Naproxen reduces excitotoxic neurodegeneration in vivo with an extended therapeutic window

Therapeutic potential of COX-2 inhibitors in neuropsychiatric disorders

Neuropsychiatric disorders such as bipolar disorder, migraine, major depressive disorder, epilepsy, attention-deficit/hyperactivity disorder, autism spectrum disorder and schizophrenia, are a huge burden on global health, impacting millions of individuals worldwide and posing significant barriers to effective treatment. Despite advancements in medication and psychotherapy, many patients continue to suffer from severe symptoms and receive little alleviation. All of these conditions are quite frequent, yet they affect people in a way that is exceedingly detrimental. The increasing evidence suggests the connection between these disorders and inflammation. Therefore, the use of anti-inflammatory agents, namely cyclooxygenase-2 (COX-2) inhibitors, offers a new approach to prevent and treat neuropsychiatric disorders. This review discusses about the COX pathway and the role of COX-2 in the neuroinflammation. Furthermore, this review highlights the COX-2 inhibitors as a promising therapeutic agent in these neuropsychiatric disorders, however, further studies are required to assess appropriate illness stage-related indication.

A Narrative Review of the Published Pre-Clinical Evaluations: Multiple Effects of Arachidonic Acid, its Metabolic Enzymes and Metabolites in Epilepsy

Arachidonic acid (AA), an important polyunsaturated fatty acid in the brain, is hydrolyzed by a direct action of phospholipase A2 (PLA2) or through the combined action of phospholipase C and diacylglycerol lipase, and released into the cytoplasm. Various derivatives of AA can be synthesized mainly through the cyclooxygenase (COX), lipoxygenase (LOX) and cytochrome P450 (P450) enzyme pathways. AA and its metabolic enzymes and metabolites play important roles in a variety of neurophysiological activities. The abnormal metabolites and their catalytic enzymes in the AA cascade are related to the pathogenesis of various central nervous system (CNS) diseases, including epilepsy. Here, we systematically reviewed literatures in PubMed about the latest randomized controlled trials, animal studies and clinical studies concerning the known features of AA, its metabolic enzymes and metabolites, and their roles in epilepsy. The exclusion criteria include non-original studies and articles not in English.

Neuroprotection of cordycepin in NMDA-induced excitotoxicity by modulating adenosine A1 receptors

Cerebral ischemia impairs physiological form of synaptic plasticity such as long-term potentiation (LTP). Clinical symptoms of cognitive dysfunction resulting from cerebral ischemia are associated with neuron loss and synaptic function impairment in hippocampus. It has been widely reported that cordycepin displays neuroprotective effect on ameliorating cognitive dysfunction induced by cerebral ischemia. Therefore, it is necessary to study whether cordycepin recovers cognitive function after brain ischemia through improving LTP induction. However, there has been very little discussion about the effects of cordycepin on LTP of cerebral ischemia so far. In the present study, we investigated the effects of cordycepin on LTP impairment and neuron loss induced by cerebral ischemia and excitotoxicity, using electrophysiological recording and Nissl staining techniques. The models were obtained by bilateral common carotid artery occlusion (BCCAO) and intrahippocampal NMDA microinjection. We also explored whether adenosine A₁ receptors involve in the neuroprotection of cordycepin by using western blot. We found that cordycepin remarkably alleviated LTP impairment and protected pyramidal cell of hippocampal CA1 region against cerebral ischemia and excitotoxicity. Meanwhile, cordycepin prevented the reduction on adenosine A₁ receptor level caused by ischemia but did not alter the adenosine A_2A receptor level in hippocampal CA1 area. The improvement of LTP in the excitotoxic rats after cordycepin treatment could be blocked by DPCPX, a selective antagonist of adenosine A₁ receptor. In summary, our findings provided new insights into the mechanisms of cordycepin neuroprotection in excitotoxic diseases, which is through regulating adenosine A₁ receptor to improve LTP formation and neuronal survival.

Protein arginine methyltransferase 1 may be involved in pregnane x receptor-activated overexpression of multidrug resistance 1 gene during acquired multidrug resistant

PURPOSE

Pregnane x receptor (PXR) - activated overexpression of the multidrug resistance 1 (MDR1) gene is an important way for tumor cells to acquire drug resistance. However, the detailed mechanism still remains unclear. In the present study, we aimed to investigate whether protein arginine methyl transferase 1(PRMT1) is involved in PXR - activated overexpression of MDR1 during acquired multidrug resistant.

EXPERIMENTAL DESIGN

Arginine methyltransferase inhibitor 1 (AMI-1) was used to pharmacologically block PRMT1 in resistant breast cancer cells (MCF7/adr). The mRNA and protein levels of MDR1 were detected by real-time PCR and western blotting analysis. Immunofluorescence microscopy and co-immunoprecipitation were used to investigate the physical interaction between PXR and PRMT1. Then, 136 candidate compounds were screened for PRMT1 inhibitors. Lastly, luciferase reporter gene and nude mice bearing resistant breast cancer xenografts were adopted to investigate the anti-tumor effect of PRMT1 inhibitors when combined with adriamycin.

RESULTS

AMI-1 significantly suppressed the expression of MDR1 in MCF7/adr cells and increased cells sensitivity of MCF7/adr to adriamycin. Physical interaction between PRMT1 and PXR exists in MCF7/adr cells, which could be disrupted by AMI-1. Those results suggest that PRMT1 may be involved in PXR-activated overexpression of MDR1 in resistant breast cancer cells, and AMI-1 may suppress MDR1 by disrupting the interaction between PRMT1 and PXR. Then, five compounds including rutin, isoquercitrin, salvianolic acid A, naproxen, and felodipline were identified to be PRMT1 inhibitors. Finally, those PRMT1 inhibitors were observed to significantly decrease MDR1 promoter activity in vitro and enhance the antitumor effect of adriamycin in nude mice that bearing resistant breast cancer xenografts.

CONCLUSIONS

PRMT1 may be an important co-activator of PXR in activating MDR1 gene during acquired resistance, and PRMT1 inhibitor combined with chemotherapy drugs may be a new strategy for overcoming tumor MDR.

Pathophysiological Roles of Cyclooxygenases and Prostaglandins in the Central Nervous System

Cyclooxygenases (COXs) oxidize arachidonic acid to prostaglandin (PG) G2 and H2 followed by PG synthases that generates PGs and thromboxane (TX) A2. COXs are divided into COX-1 and COX-2. In the central nervous system, COX-1 is constitutively expressed in neurons, astrocytes, and microglial cells. COX-2 is upregulated in these cells under pathophysiological conditions. In hippocampal long-term potentiation, COX-2, PGE synthase, and PGE2 are induced in post-synaptic neurons. PGE2 acts pre-synaptic EP2 receptor, generates cAMP, stimulates protein kinase A, modulates voltage-dependent calcium channel, facilitates glutamatergic synaptic transmission, and potentiates long-term plasticity. PGD2, PGE2, and PGI2 exhibit neuroprotective effects via Gs-coupled DP1, EP2/EP4, and IP receptors, respectively. COX-2, PGD2, PGE2, PGF2α, and TXA2 are elevated in stroke. COX-2 inhibitors exhibit neuroprotective effects in vivo and in vitro models of stroke, Alzheimer's disease, Parkinson's disease, multiple sclerosis, amyotrophic lateral sclerosis, epilepsy, and schizophrenia, suggesting neurotoxicities of COX products. PGE2, PGF2α, and TXA2 can contribute to the neurodegeneration via EP1, FP, and TP receptors, respectively, which are coupled with Gq, stimulate phospholipase C and cleave phosphatidylinositol diphosphate to produce inositol triphosphate and diacylglycerol. Inositol triphosphate binds to inositol triphosphate receptor in endoplasmic reticulum, releases calcium, and results in increasing intracellular calcium concentrations. Diacylglycerol activates calcium-dependent protein kinases. PGE2 disrupts Ca(2+) homeostasis by impairing Na(+)-Ca(2+) exchange via EP1, resulting in the excess Ca(2+) accumulation. Neither PGE2, PGF2α, nor TXA2 causes neuronal cell death by itself, suggesting that they might enhance the ischemia-induced neurodegeneration. Alternatively, PGE2 is non-enzymatically dehydrated to a cyclopentenone PGA2, which induces neuronal cell death. Although PGD2 induces neuronal apoptosis after a lag time, neither DP1 nor DP2 is involved in the neurotoxicity. As well as PGE2, PGD2 is non-enzymatically dehydrated to a cyclopentenone 15-deoxy-Δ(12,14)-PGJ2, which induces neuronal apoptosis without a lag time. However, neurotoxicities of these cyclopentenones are independent of their receptors. The COX-2 inhibitor inhibits both the anchorage-dependent and anchorage-independent growth of glioma cell lines regardless of COX-2 expression, suggesting that some COX-2-independent mechanisms underlie the antineoplastic effect of the inhibitor. PGE2 attenuates this antineoplastic effect, suggesting that the predominant mechanism is COX-dependent. COX-2 or EP1 inhibitors show anti-neoplastic effects. Thus, our review presents evidences for pathophysiological roles of cyclooxygenases and prostaglandins in the central nervous system.

Cyclooxygenase-2 in epilepsy

Epilepsy is one of the more prevalent neurologic disorders in the world, affecting approximately 50 million people of different ages and backgrounds. Epileptic seizures propagating through both lobes of the forebrain can have permanent debilitating effects on a patient's cognitive and somatosensory brain functions. Epilepsy, defined by the sporadic occurrence of spontaneous recurrent seizures (SRS), is often accompanied by inflammation of the brain. Pronounced increases in the expression of key inflammatory mediators (e.g., interleukin -1β [IL-1β], tumor necrosis factor alpha [TNFα], cyclooxygenase-2 [COX-2], and C-X-C motif chemokine 10 [CXCL10]) after seizures may cause secondary damage in the brain and increase the likelihood of repetitive seizures. The COX-2 enzyme is induced rapidly during seizures. The increased level of COX-2 in specific areas of the epileptic brain can help to identify regions of seizure-induced brain inflammation. A good deal of effort has been expended to determine whether COX-2 inhibition might be neuroprotective and represent an adjunct therapeutic strategy along with antiepileptic drugs used to treat epilepsy. However, the effectiveness of COX-2 inhibitors on epilepsy animal models appears to depend on the timing of administration. With all of the effort placed on making use of COX-2 inhibitors as therapeutic agents for the treatment of epilepsy, inflammation, and neurodegenerative diseases there has yet to be a selective and potent COX-2 inhibitor that has shown a clear therapeutic outcome with acceptable side effects.

Exposure to nerve agents: from status epilepticus to neuroinflammation, brain damage, neurogenesis and epilepsy

Epilepsy is a common neurological disorder characterized by an initial injury due to stroke, traumatic brain injury, brain infection, or febrile seizures causing status epilepticus (SE). This phenomenon precedes recurrent (secondary) seizures, the latent period (period without seizures) and downstream appearance of spontaneous recurrent seizures (SRS). Epilepsy inducers include the organophosphorous (OP) compounds modified as chemical warfare nerve agents, such as soman. SE induced by soman is a result of cholinergic system hyperactivity caused by the irreversible inhibition of acetylcholinesterase, and the subsequent increase in the amount of the neurotransmitter acetylcholine at central and peripheral sites. SE leads to profound, permanent, complex and widespread brain damage and associated cognitive and behavioral deficits, accompanied by impaired neurogenesis. Several anticonvulsant and neuroprotective strategies have been studied in order to avoid the epileptogenesis which occurs after SE caused by soman exposure. In recent studies, we showed that SRS occur post-soman exposure and neuropathology can be reduced with diazepam (DZP) and valproic acid (VPA) when administered in combination treatment. These effects are accompanied by neurogenesis seen 15 days post-exposure in the hippocampal dentate gyrus (DG). This review discusses several findings about epilepsy induced by soman exposure such as behavioral changes, EEG anomalies, neuropathology, neuroinflammation, neurogenesis, possible circuitry changes and current strategies for treatment. The soman seizure model is an important model of temporal lobe epilepsy (TLE) and comparable in certain respects with well studied models in the literature such as pilocarpine and kainic acid. All these models together allow for a greater understanding of the different mechanisms of seizure induction, propagation and options for treatment. These studies are very necessary for current military and civilian treatment regimens, against OP nerve agent exposure, which fail to prevent SE resulting in severe neuropathology and epilepsy.

In vitro and in vivo investigation of dexibuprofen derivatives for CNS delivery

AIM

Dexibuprofen, the S(+)-isomer of ibuprofen, is an effective therapeutic agent for the treatment of neurodegenerative disorders. However, its clinical use is hampered by a limited brain distribution. The aim of this study was to design and synthesize brain-targeting dexibuprofen prodrugs and to evaluate their brain-targeting efficiency using biodistribution and pharmacokinetic analysis.

METHODS

In vitro stability, biodistribution and pharmacokinetic studies were performed on male Sprague-Dawley rats. The concentrations of dexibuprofen in biosamples, including the plasma, brain, heart, liver, spleen, lung, and kidney, were measured using high pressure lipid chromatography (HPLC). The pharmacokinetic parameters of the drug in the plasma and tissues were calculated using obtained data and statistics.

RESULTS

Five dexibuprofen prodrugs that were modified to contain ethanolamine-related structures were designed and synthesized. Their chemical structures were confirmed using (1)H NMR, (13)C NMR, IR, and HRMS. In the biodistribution study, 10 min after intravenous administration of dexibuprofen (11.70 mg/kg) and its prodrugs (the dose of each compound was equivalent to 11.70 mg/kg of dexibuprofen) in male Sprague-Dawley rats, the dexibuprofen concentrations in the brain and plasma were measured. The C(brain)/C(plasma) ratios of prodrugs 1, 2, 3, 4, and 5 were 17.0-, 15.7-, 7.88-, 9.31-, and 3.42-fold higher than that of dexibuprofen, respectively (P<0.01). Thus, each of the prodrugs exhibited a significantly enhanced brain distribution when compared with dexibuprofen. In the pharmacokinetic study, prodrug 1 exhibited a brain-targeting index of 11.19 {DTI=(AUC(brain)/AUC(plasma))(1)/(AUC(brain)/AUC(plasma))(dexibuprofen)}.

CONCLUSION

The ethanolamine-related structures may play an important role in transport across the brain blood barrier.

Neuroprotective effect of cyclooxygenase inhibitors in ICV-STZ induced sporadic Alzheimer's disease in rats

Sporadic Alzheimer's disease is an age-related neurological and psychiatric disorder characterized by impaired energy metabolism. Oxidative stress and neuroinflammation have been implicated in pathophysiology of sporadic type of dementia. The central streptozotocin administration induces behavioral and biochemical alterations resembling those in sporadic type of Alzheimer's patients. The present study was designed to investigate the effects of chronic pretreatment with cyclooxygenase-1 or cyclooxygenase-2 or cyclooxygenase-3 selective inhibitors on cognitive dysfunction and oxidative stress markers in intracerebroventricular streptozotocin-treated rats. Chronic treatment with valeryl salicylate (5 and 10 mg/kg, i.p.) and etoricoxib (5 and 10 mg/kg, i.p.) on a daily basis for a period of 21 days, beginning 1 h prior to first intracerebroventricular streptozotocin injection, significantly improved streptozotocin-induced cognitive impairment. However, phenacetin (20 and 40 mg/kg, i.p.) failed to restore the cognitive performances of streptozotocin-treated rats. Besides, improving cognitive dysfunction, chronic administration of highly selective cyclooxygenase-1 and/or cyclooxygenase-2 inhibitors (valeryl salicylate and etoricoxib, respectively), but not cyclooxygenase-3 inhibitor (phenacetin), significantly reduced elevated malondialdehyde, nitrite levels, and restored reduced glutathione and superoxide dismutase levels. Furthermore, cyclooxygenase-1 and/or cyclooxygenase-2 inhibitors significantly increased the survival of pyramidal neurons. In summary, we demonstrate for the first time that both cyclooxygenase-1 and cyclooxygenase-2 isoforms, but not cyclooxygenase-3, are involved in the progression of neuronal damage in intracerebroventricular streptozotocin-treated rats.

Attenuation of hematoma size and neurological injury with curcumin following intracerebral hemorrhage in mice

OBJECT

Intracerebral hemorrhage (ICH) is associated with significant morbidity and mortality. Acute hematoma enlargement is an important predictor of neurological injury and poor clinical prognosis; but neurosurgical clot evacuation may not be feasible in all patients and treatment options remain largely supportive. Thus, novel therapeutic approaches to promote hematoma resolution are needed. In the present study, the authors investigated whether the curry spice curcumin limited neurovascular injury following ICH in mice.

METHODS

Intracerebral hemorrhage was induced in adult male CD-1 mice by intracerebral administration of collagenase or autologous blood. Clinically relevant doses of curcumin (75-300 mg/kg) were administered up to 6 hours after ICH, and hematoma volume, inflammatory gene expression, blood-brain barrier permeability, and brain edema were assessed over the first 72 hours. Neurological assessments were performed to correlate neurovascular protection with functional outcomes.

RESULTS

Curcumin increased hematoma resolution at 72 hours post-ICH. This effect was associated with a significant reduction in the expression of the proinflammatory mediators, tumor necrosis factor-α, interleukin-6, and interleukin-1β. Curcumin also reduced disruption of the blood-brain barrier and attenuated the formation of vasogenic edema following ICH. Consistent with the reduction in neuroinflammation and neurovascular injury, curcumin significantly improved neurological outcome scores after ICH.

CONCLUSIONS

Curcumin promoted hematoma resolution and limited neurological injury following ICH. These data may indicate clinical utility for curcumin as an adjunct therapy to reduce brain injury and improve patient outcome.

Protective effects of selective and non-selective cyclooxygenase inhibitors in an animal model of chronic stress

OBJECTIVE

Cyclooxygenase isoenzyme is known to be expressed in different regions of brain, and is mainly used for the treatment of pain and inflammation. Recently, it is proposed that cyclooxygenase isoenzyme may also play a key role in the pathophysiology of various brain-related disorders. The present study was aimed to explore the protective effect of cyclooxygenase inhibitors on stress by using an animal model of chronic stress.

METHODS

The animals were forced to swim individually for a period of 6 min every day for 15 d. Then, the behavior (locomotor activity, anxiety and memory) and biochemical (lipid peroxidation, nitrite level, reduced glutathione, and catalase) alterations were assessed.

RESULTS

Forced swimming for 15 d caused impaired locomotor activity, anxiety-like behavior and decreased percentage of memory retention, as compared to naive mice (without chronic fatigue treatment). Biochemical analysis revealed significant increases in lipid peroxidation and nitrite level, while levels of reduced glutathione and catalase activity were both decreased. Chronic treatment with naproxen (14 mg/kg, i.p.), rofecoxib (5 mg/kg, i.p.), meloxicam (5 mg/kg, i.p.), nimesulide (5 mg/kg, i.p.) and valdecoxib (10 mg/kg, i.p.) significantly attenuated these behavioral and biochemical (oxidative damage) alterations in chronic-stressed mice.

CONCLUSION

The cyclooxygenase inhibitors could be used in the management of chronic fatigue-like conditions.

Mast cells, histamine, and IL-6 regulate the selective influx of dendritic cell subsets into an inflamed lymph node

In response to bacterial stimuli, multiple dendritic cell (DC) populations accumulate within the draining lymph node, thus enhancing opportunities for effective T cell-DC interaction. DC subpopulations, such as plasmacytoid, CD8(+), and CD11b(+) subsets, have distinct roles in determining the nature of the immune response. The mechanisms whereby individual DC subpopulations are mobilized and the extent to which these processes are linked to increases in overall lymph node cellularity have not been determined. In the current study, the mechanisms of DC subset mobilization to the draining auricular lymph node were examined after intradermal injection of Staphylococcus aureus-derived peptidoglycan. Using mast cell-deficient mice and local mast cell reconstitution, plasmacytoid and CD8(+) DC responses were shown to be mast cell dependent, whereas the CD11b(+) DC response was not. A histamine H2 receptor-dependent, CXCL9-independent pathway controlled the selective influx of both plasmacytoid and CD11b(+) DC into the lymph node, but not lymph node cellularity. In contrast, IL-6 was important for the mobilization of CD8(+) and CD11b(+) DC. TNF and IL-1 receptor were dispensable for plasmacytoid, CD11b(+), and CD8(+) DC responses. These findings provide novel opportunities for the selective mobilization of specific DC subsets to lymph nodes and demonstrate critical roles for both histamine and IL-6 in this process.

A randomized, double-blind, placebo-controlled study of preemptively administered intravenous parecoxib: effect on anxiety levels and procedural pain during epidural catheter placement for surgical operations or for chronic pain therapy

BACKGROUND

The effect of parecoxib, when used perioperatively or during interventional techniques, is well demonstrated in the literature. Little is known about its effects on anxiety levels before the analgesic technique application. The aim of this prospective, randomized, double-blind, placebo-controlled, clinical study is to investigate whether parecoxib, preemptively administrated, has an effect on anxiety levels reported prior to an epidural puncture, and if it influences the reported pain of the interventional technique itself.

MATERIAL AND METHODS

The study protocol involved 110 patients, scheduled for epidural catheter placement for chronic pain therapy--Group I, as well as 112 patients scheduled for orthopedic operations under epidural anesthesia--Group II. Patients in each group were randomly allocated into two subgroups in relation to parecoxib/placebo administration before epidural catheter placement: Group Ia, parecoxib 40 mg i.v. (n = 54), Group Ib, placebo (n = 56), Group IIa, parecoxib 40 mg i.v. (n = 57), Group IIb, placebo (n = 55). Patients were given a self-administered inventory to measure the anxiety level of the presurgical/preprocedural state (State-Trait Spielberger Anxiety Inventory) and anxiety levels were recorded 1 hour before epidural puncture, 20 minutes postdosing, and 1 hour after epidural catheter placement. Anxiety levels were also measured and recorded using visual analog scale (VAS). One hour after epidural puncture, reported procedural pain was recorded (VAS). One hour and 6 hours postepidural, patients' satisfaction was also recorded, on a 4-point scale.

RESULTS

All four subgroups were similar regarding demographic, operative/procedural data, and coexisting diseases. Preprocedural anxiety levels were significantly decreased with parecoxib administration in comparison with placebo in both groups (P < 0.05). Reported VAS regarding pain from epidural puncture was lower in Groups IA and Ib. Patients' satisfaction was greater with parecoxib in comparison with placebo.

CONCLUSION

The levels of anxiety have been investigated in several medical procedures and early, in the study of pain. The higher the expectation of pain and the anxiety are, the higher the intensity of the pain. Parecoxib seems to exert positive influence on pain and anxiety levels of interventional procedure. Further studies are needed to elucidate the actual mechanisms that are involved.

Cytosolic phospholipase A2 alpha inhibition prevents neuronal NMDA receptor-stimulated arachidonic acid mobilization and prostaglandin production but not subsequent cell death

Phospholipase A(2) (PLA(2)) enzymes encompass a superfamily of at least 13 extracellular and intracellular esterases that hydrolyze the sn-2 fatty acyl bonds of phospholipids to yield fatty acids and lysophospholipids. The purpose of this study was to characterize which phospholipase paralog regulates NMDA receptor-mediated arachidonic acid (AA) release. Using mixed cortical cell cultures containing both neurons and astrocytes, we found that [(3)H]-AA released into the extracellular medium following NMDA receptor stimulation (100 microM) increased with time and was completely prevented by the addition of the NMDA receptor antagonist MK-801 (10 microM) or by removal of extracellular Ca(2+). Neither diacylglycerol lipase inhibition (RHC-80267; 10 microM) nor selective inhibition of Ca(2+)-independent PLA(2) [bromoenol lactone (BEL); 10 microM] alone had an effect on NMDA receptor-stimulated release of [(3)H]-AA. Release was prevented by methyl arachidonyl fluorophosphonate (MAFP) (5 microM) and AACOCF(3) (1 microM), inhibitors of both cytosolic PLA(2) (cPLA(2)) and Ca(2+)-independent PLA(2) isozymes. This inhibition effectively translated to block of NMDA-induced prostaglandin (PG) production. An inhibitor of p38MAPK, SB 203580 (7.5 microM), also significantly reduced NMDA-induced PG production providing suggestive evidence for the role of cPLA(2)alpha. Its involvement in release was confirmed using cultures derived from mice deficient in cPLA(2)alpha, which failed to produce PGs in response to NMDA receptor stimulation. Interestingly, neither MAFP, AACOCF(3) nor cultures derived from cPLA(2)alpha null mutant animals showed any protection against NMDA-mediated neurotoxicity, indicating that inhibition of this enzyme may not be a viable protective strategy in disorders of the cortex involving over-activation of the NMDA receptor.

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

Systemic administration of 3-nitropropionic acid (3-NP), a complex II inhibitor of the electron transport chain, causes motor and cognitive deficits that are associated with excitotoxicity and excessive free radical generation. Recently, cyclooxygenase (COX) inhibitors have been implicated as a neuroprotectant in the treatment of various neurological disorders. The present study was designed to investigate the effects of COX inhibitors in 3-NP-induced cognitive impairment and oxidative stress in rats. Intraperitoneal administration of 3-NP (20 mg/kg for 4 days) showed motor abnormalities and cognitive impairment in rats. Chronic treatment with naproxen (10 and 20 mg/kg) and valdecoxib (5 and 10 mg/kg) once daily for a period of 8 days beginning 4 days prior to 3-NP administration significantly improved 3-NP-induced motor and cognitive impairment in rats. Biochemical analysis revealed that systemic 3-NP administration significantly increased lipid peroxidation and nitrite levels, depleted reduced glutathione levels and reduced succinate dehydrogenase (SDH) activity in the brains of rats, whereas administration of naproxen, a nonselective COX inhibitor (10 and 20 mg/kg p.o.) and valdecoxib, a selective COX-2 inhibitor (5 and 10 mg/kg p.o.) significantly attenuated 3-NP-induced oxidative stress. Cyclooxygenase inhibitors also significantly restored the decreased SDH activity. The results of the present study clearly indicate that naproxen and valdecoxib showed protection against 3-NP-induced motor and cognitive impairment by decreasing oxidative stress.

Effect of rofecoxib, a cyclo-oxygenase-2 inhibitor, on various biochemical parameters of brain associated with pentylenetetrazol-induced chemical kindling in mice

Cyclo-oxygenase (COX) has been reported to play a significant role in neurodegeneration and other brain-related disorders. Recent studies have reported that COX plays a significant role in the pathophysiology of brain-related disorders and COX-2 inhibitors could be useful drug therapy in neurodegenerative disorders. The aim of the present study was to explore the possible role of COX and the effect of COX-2 inhibitor, rofecoxib in epilepsy. In the present study, kindling was induced in mice by chronic administration of a subconvulsive dose of pentylenetetrazol (PTZ, 40 mg/kg, i.p.) on every other day for a period of 15 days. Rofecoxib was administered orally daily 45 min before either PTZ or vehicle. The kindling score was recorded after PTZ administration. Seizure severity was measured according to a prevalidated scoring scale. Biochemical estimations were performed on the day 16 of PTZ treatment (24 h after the last dose of PTZ). Chronic treatment with selective COX-2 inhibitor, rofecoxib (2.0 and 5.0 mg/kg, p.o.) for 15 days showed significant decrease in PTZ-induced kindling score. Biochemical analysis showed that chronic treatment with PTZ significantly increased lipid peroxidation, nitrite levels (NO levels), and myeloperoxidase levels and decreased the reduced glutathione levels in brain homogenate. Chronic treatment with rofecoxib, a selective COX-2 inhibitor, significantly reversed the PTZ-induced kindling score as well as various biochemical alterations suggesting the use of COX-2 inhibitor rofecoxib in epilepsy. In conclusion, results of the present study suggested that COX-2 plays an important role in the pathophysiology of PTZ-induced kindling in mice and rofecoxib is protective against various biochemical alterations against PTZ-induced kindling in mice.

Oral treatment with rofecoxib reduces hippocampal excitotoxic neurodegeneration

The purpose of this study was to determine whether the selective cyclooxygenase-2 (COX-2) inhibitor rofecoxib [4-[4-(methylsulfonyl)phenyl]-3-phenyl-2(5H)-furanone] could effectively prevent hippocampal neuronal injury in an animal model of excitotoxic neurodegeneration. COX-2 protein levels increased between 3 and 6 h, peaked at 12 h, and declined to near baseline levels 24 h after injection of N-methyl-d-aspartate (NMDA; 18 nmol) into the CA1 region of the left hippocampus. Mice that were fed ad libitum a control rodent diet for 4 days before and 3 days after injection of NMDA demonstrated marked neuronal loss in the primary cell layers of the ipsilateral CA1, CA3, and dentate gyrus (50, 30, and 20% cell loss, respectively). This injury was potently and dose-dependently reduced by feeding animals a diet standardized to deliver 15 or 30 mg/kg rofecoxib per day. Neurodegeneration in the CA1 region was reduced by 30.1 +/- 5.6 and 51.5 +/- 9.0%, respectively; in the CA3 by 64.6 +/- 12.4 and 69.0 +/- 14.1%, respectively; and in the dentate gyrus by 47.8 +/- 15.2 and 58.0 +/- 18.2%, respectively. Moreover, rofecoxib chow slightly but significantly reduced injury-induced brain edema. These findings demonstrate that rofecoxib can ameliorate excitotoxic neuronal injury in vivo and, as such, may be a particularly promising pharmaceutical for the treatment of neurological diseases associated with overactivation of NMDA receptors.

Protective effect of naproxen (non-selective COX-inhibitor) or rofecoxib (selective COX-2 inhibitor) on immobilization stress-induced behavioral and biochemical alterations in mice

Chronic stress precipitates many neuropsychiatric disorders and alters the various oxidative stress parameters in brain. Cyclooxygenase (COX) is reported to play an important role in pathogenesis of various neurodegenerative disorders including stroke and seizures. In the present study, we examined the effect of naproxen (non-selective COX-inhibitor having much potency towards COX-I isoform) or rofecoxib (a selective COX-2 inhibitor) in subchronic immobilization stress. Mice were subjected to immobilized stress for 6 h daily for a period of seven days. Naproxen (7 mg/kg, i.p.) or rofecoxib (2 mg/kg, i.p.) was administered daily for 7 days before challenging them to immobilization stress. Behavioral analysis revealed the hyperlocomotor activity and increased anxiety response. Subchronic stress decreased percent retention of memory and also caused hyperalgesia in mice. Biochemical analysis revealed that chronic immobilization stress significantly increased lipid peroxidation and nitrite levels and decreased the reduced glutathione and adrenal ascorbic acid levels. Chronic treatment with naproxen or rofecoxib significantly attenuated the immobilization stress-induced behavioral and biochemical alterations. These results suggested that the use of COX-inhibitors (naproxen or rofecoxib) could be a useful neuroprotective strategy in the treatment of stress.