Time-course gait analysis of hemiparkinsonian rats following 6-hydroxydopamine lesion

Effects of puerarin on gait disturbance in a 6-hydroxydopamine mouse model of Parkinson's disease

BACKGROUND

Parkinson's disease (PD) is a neurodegenerative disorder caused by dopamine (DA) neuronal dysfunction. Although DA agonists and N-methyl-D-aspartate receptor (NMDAR) antagonists are used to treat PD, chronic use causes severe side effects. Puerarin (PUE) is a natural bioactive compound that affects the DA system; however, its effect on PD-associated motor functions is unknown. Therefore, we investigated whether PUE treatment in a 6-hydroxydopamine (6-OHDA) PD mouse model affects motor dysfunction.

METHODS

Adult male ICR mice received unilateral 6-OHDA microinfusion into the right medial forebrain bundle. After a 2-week recovery period, PUE (20 or 50 mg/kg) or the vehicle (saline, VEH) was administered intraperitoneally once daily for 21 days. Motor dysfunction was assessed using the locomotion, gait cycle, and rotation tests. Local field potentials (LFPs) were measured in the substantia nigra compacta (SNc), striatum (STR), subthalamic nucleus (STN), and primary motor cortex.

RESULTS

6-OHDA-lesioned PD mice showed increased gait cycle disturbance and unidirectional rotation. PUE treatment ameliorated the gait cycle disturbance, but not unidirectional rotation of PD mice. These effects differed with DA agonist treatment (which improved PD symptoms) and NMDAR antagonist treatment (which aggravated PD symptoms). Moreover, locomotion was increased only in NMDAR antagonist treatment. PUE treatment induced no changes in the attenuated LFP of the beta wave in the STR and STN, and SNc-STN delta-wave coherence was shown in PD animals.

CONCLUSIONS

This study suggests that PUE is a beneficial co-therapeutic agent for alleviating gait cycle disturbance in PD symptoms.

Cerebellar activity in hemi-parkinsonian rats during volitional gait and freezing

Parkinson's disease is a neurodegenerative disease characterized by gait dysfunction in the advanced stages of the disease. The unilateral 6-hydroxydopamine toxin-induced model is the most studied animal model of Parkinson's disease, which reproduces gait dysfunction after >68% dopamine loss in the substantia nigra pars compacta. The extent to which the neural activity in hemi-parkinsonian rats correlates to gait dysfunction and dopaminergic cell loss is not clear. In this article, we report the effects of unilateral dopamine depletion on cerebellar vermis activity using micro-electrocorticography during walking and freezing on a runway. Gait and neural activity were measured in 6-hydroxydopamine- and sham-lesioned rats aged between 4 and 5 months at 14, 21 and 28 days after infusion of 6-hydroxydopamine or control vehicle into the medial forebrain bundle (n = 20). Gait deficits in 6-hydroxydopamine rats were different from sham rats at 14 days (P < 0.05). Gait deficits in 6-hydroxydopamine rats improved at 21 and 28 days except for run speed, which decreased at 28 days (P = 0.018). No differences in gait deficits were observed in sham-lesioned rats at any time points. Hemi-parkinsonian rats showed hyperactivity in the cerebellar vermis at 21 days (P < 0.05), but not at 14 and 28 days, and the activity was reduced during freezing epochs in Lobules VIa, VIb and VIc (P < 0.05). These results suggest that dopaminergic cell loss causes pathological cerebellar activity at 21 days post-lesion and suggest that compensatory mechanisms from the intact hemisphere contribute to normalized cerebellar activity at 28 days. The decrease in cerebellar oscillatory activity during freezing may be indicative of neurological changes during freezing of gait in patients with Parkinson's disease making this region a potential location for biomarker detection. Although the unilateral 6-hydroxydopamine model presents gait deficits that parallel clinical presentations of Parkinson's disease, further studies in animal models of bilateral dopamine loss are needed to understand the role of the cerebellar vermis in Parkinson's disease.

Pink1/Parkin deficiency alters circulating lymphocyte populations and increases platelet-T cell aggregates in rats

Parkinson's disease (PD) is the most common progressive neurodegenerative movement disorder and results from the selective loss of dopaminergic neurons in the substantia nigra pars compacta. Pink1 and Parkin are proteins that function together in mitochondrial quality control, and when they carry loss-of-function mutations lead to familial forms of PD. While much research has focused on central nervous system alterations in PD, peripheral contributions to PD pathogenesis are increasingly appreciated. We report Pink1/Parkin regulate glycolytic and mitochondrial oxidative metabolism in peripheral blood mononuclear cells (PBMCs) from rats. Pink1/Parkin deficiency induces changes in the circulating lymphocyte populations, namely increased CD4 + T cells and decreased CD8 + T cells and B cells. Loss of Pink1/Parkin leads to elevated platelet counts in the blood and increased platelet-T cell aggregation. Platelet-lymphocyte aggregates are associated with increased thrombosis risk suggesting targeting the Pink1/Parkin pathway in the periphery might have therapeutic potential.

Benfotiamine protects MPTP-induced Parkinson's disease mouse model via activating Nrf2 signaling pathway

The pursuit of drugs and methods to safeguard dopaminergic neurons holds paramount importance in Parkinson's disease (PD) research. Benfotiamine (BFT) has demonstrated neuroprotective properties, yet its precise mechanisms in PD remain elusive. This study investigated BFT's potential protective effects against dopamine neuron damage in a PD animal model and the underlying mechanisms. The PD mouse model was induced by 5 consecutive MPTP injections, followed by BFT intervention for 28 days. Motor deficits were assessed via pole test, hang test, gait analysis, and open field test, while dopaminergic neuron damage was evaluated through Immunofluorescence, Nissl staining, and Western blot analysis of Tyrosine Hydroxylase (TH) in the substantia nigra and striatum. High Performance Liquid Chromatography quantified dopamine (DA) levels and its metabolites. Genetic pathways were explored using RNA-seq and bioinformatics analysis on substantia nigra tissues, confirmed by qPCR. Activation of the Nrf2 pathway was examined through nuclear translocation and expression of downstream antioxidant enzymes HO-1, GCLM, and NQO1 at mRNA and protein levels. Additionally, measurements of MDA content, GSH activity, and SOD activity were taken in the substantia nigra and striatum. BFT administration improved motor function and protected against dopaminergic neuron degeneration in MPTP mice, with partial recovery in TH expression and DA levels. RNA-seq analysis revealed distinct effects of BFT and the NLRP3 inhibitor MCC950 on Parkinson-related pathways and genes. Control of Nrf2 proved crucial for BFT, as it facilitated Nrf2 movement to the nucleus, upregulating antioxidant genes and enzymes while mitigating oxidative damage. This study elucidates BFT's neuroprotective effects in a PD mouse model via Nrf2-mediated antioxidant mechanisms and gene expression modulation, underscoring its potential as a therapeutic agent for PD.

Pink1/Parkin deficiency alters circulating lymphocyte populations and increases platelet-T cell aggregates in rats

Parkinson's disease (PD) is the most common progressive neurodegenerative movement disorder and results from the selective loss of dopaminergic neurons in the substantia nigra pars compacta. Pink1 and Parkin are proteins that function together in mitochondrial quality control, and when they carry loss-of-function mutations lead to familial forms of PD. While much research has focused on central nervous system alterations in PD, peripheral contributions to PD pathogenesis are increasingly appreciated. We report Pink1/Parkin regulate glycolytic and mitochondrial oxidative metabolism in peripheral blood mononuclear cells (PBMCs) from rats. Pink1/Parkin deficiency induces changes in the circulating lymphocyte populations, namely increased CD4 + T cells and decreased CD8 + T cells and B cells. Loss of Pink1/Parkin leads to elevated platelet counts in the blood and increased platelet-T cell aggregation. Platelet-lymphocyte aggregates are associated with increased thrombosis risk, and venous thrombosis is a cause of sudden death in PD, suggesting targeting the Pink1/Parkin pathway in the periphery has therapeutic potential.

Dopamine lesions alter the striatal encoding of single-limb gait

The striatum serves an important role in motor control, and neurons in this area encode the body's initiation, cessation, and speed of locomotion. However, it remains unclear whether the same neurons also encode the step-by-step rhythmic motor patterns of individual limbs that characterize gait. By combining high-speed video tracking, electrophysiology, and optogenetic tagging, we found that a sizable population of both D1 and D2 receptor expressing medium spiny projection neurons (MSNs) were phase-locked to the gait cycle of individual limbs in mice. Healthy animals showed balanced limb phase-locking between D1 and D2 MSNs, while dopamine depletion led to stronger phase-locking in D2 MSNs. These findings indicate that striatal neurons represent gait on a single-limb and step basis, and suggest that elevated limb phase-locking of D2 MSNs may underlie some of the gait impairments associated with dopamine loss.

Neurophysiological treatment effects of mesdopetam, pimavanserin and clozapine in a rodent model of Parkinson's disease psychosis

Psychosis in Parkinson's disease is a common phenomenon associated with poor outcomes. To clarify the pathophysiology of this condition and the mechanisms of antipsychotic treatments, we have here characterized the neurophysiological brain states induced by clozapine, pimavanserin, and the novel prospective antipsychotic mesdopetam in a rodent model of Parkinson's disease psychosis, based on chronic dopaminergic denervation by 6-OHDA lesions, levodopa priming, and the acute administration of an NMDA antagonist. Parallel recordings of local field potentials from eleven cortical and sub-cortical regions revealed shared neurophysiological treatment effects for the three compounds, despite their different pharmacological profiles, involving reversal of features associated with the psychotomimetic state, such as a reduction of aberrant high-frequency oscillations in prefrontal structures together with a decrease of abnormal synchronization between different brain regions. Other drug-induced neurophysiological features were more specific to each treatment, affecting network oscillation frequencies and entropy, pointing to discrete differences in mechanisms of action. These findings indicate that neurophysiological characterization of brain states is particularly informative when evaluating therapeutic mechanisms in conditions involving symptoms that are difficult to assess in rodents such as psychosis, and that mesdopetam should be further explored as a potential novel antipsychotic treatment option for Parkinson psychosis.

Dopamine lesions alter the striatal encoding of single-limb gait

The striatum serves an important role in motor control, and neurons in this area encode the body's initiation, cessation, and speed of locomotion. However, it remains unclear whether the same neurons also encode the step-by-step rhythmic motor patterns of individual limbs that characterize gait. By combining high-speed video tracking, electrophysiology, and optogenetic tagging, we found that a sizable population of both D1 and D2 receptor expressing medium spiny projection neurons (MSNs) were phase-locked to the gait cycle of individual limbs in mice. Healthy animals showed balanced limb phase-locking between D1 and D2 MSNs, while dopamine depletion led to stronger phase-locking in D2 MSNs. These findings indicate that striatal neurons represent gait on a single-limb and step basis, and suggest that elevated limb phase-locking of D2 MSNs may underlie some of the gait impairments associated with dopamine loss.

Neuroprotective effect of dexpanthenol on rotenone-induced Parkinson's disease model in rats

Parkinson's disease (PD) is the second most common and progressive neurodegenerative disease. This experimental study was designed to investigate the neuroprotective effects of dexpanthenol on antioxidant and anti-inflammatory processes in a rotenone-induced Parkinson's disease model in rats. Twenty-one male rats were randomly divided into 2 groups. The rotenone group (n = 14) was administered rotenone by intrastriatal injection, and the vehicle group (n = 7) was administered DMSO with the same application route. All animals underwent rotational movement testing with apomorphine injection 10 days later. Those with Parkinson's disease model were randomly divided into 2 groups. While 1 ml/kg of saline was applied to the saline group (n = 7), 500 mg/kg was administered to the dexpanthenol group intraperitoneally for 28 days. After 28 days, all rats were euthanized and brain tissue was removed. While striatal areas were evaluated immunohistochemically, brain MDA, TNF-α, and HVA levels were measured to evaluate their anti-oxidative and anti-inflammatory effects. In the dexpanthenol group, the total count (p < 0.001) and intensity (p < 0.001) of dopaminergic neurons in the striatal areas increased compared to the saline group. It was revealed that MDA (nmol/g) (p < 0.001) and TNF-α (pg/g) (p < 0.001) levels decreased in the dexpanthenol group, while HVA (ng/mg) levels increased (p < 0.01). This study suggests that dexpanthenol may have a neuroprotective effect by reducing neuronal loss, oxidative damage, and neuroinflammation in the striatum in rats.

Evoked responses to single pulse electrical stimulation reveal impaired striatal excitability in a rat model of Parkinson's disease

BACKGROUND

Sensorimotor beta oscillations are increased in Parkinson's disease (PD) due to the alteration of dopaminergic transmission. This electrophysiological read-out is reported both in patients and in animal models such as the 6-OHDA rat model obtained with unilateral nigral injection of 6-hydroxydopamine (6-OHDA). Current treatments, based on dopaminergic replacement, transiently normalize this pathological beta activity and improve patients' quality of life.

OBJECTIVES

We wanted to assess in vivo whether the abnormal beta oscillations can be correlated with impaired striatal or cortical excitability of the sensorimotor system and modulated by the pharmacological manipulation of the dopaminergic system.

METHODS

In the unilateral 6-OHDA rat model and control animals, we used intra-striatal and intra-cortical single-pulse electrical stimulation (SPES) and concurrent local field potentials (LFP) recordings. In the two groups, we quantified basal cortico-striatal excitability from time-resolved spectral analyses of LFP evoked responses induced remotely by intracerebral stimulations. The temporal dependance of cortico-striatal excitability to dopaminergic transmission was further tested using electrophysiological recordings combined with levodopa injection.

RESULTS

LFP evoked responses after striatal stimulation showed a transient reduction of power in a large time-frequency domain in the 6-OHDA group compared to the sham group. This result was specific to the striatum, as no significant difference was observed in cortical LFP evoked responses between the two groups. This impaired striatal excitability in the 6-OHDA group was observed in the striatum at least during the first 3 months after the initial lesion. In addition, the striatum responses to SPES during a levodopa challenge showed a transient potentiation of the decrease of responsiveness in frequencies below 40 Hz.

CONCLUSION

The spectral properties of striatal responses to SPES show high sensitivity to dopaminergic transmission in the unilateral 6-OHDA rat model. We thus propose that this approach could be used in preclinical models as a time-resolved biomarker of impaired dopaminergic transmission capable of monitoring progressive neurodegeneration and/or challenges to drug intake.

Alteration of Postural Reactions in Rats with Different Levels of Dopamine Depletion

Dopamine (DA) is the critical neurotransmitter involved in the unconscious control of muscle tone and body posture. We evaluated the general motor capacities and muscle responses to postural disturbance in three conditions: normal DA level (wild-type rats, WT), mild DA deficiency (WT after administration of α-methyl-p-tyrosine-AMPT, that blocks DA synthesis), and severe DA depletion (DAT-KO rats after AMPT). The horizontal displacements in WT rats elicited a multi-component EMG corrective response in the flexor and extensor muscles. Similar to the gradual progression of DA-related diseases, we observed different degrees of bradykinesia, rigidity, and postural instability after AMPT. The mild DA deficiency impaired the initiation pattern of corrective responses, specifically delaying the extensor muscles' activity ipsilaterally to displacement direction and earlier extensor activity from the opposite side. DA depletion in DAT-KO rats after AMPT elicited tremors, general stiffness, and akinesia, and caused earlier response to horizontal displacements in the coactivated flexor and extensor muscles bilaterally. The data obtained show the specific role of DA in postural reactions and suggest that this experimental approach can be used to investigate sensorimotor control in different dopamine-deficient states and to model DA-related diseases.

Activated Microglia in the Early Stage of a Rat Model of Parkinson's Disease: Revealed by PET-MRI Imaging by [18F]DPA-714 Targeting TSPO

In the past decades, translocator protein (TSPO) has been considered as an in vivo biomarker to measure the presence of neuroinflammatory reactions. In this study, expression of TSPO was quantified via [¹⁸F]DPA-714 positron emission tomography-magnetic resonance imaging (PET-MRI) imaging to investigate the effects of microglial activation associated with motor behavioral impairments in the 6-hydroxydopamine (6-OHDA)-treated rodent model of Parkinson's disease (PD). [¹⁸F]FDG PET-MRI (for non-specific inflammation), [¹⁸F]D₆-FP-(+)-DTBZ PET-MRI (for damaged dopaminergic neurons), post-PET immunofluorescence, and Pearson's correlation analyses were also performed. The time course of the striatal [¹⁸F]DPA-714 binding ratio elevated in 6-OHDA-treated rats during 1-3 weeks post-treatment, with the peak TSPO binding in the 1st week. No differences between bilateral striatum in [¹⁸F]FDG PET imaging were found. Moreover, an obvious correlation between [¹⁸F]DPA-714 SUV_R^R/L and rotation numbers was found (r = 0.434, *p = 0.049). No correlation between [¹⁸F]FDG SUV_R^R/L and rotation behavior was found. [¹⁸F]DPA-714 appeared to be a potential PET tracer for imaging the microglia-mediated neuroinflammation in the early stage of PD.

Activated Microglia in the Early Stage of a Rat Model of Parkinson's Disease: Revealed by PET-MRI Imaging by [18F]DPA-714 Targeting TSPO

In the past decades, translocator protein (TSPO) has been considered as an in vivo biomarker to measure the presence of neuroinflammatory reactions. In this study, expression of TSPO was quantified via [¹⁸F]DPA-714 positron emission tomography-magnetic resonance imaging (PET-MRI) to investigate the effects of microglial activation associated with motor behavioral impairments in the 6-hydroxydopamine (6-OHDA)-treated rodent model of Parkinson's disease (PD). [¹⁸F]FDG PET-MRI (for non-specific inflammation), [¹⁸F]D₆-FP-(+)-DTBZ PET-MRI (for damaged dopaminergic (DA) neurons), post-PET immunofluorescence, and Pearson's correlation analyses were also performed. The time course of striatal [¹⁸F]DPA-714 binding ratio was elevated in 6-OHDA-treated rats during 1-3 weeks post-treatments, with peak TSPO binding in the 1st week. No difference between the bilateral striatum in [¹⁸F]FDG PET imaging were found. Moreover, an obvious correlation between [¹⁸F]DPA-714 SUV_R^R/L and rotation numbers was found (r = 0.434, *p = 0.049). No correlation between [¹⁸F]FDG SUV_R^R/L and rotation behavior was found. [¹⁸F]DPA-714 appeared to be a potential PET tracer for imaging the microglia-mediated neuroinflammation in the early stage of PD.

Neuroprotective and Immunomodulatory Effects of Probiotics in a Rat Model of Parkinson's Disease

It is now well recognized that a bidirectional relationship between gut microbiota and the brain, referred to as the gut-brain axis, plays a prominent role in maintaining homeostasis and that a disruption in this axis can result in neuroinflammatory response and neurological disorders such as Parkinson's disease (PD). The protective action of probiotics such as Bifidobacterium animalis ssp. lactis Bb12 and Lactobacillus rhamnosus GG in various animal models of PD has been reported. Therefore, in this study, we used an inflammatory model of PD to assess the effects of a combination of these two probiotics (Microbiot^®) on motor behavior as well as on the response of microglia, including microglia morphology, to gain a better understanding of their mechanism of action. Microbiot^® (300 µL) was administered orally once daily for 15 days in a lipopolysaccharide-induced PD model using male Wistar rats. Although LPS-induced motor asymmetry in cylinder test was not affected by Microbiot^®, impairment of motor coordination in the narrow-beam test was significantly reduced by this probiotic. Moreover, Microbiot^® treatment reduced microglial activation suggesting an anti-inflammatory effect. While further mechanistic investigation of Microbiot^® in neurodegenerative diseases is warranted, our results support the potential utility of probiotics in PD.

Time-course gait pattern analysis in a rat model of foot drop induced by ventral root avulsion injury

Foot drop is a common clinical gait impairment characterized by the inability to raise the foot or toes during walking due to the weakness of the dorsiflexors of the foot. Lumbar spine disorders are common neurogenic causes of foot drop. The accurate prognosis and treatment protocols of foot drop are not well delineated in the scientific literature due to the heterogeneity of the underlying lumbar spine disorders, different severities, and distinct definitions of the disease. For translational purposes, the use of animal disease models could be the best way to investigate the pathogenesis of foot drop and help develop effective therapeutic strategies for foot drops. However, no relevant and reproducible foot drop animal models with a suitable gait analysis method were developed for the observation of foot drop symptoms. Therefore, the present study aimed to develop a ventral root avulsion (VRA)-induced foot drop rat model and record detailed time-course changes of gait pattern following L5, L6, or L5 + L6 VRA surgery. Our results suggested that L5 + L6 VRA rats exhibited changes in gait patterns, as compared to sham lesion rats, including a significant reduction of walking speed, step length, toe spread, and swing phase time, as well as an increased duration of the stance phase time. The ankle kinematic data exhibited that the ankle joint angle increased during the mid-swing stage, indicating a significant foot drop pattern during locomotion. Time-course observations displayed that these gait impairments occurred as early as the first-day post-lesion and gradually recovered 7-14 days post-injury. We conclude that the proposed foot drop rat model with a video-based gait analysis approach can precisely detect the foot drop pattern induced by VRA in rats, which can provide insight into the compensatory changes and recovery in gait patterns and might be useful for serving as a translational platform bridging human and animal studies for developing novel therapeutic strategies for foot drop.

Longitudinal assessment of motor function following the unilateral intrastriatal 6-hydroxydopamine lesion model in mice

Introduction

Despite the widespread use of the unilateral striatal 6-hydroxydopamine (6-OHDA) lesion model in mice in recent years, the stability of behavioral deficits in the 6-OHDA striatal mouse model over time is not yet clear, raising concerns about using this model to evaluate a compound's long-term therapeutic effects.

Materials and methods

In the current study, mice were tested at regular intervals in the cylinder test and gait analysis beginning 3 days after 6-OHDA injection of 4 and 8 μg and lasting until 56 days post-lesion. Apomorphine-induced rotational test and rotarod test were also performed on Day 23 and 43 post-lesion, respectively. Immunohistochemistry for dopaminergic neurons stained by tyrosine hydroxylase (TH) was also performed.

Results

Our results showed that both the 4 and 8 μg 6-OHDA lesion groups exhibited forelimb use asymmetry with a preference for the ipsilateral (injection) side on Day 3 and until Day 21 post-lesion, but did not show forelimb asymmetry on Day 28 to 56 post-lesion. The 8 μg 6-OHDA lesion group still exhibited forelimb asymmetry on Day 28 and 42 post-lesion, but not on Day 56. The gait analysis showed that the contralateral front and hind step cycles increased from Day 3 to 42 post-lesion and recovered on Day 56 post-lesion. In addition, our results displayed a dose-dependent reduction in TH⁺ cells and TH⁺ fibers, as well as dose-dependent apomorphine-induced rotations. In the rotarod test, the 8 μg 6-OHDA lesion group, but not the 4 μg group, decreased the latency to fall on the rotarod on Day 43 post-lesion.

Conclusion

In summary, unilateral striatal 6-OHDA injections of 4 and 8 μg induced spontaneous motor impairment in mice, which partially recovered starting on Day 28 post-lesion. Forced motor deficits were observed in the 8 g 6-OHDA lesion group, which remained stable on Day 43 post-lesion. In addition, the rotarod test and apomorphine-induced rotational test can distinguish between lesions of different extents and are useful tools for the assessment of functional recovery in studies screening novel potential therapies.

Impact of Environmental Risk Factors on Mitochondrial Dysfunction, Neuroinflammation, Protein Misfolding, and Oxidative Stress in the Etiopathogenesis of Parkinson's Disease

As a prevalent progressive neurodegenerative disorder, Parkinson's disease (PD) is characterized by the neuropathological hallmark of the loss of nigrostriatal dopaminergic (DAergic) innervation and the appearance of Lewy bodies with aggregated α-synuclein. Although several familial forms of PD have been reported to be associated with several gene variants, most cases in nature are sporadic, triggered by a complex interplay of genetic and environmental risk factors. Numerous epidemiological studies during the past two decades have shown positive associations between PD and several environmental factors, including exposure to neurotoxic pesticides/herbicides and heavy metals as well as traumatic brain injury. Other environmental factors that have been implicated as potential risk factors for PD include industrial chemicals, wood pulp mills, farming, well-water consumption, and rural residence. In this review, we summarize the environmental toxicology of PD with the focus on the elaboration of chemical toxicity and the underlying pathogenic mechanisms associated with exposure to several neurotoxic chemicals, specifically 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), rotenone, paraquat (PQ), dichloro-diphenyl-trichloroethane (DDT), dieldrin, manganese (Mn), and vanadium (V). Our overview of the current findings from cellular, animal, and human studies of PD provides information for possible intervention strategies aimed at halting the initiation and exacerbation of environmentally linked PD.

The role of legislation in K-12 school discipline: The silence of action

Researchers have consistently identified the disparity between teachers' practical and legal knowledge regarding teachers' right to discipline students. However, few studies have investigated teachers' construction processes that form construction outcomes, which would help navigate the role of legislation in school discipline. This study contributes to a holistic picture of the neglected disciplinary rights that teachers construct in teaching practice and their underexplored attitude toward the law, using an interview-based constructionist method on twelve teachers of Lvliang city in a Chinese K-12 context. The findings suggest that the participants prefer to acquire discipline knowledge by interacting with multiple power relations in their local environment and that their knowledge is historically and culturally specific. Although the disciplinary right they construct is never static, balanced, or essentialised, the participants' constructions are commonly not in line with legal provisions or the aims of the law. Furthermore, school discipline legislation plays a silent role in empowering teachers to discipline students, but it is more visible in holding back teachers' use of corporal punishment. These findings illustrate the complexity of implementing school disciplinary law as a universal national policy.

Long-Term Motor Cortical Electrical Stimulation Ameliorates 6-Hydroxydopamine-Induced Motor Dysfunctions and Exerts Neuroprotective Effects in a Rat Model of Parkinson's Disease

OBJECTIVE

Cortical electrical stimulation (CES) can modulate cortical excitability through a plasticity-like mechanism and is considered to have therapeutic potentials in Parkinson's disease (PD). However, the precise therapeutic value of such approach for PD remains unclear. Accordingly, we adopted a PD rat model to determine the therapeutic effects of CES. The current study was thus designed to identify the therapeutic potential of CES in PD rats.

METHODS

A hemiparkinsonian rat model, in which lesions were induced using unilateral injection of 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle, was applied to identify the therapeutic effects of long-term (4-week) CES with intermittent theta-burst stimulation (iTBS) protocol (starting 24 h after PD lesion observation, 1 session/day, 5 days/week) on motor function and neuroprotection. After the CES intervention, detailed functional behavioral tests including gait analysis, akinesia, open-field locomotor activity, apomorphine-induced rotation as well as degeneration level of dopaminergic neurons were performed weekly up to postlesion week 4.

RESULTS

After the CES treatment, we found that the 4-week CES intervention ameliorated the motor deficits in gait pattern, akinesia, locomotor activity, and apomorphine-induced rotation. Immunohistochemistry and tyrosine hydroxylase staining analysis demonstrated that the number of dopamine neurons was significantly greater in the CES intervention group than in the sham treatment group.

CONCLUSION

This study suggests that early and long-term CES intervention could reduce the aggravation of motor dysfunction and exert neuroprotective effects in a rat model of PD. Further, this preclinical model of CES may increase the scope for the potential use of CES and serve as a link between animal and PD human studies to further identify the therapeutic mechanism of CES for PD or other neurological disorders.

Dopaminergic but not cholinergic neurodegeneration is correlated with gait disturbances in PINK1 knockout rats

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by gait dysfunction in later stages of the disease. PD hallmarks include a decrease in stride length, run speed, and swing time; an increase in stride time, stance time, and base of support; dopaminergic degeneration in the basal ganglia; and cholinergic degeneration in the pedunculopontine nucleus (PPN). A progressive animal model of PD is needed to identify treatments for gait dysfunction. The goal of this study was to quantify progressive gait degeneration in PTEN-induced putative kinase 1 knockout (P1KO) rats and investigate neurodegeneration as potential underlying mechanisms. Gait analysis was performed in male P1KO and wild-type rats at 5 and 8 months of age and immunohistochemical analysis at 8 months. Multiple parameters of volitional gait were measured using a runway system. P1KO rats exhibited significant gait deficits at 5 months, but not 8 months. Gait abnormalities improved over time suggesting compensation during behavioral testing. At 8 months a 15% loss of tyrosine hydroxylase (TH) in the striatum, a 27% loss of TH-positive cells in the substantia nigra pars compacta, and no significant loss of choline acetyltransferase-positive cells in the PPN was found. Dopaminergic cell loss may contribute to gait deficits in the P1KO model, but not cholinergic cell loss. The P1KO rat with the greatest dopamine loss exhibited the most pronounced PD-like gait deficits, highlighting variability within the model. Further analysis is required to determine the suitability of the P1KO rat as a progressive model of gait abnormalities in PD.

The beneficial effect of salubrinal on neuroinflammation and neuronal loss in intranigral LPS-induced hemi-Parkinson disease model in rats

OBJECTIVE

Endoplasmic reticulum stress (ERS) and neuroinflammation are triggers for neurodegenerative disorders. Salubrinal is a selective inhibitor of protein phosphatase 1 (PP1) complex involving dephosphorylation of phosphorylated eukaryotic initiation factor-2α (eIF2α), the key crucial pathway in the ERS. Therefore, this study assessed the effects of inhibition of the ERS with salubrinal in the intranigral hemi-Parkinson disease (PD) model.

MATERIALS AND METHODS

Animals were treated with salubrinal for one week after the PD model was created by intranigral lipopolysaccharide (LPS) administration. Apomorphine-induced rotation, rotarod, cylinder, and pole tests were performed to evaluate behavioral changes. Proinflammatory cytokines and the expression level of the dual specificity protein phosphatase 2 (DUSP2), PP1, and p-eIF2α were evaluated. Nigral expression of inducible nitric oxide synthase (iNOS), nuclear factor kappaB (Nf-κB), and cyclooxygenase (COX)-2 was determined. Finally, tyrosine hydroxylase and caspase-3/ caspase-9 expressions were assessed by immunohistochemistry.

RESULTS

Salubrinal reduced the motor impairments and dopamine-related behavioral deficiencies caused by the LPS. Salubrinal attenuated the LPS-induced increased levels of interleukin (IL)-1β, IL-6, tumor necrosis factor-α, and salubrinal rescued the loss of TH expression and dopamine levels and prevented the caspase-3/9 increase in the substantial nigra (SN). LPS potently increased iNOS, Nf-κB, and COX-2 expression, but this effect was reduced after salubrinal treatment. Additionally, salubrinal attenuated the LPS-induced PP1 and DUSP2 increase.

CONCLUSION

Our results reveal that salubrinal is attenuating several inflammatory mediators and thereby decreased the inflammatory effects of LPS in the neurons of the SN. Together this results in increased cellular survival and maintained integrity of SN. Taken together our data show the beneficial effects of inhibition of ERS to restrict neuroinflammatory progression and neuronal loss in a PD model.

Disclosing Unwanted Pursuit Victimization: Indirect Effects of Negative Reactions on PTSD Symptomatology Among Undergraduate Women

A growing literature has documented that negative social reactions to disclosures of sexual and intimate partner violence (IPV), such as victim blaming or disbelief, can negatively affect survivors' recovery. However, despite growing recognition of the frequency of unwanted pursuit behaviors (UPBs; for example, stalking, excessive or threatening contact) following romantic relationships and their negative effects on survivors, research to date has not explored disclosures, social reactions, or their impacts among victims of UPBs. The purpose of the present study was to assess the frequency of disclosures of UPB victimization to various sources, social reactions received, and their associations with symptoms of posttraumatic stress disorder (PTSD). Among a sample of 318 undergraduate women (ages 18-24) who reported a breakup within the past 3 years, 59.7% (n =190) reported experiencing UPBs. Nearly all of the women (92.6%; n =176) who experienced UPBs disclosed their victimization to others. Among women who disclosed, the most frequent recipient of disclosure was a female friend (93.2%, n = 164) and women reported receiving higher mean positive than negative social reactions (p < .001). Results supported the hypothesized indirect effect of UPB victimization on PTSD symptoms through increases in negative social reactions (p < .001); these results suggest that negative social reactions to UPB victimization may increase the risk for PTSD symptomatology. By contrast, there was no indirect effect via positive social reactions (p = .205). Implications for research and clinical practice will be discussed.

Quantifying muscle alterations in a Parkinson's disease animal model using electromyographic biomarkers

Parkinson's disease (PD) is a neurodegenerative disease currently diagnosed based on characteristic motor dysfunctions. The most common Parkinson's disease animal model induces massive nigrostriatal degeneration by intracerebral infusion of 6-hydroxydopamine (6-OHDA). Motor deficits in rat models of Parkinson's disease were previously addressed in other works. However, an accurate quantification of muscle function in freely moving PD-lesioned rats over time has not been described until now. In this work, we address the muscular activity characterization of a 6-OHDA-lesion model of PD along 6 weeks post-lesion based on spectral and morphological analysis of the signals. Using chronic implanted EMG electrodes in a hindlimb muscle of freely moving rats, we have evaluated the effect of the PD neurotoxic model in the muscular activity during locomotion. EMG signals obtained from animals with different time post-injury were analyzed. Power spectral densities were characterized by the mean and median frequency, and the EMG burst stationarity was previously verified for all animals. Our results show that as the time post-lesion increases both frequency parameters decrease. Probability distribution function analysis was also performed. The results suggest that contractile dynamics of the biceps femoris muscle change with time post-lesion. We have also demonstrated here the usefulness of frequency parameters as biomarkers for monitoring the muscular function changes that could be used for early detection of motor dysfunction.

Idebenone Ameliorates Rotenone-Induced Parkinson's Disease in Rats Through Decreasing Lipid Peroxidation

Oxidative stress is considered one of the mechanisms responsible for neurodegenerative diseases, especially for Parkinson's disease. Since oxidative stress causes pathological changes in neuronal structures antioxidant compounds gained significant attention the last decades. Although several antioxidant compounds showed neuroprotective actions in Parkinson's disease models, only a few of them demonstrated protective effects against loss of striatal dopaminergic neurons. Idebenone is an analog of the well-known antioxidant compound coenzyme Q10 (CoQ10). Clinical safety of idebenone is well described, and due to its high antioxidant capacity currently used to treat Freidrich's ataxia and Alzheimer's disease. Like Parkinson's disease, these diseases are characterized by oxidative stress and impaired mitochondrial balance in neurons. However, knowledge about the effects of idebenone on Parkinson's disease is limited. Therefore, in this study we aimed to investigate and delineate the possible effects of idebenone in rotenone-induced Parkinson's disease models. Idebenone (200 mg/kg, p.o.) inhibited the decrease of striatal expression of NAD(P)H dehydrogenase[quinone]-1, which is an essential element for mitochondrial respiration. Idebenone decreased the striatal levels of the lipid peroxidation products and increased the expression of glutathione peroxidase-4 (GPx-4), which is primarily known for lipid peroxidation and ferroptosis. Furthermore, idebenone mitigated motor impairment and increased tyrosine hydroxylase-positive neuron survival. Together our results thus indicate that that idebenone has protective effects against a rotenone insult with pleiotropic actions on the cellular oxidative enzymes and lipid peroxidation.

Effects of pedunculopontine nucleus cholinergic lesion on gait and dyskinesia in hemiparkinsonian rats

Pedunculopontine nucleus (PPN) cholinergic neurons are implicated in freezing of gait in Parkinson's disease (PD) and motor stereotypy in normal animals, but the causal role of these neurons on specific gait parameters and treatment-induced dyskinesia remains speculative. Therefore, we examined whether selective cholinergic lesion of the rostral PPN affects PD motor and gait deficits, L-DOPA-induced dyskinesia and motor improvement, and DA-agonist-induced dyskinesia. Sprague-Dawley rats were assigned to one unilaterally lesioned group: Sham lesion, PPN cholinergic lesion with diphtheria urotensin II fusion toxin, medial forebrain bundle dopamine lesion with 6-hydroxydopamine, or dual acetylcholine and dopamine lesion. We used gait analysis and forepaw adjusting steps to examine PD gait and motor deficits. Forepaw adjusting steps were also used to assess motor improvement with L-DOPA treatment. The abnormal involuntary movements scale measured L-DOPA and dopamine D1- and D2-receptor agonist-induced dyskinesia. Lesions, verified via tyrosine hydroxylase and choline acetyltransferase immunohistochemistry reduced an average of 95% of nigral dopamine neurons and 80% of PPN cholinergic neurons, respectively. Rats receiving acetylcholine and dual lesion demonstrated enhanced freezing, and acetylcholine lesioned rats exhibited increased print area and stand index. Dopamine and dual lesion produced similar forepaw adjusting steps task on and off L-DOPA. Relative to DA lesioned rats, dual lesioned rats displayed reduced L-DOPA and DA agonist-induced dyskinesia at specific time points. Our results indicate that PPN cholinergic neurons affect gait parameters related to postural stability. Therefore, therapeutically targeting PPN cholinergic neurons could reduce intractable postural instability in PD without affecting motor benefits or side effects of L-DOPA treatment.

Early Repetitive Transcranial Magnetic Stimulation Exerts Neuroprotective Effects and Improves Motor Functions in Hemiparkinsonian Rats

Repetitive transcranial magnetic stimulation (rTMS) is a popular noninvasive technique for modulating motor cortical plasticity and has therapeutic potential for the treatment of Parkinson's disease (PD). However, the therapeutic benefits and related mechanisms of rTMS in PD are still uncertain. Accordingly, preclinical animal research is helpful for enabling translational research to explore an effective therapeutic strategy and for better understanding the underlying mechanisms. Therefore, the current study was designed to identify the therapeutic effects of rTMS on hemiparkinsonian rats. A hemiparkinsonian rat model, induced by unilateral injection of 6-hydroxydopamine (6-OHDA), was applied to evaluate the therapeutic potential of rTMS in motor functions and neuroprotective effect of dopaminergic neurons. Following early and long-term rTMS intervention with an intermittent theta burst stimulation (iTBS) paradigm (starting 24 h post-6-OHDA lesion, 1 session/day, 7 days/week, for a total of 4 weeks) in awake hemiparkinsonian rats, the effects of rTMS on the performance in detailed functional behavioral tests, including video-based gait analysis, the bar test for akinesia, apomorphine-induced rotational analysis, and tests of the degeneration level of dopaminergic neurons, were identified. We found that four weeks of rTMS intervention significantly reduced the aggravation of PD-related symptoms post-6-OHDA lesion. Immunohistochemically, the results showed that tyrosine hydroxylase- (TH-) positive neurons in the substantia nigra pars compacta (SNpc) and fibers in the striatum were significantly preserved in the rTMS treatment group. These findings suggest that early and long-term rTMS with the iTBS paradigm exerts neuroprotective effects and mitigates motor impairments in a hemiparkinsonian rat model. These results further highlight the potential therapeutic effects of rTMS and confirm that long-term rTMS treatment might have clinical relevance and usefulness as an additional treatment approach in individuals with PD.

Rapid and robust patterns of spontaneous locomotor deficits in mouse models of Huntington's disease

Huntington's disease (HD) is an inherited neurodegenerative disorder characterized by severe disruption of cognitive and motor functions, including changes in posture and gait. A number of HD mouse models have been engineered that display behavioral and neuropathological features of the disease, but gait alterations in these models are poorly characterized. Sensitive high-throughput tests of fine motor function and gait in mice might be informative in evaluating disease-modifying interventions. Here, we describe a hypothesis-free workflow that determines progressively changing locomotor patterns across 79 parameters in the R6/2 and Q175 mouse models of HD. R6/2 mice (120 CAG repeats) showed motor disturbances as early as at 4 weeks of age. Similar disturbances were observed in homozygous and heterozygous Q175 KI mice at 3 and 6 months of age, respectively. Interestingly, only the R6/2 mice developed forelimb ataxia. The principal components of the behavioral phenotypes produced two phenotypic scores of progressive postural instability based on kinematic parameters and trajectory waveform data, which were shared by both HD models. This approach adds to the available HD mouse model research toolbox and has a potential to facilitate the development of therapeutics for HD and other debilitating movement disorders with high unmet medical need.

Chronic feeding with 3% dried raw blueberries (V. corymbosum) reduces apomorphine-induced rotations and striatal dopaminergic loss in hemiparkinsonian rats

Blueberries (BB) are rich in antioxidant polyphenols, and their intake could prevent Parkinson's disease (PD). Here we assessed whether rats chronically fed dried raw BB develop resistance to dopaminergic denervation and motor disorders caused by unilateral intrastriatal injection of 6-hydroxydopamine (6-OHDA), a dopaminergic neurotoxin acting mainly by inducing oxidative stress. Male rats were fed either with LabDiet® alone or supplemented with 3% lyophilized raw BB for 2 weeks before and 3 weeks after injecting 6-OHDA (day 0) or vehicle (mock lesion) into the right striatum. The cylinder test was performed on days -14, -7, -1, +7, +14, and +21; the percentage of ipsilateral forepaw (IF) use asymmetry was determined by counting the wall contacts made with either forepaw or with both. Apomorphine (0.25 mg/kg, s.c.)-induced rotation was performed on days -1, +7, +14, and +21. Full contralateral rotations were counted in 3-min periods, every 15 min, up to 90 min. Striatal slices were immunostained for tyrosine hydroxylase (TH) and the ionized calcium-binding protein-1 adapter (Iba1) [immunoreactive area or microglia count in right striatum expressed as % of the left striatum]. Antioxidants in BB methanolic extracts neutralized the free radical 2,2-diphenyl-1-picrylhydrazyl in a concentration-dependent manner. Anthocyanins have been reported as the most abundant polyphenols in BB. Using the pH differential method, the total anthocyanin content (malvidin-3-glucoside equivalents) in raw BB averaged 21.04 mg/g dry weight. The range of anthocyanin intake by rats throughout the study varied from 37.7 to 72.2 mg/kg body weight. The time and food type factors, as well as their interaction were significant according to two-way RM-ANOVA in both the apomorphine-induced rotations and the cylinder test. Compared with LabDiet® alone, chronic supplementation with 3% dried raw BB decreased apomorphine-induced rotations on days +14 and +21 (p < 0.001) and produced a 46% reduction in total rotations post-surgery (p < 0.05), but only caused a partial, non-significant, decrease of IF asymmetry. BB supplementation reduced TH loss in the striatum (p < 0.05) but did not attenuate the increase of Iba1⁺ microglia. The consumption of 3% dried raw blueberries attenuates dopaminergic denervation and partially reverses motor disorders in the 6-OHDA-induced PD model in rats. The phytochemicals of raw blueberries that contribute to the observed neuroprotective effect are yet to be identified.

The voiding efficiency in rat models with dopaminergic brain lesions induced through unilateral and bilateral intrastriatal injections

Bladder dysfunction is a common phenomenon in Parkinson’s disease (PD) patients. A research attempt was made to analyze the voiding efficiency (VE) and bladder functions in rats with PD induced by unilateral or bilateral injections of 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle. PD rats were divided into unilateral- and bilateral-injected groups and subjected to rotation and beam walking tests. Further, the experimental rats underwent cystometric measurements for analyses of bladder dysfunction and VE. Immunohistochemical analysis was performed to analyze the dopaminergic neuron depletion on the target area. Outcomes of the rotation and beam walking tests revealed the extent of parkinsonism in the experimental rats. Urodynamic observations denoted that rats with unilateral PD exhibited a significantly decreased VE (from 68.3±3.5% to 32.7±5.8%), while rats with bilateral PD displayed a much-reduced and substantially lower level of VE of 18.3±5.1% compared to the control value and to that of rats with unilateral PD. Rats with bilateral PD showed more-extensive behavioral deficits and urodynamic changes than did rats with unilateral PD. These significant changes in motor, behavioral, bladder function and VE were due to an extensive degeneration of dopaminergic neurons in the substantia nigra region on both sides of the brain. The obtained results were substantiated with appropriate immunohistochemical results.

The Impact of Perpetrator Characteristics on the Completion of a Partner Abuse Intervention Program

This study examined how type of perpetrator (family only [FO] vs. generally violent [GV]), readiness to change, and stake in conformity function separately and together in predicting completion of a partner abuse intervention program (PAIP). Data were collected from 192 male perpetrators of intimate partner violence (IPV) who were court mandated to attend a PAIP. Participants were categorized as FO violent or GV based on a combination of their self-report and official records of violence. Stake in conformity has been defined as the degree to which an individual is invested in the values and institutions of a society. A composite stake in conformity score was computed for each participant based on his education level, and marital and employment status. Each participant was also assigned a stage of change score based on his responses on a validated measure of stage of change for domestic violence perpetrators. Analyses indicated that stage of change was not related to program completion or attendance. Type of perpetrator and stake in conformity composite score were significantly related to program completion. Perpetrators with higher stake in conformity scores and individuals categorized as FO attended more PAIP sessions and were more likely to complete the program. When both predictors were examined together, only stake in conformity composite score uniquely predicted program attendance and completion. These findings provide additional evidence that subtype of IPV perpetrator has implications for treatment responsiveness and provide preliminary evidence for the value of improved measurement of investment in societal institutions.

The neuroprotective action of lenalidomide on rotenone model of Parkinson's Disease: Neurotrophic and supportive actions in the substantia nigra pars compacta

Lenalidomide is a centrally active thalidomide analog that has potent anti-inflammatory and antiangiogenic activities. Currently, it is primarily used in the treatment of multiple myeloma and myelodysplastic syndromes. However, recent studies have revealed in addition to neuroprotection and neuromodulation of lenalidomide. Because of this combination of inflammation and neuro-immunogenic properties, lenalidomide is considered as a high potential compound for the treatment of neurodegenerative diseases. Despite intensive research during the last decade, the role of neurotrophic elements in the effect of lenalidomide is still not well understood. Therefore, in the current study, the effects of lenalidomide on neurodegeneration were investigated in a rotenone model of Parkinson's disease (PD) rat model. The PD rat model was generated by rotenone injection into the substantia nigra pars compacta (SNpc). After validation of the PD model, the rats were treated with lenalidomide (100 mg/kg) for 28 days. Our data shows that lenalidomide alleviated rotenone-induced motor impairments and deficits in dopamine-related behaviors and resulted in increased levels of tumor necrosis factor-α and calcium-binding protein B in the SNpc. Moreover, chronic lenalidomide treatment resulted increase in transforming growth factor immunoreactivity and brain derived neurotrophic factor expression in the SNPc. In addition, chronic treatment mitigated tyrosine hydroxylase expression prevented the rotenone-induced decrease in dopamine levels, and consequently a decrease in caspase-3/9 immunoreactivity. This thus shows that chronic lenalidomide treatment improves neuronal survival. Together with our data demonstrate that lenalidomide, in addition to its anti-inflammatory and immunomodulatory actions, is also capable of increasing neurotrophic factors in the SNpc, thereby preventing rotenone-induced motor impairments.

Neuroprotective action of agmatine in rotenone-induced model of Parkinson's disease: Role of BDNF/cREB and ERK pathway

Numerous studies have investigated the role of agmatine in the central nervous system and indicated neuroprotective properties. In addition to its potent antioxidant effects, agmatine is an endogenous neuromodulator and has wide spectrum molecular actions on different receptor subtypes (NMDA, Imidazoline 1-2, alpha-2 adrenoreceptor, 5-HT2a, 5-HT3) and cellular signaling pathways (MAPK, PKA, NO, BDNF). Although the neuroprotective effects of agmatine demonstrated in experimental Parkinson's disease model, the effects of agmatine with the aspect of neuroplasticity and possible signaling mechanisms behind agmatine actions have not been investigated. Herein, in this study, we investigated the role of the of agmatine on rotenone-induced Parkinson's disease model. Agmatine at the dose of 100 mg/kg i.p., was mitigated oxidative damage and alleviated motor impairments which were the results of the rotenone insult. Additionally, agmatine decreased neuronal loss, tyrosine hydroxylase immunoreactivity and increased cREB, BDNF and ERK1/2 expression in the striatum, which are crucial neuroplasticity elements of striatal integrity. Taken together, the present study expands the knowledge of molecular mechanisms behind neuroprotective actions of agmatine in Parkinson's disease, and as far as we have known, this is the first study to delineate agmatine treated activation of cellular pathways which are important elements in neuronal cell survival.

Reconsidering the RBANS Factor Structure: a Systematic Literature Review and Meta-Analytic Factor Analysis

The primary aim was to perform a systematic literature review and extract data necessary for a meta-analytic factor analysis of the RBANS. Secondary aims were to examine the potential validity and utility of the resulting factor structure. Literature was identified through a review of PsycINFO, PubMed, MEDLINE, Academic Search Complete, Psychology & Behavioral Sciences Collection, CINAHL Complete, Health Source: Nursing/Academic Edition, and SocINDEX. A two-stage meta-analytic structural equation modeling method was implemented to pool correlation matrices from primary studies and perform confirmatory factor analyses. Following model selection, factor scores were computed for two datasets and subjected to correlation and diagnostic accuracy analyses. A pooled correlation matrix was computed from 24 sample correlation matrices (N = 5299). Confirmatory factor analysis revealed that the theoretical five-factor model produced the best fit but only when error terms between Story Memory and Story Recall as well as between Figure Copy and Figure Recall were included. Regression-based factor scores showed mixed relationships with the manual-defined indices, and the overall diagnostic accuracy of the factor scores was adequate in both samples examined (AUC = 0.71 and 0.87). The five-factor model was an unexpected result given the failure of multiple previous studies to find support for that model. The five-factor model demonstrates several areas of potential improvement, including better representation of the factors by the indicators. The factor scores implied by this model also require further validation.

Intrastriatal administration of coenzyme Q10 enhances neuroprotection in a Parkinson's disease rat model

Parkinson's disease is a neurodegenerative disorder, and no treatment has been yet established to prevent disease progression. Coenzyme Q10, an antioxidant, has been considered a promising neuroprotective agent; however, conventional oral administration provides limited efficacy due to its very low bioavailability. In this study, we hypothesised that continuous, intrastriatal administration of a low dose of Coenzyme Q10 could effectively prevent dopaminergic neuron degeneration. To this end, a Parkinson's disease rat model induced by 6-hydroxydopamine was established, and the treatment was applied a week before the full establishment of this disease model. Behavioural tests showed a dramatically decreased number of asymmetric rotations in the intrastriatal Coenzyme Q10 group compared with the no treatment group. Rats with intrastriatal Coenzyme Q10 exposure also exhibited a larger number of dopaminergic neurons, higher expression of neurogenetic and angiogenetic factors, and less inflammation, and the effects were more prominent than those of orally administered Coenzyme Q10, although the dose of intrastriatal Coenzyme Q10 was 17,000-times lower than that of orally-administered Coenzyme Q10. Therefore, continuous, intrastriatal delivery of Coenzyme Q10, especially when combined with implantable devices for convection-enhanced delivery or deep brain stimulation, can be an effective strategy to prevent neurodegeneration in Parkinson's disease.

Docosahexaenoic acid protects motor function and increases dopamine synthesis in a rat model of Parkinson's disease via mechanisms associated with increased protein kinase activity in the striatum

Parkinson's disease (PD) is a devastating neurodegenerative disease that leads to motor deficits and selective destruction of nigrostriatal dopaminergic neurons. PD is typically treated by dopamine replacement agents; however, dopamine replacement loses effectiveness in the later stages of the disease. Here, we describe the neuroprotective effects of the omega-3 fatty acid docosahexaenoic acid (DHA) in the medial forebrain bundle 6-hydroxydopamine (6-OHDA) model of advanced-stage PD in rats. We show that daily administration of DHA protects against core symptoms of PD, including deficits in postural stability, gait integrity, and dopamine neurochemistry in motor areas of the striatum. Our results also demonstrate that DHA increases striatal dopamine synthesis via phosphorylation of the rate-limiting catecholamine synthesizing enzyme tyrosine hydroxylase, in a manner dependent on the second messenger-linked protein kinases PKA and PKC. We also show that DHA specifically reverses dopamine loss in the nigrostriatal pathway, with no effect in the mesolimbic or mesocortical pathways. This suggests that DHA is unlikely to produce pharmacotherapeutic or adverse effects that depend on dopamine pathways other than the nigrostriatal pathway. To our knowledge, previous reports have not examined the effects of DHA in such an advanced-stage model, documented that the dopamine synthesizing effects of DHA in vivo are mediated through the activation of protein kinases and regulation of TH activity, or demonstrated specificity to the nigrostriatal pathway. These novel findings corroborate the beneficial effects of omega-3 fatty acids seen in PD patients and suggest that DHA provides a novel means of protecting patients for dopamine neurodegeneration.

An Efficient, Parallelized Algorithm for Optimal Conditional Entropy-Based Feature Selection

In Machine Learning, feature selection is an important step in classifier design. It consists of finding a subset of features that is optimum for a given cost function. One possibility to solve feature selection is to organize all possible feature subsets into a Boolean lattice and to exploit the fact that the costs of chains in that lattice describe U-shaped curves. Minimization of such cost function is known as the U-curve problem. Recently, a study proposed U-Curve Search (UCS), an optimal algorithm for that problem, which was successfully used for feature selection. However, despite of the algorithm optimality, the UCS required time in computational assays was exponential on the number of features. Here, we report that such scalability issue arises due to the fact that the U-curve problem is NP-hard. In the sequence, we introduce the Parallel U-Curve Search (PUCS), a new algorithm for the U-curve problem. In PUCS, we present a novel way to partition the search space into smaller Boolean lattices, thus rendering the algorithm highly parallelizable. We also provide computational assays with both synthetic data and Machine Learning datasets, where the PUCS performance was assessed against UCS and other golden standard algorithms in feature selection.

Probiotics Alleviate the Progressive Deterioration of Motor Functions in a Mouse Model of Parkinson's Disease

Parkinson’s disease (PD) is one of the common long-term degenerative disorders that primarily affect motor systems. Gastrointestinal (GI) symptoms are common in individuals with PD and often present before motor symptoms. It has been found that gut dysbiosis to PD pathology is related to the severity of motor and non-motor symptoms in PD. Probiotics have been reported to have the ability to improve the symptoms related to constipation in PD patients. However, the evidence from preclinical or clinical research to verify the beneficial effects of probiotics for the motor functions in PD is still limited. An experimental PD animal model could be helpful in exploring the potential therapeutic strategy using probiotics. In the current study, we examined whether daily and long-term administration of probiotics has neuroprotective effects on nigrostriatal dopamine neurons and whether it can further alleviate the motor dysfunctions in PD mice. Transgenic MitoPark PD mice were chosen for this study and the effects of daily probiotic treatment on gait, beam balance, motor coordination, and the degeneration levels of dopaminergic neurons were identified. From the results, compared with the sham treatment group, we found that the daily administration of probiotics significantly reduced the motor impairments in gait pattern, balance function, and motor coordination. Immunohistochemically, a tyrosine hydroxylase (TH)-positive cell in the substantia nigra was significantly preserved in the probiotic-treated PD mice. These results showed that long-term administration of probiotics has neuroprotective effects on dopamine neurons and further attenuates the deterioration of motor dysfunctions in MitoPark PD mice. Our data further highlighted the promising possibility of the potential use of probiotics, which could be the relevant approach for further application on human PD subjects.

Early transcranial direct current stimulation treatment exerts neuroprotective effects on 6-OHDA-induced Parkinsonism in rats

BACKGROUND

Transcranial direct current stimulation (tDCS) has been proven to be able to modulate motor cortical plasticity might have potential as an alternative, adjunctive therapy for Parkinson's disease (PD). However, the efficacy of tDCS in PD is still uncertain. A disease animal model may be useful to clarify the existence of a treatment effect and to explore an effective therapeutic strategy using tDCS protocols.

OBJECTIVE

The current study was designed to identify the comprehensive therapeutic effects of tDCS in 6-hydroxydopamine (6-OHDA)-lesioned PD rats.

METHODS

Following early and long-term tDCS application (starting 24 h after PD lesion, 300 μA anodal tDCS, 20 min/day, 5 days/week) in awake PD animals for a total of 4 weeks, the effects of tDCS on motor and non-motor behaviors as well as dopaminergic neuron degeneration levels, were identified.

RESULTS

We found that the 4-week tDCS intervention significantly alleviated 6-OHDA-induced motor deficits in locomotor activity, akinesia, gait pattern and anxiety-like behavior, but not in apomorphine-induced rotations, recognition memory and depression-like behavior. Immunohistochemically, tyrosine hydroxylase (TH)-positive neurons in the substantia nigra were significantly preserved in the tDCS intervention group.

CONCLUSIONS

These results suggest that early and long-term tDCS could exert neuroprotective effects and reduce the aggravation of motor dysfunctions in a 6-OHDA-induced PD rat model. Furthermore, this preclinical model may enhance the promising possibility of the potential use of tDCS and serve as a translational platform to further identify the therapeutic mechanism of tDCS for PD or other neurological disorders.

Sufficient Solvability Conditions for Systems of Partial Fuzzy Relational Equations

This paper focuses on searching sufficient conditions for the solvability of systems of partial fuzzy relational equations. In the case of solvable systems, we provide solutions of the systems. Two standard systems of fuzzy relational equations – namely the systems built on the basic composition and on the Bandler-Kohout subproduct – are considered under the assumption of partiality. Such an extension requires to employ partial algebras of operations for dealing with undefined values. In this investigation, we consider seven most-known algebras of undefined values in partial fuzzy set theory such as the Bochvar, Bochvar external, Sobociński, McCarthy, Nelson, Kleene, and the Łukasiewicz algebra. Conditions that are sufficient for the solvability of the systems are provided. The crucial role will be played by the so-called boundary condition.

Long-Term Voluntary Physical Exercise Exerts Neuroprotective Effects and Motor Disturbance Alleviation in a Rat Model of Parkinson's Disease

Background

Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder affecting 7–10 million individuals. The pathologic hallmark of PD is nigrostriatal dopaminergic neuron loss, leading to several motor and nonmotor disturbances, such as akinesia, gait disturbance, depression, and anxiety. Recent animal studies have demonstrated that physical exercise improves behavioral and neuropathological deficits in PD. However, the exact underlying mechanism underlying this effect remains unclear. In this study, we investigated whether long-term exercise has neuroprotective effects on dopaminergic nigrostriatal neurons and whether it further alleviates impairment of the gait pattern, locomotor activity, akinesia, and anxiety-like behavior in PD rats.

Methods

A hemiparkinsonian rat model, generated by unilateral injection of 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle, was applied to evaluate neuroprotective effects and motor behaviors. Comprehensive spatiotemporal gait analysis, open-field locomotor activity, akinesia, apomorphine-induced rotational analysis, and dopaminergic neuron degeneration level were assessed every week and up to 8 weeks after daily voluntary running wheel exercise.

Results

Compared with the sham-treated group, we found that 10 weeks of voluntary exercise (i.e., 2-week exercise before PD lesion and 8-week exercise post-PD lesion) significantly reduced 6-OHDA-induced motor deficits in the gait pattern, akinesia, and rotational behavior in the exercise group. Immunohistochemically, a tyrosine hydroxylase-positive neuron in the substantia nigra was significantly preserved in the exercise group.

Conclusions

Our results demonstrated that long-term exercise training is effective for neuroprotection and further attenuates motor declines induced by 6-OHDA in an experimental model of PD. Our data further highlighted potential therapeutic effects of long-term physical exercise relevant to clinical effects for further potential application on human PD subjects.

Metabolomic studies of Pseudomonas aeruginosa

Pseudomonas aeruginosa is a common, Gram-negative environmental organism. It can be a significant pathogenic factor of severe infections in humans, especially in cystic fibrosis patients. Due to its natural resistance to antibiotics and the ability to form biofilms, infection with this pathogen can cause severe therapeutic problems. In recent years, metabolomic studies of P. aeruginosa have been performed. Therefore, in this review, we discussed recent achievements in the use of metabolomics methods in bacterial identification, differentiation, the interconnection between genome and metabolome, the influence of external factors on the bacterial metabolome and identification of new metabolites produced by P. aeruginosa. All of these studies may provide valuable information about metabolic pathways leading to an understanding of the adaptations of bacterial strains to a host environment, which can lead to new drug development and/or elaboration of new treatment and diagnostics strategies for Pseudomonas.

Brain Changes during Phyletic Dwarfing in Elephants and Hippos

Of all known insular mammals, hippos and elephants present the extremes of body size decrease, reducing to 4 and a mere 2% of their ancestral mainland size, respectively. Despite the numerous studies on these taxa, what happens to their relative brain size during phyletic dwarfing is not well known, and results are sometimes conflicting. For example, relative brain size increase has been noted in the Sicilian dwarf elephant, Palaeoloxodon falconeri, whereas relative brain size decrease has been postulated for Malagasy dwarf hippos. Here, I perform an analysis of brain, skull, and body size of 3 insular elephants (Palaeoloxodon "mnaidriensis," P. tiliensis, and P. falconeri) and 3 insular hippos (Hippopotamus madagascariensis, H. lemerlei, and H. minor) to address this issue and to test whether relative brain size in phyletic dwarf species can be predicted. The results presented here show that the encephalization of all insular elephants and hippos is higher than that of their continental relatives. P. falconeri in particular has an enormous encephalization increase, which has so far not been reported in any other insular mammal. Insular brain size cannot be reliably predicted using either static allometric or ontogenetic scaling models. The results of this study indicate that insular dwarf species follow brain-body allometric relationships different from the expected patterns seen for their mainland relatives.

Translational methods to detect asymmetries in temporal and spatial walking metrics in parkinsonian mouse models and human subjects with Parkinson's disease

Clinical signs in Parkinson's disease (PD), including parkinsonian gait, are often asymmetric, but mechanisms underlying gait asymmetries in PD remain poorly understood. A translational toolkit, a set of standardized measures to capture gait asymmetries in relevant mouse models and patients, would greatly facilitate research efforts. We validated approaches to quantify asymmetries in placement and timing of limbs in mouse models of parkinsonism and human PD subjects at speeds that are relevant for human walking. In mice, we applied regression analysis to compare left and right gait metrics within a condition. To compare alternation ratios of left and right limbs before and after induction of parkinsonism, we used circular statistics. Both approaches revealed asymmetries in hind- and forelimb step length in a unilateral PD model, but not in bilateral or control models. In human subjects, a similar regression approach showed a step length asymmetry in the PD but not control group. Sub-analysis of cohorts with predominant postural instability-gait impairment and with predominant tremor revealed asymmetries for step length in both cohorts and for swing time only in the former cohort. This translational approach captures asymmetries of gait in mice and patients. Application revealed striking differences between models, and that spatial and temporal asymmetries may occur independently. This approach will be useful to investigate circuit mechanisms underlying the heterogeneity between models.

Effective Parameters for Gait Analysis in Experimental Models for Evaluating Peripheral Nerve Injuries in Rats

Objective

Chronic constriction injury (CCI) of the sciatic nerve is a peripheral nerve injury widely used to induce mononeuropathy. This study used machine learning methods to identify the best gait analysis parameters for evaluating peripheral nerve injuries.

Methods

Twenty-eight male Wistar rats (weighing 270±10 g), were used in the present study and divided into the following 4 groups: CCI with 4 ligatures around the sciatic nerve (CCI-4L; n=7), a modified CCI model with 1 ligature (CCI-1L; n=7), a sham group (n=7), and a healthy control group (n=7). All rats underwent gait analysis 7 and 28 days postinjury. The data were evaluated using Kinovea and WeKa software (machine learning and neural networks).

Results

In the machine learning analysis of the experimental groups, the pre-swing (PS) angle showed the highest ranking in all 3 analyses (sensitivity, specificity, and area under the receiver operating characteristics curve using the Naive Bayes, k-nearest neighbors, radial basis function classifiers). Initial contact (IC), step length, and stride length also performed well. Between 7 and 28 days after injury, there was an increase in the total course time, step length, stride length, stride speed, and IC, and a reduction in PS and IC-PS. Statistically significant differences were found between the control group and experimental groups for all parameters except speed. Interactions between time after injury and nerve injury type were only observed for IC, PS, and IC-PS.

Conclusion

PS angle of the ankle was the best gait parameter for differentiating nonlesions from nerve injuries and different levels of injury.

Biomimetic Photocurable Three-Dimensional Printed Nerve Guidance Channels with Aligned Cryomatrix Lumen for Peripheral Nerve Regeneration

Repair and regeneration of critically injured peripheral nerves is one of the most challenging reconstructive surgeries. Currently available and FDA approved nerve guidance channels (NGCs) are suitable for small gap injuries, and their biological performance is inferior to that of autografts. Development of biomimetic NGCs with clinically relevant geometrical and biological characteristics such as topographical, biochemical, and haptotactic cues could offer better regeneration of the long-gap complex nerve injuries. Here, in this study, we present the development and preclinical analysis of three-dimensional (3D) printed aligned cryomatrix-filled NGCs along with nerve growth factor (NGF) (aCG + NGF) for peripheral nerve regeneration. We demonstrated the application of these aCG + NGF NGCs in the enhanced and successful regeneration of a critically injured rat sciatic nerve in comparison to random cryogel-filled NGCs, multichannel and clinically preferred hollow conduits, and the gold standard autografts. Our results indicated similar effect of the aCG + NGF NGCs viz-a-viz that of the autografts, and they not only enhanced the overall regenerated nerve physiology but could also mimic the cellular aspects of regeneration. This study emphasizes the paradigm that these biomimetic 3D printed NGCs will lead to a better functional regenerative outcome under clinical settings.

Exceptional dinosaur fossils reveal early origin of avian-style digestion

Birds have a highly specialized and efficient digestive system, but when this system originated remains uncertain. Here we report six gastric pellets attributable to the recently discovered 160-million-year-old troodontid dinosaur Anchiornis, which is among the key taxa for understanding the transition to birds. The gastric pellets contain lightly acid-etched lizard bones or fish scales, and some are associated with Anchiornis skeletons or even situated within the oesophagus. Anchiornis is the earliest and most basal theropod known to have produced gastric pellets. In combination with other lines of evidence, the pellets suggest that a digestive system resembling that of modern birds was already present in basal members of the Paraves, a clade including troodontids, dromaeosaurids, and birds, and that the evolution of modern avian digestion may have been related to the appearance of aerial locomotion in this lineage.

Glucose-Dependent Insulinotropic Polypeptide Mitigates 6-OHDA-Induced Behavioral Impairments in Parkinsonian Rats

In the present study, the effectiveness of glucose-dependent insulinotropic polypeptide (GIP) was evaluated by behavioral tests in 6-hydroxydopamine (6-OHDA) hemi-parkinsonian (PD) rats. Pharmacokinetic measurements of GIP were carried out at the same dose studied behaviorally, as well as at a lower dose used previously. GIP was delivered by subcutaneous administration (s.c.) using implanted ALZET micro-osmotic pumps. After two days of pre-treatment, male Sprague Dawley rats received a single unilateral injection of 6-OHDA into the medial forebrain bundle (MFB). The neuroprotective effects of GIP were evaluated by apomorphine-induced contralateral rotations, as well as by locomotor and anxiety-like behaviors in open-field tests. Concentrations of human active and total GIP were measured in plasma during a five-day treatment period by ELISA and were found to be within a clinically translatable range. GIP pretreatment reduced behavioral abnormalities induced by the unilateral nigrostriatal dopamine (DA) lesion produced by 6-OHDA, and thus may be a novel target for PD therapeutic development.

Gait Analysis for Early Detection of Motor Symptoms in the 6-OHDA Rat Model of Parkinson's Disease

Computer-supported gait analysis has proven to be effective for the comprehensive assessment of gait changes in rodent models of neurodegenerative and neurological disorders. However, full characterization of individual gait parameters is required for specific neurological or neurodegenerative disorders such as Parkinson's disease (PD). Gait disturbances in particular present as the most constraining set of symptoms in PD, finally depriving patients from most activities of normal daily living. In this study, we have characterized the gait pattern abnormalities observed in two rat models of PD: the medial forebrain bundle (MFB) 6-OHDA lesion model and the striatal 6-OHDA lesion model. Our data indicates significant changes in 21 different gait parameters in the MFB lesion cohort. We observed a steady decline in the overall walking speed and cadence, as well as significant alterations in the gait parameters stride length, initial dual stance, paw print position, step cycle, swing phase of the step cycle, stand index, phase dispersion, print length, and print area in at least one of the paws. These alterations correlated with the extent of tyrosine hydroxylase (TH) neuronal loss observed in this group. These alterations were detected as early as 1 week post lesion. In contrast, limited gait dysfunction was detected in the striatal lesion cohort related to the low level of TH neuronal loss detected in this group. In this study we have demonstrated that gait analysis is a reliable method for the detection of motor deficiencies in a MFB 6-OHDA lesion model of PD and may prove a clinically relevant, low impact method of testing functional impairment as early as 1 week post lesion.

Exercise Ameliorates Motor Deficits and Improves Dopaminergic Functions in the Rat Hemi-Parkinson's Model

To determine the influences of exercise on motor deficits and dopaminergic transmission in a hemiparkinson animal model, we measured the effects of exercise on the ambulatory system by estimating spatio-temporal parameters during walking, striatal dopamine (DA) release and reuptake and synaptic plasticity in the corticostriatal pathway after unilateral 6-OHDA lesions. 6-OHDA lesioned hemiparkinsonian rats were exercised on a fixed speed treadmill for 30 minutes per day. Controls received the same lesion but no exercise. Animals were subsequently analyzed for behavior including gait analysis, rotarod performance and apomorphine induced rotation. Subsequently, in vitro striatal dopamine release was analyzed by using FSCV and activity-dependent plasticity in the corticostriatal pathway was measured in each group. Our data indicated that exercise could improve motor walking speed and increase the apomorphine-induced rotation threshold. Exercise also ameliorated spatiotemporal impairments in gait in PD animals. Exercise increased the parameters of synaptic plasticity formation in the corticostriatal pathway of PD animals as well as the dynamics of dopamine transmission in PD animals. Fixed speed treadmill training 30 minutes per day could ameliorate spatial-temporal gait impairment, improve walking speed, dopamine transmission as well as corticostriatal synaptic plasticity in the unilateral 6-OHDA lesioned rat model.