Udaiyappan Janakiraman

Erratum to: Neuroprotective Effect of Hesperidin on Aluminium Chloride Induced Alzheimer's Disease in Wistar Rats.

The present study was aimed to evaluate the protective effect of hesperidin (Hes) on aluminium chloride (AlCl3) induced neurobehavioral and pathological changes in Alzheimeric rats. Intraperitonial injection of AlCl3 (100 mg/kg body weight) for 60 days significantly elevated the levels of aluminium (Al), activity of acetylcholinesterase (AChE) and protein expressions of amyloid precursor protein (APP), β amyloid (Aβ1–42), β and γ secretases as compared to control group in hippocampus and cortex of rat brain. Hes administration orally along with AlCl3 injection for 60 days, significantly revert the Al concentration, AChE activity and Aβ synthesis-related molecules in the studied brain regions. Our results showed that aluminum exposure was significantly reduced the spontaneous locomotor and exploratory activities in open field test and enhanced the learning and memory impairments in morris water maze test. The behavioral impairments caused by aluminum were significantly attenuated by Hes. The histopathological studies in the hippocampus and cortex of rat brain also supported that Hes (100 mg/kg) markedly reduced the toxicity of AlCl3 and preserved the normal histoarchitecture pattern of the hippocampus and cortex. From these results, it is concluded that hesperidin can reverse memory loss caused by aluminum intoxication through attenuating AChE activity and amyloidogenic pathway.

Theaflavin ameliorates behavioral deficits, biochemical indices and monoamine transporters expression against subacute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of Parkinson's disease.

Evidence from clinical and experimental studies indicates that degeneration of nigrostriatal dopaminergic neurons is a pathological hallmark of Parkinsons disease (PD). The present study was designed to investigate the neuroprotective potential of theaflavin (TF) on oxidative stress, monoamine transporters and behavioral abnormalities in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurodegeneration. TF, a black tea polyphenol, has been known to possess neuroprotective effects against ischemia, Alzheimers disease and other neurodegenerative disorders, but the mechanisms underlying its beneficial effects on MPTP-induced dopaminergic neurodegeneration are poorly defined. Administration of MPTP (30 mg/kg bw for four consecutive days) led to increased oxidative stress and reduced behavior patterns (open field, rotarod and hang test), nigrostriatal dopamine transporter (DAT) (immunohistochemistry and Western blot) and vesicular monoamine transporter 2 (VMAT2) (Western blot) expressions. Pre-treatment with TF reduces oxidative stress, improves motor behavior and expression of DAT and VMAT2 in striatum and substantia nigra. These results indicate that TF might be beneficial in mitigating MPTP-induced damage of dopaminergic neurons, possibly via its neuroprotective and its antioxidant potential.

Escin attenuates behavioral impairments, oxidative stress and inflammation in a chronic MPTP/probenecid mouse model of Parkinson׳s disease

Parkinsons disease (PD) is a progressive neurodegenerative disorder that results mainly due to the death of dopaminergic neurons in the substantia nigra (SN), and subsequently has an effect on ones motor function and coordination. The current investigation explored the neuroprotective potential of escin, a natural triterpene-saponin on chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/probenecid (MPTP/p) induced mouse model of PD. Administration of MPTP led to the depleted striatal dopamine content, impaired patterns of behavior, enhanced oxidative stress and diminished expression of tyrosine hydroxylase (TH), dopamine transporter (DAT) and vesicular monoamine transporter-2 (VMAT-2). The expressions of interleukin-6 and -10, glial fibrillary acidic protein (GFAP), ionized calcium-binding adaptor protein-1 (IBA-1), tumor necrosis factor-α (TNF-α) and inducible nitric oxide synthase (iNOS) in SN were also enhanced. Oral treatment of escin significantly attenuated MPTP/p induced dopaminergic markers depletion, physiological abnormalities, oxidative stress and inhibit neuroinflammatory cytokine expressions in SN. The result of our study confirmed that escin mediated its protection against experimental PD through its antioxidant and anti-inflammatory properties.

Neuroprotective effect of lycopene against MPTP induced experimental Parkinson’s disease in mice

Parkinsons disease (PD) is the second most common neurodegenerative disorder that mainly affects the movement of the aged populations. Lycopene is a carotenoid with unique pharmacological properties and its efficacy on experimental Hungintons disease and brain ischemia has shown intense neuroprotective effects. The present study was aimed to explore the neuroprotective effect of lycopene against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced PD mice. Administration of lycopene (5, 10 and 20 mg/kg/day orally) protected MPTP induced depletion of striatal dopamine (DA) and its metabolites in a dose dependent manner. It also attenuated MPTP-induced oxidative stress and motor abnormalities seen in PD mice. Our western blot studies showed that treatment with lycopene reversed MPTP induced apoptosis may be due to its antioxidant and antiapoptotic properties. As to conclude, lycopene reverses neurochemical deficts, oxidative stress, apoptosis and physiological abnormalities in PD mice and offer promise strategy in the treatment of this neurodegenerative disease.

Hesperidin ameliorates cognitive dysfunction, oxidative stress and apoptosis against aluminium chloride induced rat model of Alzheimer's disease

Background/aims: Deregulation of metal ion homeostasis has been assumed as one of the key factors in the progression of neurodegenerative diseases. Aluminium (Al) has been believed as a major risk factor for the cause and progression of Alzheimers disease (AD). In our lab, we have previously reported that hesperidin, a citrus bioflavonoid reversed memory loss caused by aluminium intoxication through attenuating acetylcholine esterase activity and the expression of Amyloid β biosynthesis related markers. Al has been reported to cause oxidative stress associated apoptotic neuronal loss in the brain. So in the present study, protective effect of hesperidin against aluminium chloride (AlCl3) induced cognitive impairment, oxidative stress and apoptosis was studied. Methods: Male Wistar rats were divided into control, AlCl3 treated (100 mg/kg., b.w.), AlCl3 and hesperidin (100 mg/kg., b.w.) co-treated and hesperidin alone treated groups. In control and experimental rats, learning and memory impairment were measured by radial arm maze, elevated plus maze and passive avoidance tests. In addition, oxidative stress and expression of pro and anti-apoptotic markers were also evaluated. Results: Intraperitoneal injection of AlCl3 (100 mg/kg., b.w.) for 60 days significantly enhanced the learning and memory deficits, levels of thiobarbituric acid reactive substances and the expression of Bax and diminished the levels of reduced glutathione, activities of enzymatic antioxidants and the expression of B-cell lymphoma-2 (Bcl-2) as compared to control group in the hippocampus, cortex, and cerebellum. Coadministration of hesperidin (100 mg/kg., b.w. oral) for 60 days prevented the cognitive deficits, biochemical anomalies and apoptosis induced by AlCl3 treatment. Conclusion: Results of the present study demonstrated that hesperidin could be a potential therapeutic agent in the treatment of oxidative stress and apoptosis associated neurodegenerative diseases including AD.

Influences of Chronic Mild Stress Exposure on Motor, Non-Motor Impairments and Neurochemical Variables in Specific Brain Areas of MPTP/Probenecid Induced Neurotoxicity in Mice

Parkinsons disease (PD) is regarded as a movement disorder mainly affecting the elderly population and occurs due to progressive loss of dopaminergic (DAergic) neurons in nigrostriatal pathway. Patients suffer from non-motor symptoms (NMS) such as depression, anxiety, fatigue and sleep disorders, which are not well focussed in PD research. Depression in PD is a predominant /complex symptom and its pathology lies exterior to the nigrostriatal system. The main aim of this study is to explore the causative or progressive effect of chronic mild stress (CMS), a paradigm developed as an animal model of depression in1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (25 mg/kg. body wt.) with probenecid (250 mg/kg, s.c.) (MPTP/p) induced mice model of PD. After ten i.p. injections (once in 3.5 days for 5 weeks) of MPTP/p or exposure to CMS for 4 weeks, the behavioural (motor and non-motor) impairments, levels and expressions of dopamine (DA), serotonin (5-HT), DAergic markers such as tyrosine hydroxylase (TH), dopamine transporter (DAT), vesicular monoamine transporters—2 (VMAT 2) and α-synuclein in nigrostriatal (striatum (ST) and substantia nigra (SN)) and extra-nigrostriatal (hippocampus, cortex and cerebellum) tissues were analysed. Significantly decreased DA and 5-HT levels, TH, DAT and VMAT 2 expressions and increased motor deficits, anhedonia-like behaviour and α-synuclein expression were found in MPTP/p treated mice. Pre and/or post exposure of CMS to MPTP/p mice further enhanced the MPTP/p induced DA and 5-HT depletion, behaviour abnormalities and protein expressions. Our results could strongly confirm that the exposure of stress after MPTP/p injections worsens the symptoms and neurochemicals status of PD.

Vanillin Attenuated Behavioural Impairments, Neurochemical Deficts, Oxidative Stress and Apoptosis Against Rotenone Induced Rat Model of Parkinson’s Disease

Vanillin (4-hydroxy-3-methoxybenzaldehyde), a pleasant smelling organic aromatic compound, is widely used as a flavoring additive in food, beverage, cosmetic and drug industries. It is reported to cross the blood brain barrier and also displayed antioxidant and neuroprotective activities. We previously reported the neuroprotective effect of vanillin against rotenone induced in in vitro model of PD. The present experiment was aimed to analyze the neuroprotective effect of vanillin on the motor and non-motor deficits, neurochemical variables, oxidative, anti-oxidative indices and the expression of apoptotic markers against rotenone induced rat model of Parkinson’s disease (PD). Rotenone treatment exhibited motor and non-motor impairments, neurochemical deficits, oxidative stress and apoptosis, whereas oral administration of vanillin attenuated the above-said indices. However further studies are needed to explore the mitochondrial protective and anti-inflammatory properties of vanillin, as these processes play a vital role in the cause and progression of PD.

Antioxidant and anti-inflammatory potential of hesperidin against 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine-induced experimental Parkinson's disease in mice

Background : There is mounting evidence that flavonoid consumption is potentially beneficial to those suffering from neurodegenerative diseases, cardiovascular disease, and cancer. These beneficial properties are largely attributed to their medicinal values. Objectives: In this study, we evaluated the neuro-protective effect of black hesperidin against 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) induced behavioral deficits, oxidative stress, and inflammation. Results: Behavioral analyses showed that hesperidin ameliorates MPTP-induced motor dysfunction. Elevated level of thiobarbituric acid reactive substances and enhanced activities of superoxide dismutase and catalase with deprived levels of reduced glutathione and activities of glutathione peroxidase in MPTP group was attenuated significantly in hesperidin-treated group. Administration of MPTP-induced glial activation observed by primary marker Glial Fibrillary Acidic Protein increased the release of pro-oxidant Cyclooxygenase - 2 and inflammatory cytokines such as Interleukin-1β, Tumor necrosis factor-α, IL-6, IL-4, and IL-10 in striatum and substania nigra. Treatment of hesperidin significantly protects microglia activation and reduces the release of inflammatory cytokines proving the anti-inflammatory effect of hesperidin. Conclusion: These findings suggest that hesperidin partially attenuates MPTP-induced neurotoxicity through its antioxidant and anti-inflammatory properties.

Chronic mild stress augments MPTP induced neurotoxicity in a murine model of Parkinson's disease

Depression is frequently encountered during Parkinsons disease (PD) as a non-motor feature, which has been reported to cause and exaggerate motor deficits and neurodegenerative events in experimental PD models. We studied the effect of chronic mild stress (CMS) (pre, post and pre & post) exposure mediated depression on motor and non-motor symptoms, oxidative stress, inflammation and brain derived neurotrophic factor (BDNF) levels and its related signalling molecules against the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/probenecid (MPTP/p) induced neurotoxicity in mice. CMS and MPTP/p-coexposed C57BL/6 mice exhibited low neuromuscular strength and stride length with enhanced oxidative stress and inflammation as compared to CMS or MPTP/p alone exposed mice. Coexposure diminished the levels of BDNF and expressions of p-TrkB, p-ERK/ERK, p-AKT/AKT and p-CREB in nigrostriatal regions as compared to those of the alone exposure. CMS alone exposed mice showed more anxiety related behaviour with diminished expression of serotonin transporter as compared to MPTP/p alone injected group. Post-stress exposure to MPTP/p mice exhibited lowest motor and reflecting higher anxiety state with greatest enhancement in inflammation and reduction in the protein expression of stress and cell signalling markers as compared to pre and pre & post stress exposed PD mice. However, pre- and pre & post CMS exposed PD animals are more vulnerable to oxidative stress as compared with post-stress experienced MPTP/p mice. CMS mediated depression exacerbates motor/non-motor symptoms in MPTP/p-PD animals by modulating oxidative stress and various signalling molecules. Our results suggested that stress induced NMS can accelerate neurodegenerative processes in the PD in a progressive or expedited manner.

Demethoxycurcumin, a natural derivative of curcumin abrogates rotenone-induced dopamine depletion and motor deficits by its antioxidative and anti-inflammatory properties in Parkinsonian rats

Background: Parkinsons disease (PD) is a progressive neurodegenerative disorder (NDD) associated with the loss of dopaminergic neurons in the substantia nigra and subsequently has an effect on motor function and coordination. The pathology of PD is multifactorial, in which neuroinflammation and oxidative damage are the two of the main protagonists. Objectives: The present study aims to assess the potential antioxidant and anti-inflammatory effects of demethoxycurcumin (DMC), a natural derivative of curcumin, against rotenone-induced PD in rats. Materials and Methods: Rats were randomized and divided into six groups: control, rotenone (0.5 mg/kg/day, intraperitoneal in sunflower oil) treated for 7 days, rotenone and DMC (5, 10, and 20 mg/kg b.w) cotreated, and DMC (20 mg/kg b.w) alone treated groups. Results: Based on the dopamine concentration and biochemical estimations, the effective dose of DMC was selected and the chronic study was performed. At the end of the experimental period, behavioral studies and protein expression patterns of inflammatory markers were analyzed. Rotenone treatment led to motor dysfunctions, neurochemical deficits, and oxidative stress and enhanced expressions of inflammatory markers, whereas oral administration of DMC attenuated all the above. Conclusion: Even though further research is needed to prove its efficacy in clinical trial, the results of our study showed that DMC may offer a promising and new therapeutic lead for the treatment of NDDs including PD. Abbreviations used: COX-2: Cyclooxygenase-2; DA: Dopamine; DMC: Demethoxycurcumin; DMRT: Duncans multiple range test; GSH: Reduced glutathione; GPx: Glutathione peroxidase; IL-1 β: Interleukin-1 β; IL-6: Interleukin-6; iNOS: Inducible nitric oxide synthase; PD: Parkinsons disease; SN: Substantia nigra; SOD: Superoxide dismutase; TBARS: Thiobarbituric acid reactive substances; TNF-α: Tumor necrosis factor-α.