Ibuprofen or piroxicam protects nigral neurons and delays the development of l-dopa induced dyskinesia in rats with experimental Parkinsonism: Influence on angiogenesis

Hesperetin protects against rotenone-induced motor disability and neurotoxicity via the regulation of SIRT1/NLRP3 signaling

Rotenone is a pesticide that causes complex I inhibition and is widely known to induce motor disability and experimental Parkinson's disease (PD) in rodents. Evidence suggests a crucial role for sirtuin/nuclear factor-kappaB/nod-like receptor family, pyrin domain-containing 3 (SIRT1/NFκB/NLRP3) signaling and inflammation in PD and rotenone neurotoxicity. Hesperetin (C16H14O6) is a citrus flavonoid with documented anti-inflammatory activity. We investigated the value of hesperetin in delaying rotenone-induced PD in mice and the possible modulation of inflammatory burden. PD was induced in mice via rotenone injections. Groups were assigned as a vehicle, PD, or PD + hesperetin (50 or 100 mg/kg) and compared for the motor function, protein level (by ELISA), and gene expression (by real-time PCR) of the target proteins, histopathology, and immunohistochemistry for tyrosine hydroxylase enzyme. Hesperetin (50 or 100 mg/kg) alleviated the motor disability and the striatal dopamine level and decreased the expression of NLRP3 and NF-κB but increased SIRT1 expression (p < 0.05). Further, it enhanced the neural viability and significantly decreased neural degeneration in the substantia nigra, hippocampus, and cerebral cortex (p < 0.05). Taken together, we propose that hesperetin mediates its neuroprotective function via alleviating modulation of the SIRT1/NFκB/NLRP3 pathway. Therefore, hesperetin might delay the PD progression.

Neuroinflammation and Dyskinesia: A Possible Causative Relationship?

Levodopa (L-DOPA) treatment represents the gold standard therapy for Parkinson's disease (PD) patients. L-DOPA therapy shows many side effects, among them, L-DOPA-induced dyskinesias (LIDs) remain the most problematic. Several are the mechanisms underlying these processes: abnormal corticostriatal neurotransmission, pre- and post-synaptic neuronal events, changes in gene expression, and altered plasticity. In recent years, researchers have also suggested non-neuronal mechanisms as a possible cause for LIDs. We reviewed recent clinical and pre-clinical studies on neuroinflammation contribution to LIDs. Microglia and astrocytes seem to play a strategic role in LIDs phenomenon. In particular, their inflammatory response affects neuron-glia communication, synaptic activity and neuroplasticity, contributing to LIDs development. Finally, we describe possible new therapeutic interventions for dyskinesia prevention targeting glia cells.

Marula oil nanoemulsion improves motor function in experimental parkinsonism via mitigation of inflammation and oxidative stress

Introduction: Parkinson's disease (PD) is a neurologic condition exhibiting motor dysfunction that affects old people. Marula oil (M-Oil) has been used longley in cosmetics and curing skin disorders. M-Oil is particularly stable due to its high concentration of monounsaturated fatty acids and natural antioxidants. The current study formulated M-Oil in an o/w nanoemulsion (M-NE) preparations and tested its anti-inflammatory and antioxidant actions against experimental parkinsonism. Methods: Four experimental groups of male albino mice were used and assigned as vehicle, PD, PD + M-Oil and PD + M-NE. Locomotor function was evaluated using the open field test and the cylinder test. Striatal samples were used to measure inflammatory and oxidative stress markers. Results: The results indicated poor motor performance of the mice in PD control group then, improvements were recorded after treatment with crude M-Oil or M-NE. In addition, we found high expression and protein of inflammatory markers and malondialdehyde levels in PD group which were downregulated by using doses of crude M-Oil or M-NE. Hence, formulating M-Oil in form of M-NE enhanced its physical characters. Discussion: This finding was supported by enhanced biological activity of M-NE as anti-inflammatory and antioxidant agent that resulted in downregulation of the inflammatory burden and alleviation of locomotor dysfunction in experimental PD in mice.

Betanin improves motor function and alleviates experimental Parkinsonism via downregulation of TLR4/MyD88/NF-κB pathway: Molecular docking and biological investigations

Parkinson's disease (PD) is a progressive neuroinflammatory and degenerative disease. In this study, we investigated the neuroprotective action of betanin in the rotenone-induced Parkinson-like mice model. Twenty-eight adult male Swiss albino mice were divided into four groups: Vehicle, Rotenone, Rotenone + Betanin 50 mg/kg, and Rotenone + Betanin 100 mg/kg. Parkinsonism was induced by subcutaneous injection of 9 doses of rotenone (1 mg/kg/48 h) plus betanin at 50 and 100 mg/kg/48 h in rotenone + betanin groups for twenty days. Motor dysfunction was assessed after the end of the therapeutic period using the pole, rotarod, open-field, grid, and cylinder tests. Malondialdehyde, reduced glutathione (GSH), Toll-like receptor 4 (TLR4), myeloid differentiation primary response-88 (MyD88), nuclear factor kappa- B (NF-κB), neuronal degeneration in the striatum were evaluated. In addition, we assessed the immunohistochemical densities of tyrosine hydroxylase (TH) in Str and in substantia nigra compacta (SNpc). Our results showed that rotenone remarkably decreased (results of tests), increased decreased TH density with a significant increase in MDA, TLR4, MyD88, NF-κB, and a decrease in GSH (p < 0.05). Treatment with betanin significantly results of tests), increased TH density. Furthermore, betanin significantly downregulated malondialdehyde and improved GSH. Additionally, the expression of TLR4, MyD88, and NF-κB was significantly alleviated. Betanin's powerful antioxidative and anti-inflammatory properties can be related to its neuroprotective potential as well as its ability to delay or prevent neurodegeneration in PD.

Cilostazol novel neuroprotective mechanism against rotenone-induced Parkinson's disease in rats: Correlation between Nrf2 and HMGB1/TLR4/PI3K/Akt/mTOR signaling

Neuroinflammation induced by activation of the high mobility group box 1/ toll-like receptor 4 (HMGB1/TLR4) axis is one of the principal mechanisms involved in dopaminergic neuronal loss in Parkinson's disease (PD), and its activation exacerbates oxidative stress augmenting neurodegeneration.

AIMS

This study investigated the novel neuroprotective effect of cilostazol on rotenone-intoxicated rats focusing on the HMGB1/TLR4 axis, erythroid-related factor 2 (Nrf2)/hemeoxygenase-1 (HO-1), and phosphoinositide 3-kinase (PI3K)/Protein kinase B (Akt)/the mammalian target of rapamycin (mTOR) pathway. The aim is extended to correlate the Nrf2 expression with all assessed parameters as promising therapeutic targets for neuroprotection.

MAIN METHODS

Our experiment was designed as follows: vehicle group, cilostazol group, rotenone group (1.5 mg/kg, s.c), and the rotenone pretreated with cilostazol (50 mg/kg, p.o.) group. Eleven rotenone injections were injected day after day, while cilostazol was administered daily for 21 days.

KEY FINDINGS

Cilostazol significantly improved the neurobehavioral analysis, the histopathological examination, and dopamine levels. Moreover, the immunoreactivity of tyrosine hydroxylase (TH) in substantia nigra pars compacta (SNpc) enhanced. These effects were associated with enhancement of the antioxidant expression of Nrf2 and HO-1 by 1.01 and 1.08-fold, respectively, and repression of HMGB1/TLR4 pathway by 50.2 % and 39.3 %, respectively. Upregulation of the neuro-survival PI3K and Akt expression by 2.26 and 2.69-fold, respectively, and readjusting mTOR overexpression.

SIGNIFICANCE

Cilostazol exerts a novel neuroprotective strategy against rotenone-induced neurodegeneration via activation of Nrf2/HO-1, suppression of HMGB1/TLR4 axis, upregulation of PI3K/Akt besides mTOR inhibition that compels more investigations with different PD models to clarify its precise role.

Ring Expansion Strategies for the Synthesis of Medium Sized Ring and Macrocyclic Sulfonamides

Two new ring expansion strategies are reported for the synthesis of medium sized ring and macrocyclic sulfonamides. Both methods can be performed without using classical protecting groups, with the key ring expansion step initiated by nitro reduction and amine conjugate addition respectively. Each method can be used to make diversely functionalised cyclic sulfonamides in good to excellent yields, in a range of ring sizes. The ring size dependency of the synthetic reactions is in good agreement with the outcomes modelled by Density Functional Theory calculations.

Anti-inflammatory Therapy Protects Spiral Ganglion Neurons After Aminoglycoside Antibiotic-Induced Hair Cell Loss

Destruction of cochlear hair cells by aminoglycoside antibiotics leads to gradual death of the spiral ganglion neurons (SGNs) that relay auditory information to the brain, potentially limiting the efficacy of cochlear implants. Because the reasons for this cochlear neurodegeneration are unknown, there are no neuroprotective strategies for patients. To investigate this problem, we assessed transcriptomic changes in the rat spiral ganglion following aminoglycoside antibiotic (kanamycin)-induced hair cell destruction. We observed selectively increased expression of immune and inflammatory response genes and increased abundance of activated macrophages in spiral ganglia by postnatal day 32 in kanamycin-deafened rats, preceding significant SGN degeneration. Treatment with the anti-inflammatory medications dexamethasone and ibuprofen diminished long-term SGN degeneration. Ibuprofen and dexamethasone also diminished macrophage activation. Efficacy of ibuprofen treatment was augmented by co-administration of the nicotinamide adenine dinucleotide-stabilizing agent P7C3-A20. Our results support a critical role of neuroinflammation in SGN degeneration after aminoglycoside antibiotic-mediated cochlear hair cell loss, as well as a neuroprotective strategy that could improve cochlear implant efficacy.

Microglia activation in central nervous system disorders: A review of recent mechanistic investigations and development efforts

Microglia are the principal resident immune cells in the central nervous system (CNS) and play important roles in the development of CNS disorders. In recent years, there have been significant developments in our understanding of microglia, and we now have greater insight into the temporal and spatial patterns of microglia activation in a variety of CNS disorders, as well as the interactions between microglia and neurons. A variety of signaling pathways have been implicated. However, to date, all published clinical trials have failed to demonstrate efficacy over placebo. This review summarizes the results of recent important studies and attempts to provide a mechanistic view of microglia activation, inflammation, tissue repair, and CNS disorders.

Biomarker of Neuroinflammation in Parkinson's Disease

Parkinson's disease (PD) is caused by abnormal accumulation of α-synuclein in dopaminergic neurons of the substantia nigra, which subsequently causes motor symptoms. Neuroinflammation plays a vital role in the pathogenesis of neurodegeneration in PD. This neuroinflammatory neurodegeneration involves the activation of microglia, upregulation of proinflammatory factors, and gut microbiota. In this review, we summarized the recent findings on detection of PD by using inflammatory biomarkers, such as interleukin (IL)-1β, IL-2, IL-6, IL-10, tumor necrosis factor (TNF)-α; regulated upon activation, normal T cell expressed and presumably secreted (RANTES) and high-sensitivity c-reactive protein (hsCRP); and radiotracers such as [11C]PK11195 and [18F]-FEPPA, as well as by monitoring disease progression and the treatment response. Many PD-causing mutations in SNCA, LRRK2, PRKN, PINK1, and DJ-1 are also associated with neuroinflammation. Several anti-inflammatory medications, including nonsteroidal anti-inflammatory drugs (NSAID), inhibitors of TNF-α and NLR family pyrin domain containing 3 (NLRP3), agonists of nuclear factor erythroid 2-related factor 2 (NRF2), peroxisome proliferator-activated receptor gamma (PPAR-γ), and steroids, have demonstrated neuroprotective effects in in vivo or in vitro PD models. Clinical trials applying objective biomarkers are required to investigate the therapeutic potential of anti-inflammatory medications for PD.

Fluoxetine ameliorates Alzheimer's disease progression and prevents the exacerbation of cardiovascular dysfunction of socially isolated depressed rats through activation of Nrf2/HO-1 and hindering TLR4/NLRP3 inflammasome signaling pathway

Depression is a risk factor for Alzheimer's (AD) and cardiovascular diseases (CVD). Therefore, depression treatment restricts its deteriorating effects on mood, memory and CV system. Fluoxetine is the most widely used antidepressant drug, it has neuroprotective effect through its antioxidant/anti-inflammatory properties. The current study investigated for the first-time the cross link between depression, AD and CVD besides, role of fluoxetine in mitigating such disorders. Depression was induced in rats by social isolation (SI) for 12 weeks, AlCL3 (70 mg/kg/day, i.p.) was used to induce AD which was administered either in SI or normal control (NC) grouped rats starting at 8th week till the end of the experiment, fluoxetine (10 mg/kg/day, p.o) treatment also was started at 8th week. SI and AD showed a statistically significant deteriorated effect on behavioral, neurochemical and histopathological analysis which was exaggerated when two disorder combined than each alone. Fluoxetine treatment showed protective effect against SI, AD and prevents exacerbation of CVD. Fluoxetine improved animals' behavior, increased brain monoamines, BDNF besides increased antioxidant defense mechanism of SOD, TAC contents and increased protein expression of Nrf2/HO-1 with significant decrease of AChE activity, β-amyloid, Tau protein, MDA, TNF-α, IL1β contents as well as decreased protein expression of NF-kB, TLR4, NLRP3 and caspase1. It also showed cardioprotective effects as it improved lipid profile with pronounced decrease of cardiac enzymes of CK-MB, troponin and MEF2. In conclusion, fluoxetine represents as a promising drug against central and peripheral disorders through its anti-inflammatory/antioxidant effects via targeting antioxidant Nrf2/HO-1 and hindering TLR4/NLRP3 inflammasome signaling pathways.

Inhibition of Nigral Microglial Activation Reduces Age-Related Loss of Dopaminergic Neurons and Motor Deficits

Parkinson's disease (PD) is an age-related neurodegenerative disease caused by a selective loss of dopaminergic (DA) neurons in the substantia nigra (SN). Microglial activation is implicated in the pathogenesis of PD. This study aimed to characterize the role of microglial activation in aging-related nigral DA neuron loss and motor deficits in mice. We showed that, compared to 3-month-old mice, the number of DA neurons in the SN and the expression of dopamine transporter (DAT) in the striatum decreased during the period of 9 to 12 months of age. Motor deficits and microglial activation in the SN were also evident during these months. The number of DA neurons was negatively correlated with the degrees of microglial activation. The inhibition of age-related microglial activation by ibuprofen during these 3 months decreased DA neuron loss in the SN. Eliminating the microglia prevented systemic inflammation-induced DA neuron death. Forcing mice to run during these 3 months inhibited microglial activation and DA neuron loss. Blocking the brain-derived neurotrophic factor (BDNF) signaling eliminated the exercise-induced protective effects. In conclusion, nigral DA neurons were susceptible to local microglial activation. Running exercise upregulated BDNF-TrkB signaling and inhibited microglial activation during aging. Long-term exercise can be considered as a non-pharmacological strategy to ameliorate microglial activation and related neurodegeneration.

Neuroprotective effects of indole-3-carbinol on the rotenone rat model of Parkinson's disease: Impact of the SIRT1-AMPK signaling pathway

Parkinson's disease (PD) is the second most common progressive neurodegenerative disorder. Although mounting studies have been conducted, no effective therapy is available to halt its progression. Indole-3-carbinol (I3C) is a naturally occurring compound obtained by β-thioglucosidase-mediated autolysis of glucobrassicin in cruciferous vegetables. Besides its powerful antioxidant activity, I3C has shown neuroprotection against depression and chemically induced neurotoxicity via its anti-inflammatory and antiapoptotic effects. This study aimed to investigate the neuroprotective effects of I3C against rotenone (ROT)-induced PD in male albino rats. The possible protective mechanisms were also explored. PD was induced by subcutaneous administration of ROT (2 mg/kg) for 28 days. The effects of I3C (25, 50, and 100 mg/kg/day) were assessed by catalepsy test (bar test), spontaneous locomotor activity, rotarod test, weight change, tyrosine hydroxylase (TH) expression, α-synuclein (α-Syn) expression, striatal dopamine (DA) content, and histological examination. The highest dose of I3C (100 mg/kg) was the most effective to prevent ROT-mediated motor dysfunctions and amend striatal DA decrease, weight loss, neurodegeneration, TH expression reduction, and α-Syn expression increase in both the midbrain and striatum. Further mechanistic investigations revealed that the neuroprotective effects of I3C are partially attributed to its anti-inflammatory and antiapoptotic effects and the activation of the sirtuin 1/AMP-activated protein kinase pathway. Altogether, these results suggested that I3C could attenuate biochemical, molecular, and functional changes in a rat PD model with following repeated rotenone exposures.

Animal models of Parkinson's disease: a guide to selecting the optimal model for your research

Parkinson's disease (PD) is a complex, multisystem disorder characterised by α-synuclein (SNCA) pathology, degeneration of nigrostriatal dopaminergic neurons, multifactorial pathogenetic mechanisms and expression of a plethora of motor and non-motor symptoms. Animal models of PD have already been instructive in helping us unravel some of these aspects. However, much remains to be discovered, requiring continued interrogation by the research community. In contrast with the situation for many neurological disorders, PD benefits from of a wide range of available animal models (pharmacological, toxin, genetic and α-synuclein) but this makes selection of the optimal one for a given study difficult. This is especially so when a study demands a model that displays a specific combination of features. While many excellent reviews of animal models already exist, this review takes a different approach with the intention of more readily informing this decision-making process. We have considered each feature of PD in turn - aetiology, pathology, pathogenesis, motor dysfunctions and non-motor symptoms (NMS) - highlighting those animal models that replicate each. By compiling easily accessible tables and a summary figure, we aim to provide the reader with a simple, go-to resource for selecting the optimal animal model of PD to suit their research needs.

Resveratrol Alleviates Levodopa-Induced Dyskinesia in Rats

Dyskinesia is a serious complication of Parkinson’s disease during levodopa (L-DOPA) treatment. The pathophysiology of L-DOPA-induced dyskinesia (LID) is complex and not fully illuminated. At present, treatment of dyskinesia is quite limited. Recent studies demonstrated neuroinflammation plays an important role in development of LID. Thus, inhibition of neuroinflammation might open a new avenue for LID treatment. Resveratrol (RES) is the most well-known polyphenolic stilbenoid and verified to possess a large variety of biological activities. DA neurotoxicity was assessed via behavior test and DA neuronal quantification. The movement disorders of dyskinesia were detected by the abnormal involuntary movements scores analysis. Effects of RES on glial cells-elicited neuroinflammation were also explored. Data showed that RES attenuated dyskinesia induced by L-DOPA without affecting L-DOPA’s anti-parkinsonian effects. Furthermore, RES generated neuroprotection against long term treatment of L-DOPA-induced DA neuronal damage. Meanwhile, RES reduced protein expression of dyskinesia molecular markers, ΔFOS B and ERK, in the striatum. Also, there was a strong negative correlation between DA system damage and ΔFOS B level in the striatum. In addition, RES inhibited microglia and astroglia activation in substantia nigra and subsequent inflammatory responses in the striatum during L-DOPA treatment. RES alleviates dyskinesia induced by L-DOPA and these beneficial effects are closely associated with protection against DA neuronal damage and inhibition of glial cells-mediated neuroinflammatory reactions.

Expression of Transcription Factors in CD4 + T Cells as Potential Biomarkers of Motor Complications in Parkinson's Disease

Background:

Management of motor complications (MC) represents a major challenge in the long-term treatment of Parkinson’s disease (PD) patients. In this context, the role of peripheral adaptive immunity may provide new insights, since neuroinflammatory mechanisms have been proved crucial in the disease.

Objective:

The aim of this study was to analyze the transcription factors genes involved in CD4 + T cells development to uncover specific molecular signatures in patients with (PMC) and without (WMC) motor complications.

Methods:

mRNA levels of CD4 + T lymphocytes transcription factor genes TBX21, STAT1, STAT3, STAT4, STAT6, RORC, GATA3, FOXP3, and NR4A2 were measured from 40 PD patients, divided into two groups according to motor complications. Also, 40 age- and sex-matched healthy controls were enrolled.

Results:

WMC patients had higher levels of STAT1 and NR4A2 (p = 0.004; p = 0.003), whereas in PMC we found higher levels of STAT6 (p = 0.04). Also, a ROC curve analysis confirmed STAT1 and NR4A2 as feasible biomarkers to discriminate WMC (AUC = 0.76, 95%CI 0.59–0.92, p = 0.005; AUC = 0.75, 95%CI 0.58–0.90, p = 0.007). Similarly, STAT6 detected PMC patients (AUC = 0.69, 95%CI 0.52–0.86, p = 0.037).

Conclusion:

These results provide evidence of different molecular signatures in CD 4 + T cells of PD patients with and without MC, thus suggesting their potential as biomarkers of MC development.

Interferon-γ Involvement in the Neuroinflammation Associated with Parkinson's Disease and L-DOPA-Induced Dyskinesia

Interferon-γ (IFN-γ) is a proinflammatory cytokine that activates glial cells. IFN-γ is increased in the plasma and brain of Parkinson's disease patients, suggesting its potential role in the disease. We investigated whether the IFN-γ deficiency could interfere with nigrostriatal degeneration induced by the neurotoxin 6-hydroxydopamine, L-DOPA-induced dyskinesia, and the neuroinflammatory features as astrogliosis, microgliosis, and induced nitric oxide synthase (iNOS) immunoreactivity induced by L-DOPA treatment. Wild type (WT) and IFN-γ knockout (IFN-γ/KO) mice received unilateral striatal microinjections of 6-hydroxydopamine. Animals were sacrificed 1, 3, 7, and 21 days after lesions. Additional group of WT and IFN-γ/KO parkinsonian mice, after 3 weeks of neurotoxin injection, received L-DOPA (intraperitoneally, for 21 days) resulting in dyskinetic-like behavior. Tyrosine hydroxylase immunostaining indicated the starting of dopaminergic lesion since the first day past toxin administration, progressively increased until the third day when it stabilized. There was no difference in the lesion and L-DOPA-induced dyskinesia intensity between WT and IFN-γ/KO mice. Remarkably, IFN-γ/KO mice treated with L-DOPA presented in the lesioned striatum an increase of iNOS and glial fibrilary acid protein (GFAP) density, compared with the WT group. Morphological analysis revealed the rise of astrocytes and microglia reactivity in IFN-γ/KO mice exibiting dyskinesia. In conclusion, IFN-γ/KO mice presented an intensification of the inflammatory reaction accompanying L-DOPA treatment and suggest that iNOS and GFAP increase, and the activation of astrocytes and microglia induced afterward L-DOPA treatment was IFN-γ independent events. Intriguingly, IFN-γ absence did not affect the degeneration of dopaminergic neurons or LID development.

Synthesis of novel isoflavone/benzo-δ-sultam hybrids as potential anti-inflammatory drugs

A small series of novel isoflavone/benzo-δ-sultam hybrids was synthesised and evaluated as potential anti-inflammatory and neuroprotective drugs in LPS-activated BV2 microglia. The benzo-δ-sultam core was constructed in a two-step reaction by coupling 2-halobenzenesulfonamide derivatives with terminal alkynes, followed by a 6-endo-dig cyclisation. The synthesised compounds, including precursors and hybrids, were tested for their ability to inhibit NO and TNF-α production in LPS-stimulated BV2 microglial cells, and the results are promising. The most potent hybrid reduces the NO production to 41%, and the TNF-α to 34% at 20 µM final concentration in the well.

Contributive Role of TNF-α to L-DOPA-Induced Dyskinesia in a Unilateral 6-OHDA Lesion Model of Parkinson's Disease

Our present objective was to better characterize the mechanisms that regulate striatal neuroinflammation in mice developing L-DOPA-induced dyskinesia (LID). For that, we used 6-hydroxydopamine (6-OHDA)-lesioned mice rendered dyskinetic by repeated intraperitoneal injections of 3,4-dihydroxyphenyl-L-alanine (L-DOPA) and quantified ensuing neuroinflammatory changes in the dopamine-denervated dorsal striatum. LID development was associated with a prominent astrocytic response, and a more moderate microglial cell reaction restricted to this striatal area. The glial response was associated with elevations in two pro-inflammatory cytokines, tumor necrosis factor-α (TNF-α) and interleukin-1β. Treatment with the phytocannabinoid cannabidiol and the transient receptor potential vanilloid-1 (TRPV-1) channel antagonist capsazepine diminished LID intensity and decreased TNF-α levels without impacting other inflammation markers. To possibly reproduce the neuroinflammatory component of LID, we exposed astrocyte and microglial cells in culture to candidate molecules that might operate as inflammatory cues during LID development, i.e., L-DOPA, dopamine, or glutamate. Neither L-DOPA nor dopamine produced an inflammatory response in glial cell cultures. However, glutamate enhanced TNF-α secretion and GFAP expression in astrocyte cultures and promoted Iba-1 expression in microglial cultures. Of interest, the antidyskinetic treatment with cannabidiol + capsazepine reduced TNF-α release in glutamate-activated astrocytes. TNF-α, on its own, promoted the synaptic release of glutamate in cortical neuronal cultures, whereas cannabidiol + capsazepine prevented this effect. Therefore, we may assume that the release of TNF-α by glutamate-activated astrocytes may contribute to LID by exacerbating corticostriatal glutamatergic inputs excitability and maintaining astrocytes in an activated state through a self-reinforcing mechanism.

The protective effect of biochanin A against rotenone-induced neurotoxicity in mice involves enhancing of PI3K/Akt/mTOR signaling and beclin-1 production

Rotenone is an insecticide that generates oxidative stress in the CNS and induces locomotor dysfunction and neurodegeneration in rodents. Biochanin A [BioA] is an isoflavone with antioxidant and anti-inflammatory actions. The antioxidant and the modulatory action of BioA on PI3K/Akt/mTOR signaling and autophagy were tested in rotenone-Parkinsonian mice. Mice were allocated into; Group I: oil control group, Group II: rotenone group [1-mg/kg/48h, subcutaneously], group III: rotenone and BioA [10-mg/kg]. Rotenone injection resulted in locomotor disturbances in mice, degeneration in dopaminergic neurons [tyrosine hydroxylase-immunoreactive cells], low striatal dopamine, increased malondialdehyde and decreased level of glutathione. Neuroinflammation was evidenced by upregulation of astrocytes [glia fibrillary acidic protein, GFAP] and elevated levels of cytokines. The phosphorylation of PI3K/Akt/mTOR and the autophagy-related protein, beclin-1, were decreased significantly as indicated by Western blot analysis. BioA treatment enhanced locomotor activity and afforded nigral neuroprotection. The mechanism by which BioA produced this effect includes increased antioxidant defenses, lessened proinflammatory cytokines, increased phosphorylation of PI3K/Akt/mTOR proteins and upregulated beclin-1. Importantly, BioA suppressed the striatal astrocyte marker [GFAP]. Overall, the currents study highlighted that BioA activates PI3K/Akt/mTOR signaling and enhances beclin-1 leading to neuroprotection for nigral dopaminergic neurons.

Cerebral and cerebellar histological changes in the rat animal model of rotenone induced parkinsonism can be ameliorated by bone marrow derived stem cell conditioned media

Parkinson disease is the second most common neurodegenerative disease affecting elderly patients. It occurs due to the progressive degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc). We continue our work in this model focusing on other brain areas affected with this disorder; cerebral cortex and cerebellum (areas other than substantia nigra) for better understanding the motor and behavior effect of the Parkinson disease as a forward steep for its treatment and medical control. This work aims to evaluate the therapeutic effect of stem cell-conditioned medium in the Parkinsonism model. In this study, Parkinsonism model was induced in rats by daily subcutaneous injection of 0.5 mg/Kg of rotenone for 28 days. Thirty rats were divided randomly into 3 groups; control, Parkinson, and conditioned medium (CM) treated groups. Cerebral Cortex and Cerebellum were obtained for histological, immunohistochemical and biochemical studies. In the Parkinsonism group, marked histological changes were observed. These findings were nearly ameliorated in CM treated group as confirmed by the biochemical, histological, and immunohistochemical (anti-alpha synculein, anti GFAP and anti nestin) studies. It could be concluded that CM had a good therapeutic effect on Parkinsonism induced damage in both the cerebral cortex and cerebellum.

Neurodegeneration and Inflammation-An Interesting Interplay in Parkinson's Disease

Parkinson's disease (PD) is a neurodegenerative disorder, caused by, so far, unknown pathogenetic mechanisms. There is no doubt that pro-inflammatory immune-mediated mechanisms are pivotal to the pathogenicity and progression of the disease. In this review, we highlight the binary role of microglia activation in the pathophysiology of the disorder, both neuroprotective and neuromodulatory. We present how the expression of several cytokines implicated in dopaminergic neurons (DA) degeneration could be used as biomarkers for PD. Viral infections have been studied and correlated to the disease progression, usually operating as trigger factors for the inflammatory process. The gut-brain axis and the possible contribution of the peripheral bowel inflammation to neuronal death, mainly dopaminergic neurons, seems to be a main contributor of brain neuroinflammation. The role of the immune system has also been analyzed implicating a-synuclein in the activation of innate and adaptive immunity. We also discuss therapeutic approaches concerning PD and neuroinflammation, which have been studied in experimental and in vitro models and data stemming from epidemiological studies.

S-adenosylmethionine administration inhibits levodopa-induced vascular endothelial growth factor-A expression

Background: Studies have demonstrated that S-adenosylmethionine could effectively affect the clinical wearing-off phenomena of levodopa, an antiparkinsonian agent; however, the detailed mechanisms for this effect need to be further clarified.

Results: S-adenosylmethionine and levodopa had opposite effects on the protein stability of vascular endothelial growth factor-A. The analysis of tube formation and cell viability also showed the nonconforming functions of S-adenosylmethionine and levodopa on cell angiogenesis and proliferation. Meanwhile, S-adenosylmethionine could significantly abolish the increased angiogenesis and cell viability induced by levodopa. S-adenosylmethionine resulted in G1/S phase arrest, with decreased cyclin dependent kinase 4/6 and increased p16, a specific cyclin dependent kinase inhibitor. Mechanically, the different effects of levodopa and S-adenosylmethionine were dependent on the phosphorylation and activation of extracellular signal-regulated kinase. S-adenosylmethionine could be fitted into the predicted docking pocket in the crystal structure of vascular endothelial growth factor-A, enhancing its acetylation level and reducing half-life.

Conclusions: These observations suggested that methyl donor S-adenosylmethionine could act as a potential agent against vascular endothelial growth factor-A-related diseases induced by levodopa treatment.

Methods: We performed in vitro cytological analyses to assess whether S-adenosylmethionine intake could influence levodopa-induced vascular endothelial growth factor-A expression in human umbilical vein endothelial cells.

Rho kinase inhibitor fasudil reduces l-DOPA-induced dyskinesia in a rat model of Parkinson's disease

BACKGROUND AND PURPOSE

Rho kinase (ROCK) activation is involved in neuroinflammatory processes leading to progression of neurodegenerative diseases such as Parkinson's disease. Furthermore, ROCK plays a major role in angiogenesis. Neuroinflammation and angiogenesis are mechanisms involved in developing l-DOPA-induced dyskinesias (LID). However, it is not known whether ROCK plays a role in LID and whether ROCK inhibitors may be useful against LID.

EXPERIMENTAL APPROACH

In rats, we performed short- and long-term dopaminergic lesions using 6-hydroxydopamine and developed a LID model. Effects of dopaminergic lesions and LID on the RhoA/ROCK levels were studied by western blot, real-time PCR analyses and ROCK activity assays in the substantia nigra and striatum. The effects of the ROCK inhibitor fasudil on LID were particularly investigated.

KEY RESULTS

Short-term 6-hydroxydopamine lesions increased nigrostriatal RhoA/ROCK expression, apparently related to the active neuroinflammatory process. However, long-term dopaminergic denervation (completed and stabilized lesions) led to a decrease in RhoA/ROCK levels. Rats with LID showed a significant increase of RhoA and ROCK expression. The development of LID was reduced by the ROCK inhibitor fasudil (10 and 40 mg·kg^-1 ), without interfering with the therapeutic effect of l-DOPA. Interestingly, treatment of 40 mg·kg^-1 of fasudil also induced a significant reduction of dyskinesia in rats with previously established LID.

CONCLUSION AND IMPLICATIONS

The present results suggest that ROCK is involved in the pathophysiology of LID and that ROCK inhibitors such as fasudil may be a novel target for preventing or treating LID. Furthermore, previous studies have revealed neuroprotective effects of ROCK inhibitors.

Methanolic extracts of a selected Egyptian Vicia faba cultivar mitigate the oxidative/inflammatory burden and afford neuroprotection in a mouse model of Parkinson's disease

Vicia faba L. is a legume from the family Fabaceae. Ancient Egyptians consumed fava beans thousands of years ago and they are still one of the most popular foods in Egypt. The current study examined the anti-Parkinson effect of 80% methanolic extracts of seeds or sprouts of the fava 'Sakha 3 'cultivar which has been selected based on the total phenol content among three cultivars tested. In addition, the extracts were characterized by reversed-phase high-performance liquid chromatography coupled with diode array detection and quadrupole-time-of-flight-mass spectrometry (RP-HPLC-DAD-QTOF-MS). Three doses (200, 400, and 600 mg/kg) of 80% methanol extracts of seeds or sprouts of the Sakha 3 cultivar were evaluated in rotenone-Parkinsonian mice from behavioral, biochemical, and histopathological aspects. The extract of fava sprouts (600 mg/kg dose) showed the most beneficial effect. It improved motor activity, enhanced striatal dopamine level, and decreased the striatal malondialdehyde, as well as the expression of the inflammatory markers, compared with the rotenone control group and groups receiving lower therapeutic doses of the extracts or L-Dopa. In addition, these findings were supported by a histopathological investigation which indicated that mice treated with the 600-mg/kg dose of the sprout extract showed a low number of degenerated neurons. The application of RP-HPLC-DAD-QTOF-MS and mass/mass spectroscopy enabled the metabolic profiling of the sprouts and seeds of the 'Sakha 3' cultivar. It is obvious that germination increased the amounts of phenolic acids, saponins, and aromatic amino acids, together with a dramatic increase in flavonoids. In conclusion, the 80% methanolic extract of sprouts of the fava "Sakha 3" cultivar may be a promising candidate for treating Parkinsonism if appropriate safety data are available.

Retinoprotective effect of donepezil in diabetic mice involves mitigation of excitotoxicity and activation of PI3K/mTOR/BCl2 pathway

Donepezil (DNPZ) has shown neuroprotective effect in many disorders. The current study tested the putative retinoprotection provided by donepezil in mouse diabetic retinopathy. Swiss albino mice were allocated to, 1] saline control, 2] diabetic, 3&4] diabetic+DNPZ (1 or 4 mg/kg). After induction of diabetes, mice were maintained for 8 weeks then DNPZ therapy was launched for 28 days. Retinas were isolated and used for histopathology and immunohistochemistry for caspase 3 and the anti-apoptotic protein, B-cell lymphoma 2 (BCl2). Retinas were examined for glutamate, acetylcholine and oxidation markers. Western blot analysis measured inflammatory cytokines, N-methyl-d-aspartate receptors (NMDARs), phosphorylated and total phosphatidylinositol-3 kinase and mTOR, BCl2 and cleaved caspase 3. Significant histopathological changes and decreased thickness were found in diabetic retinas (125.52 ± 2.85 vs. 157.15 ± 7.55 in the saline group). In addition, retinal glutamate (2.39-fold), inflammatory cytokines and NMDARs proteins (4.9-fold) were higher in the diabetic retinas. Western blot analysis revealed low ratio of phosphorylated/total PI3K (0.21 ± 0.043 vs. 1 ± 0.005) and mTOR (0.18 ± 0.04 vs. 1 ± 0.005), low BCl2 (0.28 ± 0.06 vs. 1 ± 0.005) and upregulated cleaved caspase 3 (5.18 ± 1.27 vs. 1 ± 0.05 in the saline group) versus the saline control. DNPZ ameliorated the histopathologic manifestations and to prevent the decrease in retinal thickness. DNPZ (4 mg/kg) improved phosphorylation of PI3K (0.76 ± 0.12 vs. 0.21 ± 0.04) and mTOR (0.59 ± 0.09 vs. 0.18 ± 0.04) and increased BCl2 (0.75 ± 0.08 vs. 0.28 ± 0.06) versus the diabetic control group. This study explained the retinoprotective effect of DNPZ in mouse diabetic retinopathy and highlighted that mitigation of excitotoxicity, improving phosphorylation of PI3K/mTOR and increasing BCl2 contribute to this effect.

Neurochemical, neurobehavioral and histochemical effects of therapeutic dose of l-dopa on striatal neurons in rats: Protective effect of virgin coconut oil

Despite the fact that levodopa has proven its effectiveness in treating the symptoms of Parkinson's disease (PD), increasing concerns have emerged about its possible long-term toxic effects on dopamine (DA) neurons. The study investigated the possible ameliorative effect of virgin coconut oil against l-dopa- induced neurotoxicity in adult rats. A total number of 40 rats were divided into four groups. Briefly, the first served as control, the second was orally administered virgin coconut oil (1.42 mL/kg), the third group was administered a single daily dose of l-dopa/carbidopa (100/10 mg/kg/day, p.o) and the fourth group pre-treated with virgin coconut oil then administered a single daily dose of l-dopa/carbidopa. The different treatments were extended for 30 days. l-dopa treated group exhibited aggressive behavior and behavioral abnormalities in open field test compared to control group. In addition, l-dopa treatment caused significant increase in the levels of striatal dopamine and norepinephrine and their metabolites with concomitant decrease of serotonin and its metabolite. Moreover, l-dopa treatment increased histamine and GABA levels. In addition, l-dopa treatment induced oxidative stress and energy crisis. The histological and immunohistochemical studies showed that l-dopa caused a remarkable neurodegeneration and increased glial fibrillary acidic protein (GFAP) immunoexpression in the striatal area. Virgin coconut oil co-treatment significantly minimized the harmful effects of l-dopa. In conclusion, the present study revealed that virgin coconut oil provided a notable protection against l-dopa's untoward effects.

Rojo A, Manda G, Boscá L, Cuadrado A. Inflammation in Parkinson's Disease: Mechanisms and Therapeutic Implications

Parkinson's disease (PD) is a common neurodegenerative disorder primarily characterized by the death of dopaminergic neurons that project from the substantia nigra pars compacta. Although the molecular bases for PD development are still little defined, extensive evidence from human samples and animal models support the involvement of inflammation in onset or progression. However, the exact trigger for this response remains unclear. Here, we provide a systematic review of the cellular mediators, i.e., microglia, astroglia and endothelial cells. We also discuss the genetic and transcriptional control of inflammation in PD and the immunomodulatory role of dopamine and reactive oxygen species. Finally, we summarize the preclinical and clinical approaches targeting neuroinflammation in PD.

Metformin Protects From Rotenone-Induced Nigrostriatal Neuronal Death in Adult Mice by Activating AMPK-FOXO3 Signaling and Mitigation of Angiogenesis

Parkinson’s disease (PD) is a neurodegenerative disease that affects substantia nigra dopamine neurons. Many studies have documented the role of oxidative stress and angiogenesis in the pathogenesis of PD. Metformin (MTF) is an antidiabetic medication and AMP-activated protein kinase (AMPK) regulator that has shown antioxidant and antiangiogenic properties in many disorders. The aim of this study is to investigate the neuroprotective effect of MTF in a mouse model of rotenone-prompted PD with a highlight on its influence on the AMPK/forkhead box transcription factor O3 (FOXO3) pathway and striatal angiogenesis. In the running study, PD was induced in mice using repeated doses of rotenone and concomitantly treated with MTF 100 or 200 mg/kg/day for 18 days. Rotarod and pole tests were used to examine the animals’ motor functionality. After that, animals were sacrificed, and brains were isolated and processed for immunohistochemical investigations or biochemical analyses. Oxidant stress and angiogenic markers were measured, including reduced glutathione, malondialdehyde, the nuclear factor erythroid 2–related factor 2 (Nrf2), hemoxygenase-1, thioredoxin, AMPK, FOXO3, and vascular endothelial growth factor (VEGF). Results indicated that MTF improved animals’ motor function, improved striatal glutathione, Nrf2, hemoxygenase-1, and thioredoxin. Furthermore, MTF upregulated AMPK-FOXO3 proteins and reduced VEGF and cleaved caspase 3. MTF also increased the number of tyrosine hydroxylase (TH)–stained neurons in the substantia nigra neurons and in striatal neuronal terminals. This study is the first to highlight that the neuroprotective role of MTF is mediated through activation of AMPK-FOXO3 signaling and inhibition of the proangiogenic factor, VEGF. Further studies are warranted to confirm this mechanism in other models of PD and neurodegenerative diseases.

Nano selenium ameliorates oxidative stress and inflammatory response associated with cypermethrin-induced neurotoxicity in rats

Cypermethrin (CYP), a class II synthetic pyrethroid, is used to control household insects. CYP can cross the blood-brain barrier to exert neurotoxicity through changes in sodium ion channels. Selenium is an essential component of glutathione peroxidise enzyme; in addition, it shows a potential anti-inflammatory property. The present study aimed to investigate the neuroprotective role of Nano-Se on CYP-induced neurotoxicity. Twenty-four adult male Wister rats were randomly divided into three groups: a) control, b) CYP (1mg/kg) administered orally for 21 days, c) CYP (1mg/kg) administered orally for 21 days and Nano-Se (2.5 mg/kg) given once a day three times a week for three weeks). Locomotor activity was assessed using open field test then rats were sacrificed under anaesthesia, and their brains were dissected out and processed for biochemical and histopathological studies. Histological examination of CYP-treated rats demonstrated some degenerative changes; besides, CYP affected rat locomotor activity. CYP-treated rats showed increased levels of malondialdehyde (MDA), TNF-α and IL-1β in addition to the reduction of glutathione (GSH) levels and gamma-Aminobutyric acid (GABA). Nano-Se restored normal behavioural function and significantly attenuated CYP-evoked degenerative changes. Nano-Se increased levels of GABA and glutathione; on the other hand, it significantly prevented the rise in the levels of MDA, TNF-α and IL-1β. Therefore, Nano-Se demonstrated both anti-oxidant and anti-inflammatory potential. Nano-Se may be suggested to be a prospective candidate to ameliorate CYP-induced neurotoxicity.

Cannabidiol and Cannabinoid Compounds as Potential Strategies for Treating Parkinson's Disease and L-DOPA-Induced Dyskinesia

Parkinson's disease (PD) and L-DOPA-induced dyskinesia (LID) are motor disorders with significant impact on the patient's quality of life. Unfortunately, pharmacological treatments that improve these disorders without causing severe side effects are not yet available. Delay in initiating L-DOPA is no longer recommended as LID development is a function of disease duration rather than cumulative L-DOPA exposure. Manipulation of the endocannabinoid system could be a promising therapy to control PD and LID symptoms. In this way, phytocannabinoids and synthetic cannabinoids, such as cannabidiol (CBD), the principal non-psychotomimetic constituent of the Cannabis sativa plant, have received considerable attention in the last decade. In this review, we present clinical and preclinical evidence suggesting CBD and other cannabinoids have therapeutic effects in PD and LID. Here, we discuss CBD pharmacology, as well as its neuroprotective effects and those of other cannabinoids. Finally, we discuss the modulation of several pro- or anti-inflammatory factors as possible mechanisms responsible for the therapeutic/neuroprotective potential of Cannabis-derived/cannabinoid synthetic compounds in motor disorders.

Immunomodulatory drugs alleviate l-dopa-induced dyskinesia in a rat model of Parkinson's disease

BACKGROUND

Thalidomide and closely related analogues are used clinically for their immunomodulatory and antiangiogenic properties mediated by the inhibition of the proinflammatory cytokine tumor necrosis factor α. Neuroinflammation and angiogenesis contribute to classical neuronal mechanisms underpinning the pathophysiology of l-dopa-induced dyskinesia, a motor complication associated with l-dopa therapy in Parkinson's disease. The efficacy of thalidomide and the more potent derivative 3,6'-dithiothalidomide on dyskinesia was tested in the 6-hydroxydopamine Parkinson's disease model.

METHODS

Three weeks after 6-hydroxydopamine infusion, rats received 10 days of treatment with l-dopa plus benserazide (6 mg/kg each) and thalidomide (70 mg/kg) or 3,6'-dithiothalidomide (56 mg/kg), and dyskinesia and contralateral turning were recorded daily. Rats were euthanized 1 hour after the last l-dopa injection, and levels of tumor necrosis factor-α, interleukin-10, OX-42, vimentin, and vascular endothelial growth factor immunoreactivity were measured in their striatum and substantia nigra reticulata to evaluate neuroinflammation and angiogenesis. Striatal levels of GLUR1 were measured as a l-dopa-induced postsynaptic change that is under tumor necrosis factor-α control.

RESULTS

Thalidomide and 3,6'-dithiothalidomide significantly attenuated the severity of l-dopa-induced dyskinesia while not affecting contralateral turning. Moreover, both compounds inhibited the l-dopa-induced microgliosis and excessive tumor necrosis factor-α in the striatum and substantia nigra reticulata, while restoring physiological levels of the anti-inflammatory cytokine interleukin-10. l-Dopa-induced angiogenesis was inhibited in both basal ganglia nuclei, and l-dopa-induced GLUR1 overexpression in the dorsolateral striatum was restored to normal levels.

CONCLUSIONS

These data suggest that decreasing tumor necrosis factor-α levels may be useful to reduce the appearance of dyskinesia, and thalidomide, and more potent derivatives may provide an effective therapeutic approach to dyskinesia. © 2019 International Parkinson and Movement Disorder Society.

Immune-Based Therapies for Traumatic Brain Injury: Insights from Pre-Clinical Studies

Traumatic Brain Injury (TBI) is a major public health problem. It is the leading cause of death and disability, especially among children and young adults. The neurobiology basis underlying TBI pathophysiology remains to be fully revealed. Over the past years, emerging evidence has supported the hypothesis that TBI is an inflammatory based condition, paving the way for the development of potential therapeutic targets. There is no treatment capable to prevent or minimize TBIassociated outcomes. Therefore, the search for effective therapies is a priority goal. In this context, animal models have become valuable tools to study molecular and cellular mechanisms involved in TBI pathogenesis as well as novel treatments. Herein, we discuss therapeutic strategies to treat TBI focused on immunomodulatory and/or anti-inflammatory approaches in the pre-clinical setting.

Neuroprotective effect of levetiracetam in mouse diabetic retinopathy: Effect on glucose transporter-1 and GAP43 expression

AIMS

Retinopathy is a neurodegenerative complication associating diabetes mellitus. Diabetic retinopathy (DR) is the primary reason of visual loss during early adulthood. DR has a complicated multifactorial pathophysiology initiated by hyperglycaemia-induced ischaemic neurodegenerative retinal changes, followed by vision-threatening consequences. The main therapeutic modalities for DR involve invasive delivery of intravitreal antiangiogenic agents as well as surgical interventions. The current work aimed to explore the potential anti-inflammatory and retinal neuroprotective effects of levetiracetam.

MAIN METHODS

This study was performed on alloxan-induced diabetes in mice (n: 21). After 10 weeks, a group of diabetic animals (n: 7) was treated with levetiracetam (25 mg/kg) for six weeks. Retinal tissues were dissected and paraffin-fixed for examination using (1) morphometric analysis with haematoxylin and eosin (HE), (2) immunohistochemistry (GLUT1, GFAP and GAP43), and (3) RT-PCR-detected expression of retinal inflammatory and apoptotic mediators (TNF-α, IL6, iNOS, NF-κB and Tp53).

KEY FINDINGS

Diabetic mice developed disorganized and debilitated retinal layers with upregulation of the gliosis marker GFAP and downregulation of the neuronal plasticity marker GAP43. Additionally, diabetic retinae showed increased transcription of NF-κB, TNF-α, IL6, iNOS and Tp53. Levetiracetam-treated mice showed downregulation of retinal GLUT1 with relief and regression of retinal inflammation and improved retinal structural organization.

SIGNIFICANCE

Levetiracetam may represent a potential neuroprotective agent in DR. The data presented herein supported an anti-inflammatory role of levetiracetam. However, further clinical studies may be warranted to confirm the effectiveness and safety of levetiracetam in DR patients.

Dual-targeting for brain-specific drug delivery: synthesis and biological evaluation

Ibuprofen is one of the most potent non-steroid anti-inflammatory drugs (NSAIDs) and plays an important role in the treatment of neurodegenerative diseases. However, its poor brain penetration and serious side effects at therapeutic doses, has hindered its further application. Thus, it is of great interest to develop a carrier-mediated transporter (CMT) system that is capable of more efficiently delivering ibuprofen into the brain at smaller doses to treat neurodegenerative diseases. In this study, a dual-mediated ibuprofen prodrug modified by glucose (Glu) and vitamin C (Vc) for central nervous system (CNS) drug delivery was designed and synthesized in order to effectively deliver ibuprofen to brain. Ibuprofen could be released from the prepared prodrugs when incubated with various buffers, mice plasma and brain homogenate. Also, the prodrug showed superior neuroprotective effect in vitro and in vivo than ibuprofen. Our results suggest that chemical modification of therapeutics with warheads of glucose and Vc represents a promising and efficient strategy for the development of brain-targeting prodrugs by utilizing the endogenous transportation mechanism of the warheads.

Caffeic acid improves locomotor activity and lessens inflammatory burden in a mouse model of rotenone-induced nigral neurodegeneration: Relevance to Parkinson's disease therapy

BACKGROUND

Caffeic acid phenethyl ester is found in honey bee propolis. It has immunomodulatory, anti-inflammatory and anti-cancer properties. Rotenone is a pesticide commonly used for inducing experimental Parkinson's disease (PD) due to complex I inhibition and microglia activating properties. The current study examined neuroprotective effect of caffeic acid against rotenone-induced neurodegeneration in groups of seven mice.

METHODS

Mice received protective doses of caffeic acid (2.5, 5 or 10 mg/kg) daily and nine injections of rotenone (1 mg kg, subcutaneously) - every 48 h. Behavioral evaluation of motor function was done by a battery of tests including open-field test, cylinder test, pole test and rotarod test; all these tests showed motor impairment.

RESULTS

Assay of striatal dopamine highlighted a significant decrease and increases in inflammatory markers. In addition, histopathological assessment of substantia nigra neurons demonstrated low immunostaining for tyrosine hydroxylase (TH) in rotenone treated mice. PCR analysis highlighted upregulation for genes encoding CD₁₁b (a microglia surface antigen), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS) and nuclear factor-κB (NFκB). Treatment with caffeic acid (5 or 10 mg/kg) amended most of rotenone-induced motor deficits, lessened microglia expression and inflammatory mediators and improved the nigral TH immunostaining.

CONCLUSION

These results confirmed the anti-inflammatory activity of caffeic acid and highlighted its neuroprotective activity against rotenone-induced neurodegeneration in mice.

VEGF Signaling in Neurological Disorders

Vascular endothelial growth factor (VEGF) is a potent growth factor playing diverse roles in vasculogenesis and angiogenesis. In the brain, VEGF mediates angiogenesis, neural migration and neuroprotection. As a permeability factor, excessive VEGF disrupts intracellular barriers, increases leakage of the choroid plexus endothelia, evokes edema, and activates the inflammatory pathway. Recently, we discovered that a heparin binding epidermal growth factor like growth factor (HB-EGF)—a class of EGF receptor (EGFR) family ligands—contributes to the development of hydrocephalus with subarachnoid hemorrhage through activation of VEGF signaling. The objective of this review is to entail a recent update on causes of death due to neurological disorders involving cerebrovascular and age-related neurological conditions and to understand the mechanism by which angiogenesis-dependent pathological events can be treated with VEGF antagonisms. The Global Burden of Disease study indicates that cancer and cardiovascular disease including ischemic and hemorrhagic stroke are two leading causes of death worldwide. The literature suggests that VEGF signaling in ischemic brains highlights the importance of concentration, timing, and alternate route of modulating VEGF signaling pathway. Molecular targets distinguishing two distinct pathways of VEGF signaling may provide novel therapies for the treatment of neurological disorders and for maintaining lower mortality due to these conditions.

Simultaneous electrochemical determination of levodopa and piroxicam using a glassy carbon electrode modified with a ZnO–Pd/CNT nanocomposite

A highly conductive electrochemical sensor was constructed for the simultaneous electrochemical determination of levodopa and piroxicam by modification of a glassy carbon electrode with a ZnO–Pd/CNT nanocomposite (GCE/ZnO–Pd/CNTs). The ZnO–Pd/CNT nanocomposite was synthesized by the sol–gel procedure and was characterized by EDAX, MAP and SEM. The sensor was shown to improve the oxidation signal of levodopa and piroxicam by ∼70.2-fold and ∼41.5-fold, respectively. This marks the first time that the electrochemical behavior of levodopa and piroxicam have been investigated at the surface of GCE/ZnO–Pd/CNTs. The voltammogram showed a quasi-reversible signal and an irreversible redox signal for electro-oxidation of levodopa and piroxicam, respectively. The GCE/ZnO–Pd/CNTs showed a linear dynamic range of 0.6 to 100.0 μM (at a potential of ∼180 mV) and 0.1 to 90 μM (at a potential of ∼480 mV) with detection limits of 0.08 and 0.04 μM for the determination of levodopa and piroxicam, respectively. GCE/ZnO–Pd/CNTs were then applied for the determination of levodopa and piroxicam in real samples.

A highly conductive electrochemical sensor was constructed for the simultaneous electrochemical determination of levodopa and piroxicam by modification of a glassy carbon electrode with a ZnO–Pd/CNT nanocomposite (GCE/ZnO–Pd/CNTs).

Neuroprotective effect of arctigenin against neuroinflammation and oxidative stress induced by rotenone

Background: the present study was to investigate the neuroprotective effect of arctigenin, the major active component of a traditional Chinese medicine “Arctii Fructus”, against PD in a rat model induced by rotenone. Materials and methods: in the present study, rotenone was injected subcutaneously in the backs of rats to mimic the progressive neurodegenerative nature of PD and arctigenin was administered. Behavioral analyses including a grid test, bar test and open-field test were used to evaluate motor activities and behavioral movement abilities. Energy metabolism indexes including oxygen consumption, carbon dioxide production, heat production and energy expenditure were measured via a TSE phenoMaster/LabMaster animal monitoring system. Immunohistochemistry was performed to detect the staining of TH and the expression of α-synuclein in substantia nigra (SN). The effect of arctigenin on oxidative stress was evaluated by the levels of GSH and MDA, and activities of SOD and GSH-Px. The levels of pro-inflammatory cytokines such as IL-6, IL-1β, TNF-α, IFN-γ and PGE2, the expression of Iba-1 and GFAP, and the impression of inflammatory mediators such as COX-2 and NF-κB in the SN were measured to evaluate the effect on the inflammation of SN area induced by rotenone. Results: compared with the ROT group, the deadlock time of rats treated with arctigenin was significantly shortened and the score of locomotor activity increased in the behavioral test; the number of TH⁺ positive DA neurons of the arctigenin treated group was increased and α-synuclein immunopositive was decreased; the level of GSH and activities of SOD and GSH-Px in the arctigenin-treated group were significantly increased; arctigenin administration induced a significant decrease in the MDA level; arctigenin also significantly decreased the levels of IL-6, IL-1β, TNF-α, IFN-γ and PGE2 and reduced the impression of COX-2 and NF-κB in SN; treatment with arctigenin decreased microglia and astrocyte activation evidenced by the reduced expression of Iba-1 and GFAP. Conclusion: the findings demonstrated that arctigenin can improve the behavior changes of PD rats and the damage of DA neurons. The oxidative stress and inflammation involved in the pathogenesis of PD and arctigenin may protect DA neurons through its potent antioxidant and anti-inflammatory activities.

The present study was to investigate the neuroprotective effect of arctigenin, the major active component of a traditional Chinese medicine “Arctii Fructus”, against PD in a rat model induced by rotenone.

Increased putamen hypercapnic vasoreactivity in levodopa-induced dyskinesia

In a rodent model of Parkinson's disease (PD), levodopa-induced involuntary movements have been linked to striatal angiogenesis - a process that is difficult to document in living human subjects. Angiogenesis can be accompanied by localized increases in cerebral blood flow (CBF) responses to hypercapnia. We therefore explored the possibility that, in the absence of levodopa, local hypercapnic CBF responses are abnormally increased in PD patients with levodopa-induced dyskinesias (LID) but not in their nondyskinetic (NLID) counterparts. We used H215O PET to scan 24 unmedicated PD subjects (12 LID and 12 NLID) and 12 matched healthy subjects in the rest state under normocapnic and hypercapnic conditions. Hypercapnic CBF responses were compared to corresponding levodopa responses from the same subjects. Group differences in hypercapnic vasoreactivity were significant only in the posterior putamen, with greater CBF responses in LID subjects compared with the other subjects. Hypercapnic and levodopa-mediated CBF responses measured in this region exhibited distinct associations with disease severity: the former correlated with off-state motor disability ratings but not symptom duration, whereas the latter correlated with symptom duration but not motor disability. These are the first in vivo human findings linking LID to microvascular changes in the basal ganglia.

Anticonvulsant and Neuroprotective Activities of Phragmanthera austroarabica Extract in Pentylenetetrazole-Kindled Mice

Anticonvulsant and neuroprotective activity of Phragmanthera austroarabica extract were tested in pentylenetetrazole-kindled mice. All the chemical constituents of the plant extract were identified. Additionally, the extract was standardized and proved to contain total phenolic contents equal to 379.92 ± 1.32 mg gallic acid equivalents/g dry plant extract. Induction of kindling was achieved by repeated intraperitoneal administration of pentylenetetrazole (35 mg/kg) twice weekly. Male albino mice were given P. austroarabica extract (200, 400, or 800 mg/kg). The two higher doses (400 or 800 mg/kg) of the extract significantly caused notable reduction in seizure activity and hippocampal malondialdehyde level compared to pentylenetetrazole control group. The highest dose enhanced cortical GSH level and showed intact DNA in the laddering assay. Upon studying the neuroprotective effect, mice treated with the higher dose of the extract demonstrated an improvement in the percent of surviving neurons in the cortex and hippocampus. We concluded that P. austroarabica extract ameliorated seizure activity and protected cortical and hippocampal neurons against pentylenetetrazole-induced kindling in mice.

Anti-inflammatory and neuroprotective activity of boswellic acids in rotenone parkinsonian rats

There is evidence that inflammation and oxidative stress contribute to the neurodegenerative changes observed in Parkinson's disease. Unfortunately, there is a lack of curative treatment for this debilitating movement disorder. Boswellic acids (BAs) are pentacyclic triterpene molecules of plant origin that have been utilized for treating many inflammatory conditions. The current study was conducted to explore the protective role of BAs against rotenone-induced experimental parkinsonism. Twenty-four rats were assigned to one of four treatment groups. The first two groups were a vehicle group (no rotenone) and a rotenone control group in which rats received rotenone (1 mg/kg) every 48 h. The next 2 groups received rotenone (1 mg/kg every 48 h) plus protective oral doses of BAs (125 or 250 mg/kg daily). Rats in the rotenone group showed motor dysfunction when tested in the open-field arena and cylinder and rotarod tests. Moreover, inflammatory markers increased, whereas the dopamine level was lower in the striata of rats in the rotenone group versus those in the vehicle group. BAs taken by rats with rotenone-induced parkinsonism showed enhanced general motor performance, reduced inflammatory markers, and increased striatal dopamine level and nigral tyrosine hydroxylase immunostaining. In conclusion, BAs are promising agents in slowing the progression of Parkinson's disease if appropriate data become available about their safety and efficacy in humans.