Rat Model Of Parkinson's Disease Research Articles

Paracentrotus lividus sea urchin gonadal extract mitigates neurotoxicity and inflammatory signaling in a rat model of Parkinson's disease.

The present study investigates the neuroprotective effects of the sea urchin Paracentrotus lividus gonadal extract on rotenone-induced neurotoxicity in a Parkinson's disease (PD) rat model. Parkinson's disease, characterized by the progressive loss of dopaminergic neurons in the substantia nigra (SN), is exacerbated by oxidative stress and neuroinflammation. The study involved fifty Wistar rats divided into five groups: control, dimethyl sulfoxide (DMSO) control, Paracentrotus lividus gonadal extract-treated, rotenone-treated, and combined rotenone with Paracentrotus lividus gonadal extract-treated. Behavioral assessments included the rotarod and open field tests, while biochemical analyses measured oxidative stress markers (malondialdehyde (MDA), nitric oxide (NO), glutathione (GSH)), antioxidants (superoxide dismutase (SOD), catalase (CAT)), pro-inflammatory cytokines (interleukin-1 beta (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α)), and neurotransmitters (dopamine (DA), levodopa (L-Dopa)). Histological and immunohistochemical analyses evaluated the neuronal integrity and tyrosine hydroxylase (TH) and alpha-synuclein expression. The results showed that Paracentrotus lividus gonadal extract significantly mitigated rotenone-induced motor deficits and improved locomotor activity. Biochemically, the extract reduced oxidative stress and inflammation markers while enhancing antioxidant levels. Histologically, it restored neuronal integrity and reduced alpha-synuclein accumulation. Molecularly, it increased tyrosine hydroxylase and dopa decarboxylase gene expression, essential for dopamine synthesis. These findings suggest that Paracentrotus lividus gonadal extract exerts neuroprotective effects by modulating oxidative stress, neuroinflammation, and dopaminergic neuron integrity, highlighting its potential as a therapeutic agent for Parkinson's disease.

Potential Effects of Clitoria ternatea on Rotenone-Induced Rat Model of Parkinson Disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterised by motor dysfunction due to the loss of dopaminergic neurons in the substantia nigra. Clitoria ternatea (CT), a medicinal plant used in Ayurvedic medicine, has shown promising neuroprotective properties that may be beneficial in the context of PD. This study investigates the potential effects of CT on a rotenone-induced rat model of Parkinson's disease. Sixty adult male Sprague Dawley rats were divided into six groups: the normal control group, the positive control group treated with Levodopa, the negative control group, and three experimental groups treated with CT extract at doses of 150 mg/kg, 250 mg/kg, and 500 mg/kg, respectively, for 28 days. Behavioural analyses, including motor and cognitive assessments, and histological examinations were performed. The group treated with the highest dose (500 mg/kg) showed the most significant reduction in immobility time from day 1 to day 28. Anxiety-like behaviour was assessed using the open field test, and motor impairment was evaluated with the beam walking test. The highest dose group showed a significant increase in total distance travelled, from 72.3% to 95.4% over the treatment period, compared to the control groups. Histological analysis revealed that the 500 mg/kg treatment group had the most substantial reduction in Lewy bodies. Overall, the administration of CT extract at 500 mg/kg improved motor deficits, neurobehavioral performance, and reduced neurodegeneration. These findings suggest that CT could be a promising natural therapeutic agent for the treatment and management of PD.

Corticostriatal glutamate-mediated dynamic therapeutic efficacy of electroacupuncture in a parkinsonian rat model.

Motor impairments are the defining cardinal features of Parkinson's disease (PD), resulting from malfunction of the cortico-basal ganglia circuit. Clinical data have demonstrated that electroacupuncture (EA) stimulation may benefit motor symptoms in PD without adverse effects. However, the specific effects of EA on PD and the underlying mechanisms remain largely unclear. This study investigated the effects of EA stimulation during and after 100Hz application in a rat model of PD created by unilateral injection of 6-hydroxydopamine (6-OHDA). To establish optimal treatment parameters of EA, motor behaviours were dynamically assessed using open field and rotarod tests. Additionally, we evaluated corticostriatal spine plasticity using immunoelectron microscopy and measured the levels of dopaminergic and glutamatergic neurotransmitters through microdialysis, in vivo electrochemistry and high-performance liquid chromatography. Neural activity dynamics were recorded by measuring local field potentials in both the motor cortex and thestriatum. Furthermore, chemogenetic techniques were employed to manipulate corticostriatal glutamatergic neurons and clarify the mechanisms that contribute to the therapeutic benefits of EA in the PD rat model. Chronic EA stimulation resulted in a gradual and long-lasting alleviation of motor symptoms, independent of nigrostriatal dopamine (DA) restoration. Notably, EA stimulation modulated corticostriatal spine plasticity and reduced excessive glutamate transmission in PD model rats. Moreover, EA effectively inhibited aberrant corticostriatal synchronised high-beta (25-40Hz) oscillations, which serves as a pathological biomarker of PD. Conversely, chronic chemogenetic activation of corticostriatal glutamatergic neurons hindered these positive outcomes of EA treatment in PD model rats. This study sheds light on the temporal dynamics and optimal parameters of EA treatment in PD. It emphasises the significance of inhibiting corticostriatal glutamate transmission in EA's therapeutic benefits for PD. Targeting glutamatergic neurons with EA holds promise as a non-dopaminergic intervention for managing motor symptoms and abnormal neural activity with PD. EA commonly protects dopaminergic neuronsby reducing neuroinflammation, oxidative stress, and apoptosis. New findings reveal that EA alleviates motor symptoms in a parkinsonian rat model without restoring striatal dopamine levels. EA effectively suppresses excessiveglutamate transmission and high-beta synchronization, contributing to motorsymptom relief. Activation of corticostriatalglutamatergic projections may hinder the efficacy of EA.

Cannabinoid regulation of angiotensin II-induced calcium signaling in striatal neurons

Calcium ion (Ca2+) homeostasis is crucial for neuron function and neurotransmission. This study focused on the actions mediated by the CB1 receptor (CB1R), the most abundant G protein-coupled receptor (GPCR) in central nervous system (CNS) neurons, over by the AT1R, which is one of the few G protein-coupled CNS receptors able to regulate cytoplasmic Ca2+ levels. A functional interaction suggesting a direct association between these receptors was detected. AT1-CB1 receptor heteromers (AT1CB1Hets) were identified in HEK-293T cells by bioluminescence resonance energy transfer (BRET2). Functional interactions within the AT1-CB1 complex and their potential relevance in Parkinson’s disease (PD) were assessed. In situ proximity ligation assays (PLA) identified AT1CB1Hets in neurons, in which an important finding was that Ca2+ level increase upon AT1R activation was reduced in the presence of cannabinoids acting on CB1Rs. AT1CB1Het expression was quantified in samples from the 6-hydroxydopamine (6-OHDA) hemilesioned rat model of PD in which a lower expression of AT1CB1Hets was observed in striatal neurons from lesioned animals (versus non-lesioned). AT1CB1Het expression changed depending on both the lesion and the consequences of levodopa administration, i.e., dyskinesias versus lack of involuntary movements. A partial recovery in AT1CB1Het expression was detected in lesioned animals that developed levodopa-induced dyskinesias. These findings support the existence of a compensatory mechanism mediated by AT1CB1Hets that modulates susceptibility to levodopa-induced dyskinesias in PD. Therefore, cannabinoids may be useful in reducing calcium dyshomeostasis in dyskinesia.

Systemic inflammation accelerates neurodegeneration in a rat model of Parkinson's disease overexpressing human alpha synuclein.

Increasing efforts have been made to elucidate how genetic and environmental factors interact in Parkinson's disease (PD). In the present study, we assessed the development of symptoms on a genetic PD rat model that overexpresses human α-synuclein (Snca+/+) at a presymptomatic age, exposed to a pro-inflammatory insult by intraperitoneal injection of lipopolysaccharide (LPS), using immunohistology, high-dimensional flow cytometry, constant potential amperometry, and behavioral analyses. A single injection of LPS into WT and Snca+/+ rats triggered long-lasting increase in the activation of pro-inflammatory microglial markers, monocytes, and T lymphocytes. However, only LPS Snca+/+ rats showed dopaminergic neuronal loss in the substantia nigra pars compacta (SNpc), associated with a reduction in the release of evoked dopamine in the striatum. No significant changes were observed in the behavioral domain. We propose our double-hit animal as a reliable model to investigate the mechanisms whereby α-synuclein and inflammation interact to promote neurodegeneration in PD.

Neuroprotective Role of Transchalcone in Parkinson's Disease through AMP-activated Protein Kinase-mediated Signaling Pathway.

Parkinson's disease (PD) is a gradually worsening neurodegenerative condition marked by the deterioration of dopaminergic neurons, motor dysfunction, and mitochondrial dysfunction. Trans-chalcone, a natural flavonoid, has shown promise in various disease models because of its antioxidant and anti-inflammatory features. This study investigates the neuroprotective effects of transchalcone in a rat model of PD, focusing on its impact on the activation levels of AMP-activated protein kinase (AMPK) signaling pathway, sirtuin1 (SIRT1) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) proteins, and mitochondrial-inflammatory responses. Male Sprague Dawley rats were allocated into five groups Control, Control plus transchalcone, PD, PD plus transchalcone, PD plus compound-C, and PD plus Compound-C and trans-chalcone. PD was induced using intranigral 6-hydroxydopamine injection. Trans-chalcone (100 μg/kg) and compound-C (20 mg/kg) were intraperitoneally administered daily for 4 weeks in PD rats. Motor function was assessed using rota-rod and grid tests. Striatal dopamine and cytokines (interleukin 1-beta [IL-1 β], IL-10) and p65-nuclear factor kappa-B (NF-κB) levels were measured with enzyme-linked immunosorbent assay. Mitochondrial function was evaluated by fluorometric techniques. The expression of phosphorylated AMPK, PGC-1α, and SIRT1 was analyzed by Western blotting. Trans-chalcone treatment significantly improved motor function, evidenced by increased latency to fall in the rota-rod test and recovered traversal time in the grid test. It also restored dopamine levels, enhanced mitochondrial function (reduced reactive oxygen species levels, increased membrane potential, and adenosine triphosphate production), normalized cytokines (IL-1 β, IL-10) and p65-NF-κB, and upregulated the proteins expression in rats with PD. Inhibition of AMPK activity with compound-C suppressed the neuroprotective impacts of trans-chalcone, highlighting the contribution of AMPK signaling pathway in its mechanism of action. Neuroprotective and mitoprotective impacts of trans-chalcone were mostly mediated through the activation of AMPK-SIRT1-PGC1α pathway. These results indicate that trans-chalcone could be a promising therapeutic agent for PD, warranting further investigation to assess its efficacy and safety in human patients.

Intranasal AdipoRon Mitigated Anxiety and Depression-Like Behaviors in 6-OHDA-Induced Parkinson 's Disease Rat Model: Going Beyond Motor Symptoms.

Depression and anxiety are prevalent neuropsychiatric conditions among patients with Parkinson's disease (PD), which may manifest prior to motor symptoms. As levodopa, a prominent treatment for PD motor symptoms, provides few benefits for mood-related abnormalities, tackling non-motor symptoms is particularly important. AdipoRon (Ad), an adiponectin agonist, has demonstrated neuroprotective effects by suppressing neuroinflammatory responses and activating the AMPK/Sirt-1 signaling pathway. This study looked at the potential advantages and underlying mechanisms of intranasal Ad in a rat model of PD induced by 6-hydroxydopamine (6-OHDA). We found that Ad at doses of 1 and 10µg for 21 days exhibited anxiolytic- and antidepressant effects in the open field (OF) test, elevated plus maze (EPM), sucrose splash test, and forced swimming test in a PD model caused by a unilateral 6-OHDA injection into the medial forebrain bundle (MFB). The Ad also lowered the levels of corticosterone in the blood, decreased inflammasome components (NLRP3, caspase 1, and IL-1β), and increased Sirt-1 protein levels in the prefrontal cortex (PFC) of PD rats. We conclude that Ad ameliorates anxious and depressive-like behaviors in the PD rat model through stimulating the AMPK/Sirt-1 signaling and blocking the NLRP3 inflammasome pathways in the PFC.

Deep brain stimulation halts Parkinson’s disease-related immune dysregulation in the brain and peripheral blood

Immune dysregulation in the brain and periphery is thought to contribute to the detrimental neurodegeneration that occurs in Parkinson’s disease (PD). Identifying mechanisms to reverse this dysregulation is key to developing disease-altering therapeutics for this currently incurable disease. Here we utilized the longitudinal data from the Parkinson’s Progression Marker Initiative to demonstrate that circulating lymphocytes progressively decline in PD and can be used to predict future motor symptom progression. Deep brain stimulation (DBS), which is used as a symptomatic treatment, could halt this progressive decline. By analyzing specific immune populations from a second cohort of patients, we could show that DBS causes a shift from the pro-inflammatory CD4+ T helper 17 cells driving neurodegeneration to anti-inflammatory CD4+ regulatory T cells. RNA-sequencing and immunohistochemistry in the brain of the A53T alpha-synuclein rat model of PD revealed that DBS also decreases neuroinflammation. These data suggest a potential disease-altering role for DBS by halting inflammatory processes.

Brain-Region-Specific Differences in Protein Citrullination/Deimination in a Pre-Motor Parkinson's Disease Rat Model.

The detection of early molecular mechanisms and potential biomarkers in Parkinson's disease (PD) remains a challenge. Recent research has pointed to novel roles for post-translational citrullination/deimination caused by peptidylarginine deiminases (PADs), a family of calcium-activated enzymes, in the early stages of the disease. The current study assessed brain-region-specific citrullinated protein targets and their associated protein-protein interaction networks alongside PAD isozymes in the 6-hydroxydopamine (6-OHDA) induced rat model of pre-motor PD. Six brain regions (cortex, hippocampus, striatum, midbrain, cerebellum and olfactory bulb) were compared between controls/shams and the pre-motor PD model. For all brain regions, there was a significant difference in citrullinated protein IDs between the PD model and the controls. Citrullinated protein hits were most abundant in cortex and hippocampus, followed by cerebellum, midbrain, olfactory bulb and striatum. Citrullinome-associated pathway enrichment analysis showed correspondingly considerable differences between the six brain regions; some were overlapping for controls and PD, some were identified for the PD model only, and some were identified in control brains only. The KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways identified in PD brains only were associated with neurological, metabolic, immune and hormonal functions and included the following: "Axon guidance"; "Spinocerebellar ataxia"; "Hippo signalling pathway"; "NOD-like receptor signalling pathway"; "Phosphatidylinositol signalling system"; "Rap1 signalling pathway"; "Platelet activation"; "Yersinia infection"; "Fc gamma R-mediated phagocytosis"; "Human cytomegalovirus infection"; "Inositol phosphate metabolism"; "Thyroid hormone signalling pathway"; "Progesterone-mediated oocyte maturation"; "Oocyte meiosis"; and "Choline metabolism in cancer". Some brain-region-specific differences were furthermore observed for the five PAD isozymes (PADs 1, 2, 3, 4 and 6), with most changes in PAD 2, 3 and 4 when comparing control and PD brain regions. Our findings indicate that PAD-mediated protein citrullination plays roles in metabolic, immune, cell signalling and neurodegenerative disease-related pathways across brain regions in early pre-motor stages of PD, highlighting PADs as targets for future therapeutic avenues.

Positron emission tomography neuroimaging of [18F]fluorodeoxyglucose uptake and related behavior in the Pink1-/- rat model of Parkinson disease.

Parkinson disease (PD) is a neurodegenerative condition affecting multiple sensorimotor and cognitive systems. The Pink1-/- rat model exhibits vocal, cognitive, and limb use deficits seen in idiopathic PD. We sought to measure glucose metabolism in brain regions in Pink1-/- and wild type (WT) rats, and to associate these to measures of ultrasonic vocalization, cognition, and limb use behavior. Pink1-/- (n = 12) and WT (n = 14) rats were imaged by [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) in a repeated measures design at approximately 10 months of age and 6 weeks later. Relative regional glucose metabolism was indexed by whole brain normalized FDG uptake, which was calculated for 18 regions identified a priori for comparison. Behavioral measures included tests of communication via ultrasonic vocalization, cognition with 5-Choice Serial Reaction Time Test (5-CSRTT), and limb use with Cylinder Test and Challenge Beam. Relative glucose metabolism was significantly different in Pink1-/- rats in prelimbic area, striatum, nucleus ambiguus, globus pallidus, and posterior parietal association cortex compared to WT controls. For behavioral measures, Pink1-/- rats demonstrated quieter vocalizations with a restricted frequency range, and they showed increased number of foot-faults and hindlimb steps (shuffling) in limb motor tests. Significant behavior vs. brain correlations included associations of ultrasonic vocalization parameters with glucose metabolism indices in locus coeruleus and substantia nigra. FDG PET reveals abnormalities in relative regional brain glucose metabolism in Pink1-/- rats in brain regions that are important to cognition, vocalization, and limb motor control that are also impacted by Parkinson disease. This method may be useful for mechanistic studies of behavioral deficits and therapeutic interventions in translational studies in the Pink1-/- PD model.

Effects of dopaminergic neuron degeneration on osteocyte apoptosis and osteogenic markers in 6-OHDA male rat model of Parkinson's disease

Parkinson's disease (PD) and osteoporosis are prevalent chronic conditions that impact a significant proportion of the aging population. Observational and longitudinal studies consistently demonstrate that individuals with PD face an elevated risk of osteoporosis and reduced bone mineral density compared to control groups. However, there is currently no experimental evidence demonstrating the impact of dopaminergic neuron degeneration on bone metabolism. In the present study, we used a male rat model of PD induced by unilateral injection of 6-hydroxydopamine (6-OHDA) in the left medial forebrain bundle (MFB) to evaluate the effect of dopaminergic neuron lesion on certain parameters of bone metabolism. To confirm the dopaminergic neuron lesion, cylinder and Rotarod tests were applied to rats injected with 6-OHDA or vehicle. Osteocyte density and viability were determined through histology and TUNEL assay. Western Blot and immunohistochemistry analysis were performed to investigate whether dopaminergic degeneration influences the expression of some apoptotic markers (Caspase 3 and Cytochrome C) and some osteogenic markers (ALP, OCN, and RUNX2). Our findings show that the dopaminergic lesion resulting from the injection of 6-OHDA was successfully confirmed through behavioral tests. Furthermore, the degeneration of dopaminergic neurons induced by 6-OHDA leads to apoptosis of osteocytes associated with a significant reduction in the tissue expression of the studied osteogenic markers. Thus, our study provides evidence that 6-OHDA-induced degeneration of dopaminergic neurons leads to osteocyte apoptosis, which may contribute to the development of some signs of osteoporosis.

LRRK2 regulates production of reactive oxygen species in cell and animal models of Parkinson's disease.

Oxidative stress has long been implicated in Parkinson's disease (PD) pathogenesis, although the sources and regulation of reactive oxygen species (ROS) production are poorly defined. Pathogenic mutations in the gene encoding leucine-rich repeat kinase 2 (LRRK2) are associated with increased kinase activity and a greater risk of PD. The substrates and downstream consequences of elevated LRRK2 kinase activity are still being elucidated, but overexpression of mutant LRRK2 has been associated with oxidative stress, and antioxidants reportedly mitigate LRRK2 toxicity. Here, using CRISPR-Cas9 gene-edited HEK293 cells, RAW264.7 macrophages, rat primary ventral midbrain cultures, and PD patient-derived lymphoblastoid cells, we found that elevated LRRK2 kinase activity was associated with increased ROS production and lipid peroxidation and that this was blocked by inhibitors of either LRRK2 kinase or NADPH oxidase 2 (NOX2). Oxidative stress induced by the pesticide rotenone was ameliorated by LRRK2 kinase inhibition and was absent in cells devoid of LRRK2. In a rat model of PD induced by rotenone, a LRRK2 kinase inhibitor prevented the lipid peroxidation and NOX2 activation normally seen in nigral dopaminergic neurons in this model. Mechanistically, LRRK2 kinase activity was shown to regulate phosphorylation of serine-345 in the p47phox subunit of NOX2. This, in turn, led to translocation of p47phox from the cytosol to the membrane-associated gp91phox (NOX2) subunit, activation of the NOX2 enzyme complex, and production of ROS. Thus, LRRK2 kinase activity may drive cellular ROS production in PD through the regulation of NOX2 activity.

Insulin-Like Growth Factor Binding Protein 2 Drives Neurodegeneration in Parkinson's Disease: Insights From InVivo and InVitro Studies.

Insulin-like growth factor binding protein 2 (IGFBP2) is implicated in various neurodegenerative diseases. However, its role in Parkinson's disease (PD) is unclear. PD rat model was established by 6-OHDA injection. After 3 weeks, mRNA-seq was conducted. Rats received rIGFBP2 via intra-MFB injection 6 h prior to 6-OHDA infusion, and the effect of IGFBP2 in PD rats was investigated by western blotting, IHC, specific kits, JC-1 staining, and TUNEL analysis. Invitro, PC12 cells were treated with 6-OHDA, and CCK-8, specific kits, Hoechst 33258 staining, Western blotting, and JC-1 staining were performed to assess the IGFBP2's role. mRNA-seq revealed DEGs in PD, with attention to downregulated IGFBP2. rIGFBP2 treatment aggravated neurobehavioral deficits, decreased TH expression, Ψm, ATP level and SOD, GSH-Px activities but increased α-synuclein, ROS, MDA, mitochondrial cytochrome c contents, cell apoptosis in 6-OHDA-lesioned rats, which might be mediated through inactivating IGF-1R/AKT pathway. In 6-OHDA-treated PC12 cells, rIGFBP2 aggravated cell injury, demonstrated by decreased cell viability and increased apoptosis, oxidative stress, and mitochondrial dysfunction. Co-treatment with rIGFBP2 and rIGF-1 partially reversed the effect of rIGFBP2 on cell damage. IGFBP2 exacerbates neurodegeneration in PD through increasing oxidative stress, mitochondrial dysfunction, and apoptosis via inhibiting IGF-1R/AKT pathway.

A Single-Cell Atlas of the Substantia Nigra Reveals Therapeutic Effects of Icaritin in a Rat Model of Parkinson's Disease.

Degeneration and death of dopaminergic neurons in the substantia nigra of the midbrain are the main pathological changes in Parkinson's disease (PD); however, the mechanism underlying the selective vulnerability of specific neuronal populations in PD remains unclear. Here, we used single-cell RNA sequencing to identify seven cell clusters, including oligodendrocytes, neurons, astrocytes, oligodendrocyte progenitor cells, microglia, synapse-rich cells (SRCs), and endothelial cells, in the substantia nigra of a rotenone-induced rat model of PD based on marker genes and functional definitions. We found that SRCs were a previously unidentified cell subtype, and the tight interactions between SRCs and other cell populations can be improved by icaritin, which is a flavonoid extracted from Epimedium sagittatum Maxim. and exerts anti-neuroinflammatory, antioxidant, and immune-improving effects in PD. We also demonstrated that icaritin bound with transcription factors of SRCs, and icaritin application modulated synaptic characterization of SRCs, neuroinflammation, oxidative stress, and survival of dopaminergic neurons, and improved abnormal energy metabolism, amino acid metabolism, and phospholipase D metabolism of astrocytes in the substantia nigra of rats with PD. Moreover, icaritin supplementation also promotes the recovery of the physiological homeostasis of the other cell clusters to delay the pathogenesis of PD. These data uncovered previously unknown cellular diversity in a rat model of Parkinson's disease and provide insights into the promising therapeutic potential of icaritin in PD.

Correlational assessment of the effects of JM-20 in a rat model of parkinsonism

We previously demonstrated that JM-20, a molecule with neuroactive functions, protects rats against rotenone and 6-hydroxydopamine (6-OHDA) neurotoxicity. In addition, we demonstrated that JM-20 inhibits the aggregation and cytotoxicity of alpha-synuclein in vitro. In this study, we performed correlation studies between morphological and molecular variables, as well as the motor behavior of parkinsonian rats (6-OHDA and rotenone lesion) treated with JM-20 at different doses (oral with gavage). Our results showed that higher asymmetry evaluated in the cylinder test correlated with greater redox alterations, death of dopaminergic neurons and increased astrogliosis. In the rotenone model, our results showed that a lower number of vertical rearing was correlated with greater redox alterations and increased mitochondrial dysfunction. In both models (6-OHDA and rotenone), parkinsonian animals treated with the highest doses of JM-20 (20 and 40 mg/kg) showed reduced behavioral impairments (lower asymmetry value and higher amount of vertical rearing). Also, a reduced loss of mesencephalic dopaminergic neurons, a smaller number of astrocyte cells in this region, less redox alterations and less mitochondrial dysfunction was observed. In total, our results demonstrate a correlation between behavioral and biochemical variables evaluated in the preclinical models of parkinsonism induced by 6-OHDA and rotenone.

Plumbagin's Healing Effect on Motor Impairment in Rotenone-toxified Rodents.

Parkinson's disease is an illness marked by a gradual mitigation of dopamine neurons within the substantia nigra, which eventually leads to a deficiency of dopamine that further gives rise to mobility as well as cognitive impairments. Through long-established traditions, a wide array of Traditional Chinese Medicines (TCM) have undergone testing and are employed to avoid neurodegenerative disorders. Plumbagin is the primary active component of a medication called Baihua Dan or Plumbago zeylanica L., which is clinically used in China. This study investigated plumbagin-induced alterations in a Parkinson's disease rat model instigated by subcutaneous rotenone injection. Male rats were administered subcutaneous injections of rotenone at a dosage of 1.5 mg/kg, followed by the treatment with varying doses of plumbagin (10, 20, and 40 mg/kg) through the oral route. The rats underwent various motor ability tests, including the actophotometer, rotarod, open field, beam walk, gait evaluation, ability to grip, and catalepsy bar tests. Furthermore, the brain dopamine level was then estimated for the extracted tissues. Also, through molecular docking, the binding effectiveness of plumbagin was assessed for human MAO-B. After that, plumbagin was put through 100 ns of molecular dynamic simulations to examine the stability of its conformational binding to the target protein. Furthermore, ADMET tests were used to verify Plumbagin's druggability. Plumbagin was found to alleviate rotenone-induced motor abnormalities and restore brain dopamine levels. Furthermore, plumbagin showed excellent interactions with MAO-B (monoamine oxidase-B) when compared with selegiline (a standard drug for Parkinson's disease). These findings underscore the potential therapeutic efficacy of plumbagin in mitigating behavioural deficits in rotenone-induced rodents. Considering this, plumbagin might be a feasible pharmacological strategy for the control of rotenone-triggered behavioural impairment in rats (in vivo), and it might display interesting interactions with MAO-B (in silico).

Therapeutic potential of Canna edulis RS3-resistant starch in alleviating neuroinflammation and apoptosis in a Parkinson's disease rat model

This study aimed to investigate the effects of Miao medicinal Canna edulis RS3-resistant starch on behavioral performance and substantia nigra neuron apoptosis-related indicators in a rat model of Parkinson's disease (PD). Among the experimental groups, except for the control group, we induced PD rat models by subcutaneous injection of rotenone in the neck and back. After model induction, a 28-day drug intervention was conducted. Various techniques have been employed, including behavioral analysis, Real-time Polymerase Chain Reaction (RT-PCR), western blotting, enzyme-linked immunosorbent assay (ELISA), immunofluorescence, and terminal deoxynucleotidyltransferase-mediated UTP nick-ends. labeling (TUNEL) and Nissl staining to investigate the effect of Canna edulis RS3-resistant starch on the substantia nigra and neuronal apoptosis-related markers in the brains of PD model rats. Our study revealed that Canna edulis RS3, a resistant starch, significantly reduced the climbing time of PD model rats, prolonged their hanging time, lowered the expression levels of the inflammatory factors IL-1β, IL-6, and TNF-α, increased the number of TH-positive neurons in the substantia nigra, and decreased the levels of IL-1β, IL-6, and TNF-α. Furthermore, Canna edulis RS3 elevated the protein expression levels of tyrosine hydroxylase (TH) and Bcl-2 while reducing those of Bax, TLR4, NLRP3,and p-P65, and mitigated apoptosis and morphological changes in dopaminergic neurons in the substantia nigra region. Our results suggest that Canna edulis RS3-resistant starch may offer therapeutic benefits for PD patients with PD by potentially influencing inflammation and apoptosis in the dopaminergic system.

Bioreactor-produced iPSCs-derived dopaminergic neuron-containing neural microtissues innervate and normalize rotational bias in a dose-dependent manner in a Parkinson rat model

A breadth of preclinical studies now support the rationale of pluripotent stem cell-derived cell replacement therapies to alleviate motor symptoms in Parkinsonian patients. Replacement of the primary dysfunctional cell population in the disease, i.e. the A9 dopaminergic neurons, is the major focus of these therapies. To achieve this, most therapeutical approaches involve grafting single-cell suspensions of DA progenitors. However, most cells die during the transplantation process, as cells face anoïkis. One potential solution to address this challenge is to graft solid preparations, i.e. adopting a 3D format. Cryopreserving such a format remains a major hurdle and is not exempt from causing delays in the time to effect, as observed with cryopreserved single-cell DA progenitors. Here, we used a high-throughput cell-encapsulation technology coupled with bioreactors to provide a 3D culture environment enabling the directed differentiation of hiPSCs into neural microtissues. The proper patterning of these neural microtissues into a midbrain identity was confirmed using orthogonal methods, including qPCR, RNAseq, flow cytometry and immunofluorescent microscopy. The efficacy of the neural microtissues was demonstrated in a dose-dependent manner using a Parkinsonian rat model. The survival of the cells was confirmed by post-mortem histological analysis, characterised by the presence of human dopaminergic neurons projecting into the host striatum. The work reported here is the first bioproduction of a cell therapy for Parkinson's disease in a scalable bioreactor, leading to a full behavioural recovery 16 weeks after transplantation using cryopreserved 3D format.

BBPT attenuated 6-OHDA-induced toxicity by modulating oxidative stress, apoptotic, and inflammatory proteins in primary neurons and rat models of Parkinson's Disease

Parkinson’s disease (PD) results from the degeneration of dopaminergic neurons in substantia nigra pars compacta (SNpc). Adenosine A2AR acting through the striato-pallidal pathway has emerged as a non-dopaminergic target in the therapy of PD. In the present work, the anti-parkinsonian potential of (4E)-4-(4-bromobenzylideneamino)-3-phenyl-2,3-dihydro-2-thioxo- thiazole-5-carbonitrile (BBPT) was explored. BBPT exhibited significant antioxidant activity in situ. In the MTT assay, the BBPT treatment showed insignificant toxicity to the primary midbrain neuronal (PMDN) cells. 6-OHDA induced PMDN cells, 3h post-treated with BBPT showed 80-85% survival of the cells and restoration of dopamine and TNF-α levels. The acute and sub-acute toxicity test for BBPT was performed with Sprague Dawley (SD) rats. In toxicity assay, any significant physical, hematological, or biochemical changes in the rats were not observed. To evaluate the effect of BBPT in vivo, a 6-OHDA-induced unilaterally lesioned SD rat model of PD was established. We observed that the BBPT treatment improved the behavioral symptoms in 6-OHDA-induced unilaterally lesioned rats. The proteins of 6-OHDA-induced BBPT-treated rats were isolated from the brain tissue to assess the antioxidant effect (GSH, catalase, SOD, lipid-peroxidation, nitrite), dopamine levels, and the restoration in the apoptosis and inflammation. Our results demonstrated that BBPT increased the anti-oxidant enzyme levels, restored the caspase-3/Bcl-2 levels to arrest apoptosis, and attenuated the TNF-α/IL-6 levels, thus restoring the neuronal damage in unilaterally lesioned 6-OHDA-induced SD rats. Precisely, the findings suggested that BBPT possessed significant anti-parkinsonian activity and has the potential to prevent dopaminergic neurodegeneration.

Changes in the analgesic mechanism of oxytocin can contribute to hyperalgesia in Parkinson's disease model rats.

Pain is a major non-motor symptom of Parkinson's disease (PD). Alterations in the descending pain inhibitory system (DPIS) have been reported to trigger hyperalgesia in PD patients. However, the underlying mechanisms remain unclear. In the current study, dopaminergic nigrostriatal lesions were induced in rats by injecting 6-hydroxydopamine (6-OHDA) into their medial forebrain bundle. The neural mechanisms underlying changes in nociception in the orofacial region of 6-OHDA-lesioned rats was examined by injecting formalin into the vibrissa pad. The 6-OHDA-lesioned rats were seen to exhibit increased frequency of face-rubbing and more c-Fos immunoreactive (c-Fos-IR) cells in the trigeminal spinal subnucleus caudalis (Vc), confirming hyperalgesia. Examination of the number of c-Fos-IR cells in the DPIS nuclei [including the midbrain ventrolateral periaqueductal gray, the locus coeruleus, the nucleus raphe magnus, and paraventricular nucleus (PVN)] showed that 6-OHDA-lesioned rats exhibited a significantly lower number of c-Fos-IR cells in the magnocellular division of the PVN (mPVN) after formalin injection compared to sham-operated rats. Moreover, the 6-OHDA-lesioned rats also exhibited significantly lower plasma oxytocin (OT) concentration and percentage of oxytocin-immunoreactive (OT-IR) neurons expressing c-Fos protein in the mPVN and dorsal parvocellular division of the PVN (dpPVN), which secrete the analgesic hormone OT upon activation by nociceptive stimuli, when compared to the sham-operated rats. The effect of OT on hyperalgesia in 6-OHDA-lesioned rats was examined by injecting formalin into the vibrissa pad after intracisternal administration of OT, and the findings showed a decrease in the frequency of face rubbing and the number of c-Fos-IR cells in the Vc. In conclusion, these findings confirm presence of hyperalgesia in PD rats, potentially due to suppression of the analgesic effects of OT originating from the PVN.