Sumit Jamwal

Spermidine ameliorates 3-nitropropionic acid (3-NP)-induced striatal toxicity: Possible role of oxidative stress, neuroinflammation, and neurotransmitters.

AIM AND BACKGROUND Spermidine, a naturally occurring polyamine, is involved in various internal biological functions, due to its antioxidant and anti-inflammatory properties. A decreased level of polyamines is associated with aging and neurodegenerative disorders including Huntington disease (HD). 3-Nitropropanoic acid (3-NP) induces a spectrum of HD-like neuropathologies in rat striatum and thus serves as a good experimental model of HD. Therefore, the aim of the present study was to investigate whether spermidine confers neuroprotection against 3-NP-induced striatal toxicity and to explore its possible mechanism. METHODS Rats were administered 3-NP (10mg/kg/day, i.p.) for 21 days. Spermidine (5 and 10mg/kg/day, p.o.) was administered once a day 1h before 3-NP treatment for 21 days. Body weight and behavioral observations were recorded at weekly intervals after continuous 3-NP treatment. On the 22nd day, the animals were sacrificed, and the rat striatum was isolated for the estimation of biochemical parameters (lipid peroxidation (LPO), glutathione (GSH), and nitrite), determination of pro-inflammatory cytokine levels (tumor necrosis factor (TNF)-α and interleukin (IL)-6 and IL-1β), and neurochemical analysis (gamma-aminobutyric acid (GABA), glutamate, dopamine (DA), norepinephrine (NE), 5-HT, 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA), adenosine, inosine, and hypoxanthine). RESULTS The findings of the present study demonstrate significant alterations in motor coordination, oxidative defense, and the levels of pro-inflammatory mediators (TNF-α, IL-6, and IL-1β) and striatal neurotransmitters upon 3-NP treatment. Pretreatment with spermidine significantly attenuated 3-NP-induced alterations in motor coordination, oxidative stress, and the levels of neuroinflammatory markers and striatal neurotransmitters. CONCLUSION Our findings suggested that spermidine exerted a potential neuroprotective effect in a 3-NP model of HD, which may provide insight into the therapeutic potential of spermidine for HD.

Neuroprotective effect of hemeoxygenase-1/glycogen synthase kinase-3β modulators in 3-nitropropionic acid-induced neurotoxicity in rats.

The present study has been designed to explore the possible interaction between hemeoxygenase-1 (HO-1) and glycogen synthase kinase-3β (GSK-3β) pathway in 3-nitropropionic acid (3-NP)-induced neurotoxicity in rats. 3-NP produces neurotoxicity by inhibition of the mitochondrial complex II (enzyme succinate dehydrogenase) and by sensitizing the N-methyl-D-aspartate receptor. Recent studies have reported the therapeutic potential of HO-1/GSK-3β modulators in different neurodegenerative disorders. However, their exact role is yet to be explored. The present study is an attempt to investigate the effect of pharmacological modulation of HO-1/GSK-3β pathway against 3-NP-induced behavioral, biochemical and molecular alterations in rat. Behavioral observation, oxidative stress, pro-inflammatory [tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β)], HO-1 and GSK-3β activity were evaluated post 3-NP treatment. Findings of the present study demonstrate a significant alteration in the locomotor activity, motor coordination, oxidative burden (increased lipid peroxidation, nitrite concentration and decreased endogenous antioxidants), pro-inflammatory mediators [TNF-α, IL-1β], HO-1 and GSK-3β activity in 3-NP-treated animals. Further, administration of hemin (10- and 30-mg/kg; i.p.) and lithium chloride (LiCl) (25- and 50-mg/kg; i.p.) prevented the alteration in body weight, motor impairments, oxidative stress and cellular markers. In addition, combined administration of hemin (10-mg/kg) and LiCl (25-mg/kg) showed synergistic effect on 3-NP-treated rats. Pretreatment with Tin (IV) protoporphyrin (40 μM/kg), HO-1 inhibitor reversed the beneficial effect of LiCl and hemin. Outcomes of the present study suggest that HO-1 and GSK-3β enzymes are involved in the pathophysiology of HD. The modulators of both the pathways might be used as adjuvants or prophylactic therapy for the treatment of HD-like symptoms.

Tetrabenazine: Spotlight on Drug Review.

Background: Tetrabenazine (TBZ) is the only US Food and Drug Administration-approved drug for the treatment of chorea related to Huntingtons disease and other hyperkinetic disorders. TBZ was first synthesized in 1950, and was then used for the treatment of psychosis. But later its potential in treating hyperkinetic disorders was proved by its ability to block vesicular monoamine transporters 2 and deplete monoamine stores. There is still lack of awareness about the therapeutic potential of this drug. Summary: TBZ had been approved only for the treatment of chorea, but several clinical studies have been conducted by different research groups and it was concluded that TBZ is effective in various other conditions such as tardive dyskinesia, dystonia, tics, and Tourettes syndrome, thus, highlighting the need for further clinical trials in these conditions. Key Message: The intention of this review is to sum up the information regarding chemistry, mechanism of action, pharmacokinetics, interactions, contraindications, adverse effects, and clinical efficacy of TBZ in diseases other than Huntingtons chorea.

Beneficial effect of antidepressants against rotenone induced Parkinsonism like symptoms in rats.

Parkinsons disease is a second most common age-related neurodegenerative disorder characterized by the loss of DA neurons of SNpc region of the midbrain. Neurotransmitter dysfunction is involved in the pathogenesis of PD. Antidepressants like venlafaxine and sertraline expected to improve Parkinsonism like symptoms by modulating the levels of various neurotransmitters. The neuroprotective role of antidepressants is well explored in various CNS disorders. Therefore, this study was designed to explore and compare the mechanistic role of different antidepressants (venlafaxine and sertraline) against rotenone induced Parkinsonism like symptoms in rats. Rats were administrated with rotenone (1.5mg/kg/day; s.c.) daily for a period of 28 days. Venlafaxine (10 and 20mg/kg; p.o.), sertraline (10 and 20mg/kg; p.o.) and Levodopa combination with Carbidopa (10mg/kg; p.o.) were administered daily starting from 7th day one hour prior to rotenone administration. Behavioral parameters (body weight, rotarod, grip strength, narrow beam walk and open field) were assessed on weekly basis. On 28th day, animals were sacrificed and striatum were isolated for biochemical (LPO, GSH and nitrite), neuroinflammatory (TNF-α, IL-1β and IL-6), neurochemical (DA, NE, 5-HT, GABA, Glutamate, DOPAC, HVA and 5-HIAA) and mitochondrial complex-I estimation. Rotenone administration significantly reduced body weight, motor coordination, oxidative defense, increased pro-inflammatory mediators and decreased level of catecholamines. Pre-treatment with venlafaxine and sertraline significantly attenuated the alteration in behavioral, oxidative stress, neuroinflammatory, mitochondrial and catecholamines level in striatum. The study provides a hope that these drugs could be used as adjuvant therapy in the management and treatment of PD.

Antidepressants for neuroprotection in Huntington's disease: A review

Huntington Disease (HD), which is characterized by abnormal dance-like movements, is a neurodegenerative disorder caused by a genetic mutation that results in an expanded polyglutamine stretch in the NH2 terminus of huntingtin protein (HTT). The principal neuropathological hallmarks of disease include loss of striatal and cortical projection neurons. HTT is ubiquitously expressed and is implicated in several cellular functions including neurogenesis, cell trafficking and brain-derived neurotrophic factor (BDNF) production. Major depression is the most common symptom among pre-symptomatic HD carriers and numerous pieces of preclinical evidence have suggested the use of antidepressants in HD not only elevates mood but also slows down the disease progression by activating different neuroprotective mechanism like BDNF/TrkB pathway, MAPK/ERK signalling, neurogenesis and Wnt signalling. HTT plays major role in neurogenesis, a physiological phenomenon that is implicated in some of the behavioral effects of antidepressants. Currently, there is no clinically available treatment that can halt or slow down the progression of HD except tetrabenazine (the only FDA approved drug); however, this drug also induces depression and sedation in patients. In this review, a brief discussion has been made about the mutant HTT that induced various cellular and molecular mechanisms underlying behavioral disorders in HD. Further, an attempt has been made to understand the various cellular mechanisms involved in mediating the neuroprotective effects of antidepressants in HD.

Beneficial effects of lycopene against haloperidol induced orofacial dyskinesia in rats: Possible neurotransmitters and neuroinflammation modulation.

Tardive Dyskinesia is a severe side effect of chronic neuroleptic treatment consisting of abnormal involuntary movements, characterized by orofacial dyskinesia. The study was designed to investigate the protective effect of lycopene against haloperidol induced orofacial dyskinesia possibly by neurochemical and neuroinflammatory modulation in rats. Rats were administered with haloperidol (1mg/kg, i.p for 21 days) to induce orofacial dyskinesia. Lycopene (5 and 10mg/kg, p.o) was given daily 1hour before haloperidol treatment for 21 days. Behavioral observations (vacuous chewing movements, tongue protrusions, facial jerking, rotarod activity, grip strength, narrow beam walking) were assessed on 0th, 7th(,) 14th(,) 21st day after haloperidol treatment. On 22nd day, animals were killed and striatum was excised for estimation of biochemical parameters (malondialdehyde, nitrite and endogenous enzyme (GSH), pro-inflammatory cytokines [Tumor necrosis factor, Interleukin 1β, Interleukin 6] and neurotransmitters level (dopamine, serotonin, nor epinephrine, 5-Hydroxyindole acetic acid (5-HIAA), Homovanillic acid, 3,4- dihydroxyphenylacetic acid. Haloperidol treatment for 21 days impaired muscle co-ordination, motor activity and grip strength with an increased in orofacial dyskinetic movements. Further free radical generation increases MDA and nitrite levels, decreasing GSH levels in striatum. Neuroinflammatory markers were significantly increased with decrease in neurotransmitters levels. Lycopene (5 and 10mg/kg, p.o) treatment along with haloperidol significantly attenuated impairment in behavioral, biochemical, neurochemical and neuroinflammatory markers. Results of the present study attributed the therapeutic potential of lycopene in the treatment (prevented or delayed) of typical antipsychotic induced orofacial dyskinesia.

Sertraline and venlafaxine improves motor performance and neurobehavioral deficit in quinolinic acid induced Huntington’s like symptoms in rats: Possible neurotransmitters modulation

BACKGROUND Huntington Disease is autosomal, fatal and progressive neurodegenerative disorder for which clinically available drugs offer only symptomatic relief. Emerging strides have indicated that antidepressants improve motor performance, restore neurotransmitters level, ameliorates striatal atrophy, increases BDNF level and may enhance neurogenesis. Therefore, we investigated sertraline and venlafaxine, clinically available drugs for depression with numerous neuroprotective properties, for their beneficial effects, if any, in quinolinic acid induced Huntingtons like symptoms in rats. METHODS Rats were administered quinolinic acid (QA) (200 nmol/2μl saline) intrastriatal bilaterally on 0day. Sertraline and venlafaxine (10 and 20mg/kg, po) each were administered for 21days once a day. Motor performance was assessed using rotarod test, grip strength test, narrow beam walk test on weekly basis. On day 22, animals were sacrificed and rat striatum was isolated for biochemical (LPO, GSH and Nitrite), neuroinflammation (TNF-α, IL-1β and IL-6) and neurochemical analysis (GABA, glutamate, norepinephrine, dopamine, serotonin, DOPAC, HVA and 5-HIAA). RESULTS QA treatment significantly altered body weight, motor performance, oxidative defense (increased LPO, nitrite and decreased GSH), pro-inflammatory cytokines levels (TNF-α, IL-6 and IL-1β), neurochemical level (GABA, glutamate, nor-epinephrine, dopamine, serotonin, HVA, DOPAC, 5-HIAA). Sertraline and venlafaxine at selected doses significantly attenuated QA induced alterations in striatum. CONCLUSION The present study suggests that modulation of monoamines level, normalization of GABA and glutamatergic signaling, anti-oxidant and anti-inflammatory properties could underlie the neuroprotective effect of sertraline and venlafaxine in QA induced Huntingtons like symptoms.

L-theanine prevent quinolinic acid induced motor deficit and striatal neurotoxicity: Reduction in oxido-nitrosative stress and restoration of striatal neurotransmitters level

L-theanine has been documented to possess anti-oxidant, anti-inflammatory and neuroprotective potential in various animal models of neurological disorders. The present study was anticipated to investigate the effect of L-theanine against quinolinic acid induced motor deficits, oxido-nitrosative stress, neuro-inflammation and neurotransmitters alteration in rats. Rats were stereotaxically injected QA (200nmol/2µl saline; intrastriatal); bilaterally on 0 day and L-theanine (25 & 50mg/kg; p.o.) was administered for 21 days starting from day 1 of QA injection. Either, L-NAME (10mg/kg; i.p.), a nitric oxide synthase inhibitor and L-arginine (50mg/kg; i.p.), a nitric oxide synthase precursor were administered with L-theanine in respective groups. Behavioral observations were evaluated on weekly basis using rota-rod, grip strength, narrow beam walking and open field test. QA treatment induces significant alteration in body weight, motor coordination, oxidative defense, pro-inflammatory cytokines and striatal neurotransmitters level. L-theanine treatment alone, at both the tested doses, significantly attenuated QA induced alterations. In addition, treatment of L-theanine with L-NAME significantly enhances the protective effect of L-theanine whereas treatment of L-theanine with L-arginine significantly ameliorated the protective effect of L-theanine. The protective effect of L-theanine is attributed to its anti-oxidant, anti-inflammatory and modulatory effect on nitric oxide pathway and neurotransmitters level in striatum. This suggests use of L-theanine in the clinical settings of HD.

Neuroprotective potential of quercetin in combination with piperine against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced neurotoxicity

1-Methy-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a neurotoxin that selectively damages dopaminergic neurons in the substantia nigra pars compacta and induces Parkinsons like symptoms in rodents. Quercetin (QC) is a natural polyphenolic bioflavonoid with potent antioxidant and anti-inflammatory properties but lacks of clinical attraction due to low oral bioavailability. Piperine is a well established bioavailability enhancer used pre-clinically to improve the bioavailability of antioxidants (e.g., Quercetin). Therefore, the present study was designed to evaluate the neuroprotective potential of QC together with piperine against MPTP-induced neurotoxicity in rats. MPTP (100 μg/μL/rat, bilaterally) was injected intranigrally on days 1, 4 and 7 using a digital stereotaxic apparatus. QC (25 and 50 mg/kg, intragastrically) and QC (25 mg/kg, intragastrically) in combination with piperine (2.5 mg/kg, intragastrically) were administered daily for 14 days starting from day 8 after the 3rd injection of MPTP. On day 22, animals were sacrificed and the striatum was isolated for oxidative stress parameter (thiobarbituric acid reactive substances, nitrite and glutathione), neuroinflammatory cytokine (interleukin-1β, interleukin-6, and tumor necrosis factor-α) and neurotransmitter (dopamine, norepinephrine, serotonin, gamma-aminobutyric acid, glutamate, 3,4-dihydroxyphenylacetic acid, homovanillic acid, and 5-hydroxyindoleacetic acid) evaluations. Bilateral infusion of MPTP into substantia nigra pars compacta led to significant motor deficits as evidenced by impairments in locomotor activity and rotarod performance in open field test and grip strength and narrow beam walk performance. Both QC (25 and 50 mg/kg) and QC (25 mg/kg) in combination with piperine (2.5 mg/kg), in particular the combination therapy, significantly improved MPTP-induced behavioral abnormalities in rats, reversed the abnormal alterations of neurotransmitters in the striatum, and alleviated oxidative stress and inflammatory response in the striatum. These findings indicate that piperine can enhance the antioxidant and anti-inflammatory properties of QC, and QC in combination with piperine exhibits strong neuroprotective effects against MPTP-induced neurotoxicity.

Beneficial effect of rice bran extract against 3-nitropropionic acid induced experimental Huntington's disease in rats

Graphical abstract