex enzyme dysfunctions (complex I, II, III and IV) were subsequently assessed.

RESULTS

Animals exposed to 6 min test session on running wheel for 21 days showed a significant decrease in number of wheel rotations per 6 min indicating fatigue stress like behavior. Treatment with atorvastatin (10 and 20 mg/kg) and fluvastatin (10 mg/kg) for 21 days significantly improved the behavioral alterations [increased number of wheel rotations and locomotor activity, and anxiety like behavior (decreased number of entries and time spent in open arm)], oxidative defence and mitochondrial complex enzyme activities in brain.

CONCLUSION

Present study suggests the protective role of statins against chronic fatigue induced behavioral, biochemical and mitochondrial dysfunctions.

Neuroprotective role of PDE4 and PDE5 inhibitors in 3-nitropropionic acid induced behavioral and biochemical toxicities in rats

Phosphodiesterase inhibitors have been reported to be beneficial in cognitive and motor disorders. In the present study, we have investigated the effects of RO 20-1724 (PDE4 inhibitor) and sildenafil (PDE5 inhibitor) in 3-nitropropionic acid (3-NP) induced experimental Huntington's disease in rats. 3-Nitropropionic acid was administered for 14 days (10 mg/kg i.p.) 1h following 3-NP administration, the rats were treated with either vehicle, RO 20-1724 (0.25 and 0.5 mg/kg i.p.) or sildenafil (2 and 4 mg/kg i.p.) for 14 days. Cognitive functions were assessed by using Morris water maze whereas, motor functions were assessed by spontaneous locomotor activity, limb withdrawal and suspended wire test at different time points. Biochemically, markers of oxidative stress and cell damage, such as reduced glutathione, malondialdehyde, nitrite and lactate dehydrogenase levels were assessed terminally in the brain homogenate. Chronic administration of 3-NP produced significant decrease in body weight, showed marked abnormalities in cognitive and motor functions. Further, significant oxidative-nitrosative stress and cell damage was also observed. Chronic administration of RO 20-1724 and sildenafil in 3-NP treated rats significantly and dose dependently attenuated 3-NP induced behavioral and biochemical abnormalities in rats. Both these drugs were equally effective in attenuating 3-NP induced neurotoxicity. These results suggesting that the inhibition of PDE4 and PDE5 would be therapeutic in neurodegenerative disorders associated with cognitive and motor dysfunction.

Probucol increases striatal glutathione peroxidase activity and protects against 3-nitropropionic acid-induced pro-oxidative damage in rats

Huntington's disease (HD) is an autosomal dominantly inherited neurodegenerative disease characterized by symptoms attributable to the death of striatal and cortical neurons. The molecular mechanisms mediating neuronal death in HD involve oxidative stress and mitochondrial dysfunction. Administration of 3-nitropropionic acid (3-NP), an irreversible inhibitor of the mitochondrial enzyme succinate dehydrogenase, in rodents has been proposed as a useful experimental model of HD. This study evaluated the effects of probucol, a lipid-lowering agent with anti-inflammatory and antioxidant properties, on the biochemical parameters related to oxidative stress, as well as on the behavioral parameters related to motor function in an in vivo HD model based on 3-NP intoxication in rats. Animals were treated with 3.5 mg/kg of probucol in drinking water daily for 2 months and, subsequently, received 3-NP (25 mg/kg i.p.) once a day for 6 days. At the end of the treatments, 3-NP-treated animals showed a significant decrease in body weight, which corresponded with impairment on motor ability, inhibition of mitochondrial complex II activity and oxidative stress in the striatum. Probucol, which did not rescue complex II inhibition, protected against behavioral and striatal biochemical changes induced by 3-NP, attenuating 3-NP-induced motor impairments and striatal oxidative stress. Importantly, probucol was able to increase activity of glutathione peroxidase (GPx), an enzyme important in mediating the detoxification of peroxides in the central nervous system. The major finding of this study was that probucol protected against 3-NP-induced behavioral and striatal biochemical changes without affecting 3-NP-induced mitochondrial complex II inhibition, indicating that long-term probucol treatment resulted in an increased resistance against neurotoxic events (i.e., increased oxidative damage) secondary to mitochondrial dysfunction. These data appeared to be of great relevance when extrapolated to human neurodegenerative processes involving mitochondrial dysfunction and indicates that GPx is an important molecular target involved in the beneficial effects of probucol.

Role of prostaglandins in neuroinflammatory and neurodegenerative diseases

Increasing data demonstrates that inflammation participates in the pathophysiology of neurodegenerative diseases. Among the different inflammatory mediators involved, prostaglandins play an important role. The effects induced by prostaglandins might be mediated by activation of their known receptors or by nonclassical mechanisms. In the present paper, we discuss the evidences that link prostaglandins, as well as the enzymes that produce them, to some neurological diseases.

Role of LOX/COX pathways in 3-nitropropionic acid-induced Huntington's disease-like symptoms in rats: protective effect of licofelone

BACKGROUND AND PURPOSE

Huntington's disease (HD) is a progressive neurodegenerative disorder characterized by a degeneration of striatal neurons. The possible role of COX and lipoxygenase (LOX) pathways has been well-documented in the pathology of several neurodegenerative disorders including HD. Licofelone is a competitive inhibitor of COX-1- and COX-2 and 5-LOX isoenzymes. Therefore, the present study was designed to investigate possible neuroinflammatory and apoptotic mechanisms in the neuroprotective effect of licofelone against 3-nitropropionic acid (3-NP)-induced HD-like symptoms in rats.

EXPERIMENTAL APPROACH

Rats were administered 3-NP (10 mg·kg⁻¹ day⁻¹, i.p.) for 14 days. Licofelone (2.5, 5 and 10 mg·kg⁻¹, p.o.) was given once a day, 1 h before 3-NP treatment for 14 days. Body weight and behavioural parameters (locomotor and rotarod activity) were assessed on the 1st, 5th, 10th and 15th day post-3-NP administration. Malondialdehyde, nitrite concentration, endogenous antioxidant enzymes (superoxide dismutase and catalase levels), mitochondrial enzyme complexes, pro-inflammatory compounds (TNF-α, IL-6, NF-κB), PGs (PGE₂ and PGF(2α)) and caspase-3 activity were measured on day 15 in the striatum.

KEY RESULTS

Systemic 3-NP treatment significantly reduced body weight, locomotor activity, oxidative defence, mitochondrial enzyme complex activities and increased TNF-α, IL-6, caspase-3 activity, NF-κB and PGE₂ and PGF(2α) levels in the striatum. Licofelone (2.5, 5 and 10 mg·kg⁻¹) significantly attenuated the impairment in behavioural, biochemical and mitochondrial, pro-inflammatory and pro-apoptotic markers as compared with vehicle-treated group.

CONCLUSIONS AND IMPLICATIONS

The results demonstrate the involvement of pro-inflammatory compounds and the apoptotic cascade in the neuroprotective effect of licofelone against 3-NP-induced neurotoxicity.

Novel protective mechanisms of antidepressants against 3-nitropropionic acid induced Huntington's-like symptoms: a comparative study

Huntington's disease (HD) is characterized by progressive degeneration of neurons in the striatum, cortex and other parts of the brain, causing motor and cognitive dysfunction. 3-Nitropropionic acid (3-NP) is a well-known mycotoxin that significantly induces motor dysfunction in animals. Studies suggested the involvement of oxidative stress and nitric oxide mechanisms in HD pathogenesis. Clinical reports have also indicated the neuroprotective potential of antidepressants. Therefore, the present study has been designed to elucidate and compare the mechanistic role of different antidepressants (sertraline, venlafaxine, imipramine and trazodone) and their interaction with nitric oxide modulators if any, against 3-NP-induced neurotoxicity. Systemic 3-NP (10 mg/kg) administration for 14 days significantly reduced locomotor activity, body weight, motor coordination, oxidative defense and impaired mitochondrial complex enzyme activities in the striatum. Sertraline, venlafaxine, imipramine and trazodone treatments significantly improved behavioral, oxidative defense and mitochondrial complex enzyme activities as compared with the 3-NP-treated group. Systemic L-arginine (50 mg/kg) pretreatment with sub-effective dose of sertraline (10 mg/kg), venlafaxine (10 mg/kg), imipramine (10 mg/kg) and trazodone (10 mg/kg) for 14 days significantly attenuated their protective effect. Similarly, L-nitro-arginine methyl ester (L-NAME) (10 mg/kg) pretreatment with sub-effective dose of sertraline (10 mg/kg), venlafaxine (10 mg/kg), imipramine (10 mg/kg) and trazodone (10 mg/kg) for 14 days significantly potentiated their protective effects which were significant as compared with their effect alone, respectively. The results of the present study suggest that a nitric oxide mechanism might be involved in their protective effect against 3-NP-induced neurotoxicity.

Targeting oxidative stress, mitochondrial dysfunction and neuroinflammatory signaling by selective cyclooxygenase (COX)-2 inhibitors mitigates MPTP-induced neurotoxicity in mice

Several studies have pointed towards the role of oxidative stress, mitochondrial dysfunction and neuroinflammation in Parkinson's disease (PD). The present study was focused on the possible neuroprotective effect of selective cyclooxygenase (COX)-2-inhibitors: valdecoxib and NS-398 in 1-methyl-4-phenyl-1,2,3,6-tertahydropyridine (MPTP)-induced neurotoxicity in mice. MPTP administration in dose of 40 mg/kg, i.p (four injections of 10mg/kg, i.p. at an interval of 1h each) significantly induced the Parkinson-like symptoms in mice as indicated by change in locomotor activity, inability to correct posture (bar test), and oxidative stress (increased levels of lipid peroxidation, nitrite concentration, and depletion of antioxidant enzyme). MPTP administration significantly impaired mitochondrial complex-I activity and redox activity, upregulated the caspase-3 and NF-κB levels as compared to vehicle group. Treatment with valdecoxib (5 or 10 mg/kg, p.o.) or NS-398 (5 or 10mg/kg, p.o.) for 7 days significantly reversed behavioral, biochemical, mitochondrial complex alterations as well as attenuated the induction of proinflammatory mediators in MPTP-treated groups. The findings of the present study substantiate the neuroprotective role of selective COX-2 inhibitors in ameliorating MPTP-induced neurodegeneration in mice and suggest the possible therapeutic potential of these drugs in the management of PD.

Licofelone attenuates quinolinic acid induced Huntington like symptoms: possible behavioral, biochemical and cellular alterations

Cyclo-oxygenase and lipoxygenase enzymes are involved in arachidonic acid metabolism. Emerging evidence indicates that cyclo-oxygenase and lipoxygenase inhibitors prevent neurodegenerative processes and related complications. Therefore, the present study has been designed to explore the neuroprotective potential of licofelone (dual COX-2/5-LOX inhibitor) against quinolinic acid induced Huntington like symptom in rats. Intrastriatal administration of quinolinic acid significantly caused reduction in body weight and motor function (locomotor activity, rotarod performance and beam walk test), oxidative defense (as evidenced by increased lipid peroxidation, nitrite concentration and decreased endogenous antioxidant enzymes), alteration in mitochondrial enzyme complex (I, II and IV) activities, raised TNF-α level and striatal lesion volume as compared to sham treated animals. Licofelone (2.5, 5 and 10 mg/kg) treatment significantly improved body weight, locomotor activity, rotarod performance, balance beam walk performance, oxidative defense, mitochondrial enzyme complex activities and attenuated TNF-α level and striatal lesion as compared to control (quinolinic acid). The present study highlights that licofelone attenuates behavioral, biochemical and cellular alterations against quinolinic acid induced neurotoxicity and this could be an important therapeutic avenue to ameliorate the Huntington like symptoms.

Protective effect of montelukast against quinolinic acid/malonic acid induced neurotoxicity: possible behavioral, biochemical, mitochondrial and tumor necrosis factor-α level alterations in rats

The present study has been designed to explore the protective effect of montelukast (leukotriene receptor antagonist) against intrastriatal quinolinic acid (QA; 300 nmol) and malonic acid (MA; 6 μmol) induced Huntington's like symptoms in rats. Quinolinic acid has been reported to induce excitotoxicity by stimulating the N-methyl-D-aspartate receptor, causing calcium overload which in turn leads to the neurodegeneration. On the other hand, MA, being a reversible inhibitor of mitochondrial enzyme complex-II, leads to energy crisis and free radical generation. Recent studies have reported the therapeutic potential of leukotriene receptor antagonists in different neurodegenerative disorders. However, their exact role is yet to be established. The present study accordingly, is an attempt to investigate the effect of montelukast against QA and MA induced behavioral, biochemical and molecular alterations in rat striatum. Oxidative stress, mitochondrial enzyme complex and tumor necrosis factor-alpha (TNF-α) were evaluated on day 21st and 14th post intrastriatal QA and MA treatment, respectively. Findings of the present study demonstrate significant alteration in the locomotor activity and motor coordination as well as oxidative burden (increased lipid peroxidation, nitrite concentration and decreased endogenous antioxidants), mitochondrial enzyme complex (I, II and IV) activities and TNF-α level, in both intrastriatal QA and MA treated animals. Further, montelukast (0.4, 0.8 mg/kg p.o.) treatment for 21 and 14 days respectively, attenuated the behavioral alterations, oxidative stress, mitochondrial dysfunction and TNF-α level in these models of Huntington's disease in a significant manner. In conclusion, the present study emphasizes the neuroprotective potential of montelukast in the therapeutic management of Huntington like symptoms.