Evaluation of forelimb gait variation overground at a walk in sound and lame dogs using a combination of diagnostic techniques.

BACKGROUND: Kinetic and kinematic gait analysis is increasingly practised as a part of lameness evaluation in dogs. The aim of this study was to examine the normal short- and long-term variation in forelimb gait in sound control dogs (CD) at a walk using seven selected variables of objective kinetic and kinematic gait analyses. Also, to compare the findings in CD to a group of forelimb lame dogs with elbow osteoarthritis (OAD). An additional aim was to test a kinetic based graphic method for lameness detection; symmetry squares (SS). A prospective longitudinal study was carried out on client owned CD and OAD. Clinical and orthopaedic evaluations were performed to ensure soundness and detect and grade lameness. Seven kinetic and kinematic variables and SS were tested for lameness evaluation. The CD were divided into two subgroups, CD1 and CD2, and examined twice: CD1 with two months interval and CD2 with 3-4 h interval. The OAD group was evaluated once and compared to the CD groups' first examination. RESULTS: Thirteen CD and 19 OAD were included. For CD1 and CD2, there were no significant differences in any examined variable between examination occasions. Total peak force/impulse symmetry and fore-hind peak force/impulse symmetry differed significantly between OAD and CD. Symmetry squares had a 74% agreement to subjective orthopaedic evaluations. CONCLUSIONS: In CD, no difference in the examined variables was seen between examination occasions. Four out of seven objective variables differed significantly between CD and OAD. The graphic SS method might have diagnostic potential for lameness detection, making it possible to detect a shift from lame to non-lame limbs. Potentially, this might be especially helpful in bilaterally lame dogs, which often represent a clinical challenge in lameness evaluation.

Changes in intra- and interlimb reflexes from hindlimb cutaneous afferents after staggered thoracic lateral hemisections during locomotion in cats.

When the foot dorsum contacts an obstacle during locomotion, cutaneous afferents signal central circuits to coordinate muscle activity in the four limbs. Spinal cord injury disrupts these interactions, impairing balance and interlimb coordination. We evoked cutaneous reflexes by electrically stimulating left and right superficial peroneal nerves before and after two thoracic lateral hemisections placed on opposite sides of the cord at 9- to 13-week interval in seven adult cats (4 males and 3 females). We recorded reflex responses in ten hindlimb and five forelimb muscles bilaterally. After the first (right T5-T6) and second (left T10-T11) hemisections, coordination of the fore- and hindlimbs was altered and/or became less consistent. After the second hemisection, cats required balance assistance to perform quadrupedal locomotion. Short-latency reflex responses in homonymous and crossed hindlimb muscles largely remained unaffected after staggered hemisections. However, mid- and long-latency homonymous and crossed responses in both hindlimbs occurred less frequently after staggered hemisections. In forelimb muscles, homolateral and diagonal mid- and long-latency response occurrence significantly decreased after the first and second hemisections. In all four limbs, however, when present, short-, mid- and long-latency responses maintained their phase-dependent modulation. We also observed reduced durations of short-latency inhibitory homonymous responses in left hindlimb extensors early after the first hemisection and delayed short-latency responses in the right ipsilesional hindlimb after the first hemisection. Therefore, changes in cutaneous reflex responses correlated with impaired balance/stability and interlimb coordination during locomotion after spinal cord injury. Restoring reflex transmission could be used as a biomarker to facilitate locomotor recovery. KEY POINTS: Cutaneous afferent inputs coordinate muscle activity in the four limbs during locomotion when the foot dorsum contacts an obstacle. Thoracic spinal cord injury disrupts communication between spinal locomotor centres located at cervical and lumbar levels, impairing balance and limb coordination. We investigated cutaneous reflexes during quadrupedal locomotion by electrically stimulating the superficial peroneal nerve bilaterally, before and after staggered lateral thoracic hemisections of the spinal cord in cats. We showed a loss/reduction of mid- and long-latency responses in all four limbs after staggered hemisections, which correlated with altered coordination of the fore- and hindlimbs and impaired balance. Targeting cutaneous reflex pathways projecting to the four limbs could help develop therapeutic approaches aimed at restoring transmission in ascending and descending spinal pathways.

Rehabilitative training improves skilled forelimb motor function after cervical unilateral contusion spinal cord injury in rats.

Animal models of cervical spinal cord injury (SCI) have frequently utilized partial transection injuries to evaluate plasticity promoting treatments such as rehabilitation training of skilled reaching and grasping tasks. Though highly useful for studying the effects of cutting specific spinal tracts that are important for skilled forelimb motor function, cervical partial-transection SCI-models underappreciate the extensive spread of most human SCIs, thus offering poor predictability for the clinical setting. Conversely, moderate cervical contusion SCI models targeting the spinal tracts important for skilled reaching and grasping can better replicate the increased size of most human SCIs and are often considered more clinically relevant. However, it is unknown whether animals with moderate cervical contusion SCIs that damage key spinal motor tracts can train in skilled reaching and grasping tasks. In this study, we quantify the impact of injury size and distribution on recovery in a skilled motor task called the single pellet reaching, grasping and retrieval (SPRGR) task in rats with cervical unilateral contusion injuries (UCs), and compare to rats with a partial transection SCIs (i.e., dorsolateral quadrant transection; DLQ). We found that UCs damage key tracts important for performing skilled motor tasks, similar to DLQs, but UCs also produce more extensive grey matter damage and more ventral white matter damage than DLQs. We also compared forelimb functionality at 1, 3, and 5 weeks of rehabilitative motor training between trained and untrained rats and found a more severe drop in SPRGR performance than in DLQ SCIs. Nevertheless, despite more severe injuries and initially low SPRGR performance, rehabilitative training for contusion animals resulted in significant improvements in SPRGR performance and proportionally more recovery than DLQ rats. Our findings show that rehabilitative motor training can facilitate considerable amounts of motor recovery despite extensive spinal cord damage, especially grey matter damage, thus supporting the use of contusion or compression SCI models and showing that ventral grey and white matter damage are not necessarily detrimental to recovery after training.

Impaired Refinement of Kinematic Variability in Huntington Disease Mice on an Automated Home Cage Forelimb Motor Task.

The effective development of novel therapies in mouse models of neurologic disorders relies on behavioral assessments that provide accurate read-outs of neuronal dysfunction and/or degeneration. We designed an automated behavioral testing system (PiPaw), which integrates an operant lever-pulling task directly into the mouse home cage. This task is accessible to group-housed mice 24 h per day, enabling high-throughput longitudinal analysis of forelimb motor learning. Moreover, this design eliminates the need for exposure to novel environments and minimizes experimenter interaction, significantly reducing two of the largest stressors associated with animal behavior. Male mice improved their performance of this task over 1 week of testing by reducing intertrial variability of reward-related kinematic parameters (pull amplitude or peak velocity). In addition, mice displayed short-term improvements in reward rate, and a concomitant decrease in movement variability, over the course of brief bouts of task engagement. We used this system to assess motor learning in mouse models of the inherited neurodegenerative disorder, Huntington disease (HD). Despite having no baseline differences in task performance, male Q175-FDN HD mice were unable to modulate the variability of their movements to increase reward on either short or long timescales. Task training was associated with a decrease in the amplitude of spontaneous excitatory activity recorded from striatal medium spiny neurons in the hemisphere contralateral to the trained forelimb in WT mice; however, no such changes were observed in Q175-FDN mice. This behavioral screening platform should prove useful for preclinical drug trials toward improved treatments in HD and other neurologic disorders.SIGNIFICANCE STATEMENT In order to develop effective therapies for neurologic disorders, such as Huntington disease (HD), it is important to be able to accurately and reliably assess the behavior of mouse models of these conditions. Moreover, these behavioral assessments should provide an accurate readout of underlying neuronal dysfunction and/or degeneration. In this paper, we used an automated behavioral testing system to assess motor learning in mice within their home cage. Using this system, we were able to study motor abnormalities in HD mice with an unprecedented level of detail, and identified a specific behavioral deficit associated with an underlying impairment in striatal neuronal plasticity. These results validate the usefulness of this system for assessing behavior in mouse models of HD and other neurologic disorders.

Long-Term Suppression of c-Jun and nNOS Preserves Ultrastructural Features of Lower Motor Neurons and Forelimb Function after Brachial Plexus Roots Avulsion.

Brachial plexus root avulsions cause debilitating upper limb paralysis. Short-term neuroprotective treatments have reported preservation of motor neurons and function in model animals while reports of long-term benefits of such treatments are scarce, especially the morphological sequelae. This morphological study investigated the long-term suppression of c-Jun- and neuronal nitric oxide synthase (nNOS) (neuroprotective treatments for one month) on the motor neuron survival, ultrastructural features of lower motor neurons, and forelimb function at six months after brachial plexus roots avulsion. Neuroprotective treatments reduced oxidative stress and preserved ventral horn motor neurons at the end of the 28-day treatment period relative to vehicle treated ones. Motor neuron sparing was associated with suppression of c-Jun, nNOS, and pro-apoptotic proteins Bim and caspases at this time point. Following 6 months of survival, neutral red staining revealed a significant loss of most of the motor neurons and ventral horn atrophy in the avulsed C6, 7, and 8 cervical segments among the vehicle-treated rats (n = 4). However, rats that received neuroprotective treatments c-Jun JNK inhibitor, SP600125 (n = 4) and a selective inhibitor of nNOS, 7-nitroindazole (n = 4), retained over half of their motor neurons in the ipsilateral avulsed side compared. Myelinated axons in the avulsed ventral horns of vehicle-treated rats were smaller but numerous compared to the intact contralateral ventral horns or neuroprotective-treated groups. In the neuroprotective treatment groups, there was the preservation of myelin thickness around large-caliber axons. Ultrastructural evaluation also confirmed the preservation of organelles including mitochondria and synapses in the two groups that received neuroprotective treatments compared with vehicle controls. Also, forelimb functional evaluation demonstrated that neuroprotective treatments improved functional abilities in the rats. In conclusion, neuroprotective treatments aimed at suppressing degenerative c-Jun and nNOS attenuated apoptosis, provided long-term preservation of motor neurons, their organelles, ventral horn size, and forelimb function.

Unusual Quadrupedal Locomotion in Rat during Recovery from Lumbar Spinal Blockade of 5-HT7 Receptors.

Coordination of four-limb movements during quadrupedal locomotion is controlled by supraspinal monoaminergic descending pathways, among which serotoninergic ones play a crucial role. Here we investigated the locomotor pattern during recovery from blockade of 5-HT7 or 5-HT2A receptors after intrathecal application of SB269970 or cyproheptadine in adult rats with chronic intrathecal cannula implanted in the lumbar spinal cord. The interlimb coordination was investigated based on electromyographic activity recorded from selected fore- and hindlimb muscles during rat locomotion on a treadmill. In the time of recovery after hindlimb transient paralysis, we noticed a presence of an unusual pattern of quadrupedal locomotion characterized by a doubling of forelimb stepping in relation to unaffected hindlimb stepping (2FL-1HL) after blockade of 5-HT7 receptors but not after blockade of 5-HT2A receptors. The 2FL-1HL pattern, although transient, was observed as a stable form of fore-hindlimb coupling during quadrupedal locomotion. We suggest that modulation of the 5-HT7 receptors on interneurons located in lamina VII with ascending projections to the forelimb spinal network can be responsible for the 2FL-1HL locomotor pattern. In support, our immunohistochemical analysis of the lumbar spinal cord demonstrated the presence of the 5-HT7 immunoreactive cells in the lamina VII, which were rarely 5-HT2A immunoreactive.

Effect of thoracic spinal cord injury on forelimb somatosensory evoked potential.

In this paper, we investigate the forelimbs somatosensory evoked potential (SSEP) signals, which are representative of the integrity of ascending sensory pathways and their stability as well as function, recorded from corresponding cortices, post thoracic spinal cord injury (SCI). We designed a series of distinctive transection SCI to investigate whether forelimbs SSEPs change after right T10 hemi-transection, T8 and T10 double hemi-transection and T8 complete transection in rat model of SCI. We used electrical stimuli to stimulate median nerves and recorded SSEPs from left and right somatosensory areas of both cortices. We monitored pre-injury baseline and verified changes in forelimbs SSEP signals on Days 4, 7, 14, and 21 post-injury. We previously characterized hindlimb SSEP changes for the abovementioned transection injuries. The focus of this article is to investigate the quality and quantity of changes that may occur in the forelimb somatosensory pathways post-thoracic transection SCI. It is important to test the stability of forelimb SSEPs following thoracic SCI because of their potential utility as a proxy baseline for the traumatic SCIs in clinical cases wherein there is no opportunity to gather baseline of the lower extremities. We observed that the forelimb SSEP amplitudes increased following thoracic SCI but gradually returned to the baseline. Despite changes found in the raw signals, statistical analysis found forelimb SSEP signals become stable relatively soon. In summary, though there are changes in value (with p > 0.05), they are not statistically significant. Therefore, the null hypothesis that the mean of the forelimb SSEP signals are the same across multiple days after injury onset cannot be rejected during the acute phase.

Navicular Syndrome-related changes to collagen proportion of different cross-sections of the flexor tendons in equine distal forelimb.

The aim of this study was to quantify the distribution of aligned and non-aligned collagen in cross-sections of the superficial digital flexor tendon (SDFT) and deep digital flexor tendon (DDFT) in different levels of the distal forelimb of equines diagnosed with NS (Navicular Syndrome). Sixty equine forelimbs were collected. Was compared two groups (NA, Not affected vs. NS-group) by t-Student. Diagnosis of NS was based on clinical and lameness examination, diagnostic analgesia and radiological findings. The proportion of aligned and non-aligned collagens at 2 levels for the SDFT and 3 levels for the DDFT were measured by histochemical stains. The amount of aligned and non-aligned collagen in tendons were calculated using Colour-Based Segmentation function. Regarding collagen, there were significant differences in the amount of aligned collagen (NA: 21.2 ± 1.31; NS-group: 12.2 ± 4.67; p = 0.0026) and non-aligned collagen (NA: 21.8 ± 2.22; NS: 25.1 ± 1.73; p = 0.0241) at the DDFT insertion in the distal phalanx. We concluded that the flexor tendons of the forelimb in equines with NS have different proportions of collagen than those that do not present the diagnosis, indicated by histologically visible increased proportions of non-aligned collagen and decreased of aligned collagen in the extracellular matrix.

Forelimb Examination, Lameness Assessment, and Kinetic and Kinematic Gait Analysis.

This article contains a guide for small animal practitioners to use when confronted with the challenge of diagnosing a forelimb lameness. The examination begins by monitoring the dog at a stance and a visual gait assessment. A hands-on evaluation includes the initial examination, checking for asymmetry and muscle atrophy while the dog is standing, and step-by-step instructions for a thorough forelimb examination.

Training in a cooperative bimanual skilled reaching task, the popcorn retrieval task, improves unimanual function after motor cortical infarcts in rats.

Disuse of the paretic hand after stroke is encouraged by compensatory reliance on the nonparetic hand, to exacerbate impairment and potentially constrain motor rehabilitation efficacy. Rodent stroke model findings support that learning new unimanual skills with the nonparetic forelimb diminishes functional improvements that can be driven by rehabilitative training of the paretic forelimb. The influence of learning new ways of skillfully using the two hands together on paretic side function is much less clear. To begin to explore this, we developed a new cooperative bimanual skilled reaching task for rats, the Popcorn Retrieval Task. After motor cortical infarcts impaired an established unimanual reaching skill in the paretic forelimb, rats underwent a 7 week period of de novo bimanual training (BiT) or no-training control procedures (Cont). Probes of paretic forelimb unimanual performance revealed significant improvements during and after the training period in BiT vs. Cont. We additionally observed a striking change in the bimanual task strategy over training days: a switch from the paretic to the nonparetic forelimb for initiating reach-to-grasp sequences. This motivated another study to test whether rats that established the bimanual skill prior to the infarcts would similarly switch handedness, which they did not, though paretic paw use for manipulative movements diminished. These results indicate that unimanual function of the paretic side can be improved by novel bimanual skill practice, even when it involves compensatory reliance on the nonparetic hand. They further support the suitability of the Popcorn Retrieval Task for studying bimanual skill learning effects in rats.

A parsimonious laboratory system for the evaluation of rat reaching task: recovery from the massive destruction of motor areas.

The rat reaching task is one of the best paradigms from behavioral study of upper limb movements. Rats are trained to reach and grab a pellet by extending their hand through a vertical slit. A few conventional imaging systems specific for the rat reaching task are commercially available with a high installation cost. Based on image analysis of video recordings obtained during the reaching task, we, herewith, developed a new, low-cost laboratory system that can be used for the quantitative analysis of ten basic forearm movements, in contrast to subjective assessments used in previous studies. We quantified images of the pronated and supinated palm and the accuracy and speed of reaching the target. Applying this newly developed method, we compared the forearm movements during the reaching task before and after a massive anatomical lesion of the sensorimotor cortex performed by tissue aspiration. We also wanted to investigate the recovery of upper limb function possibly induced by repeating the task for a relatively short term of a few weeks. In the experiment, 7 injured groups and 3 control groups were used. We found characteristic abnormalities of the forearm movements and a significant recovery in the success rate of grasping the target pellet. The present results demonstrate that our method is straightforward for the quantitative evaluation of forearm movements during the reaching task primarily controlled by the sensorimotor cortex.

The tactile experience paired with vagus nerve stimulation determines the degree of sensory recovery after chronic nerve damage.

Loss of sensory function is a common consequence of neurological injury. Recent clinical and preclinical evidence indicates vagus nerve stimulation (VNS) paired with tactile rehabilitation, consisting of delivery of a variety of mechanical stimuli to the hyposensitive skin surface, yields substantial and long-lasting recovery of somatosensory function after median and ulnar nerve transection and repair. Here, we tested the hypothesis that a specific component of the tactile rehabilitation paired with VNS is necessary for recovery of somatosensory function. In a second experiment in a separate cohort, we investigated whether VNS paired with tactile rehabilitation could improve skilled forelimb motor function. Elements of the study design, including planned sample size, assessments, and statistical comparisons, were preregistered prior to beginning data collection (https://osf.io/3tm8u/). Animals received a peripheral nerve injury (PNI) causing chronic sensory loss. Eight weeks after injury, animals were given a VNS implant followed by six weeks of tactile rehabilitation sessions consisting of repeated application of one of two distinct mechanical stimuli, a filament or a paintbrush, to the previously denervated forepaw. VNS paired with either filament indentation or brushing of the paw significantly improved recovery of forelimb withdrawal thresholds after PNI compared to tactile rehabilitation without VNS. The effect size was twice as large when VNS was paired with brushing compared to VNS paired with point indentation. An independent replication in a second cohort confirmed that VNS paired with brush restored forelimb withdrawal thresholds to normal. These rats displayed significant improvements in performance on a skilled forelimb task compared to rats that did not receive VNS. These findings support the utility of pairing VNS with tactile rehabilitation to improve recovery of somatosensory and motor function after neurological injury. Additionally, this study demonstrates that the sensory characteristics of the rehabilitation paired with VNS determine the degree of recovery.

Cholinergic upregulation by optogenetic stimulation of nucleus basalis after photothrombotic stroke in forelimb somatosensory cortex improves endpoint and motor but not sensory control of skilled reaching in mice.

A network of cholinergic neurons in the basal forebrain innerve the forebrain and are proposed to contribute to a variety of functions including cortical plasticity, attention, and sensorimotor behavior. This study examined the contribution of the nucleus basalis cholinergic projection to the sensorimotor cortex on recovery on a skilled reach-to-eat task following photothrombotic stroke in the forelimb region of the somatosensory cortex. Mice were trained to perform a single pellet skilled reaching task and their pre and poststroke performance, from Day 4 to Day 28 poststroke, was assessed frame-by-frame by video analysis with endpoint, movement and sensorimotor integration measures. Somatosensory forelimb lesions produced impairments in endpoint and movement component measures of reaching and increased the incidence of fictive eating, a sensory impairment in mistaking a missed reach for a successful reach. Upregulated acetylcholine (ACh) release, as measured by local field potential recording, elicited via optogenetic stimulation of the nucleus basalis improved recovery of reaching and improved movement scores but did not affect sensorimotor integration impairment poststroke. The results show that the mouse cortical forelimb somatosensory region contributes to forelimb motor behavior and suggest that ACh upregulation could serve as an adjunct to behavioral therapy for acute treatment of stroke.

Comparative Enhancement of Motor Function and BDNF Expression Following Different Brain Stimulation Approaches in an Animal Model of Ischemic Stroke.

BACKGROUND: Combinatory intervention such as high-frequency (50-100 Hz) excitatory cortical stimulation (ECS) given concurrently with motor rehabilitative training (RT) improves forelimb function, except in severely impaired animals after stroke. Clinical studies suggest that low-frequency (≤1 Hz) inhibitory cortical stimulation (ICS) may provide an alternative approach to enhance recovery. Currently, the molecular mediators of CS-induced behavioral effects are unknown. Brain-derived neurotrophic factor (BDNF) has been associated with improved recovery and neural remodeling after stroke and thus may be involved in CS-induced behavioral recovery. OBJECTIVE: To investigate whether inhibitory stimulation during RT improves functional recovery of severely impaired rats, following focal cortical ischemia and if this recovery alters BDNF expression (study 1) and depends on BDNF binding to TrkB receptors (study 2). METHODS: Rats underwent ECS + RT, ICS + RT, or noCS + RT treatment daily for 3 weeks following a unilateral ischemic lesion to the motor cortex. Electrode placement for stimulation was either placed ipsilateral (ECS) or contralateral (ICS) to the lesion. After treatment, BDNF expression was measured in cortical tissue samples (study 1). In study 2, the TrkB inhibitor, ANA-12, was injected prior to treatment daily for 21 days. RESULTS: ICS + RT treatment significantly improved impaired forelimb recovery compared with ECS + RT and noCS + RT treatment. CONCLUSION: ICS given concurrently with rehabilitation improves motor recovery in severely impaired animals, and alters cortical BDNF expression; nevertheless, ICS-mediated improvements are not dependent on BDNF binding to TrkB. Conversely, inhibition of TrkB receptors does disrupt motor recovery in ECS + RT treated animals.

The Gigantocellular Reticular Nucleus Plays a Significant Role in Locomotor Recovery after Incomplete Spinal Cord Injury.

Traditionally, the brainstem has been seen as hardwired and poorly capable of plastic adaptations following spinal cord injury (SCI). Data acquired over the past decades, however, suggest differently: following SCI in various animal models (lamprey, chick, rodents, nonhuman primates), different forms of spontaneous anatomic plasticity of reticulospinal projections, many of them originating from the gigantocellular reticular nucleus (NRG), have been observed. In line with these anatomic observations, animals and humans with incomplete SCI often show various degrees of spontaneous motor recovery of hindlimb/leg function. Here, we investigated the functional relevance of two different modes of reticulospinal fiber growth after cervical hemisection, local rewiring of axotomized projections at the lesion site versus compensatory outgrowth of spared axons, using projection-specific, adeno-associated virus-mediated chemogenetic neuronal silencing. Detailed assessment of joint movements and limb kinetics during overground locomotion in female adult rats showed that locally rewired as well as compensatory NRG fibers were responsible for different aspects of recovered forelimb and hindlimb functions (i.e., stability, strength, coordination, speed, or timing). During walking and swimming, both locally rewired as well as compensatory NRG plasticity were crucial for recovered function, while the contribution of locally rewired NRG plasticity to wading performance was limited. Our data demonstrate comprehensively that locally rewired as well as compensatory plasticity of reticulospinal axons functionally contribute to the observed spontaneous improvement of stepping performance after incomplete SCI and are at least partially causative to the observed recovery of function, which can also be observed in human patients with spinal hemisection lesions.SIGNIFICANCE STATEMENT Following unilateral hemisection of the spinal cord, reticulospinal projections are destroyed on the injured side, resulting in impaired locomotion. Over time, a high degree of recovery can be observed in lesioned animals, like in human hemicord patients. In the rat, recovery is accompanied by pronounced spontaneous plasticity of axotomized and spared reticulospinal axons. We demonstrate the causative relevance of locally rewired as well as compensatory reticulospinal plasticity for the recovery of locomotor functions following spinal hemisection, using chemogenetic tools to selectively silence newly formed connections in behaviorally recovered animals. Moving from a correlative to a causative understanding of the role of neuroanatomical plasticity for functional recovery is fundamental for successful translation of treatment approaches from experimental studies to the clinics.

Effects of Combined Bushen Zhichan Recipe and Levodopa in a Rodent Model of Parkinson Disease: Potential Mechanisms.

BACKGROUND Parkinson disease is characterized by the loss of neurons in the substantia nigra, and under pathological conditions, glutamate can produce excitotoxic effects on nerve cells. The astrocytic excitatory amino acid transporter (EAAT) 1 can be functionally upregulated and targeted to functional compartments, resulting in reduced excitotoxicity. levodopa is the gold standard for the treatment of Parkinson disease, but prolonged levodopa treatment often leads to the development of abnormal involuntary movements. Numerous studies suggest the potential beneficial effects of traditional Chinese medicine on Parkinson disease. MATERIAL AND METHODS We validated the efficacy of a Bushen Zhichan recipe combined with levodopa in a rodent Parkinson disease model and explored its possible mechanisms. RESULTS Rats in the combined levodopa and Bushen Zhichan recipe group performed significantly better than the control group in the open field and forelimb function experiments. The number of midbrain dopaminergic neurons in rats in the levodopa and Bushen Zhichan recipe group was greater compared to controls. The levodopa and Bushen Zhichan recipe group exhibited decreased glutamate receptors and increased γ-aminobutyric acid receptors in the striatum. At the same time, EAAT1 was increased and EAAT2 was synchronized with the number of glutamate receptors. CONCLUSIONS Our results indicate that levodopa combined with Bushen Zhichan recipe significantly improves behavior and protects dopaminergic neurons in a rodent Parkinson disease model, and suggest that the mechanism involves the decrease of excitatory amino acid toxicity and the increase in the expression of EAAT1.

Forelimb Cortical Stroke Reduces Precision of Motor Control in Mice.

Background and Objective. Rodent models of stroke impairment should capture translatable features of behavioral injury. This study characterized poststroke impairment of motor precision separately from strength in an automated behavioral assay. Methods. We measured skilled distal forelimb reach-and-grasp motions within a target force range requiring moderate-strength. We assessed whether deficits reflected an increase in errors on only one or both sides of the target force range after photothrombotic cortical stroke. Results. Pull accuracy was impaired for 6 weeks after stroke, with errors redistributing to both sides of the target range. No decrease in maximum force was measured. Conclusions. This automated reach task measures sustained loss of motor precision following cortical stroke in mice.

Subsynovial connective tissue development in the rabbit carpal tunnel.

The carpal tunnel contains the digital flexor tendons and the median nerve, which are embedded in a unique network of fibrovascular interconnected subsynovial connective tissue (SSCT). Fibrous hypertrophy of the SSCT and subsequent adaptations in mechanical response are found in patients with carpal tunnel syndrome (CTS), but not much is known about the development of the SSCT. This observational study describes the morphological development of SSCT using histology and ultramicroscopy in an animal model at four time points between late-term fetuses through adulthood. A transition is seen between 3 days and 6 weeks post-partum from a dense solid SSCT matrix to a complex multilayered structure connected with collagenous fibrils. These preliminary data show a developmental pattern that matches an adaptive response of the SSCT to loading and motion. Understanding the anatomical development aids in recognizing the pathophysiology of CTS and supports research on new therapeutic approaches.

Preventing protein-energy malnutrition after cortical stroke enhances recovery of symmetry in forelimb use during spontaneous exploration.

Protein-energy malnutrition (PEM) commonly arises after stroke. We investigated the effects of preventing PEM on spontaneous recovery of forelimb use, infarct size, and the acute phase response in the chronic post-stroke period. Male, adult, Sprague-Dawley rats were acclimatized to control diet (12.5% protein), tested for pre-stroke forelimb use symmetry in the cylinder test, and exposed to photothrombotic cortical stroke or sham surgery. Food intake was monitored daily, and body weight weekly. Forelimb use was tested on day 4 after surgery, before assignment to control diet or PEM (0.5% protein), with subsequent testing on days 16 and 29. Blood, brain, and liver were collected on day 30. The low protein diet resulted in PEM, measured by decreased body weight (p < 0.001) and food intake (p = 0.016) and increased liver lipid (p < 0.001). Stroke (p = 0.016) and PEM (p = 0.001) independently elicited increases in serum α-2-macroglobulin concentration, whereas PEM alone decreased albumin (p < 0.001). PEM reduced recovery of forelimb use symmetry during exploration on days 16 (p = 0.024) and 29 (p = 0.013) but did not influence infarct size (p = 0.775). Stroke reduced reliance on the stroke-affected forelimb to initiate exploration up until day 29 (p < 0.001); PEM had no influence (p ≥ 0.463). Preventing post-stroke PEM appears to yield direct benefits for certain types of motor recovery. Novelty Preventing post-stroke malnutrition benefits certain types of motor recovery. An acute phase response may contribute to the poorer recovery with malnutrition.

Compensatory neuromuscular junction adaptations of forelimb muscles in focal cortical ischemia in rats.

INTRODUCTION: Upper limb movements are affected frequently by brain ischemia (BI). Mechanisms involved in recovery and compensatory movements have developed several studies. However, less attention is given to skeletal muscles, where neuromuscular junction (NMJ) has an important role on muscle tropism and functional performance. METHODS: Animals were divided into two groups: control (C) and BI. Then, animals were skilled to perform single-pellet retrieval task, following these procedures: habituation, shaping, and single-pellet retrieval task. BI was induced using stereotaxic surgery in order to apply endothelin-1 in motor cortex, representative of movements of dominant paw. Reaching task performance was evaluated by single-pellet retrieval task 1 day before BI induction, 4 and 15 days after BI induction. After that, biceps, triceps, fingers flexor, and extensor muscles were extracted. NMJ was assessed in morphometric characteristics (total area, total perimeter, and feret). Muscle fiber cross-sectional area and connective tissue percentage were also evaluated for characterization. Student's t test was used for comparisons between C and BI groups. Tau Kendall's correlation was applied among variables from BI group. RESULTS: An increase in all NMJ morphometric parameters, as well as increase of atrophy and fibrosis in BI group compared with C. There was a high level of direct correlation between mean values of NMJ morphometry with percentage of success in reaching task in BI group. CONCLUSION: Brain ischemia-induced NMJ compensatory expansion, muscle atrophy, and fibrosis in forelimb muscles that are related to reaching performance.