Effect of caffeic acid and rofecoxib and their combination against intrastriatal quinolinic acid induced oxidative damage, mitochondrial and histological alterations in rats

Protective Effect of CP690550 in MPTP-Induced Parkinson's Like Behavioural, Biochemical and Histological Alterations in Mice

Janus-activated kinases (JAKs) are well known to play a physiological as well as pathological role in several disease conditions such as autoimmune disorders. The present study evaluated the therapeutic potential of CP690550 (pan-JAK inhibitor) in 1-methyl-4-phenyl-1,2,3,6-tertahydropyridine (MPTP) model of Parkinson's disease. Intrastriatal administration of MPTP (30 micromol in 2 microl) produced a significant alteration in behavioural (bar test and block test). Biochemical investigations in serum and brain homogenate revealed a significant alteration in the JAK-mediated cytokine levels. MPTP administration also showed significant imbalance of inflammatory (increased TNF-α, IL-6 and NF-κb) versus anti-inflammatory cytokines (decreased IL-10 levels). MPTP-treated brain sections revealed alteration in the tissue architecture as well as undifferentiated bodies of varying contour and lesions. Chronic administration of CP690550 (3 and 10 mg/kg, po) for 7 days significantly reversed the behavioural, biochemical and histological alterations induced by MPTP. In conclusion, the findings of the present study govern the possible therapeutic potential of CP690550 in MPTP-treated mice and thus highlight the therapeutic potential of JAK inhibitors in treatment of Parkinson's disease.

Caffeic acid, a dietary polyphenol, as a promising candidate for combination therapy

Increased effectiveness and decreasing toxicity are prime objectives in drug research. Overwhelming evidence suggests the use of appropriate combination therapy for the better efficacy of drugs owing to their synergistic profile. Dietary active constituents play a major role in health outcomes. Therefore, it is possible to increase the effectiveness of the drug by combining contemporary medication with active natural/semi-synthetic constituents. One such dietary constituent, caffeic acid (CA), is a by-product of the shikimate pathway in plants and is a polyphenol of hydroxycinnamic acid class. Extensive research on CA has proposed its efficacy against inflammatory, neurodegenerative, oncologic, and metabolic disorders. The synergistic/additive effects of CA in combination with drugs like caffeine, metformin, pioglitazone, and quercetin have been reported in several experimental models and thus the present review is an attempt to consolidate outcomes of this research. Multi-target-based mechanistic studies will facilitate the development of effective combination regimens of CA.

Differential Molecular Targets for Neuroprotective Effect of Chlorogenic Acid and its Related Compounds Against Glutamate Induced Excitotoxicity and Oxidative Stress in Rat Cortical Neurons

The present study has been designed to explore the molecular mechanism and signaling pathway targets of chlorogenic acid (CGA) and its main hydrolysates, caffeic (CA) and quinic acid in the protective effect against glutamate-excitotoxicity. For this purpose 8-DIV cortical neurons in primary culture were exposed to 50 μM L-glutamic acid plus 10 µM glycine, with or without 10-100 μM tested compounds. Chlorogenic acid and caffeic acid via their antioxidant properties inhibited cell death induced by glutamate in dose depended manner. However, quinic acid slightly protects neurons at a higher dose. DCF, JC-1 and Ca²⁺sensitive fluorescent dye fura-2, were used to measure intracellular ROS accumulation, mitochondrial membrane potential integration and intracellular calcium concentration [Ca²⁺] _i . Results indicate that similarly, CGA acts as a protective agent against glutamate-induced cortical neurons injury by suppressing the accumulation of endogenous ROS and restore the mitochondrial membrane potential, activate the enzymatic antioxidant system by the increase levels of SOD activity and modulate the rise of intracellular calcium levels by increasing the rise of intracellular concentrations of Ca²⁺caused by glutamate overstimulation. PKC signaling cascade appear to be engaged in this protective mechanism. Interseling, CGA and CA also exhibit antiapoptotic properties against glutamate-induced cleaved activation of pro-caspases; caspase 1,8 and 9 and calpain (PD 150606,Calpeptin and MDL 28170).These data suggest that neuroprotective activity of CGA ester may occurs throught its hydrolysate,the caffeic acid and its interaction with intracellular molecules suggesting that CGA exert its neuroprotection via its caffeoly acid group that might potentially be used as a therapeutic agent in neurodegeneratives disorders associated with glutamate excitotoxicity.

Caffeic acid attenuates rat liver reperfusion injury through sirtuin 3-dependent regulation of mitochondrial respiratory chain

Sirtuin 3 (Sirt3) plays critical roles in regulating mitochondrial oxidative metabolism. However, whether Sirt3 is involved in liver ischemia and reperfusion (I/R) injury remains elusive. Caffeic acid (CA) is a natural antioxidant derived from Salvia miltiorrhiza. Whether CA protects against liver I/R injury through regulating Sirt3 and the mitochondrial respiratory chain (MRC) is unclear. This study investigated the effect of CA on liver I/R injury, microcirculatory disturbance, and potential mechanisms, particularly focusing on Sirt3-dependent MRC. Liver I/R of male Sprague-Dawley rats was established by occlusion of portal area vessels for 30 min followed by 120 min of reperfusion. CA (15 mg/kg/h) was continuously infused via the femoral vein starting 30 min before ischemia. After I/R, Sirt3 expression, and MRC activity decreased, acetylation of NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 9 and succinate dehydrogenase complex, subunit A, flavoprotein variant provoked, and the liver microcirculatory disturbance and injury were observed. Treatment with CA attenuated liver injury, inhibited Sirt3 down-expression, and up-regulated MRC activity. CA attenuated rat liver microcirculatory disturbance and oxidative injury through regulation of Sirt3 and the mitochondrial respiratory chain.

Pharmacological evaluation of nasal delivery of selegiline hydrochloride-loaded thiolated chitosan nanoparticles for the treatment of depression

The aim of the present study was to investigate the propensity of thiolated chitosan nanoparticles (TCNs) to enhance the nasal delivery of selegiline hydrochloride. TCNs were synthesized by the ionic gelation method. The particle size distribution (PDI), entrapment efficiency (EE), and zeta potential of modified chitosan (CS) nanoparticles were found to be 215 ± 34.71 nm, 70 ± 2.71%, and + 17.06 mV, respectively. The forced swim and the tail suspension tests were used to evaluate the anti-depressant activity, in which elevated immobility time was found to reduce on treatment. TCNs seem to be promising candidates for nose-to-brain delivery in the evaluation of antidepressant activity.

Activation of the kynurenine pathway and increased production of the excitotoxin quinolinic acid following traumatic brain injury in humans

Abstract

During inflammation, the kynurenine pathway (KP) metabolises the essential amino acid tryptophan (TRP) potentially contributing to excitotoxicity via the release of quinolinic acid (QUIN) and 3-hydroxykynurenine (3HK). Despite the importance of excitotoxicity in the development of secondary brain damage, investigations on the KP in TBI are scarce. In this study, we comprehensively characterised changes in KP activation by measuring numerous metabolites in cerebrospinal fluid (CSF) from TBI patients and assessing the expression of key KP enzymes in brain tissue from TBI victims. Acute QUIN levels were further correlated with outcome scores to explore its prognostic value in TBI recovery.

Methods

Twenty-eight patients with severe TBI (GCS ≤ 8, three patients had initial GCS = 9–10, but rapidly deteriorated to ≤8) were recruited. CSF was collected from admission to day 5 post-injury. TRP, kynurenine (KYN), kynurenic acid (KYNA), QUIN, anthranilic acid (AA) and 3-hydroxyanthranilic acid (3HAA) were measured in CSF. The Glasgow Outcome Scale Extended (GOSE) score was assessed at 6 months post-TBI. Post-mortem brains were obtained from the Australian Neurotrauma Tissue and Fluid Bank and used in qPCR for quantitating expression of KP enzymes (indoleamine 2,3-dioxygenase-1 (IDO1), kynurenase (KYNase), kynurenine amino transferase-II (KAT-II), kynurenine 3-monooxygenase (KMO), 3-hydroxyanthranilic acid oxygenase (3HAO) and quinolinic acid phosphoribosyl transferase (QPRTase) and IDO1 immunohistochemistry.

Results

In CSF, KYN, KYNA and QUIN were elevated whereas TRP, AA and 3HAA remained unchanged. The ratios of QUIN:KYN, QUIN:KYNA, KYNA:KYN and 3HAA:AA revealed that QUIN levels were significantly higher than KYN and KYNA, supporting increased neurotoxicity. Amplified IDO1 and KYNase mRNA expression was demonstrated on post-mortem brains, and enhanced IDO1 protein coincided with overt tissue damage. QUIN levels in CSF were significantly higher in patients with unfavourable outcome and inversely correlated with GOSE scores.

Conclusion

TBI induced a striking activation of the KP pathway with sustained increase of QUIN. The exceeding production of QUIN together with increased IDO1 activation and mRNA expression in brain-injured areas suggests that TBI selectively induces a robust stimulation of the neurotoxic branch of the KP pathway. QUIN’s detrimental roles are supported by its association to adverse outcome potentially becoming an early prognostic factor post-TBI.

Centella asiatica and Its Fractions Reduces Lipid Peroxidation Induced by Quinolinic Acid and Sodium Nitroprusside in Rat Brain Regions

Oxidative stress has been implicated in several pathologies including neurological disorders. Centella asiatica is a popular medicinal plant which has long been used to treat neurological disturbances in Ayurvedic medicine. In the present study, we quantified of compounds by high performance liquid chromatography (HPLC) and examined the phenolic content of infusion, ethyl acetate, n-butanolic and dichloromethane fractions. Furthermore, we analyzed the ability of the extracts from C. asiatica to scavenge the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) radical as well as total antioxidant activity through the reduction of molybdenum (VI) (Mo(6+)) to molybdenum (V) (Mo(5+)). Finally, we examined the antioxidant effect of extracts against oxidant agents, quinolinic acid (QA) and sodium nitroprusside (SNP), on homogenates of different brain regions (cerebral cortex, striatum and hippocampus). The HPLC analysis revealed that flavonoids, triterpene glycoside, tannins, phenolic acids were present in the extracts of C. asiatica and also the phenolic content assay demonstrated that ethyl acetate fraction is rich in these compounds. Besides, the ethyl acetate fraction presented the highest antioxidant effect by decreasing the lipid peroxidation in brain regions induced by QA. On the other hand, when the pro-oxidant agent was SNP, the potency of infusion, ethyl acetate and dichloromethane fractions was equivalent. Ethyl acetate fraction from C. asiatica also protected against thiol oxidation induced by SNP and QA. Thus, the therapeutic potential of C. asiatica in neurological diseases could be associated to its antioxidant activity.

The effects of bioactive compounds from plant foods on mitochondrial function: a focus on apoptotic mechanisms

Mitochondria are essential organelles for cellular integrity and functionality maintenance and their imparement is implicated in the development of a wide range of diseases, including metabolic, cardiovascular, degenerative and hyperproliferative pathologies. The identification of different compounds able to interact with mitochondria for therapeutic purposes is currently becoming of primary importance. Indeed, it is well known that foods, particularly those of vegetable origin, present several constituents with beneficial effects on health. This review summarizes and updates the most recent findings concerning the mechanisms through which different dietary compounds from plant foods affect mitochondria functionality in healthy and pathological in vitro and in vivo models, paying particular attention to the pathways involved in mitochondrial biogenesis and apoptosis.

Rosiglitazone synergizes the neuroprotective effects of valproic acid against quinolinic acid-induced neurotoxicity in rats: targeting PPARγ and HDAC pathways

Huntington's disease (HD) is an autosomal dominant progressive neurodegenerative disorder which affects medium spiny GABAergic neurons mainly in the striatum. Oxidative damage, neuro-inflammation, apoptosis, protein aggregation, and signaling of neurotrophic factors are some of the common cellular pathways involved in HD. Quinolinic acid (QA) causes excitotoxicity by stimulating N-methyl-D-aspartate receptors via calcium overload leading to neurodegeneration. Neuroprotective potential of peroxisome proliferator activated receptor-γ (PPARγ) agonists and histone deacetylase (HDAC) inhibitors have been well documented in experimental models of neurodegenerative disorders; however, their exact mechanisms are not clear. Therefore, present study has been designed to explore possible neuroprotective mechanism of valproic acid (VPA) and its interaction with rosiglitazone against QA induced HD-like symptoms in rats. Single bilateral intrastriatal QA (200 nmol/2 μl saline) administration significantly caused motor incoordination, memory impairment, oxidative damage, mitochondrial dysfunction (complex I, II, II and IV), cellular alterations [tumor necrosis factor-alpha (TNF-α), caspase-3, brain derived neurotrophic factor, acetylcholinesterase], and striatal neurodegeneration as compared to sham group. Treatment with rosiglitazone (5, 10 mg/kg) and VPA (100, 200 mg/kg) for 21 days significantly attenuated these behavioral, biochemical, and cellular alterations as compared to control (QA 200 nmol) group. However, VPA (100 mg/kg) treatment in combination with rosiglitazone (5 mg/kg) for 21 days synergized their neuroprotective effect, which was significant as compared to their effects per se in QA-treated animals. The present study provides an evidence of possible interplay of PPARγ agonists and HDAC inhibitors as a novel therapeutic strategy in the management of HD.

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.

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.

Caffeic Acid phenethyl ester protects blood-brain barrier integrity and reduces contusion volume in rodent models of traumatic brain injury

A number of studies have established a deleterious role for inflammatory molecules and reactive oxygen species (ROS) in the pathology of traumatic brain injury (TBI). Caffeic acid phenethyl ester (CAPE) has been shown to exert both antioxidant and anti-inflammatory effects. The primary objective of the present study was to examine if CAPE could be used to reduce some of the pathological consequences of TBI using rodent models. Male Sprague-Dawley rats and C57BL/6 mice were subjected to controlled cortical impact (CCI) injury. Blood-brain barrier (BBB) integrity was assessed by examining claudin-5 expression and the extravasation of Evans blue dye. The effect of post-injury CAPE administration on neurobehavioral function was assessed using vestibulomotor, motor, and two hippocampus-dependent learning and memory tasks. We report that post-TBI administration of CAPE reduces Evans blue extravasation both in rats and mice. This improvement was associated with preservation of the levels of the tight junction protein claudin-5. CAPE treatment did not improve performance in either vestibulomotor/motor function (tested using beam balance and foot-fault tests), or in learning and memory function (tested using the Morris water maze and associative fear memory tasks). However, animals treated with CAPE were found to have significantly less cortical tissue loss than vehicle-treated controls. These findings suggest that CAPE may provide benefit in the treatment of vascular compromise following central nervous system injury.

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.

Licofelone attenuates MPTP-induced neuronal toxicity: behavioral, biochemical and cellular evidence

Neuroinflammation and oxidative stress play critical role in the pathophysiology of neurodegenerative diseases including Parkinson's disease (PD). Recent reports indicate the beneficial effect of anti-inflammatory drugs in attenuating the progression of PD. Therefore, the present study is aimed to evaluate the possible role of licofelone, a dual COX/LOX-inhibitor against MPTP-induced neurotoxicity in mice. Administration of MPTP (40 mg/kg in divided doses of four injections of 10 mg/kg, i.p. each at 1 h interval) significantly impaired locomotor activity and induced catatonia, oxidative damage (elevated levels of lipid peroxidation, superoxide anion and nitrite, and decreased levels of non-protein thiols) as compared with vehicle-treated animals. Biochemical studies revealed significant alterations in mitochondrial enzyme complex activities (decreased complex-I activity and mitochondrial viability) and increased levels of caspase-3 and NF-κB/p65 as compared to vehicle treated group. Licofelone (2.5, 5 or 10 mg/kg/day, p.o.) treatment for 7 days significantly improved locomotor activity, attenuated the severity of catatonia, oxidative damage and restored mitochondrial enzyme complex activity as compared to MPTP-treated group. Licofelone treatment also attenuated the expression of apoptotic factor (caspase-3) and transcription factor (NF-κB/p65) as compared to MPTP-treated group. The findings of the present study suggest that licofelone (dual inhibitor of COX and LOX) represents a new class of anti-inflammatory agent which may provide a novel therapeutic alternative for the treatment and management of PD.

Comparative neuroprotective profile of statins in quinolinic acid induced neurotoxicity in rats

A possible neuroprotective role has been recently suggested for 3H3MGCoA reductase inhibitors (statins). Here, we sought to determine neuroprotective effect of statins in quinolinic acid induced neurotoxicity in rats. Rats were surgically administered quinolinic acid and treated with Atorvastatin (10, 20 mg/kg), simvastatin (15, 30 mg/kg) and fluvastatin (5, 10 mg/kg) once daily up to 3 weeks. Atorvastatin (10, 20 mg/kg), simvastatin (30 mg/kg) and fluvastatin (10 mg/kg) treatment significantly attenuated the quinolinic acid induced behavioral (locomotor activity, rotarod performance and beam walk test), biochemical (lipid peroxidation, nitrite concentration, SOD and catalase), mitochondrial enzyme complex alterations in rats suggesting their free radical scavenging potential. Additionally, atorvastatin (10, 20 mg/kg), simvastatin (30 mg/kg) and fluvastatin (10 mg/kg) significantly decrease the TNF-α level and striatal lesion volume in quinolinic acid treated animals indicating their anti-inflammatory effects. In comparing the protective effect of different statins, atorvastatin is effective at both the doses while simvastatin and fluvastatins at respective lower doses were not able to produce the protective effect in quinolinic acid treated animals. These modulations can account, at least partly, for the beneficial effect of statins in our rodent model of striatal degeneration. Our findings show that statins could be explored as possible neuroprotective agents for neurodegenerative disorders such as HD.