Constraint-induced movement therapy promotes motor function recovery and downregulates phosphorylated extracellular regulated protein kinase expression in ischemic brain tissue of rats

The effect and safety of constraint-induced movement therapy for post-stroke motor dysfunction: a meta-analysis and trial sequential analysis

Background

Due to motor function insufficiency, patients with post-stroke motor dysfunction (PSMD) have limitations in performing an activity, feel restricted during social participation, and feel impaired in their quality of life. Constraint-induced movement therapy (CIMT) is a neurorehabilitation technique, but its effectiveness on PSMD after stroke still remains controversial.

Objective

This meta-analysis and trial sequential analysis (TSA) aimed to comprehensively evaluate the effect and safety of CIMT for PSMD.

Methods

Four electronic databases were searched from their inception to 1 January 2023 to identify randomized controlled trials (RCTs) investigating the effectiveness of CIMT for PSMD. Two reviewers independently extracted the data and assessed the risk of bias and reporting quality. The primary outcome was a motor activity log for the amount of use (MAL-AOU) and the quality of movement (MAL-QOM). RevMan 5.4, Statistical Package for Social Sciences (SPSS) 25.0, and STATA 13.0 software were used for statistical analysis. The certainty of the evidence was appraised using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system. We also performed the TSA to assess the reliability of the evidence.

Results

A total of 44 eligible RCTs were included. Our results showed that CIMT combined with conventional rehabilitation (CR) was superior to CR in improving MAL-AOU and MAL-QOM scores. The results of TSA indicated that the above evidence was reliable. Subgroup analysis demonstrated that CIMT (≥6 h per day or duration ≤ 20 days) combined with CR was more effective than CR. Meanwhile, both CIMT and modified CIMT (mCIMT) combined with CR were more efficient than CR at all stages of stroke. No severe CIMT-related adverse events occurred.

Conclusion

CIMT may be an optional and safe rehabilitation therapy to improve PSMD. However, due to limited studies, the optimal protocol of CIMT for PSMD was undetermined, and more RCTs are required for further exploration.

Clinical trial registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=143490, identifier: CRD42019143490.

The Mechanism and Clinical Application of Constraint-Induced Movement Therapy in Stroke Rehabilitation

Constraint-induced movement therapy (CIMT) has been widely applied in stroke rehabilitation, and most relevant studies have shown that CIMT helps improve patients' motor function. In practice, however, principal issues include inconsistent immobilization durations and methods, while incidental issues include a narrow application scope and an emotional impact. Although many studies have explored the possible internal mechanisms of CIMT, a mainstream understanding has not been established.

Motor tract reorganization after acute central nervous system injury: a translational perspective

Acute central nervous system injuries are among the most common causes of disability worldwide, with widespread social and economic implications. Motor tract injury accounts for the majority of this disability; therefore, there is impetus to understand mechanisms underlying the pathophysiology of injury and subsequent reorganization of the motor tract that may lead to recovery. After acute central nervous system injury, there are changes in the microenvironment and structure of the motor tract. For example, ischemic stroke involves decreased local blood flow and tissue death from lack of oxygen and nutrients. Traumatic injury, in contrast, causes stretching and shearing injury to microstructures, including myelinated axons and their surrounding vessels. Both involve blood-brain barrier dysfunction, which is an important initial event. After acute central nervous system injury, motor tract reorganization occurs in the form of cortical remapping in the gray matter and axonal regeneration and rewiring in the white matter. Cortical remapping involves one cortical region taking on the role of another. cAMP-response-element binding protein is a key transcription factor that can enhance plasticity in the peri-infarct cortex. Axonal regeneration and rewiring depend on complex cell-cell interactions between axons, oligodendrocytes, and other cells. The RhoA/Rho-associated coiled-coil containing kinase signaling pathway plays a central role in axon growth/regeneration through interactions with myelin-derived axonal growth inhibitors and regulation of actin cytoskeletal dynamics. Oligodendrocytes and their precursors play a role in myelination, and neurons are involved through their voltage-gated calcium channels. Understanding the pathophysiology of injury and the biology of motor tract reorganization may allow the development of therapies to enhance recovery after acute central nervous system injury. These include targeted rehabilitation, novel pharmacotherapies, such as growth factors and axonal growth inhibitor blockade, and the implementation of neurotechnologies, such as central nervous system stimulators and robotics. The translation of these advances depends on careful alignment of preclinical studies and human clinical trials. As experimental data mount, the future is one of optimism.

Tongxinluo promotes axonal plasticity and functional recovery after stroke

Background

The aim of this study was to investigate the neural plasticity in contralesional cortex and the effects of tongxinluo (TXL) in cerebral ischemic rats.

Methodology

We used stroke-prone renovascular hypertensive (RHRSP) cerebral ischemia rat models to study the effect of TXL and the underlying mechanisms. We performed foot-fault and beam-walking tests to evaluate the motor function of rats after cortical infarction. Biotinylated dextran amine (BDA) was used to track axonal sprouting and neural connections.

Results

TXL enhanced the recovery of motor function in cerebral infarction rats. TXL increased axonal sprouting in the peri-infarcted area but not in the corpus callosum, indicating in situ origination instead of crossing between cortical hemispheres through the corpus callosum. TXL promoted the sprouting of corticospinal axons into the denervated side of spinal gray matter. The synaptophysin (SYN)-positive intensity in the peri-infarcted area of TXL-treated group was greater than that in the vehicle group. We observed co-localization of SYN with BDA-positive fibers in the denervated spinal cord gray matter in the TXL group, suggesting that axonal remodeling and synaptic connections were promoted by TXL.

Conclusion

TXL may promote the recovery of neurological function by promoting the axonal remodeling and synapse formation of motor neuronal fibers after focal cortical infarction in hypertensive rats.

Neurobiology of Recovery of Motor Function after Stroke: The Central Nervous System Biomarker Effects of Constraint-Induced Movement Therapy

Recovery of motor function after stroke involves many biomarkers. This review attempts to identify the biomarker effects responsible for recovery of motor function following the use of Constraint-Induced Movement Therapy (CIMT) and discuss their implications for research and practice. From the studies reviewed, the biomarker effects identified include improved perfusion of motor areas and brain glucose metabolism; increased expression of proteins, namely, Brain-Derived Neurotrophic Factor (BDNF), Vascular Endothelial Growth Factor (VEGF), and Growth-Associated Protein 43 (GAP-43); and decreased level of Gamma-Aminobutyric Acid (GABA). Others include increased cortical activation, increased motor map size, and decreased interhemispheric inhibition of the ipsilesional hemisphere by the contralesional hemisphere. Interestingly, the biomarker effects correlated well with improved motor function. However, some of the biomarker effects have not yet been investigated in humans, and they require that CIMT starts early on poststroke. In addition, one study seems to suggest the combined use of CIMT with other rehabilitation techniques such as Transcortical Direct Stimulation (tDCs) in patients with chronic stroke to achieve the biomarker effects. Unfortunately, there are few studies in humans that implemented CIMT during early poststroke. Thus, it is important that more studies in humans are carried out to determine the biomarker effects of CIMT especially early on poststroke, when there is a greater opportunity for recovery. Furthermore, it should be noted that these effects are mainly in ischaemic stroke.

Fluoxetine adjunct to therapeutic exercise promotes motor recovery in rats with cerebral ischemia: Roles of nucleus accumbens

The study aimed to explore the molecular mechanism of fluoxetine as an adjunct to therapeutic exercise to improve motor recovery using a rat cerebral ischemic model with middle cerebral artery occlusion (MCAO). We hypothesized that the nucleus accumbens (NAc) may be one of the responding areas to fluoxetine where relevant elevations in 5-hydroxytryptamine (5-HT) and ΔFosB were associated with motor behavioral recovery. Male Sprague-Dawley rats were randomly divided into five groups: rats without intervention; rats that underwent MCAO without exercise or fluoxetine; rats that underwent MCAO treated only with fluoxetine; rats that underwent MCAO treated only with exercise; and rats that underwent MCAO treated with both exercise and fluoxetine. Motor function and motivation were assessed by the fault footsteps test and the forced swimming test. 5-HT level in the bilateral NAc and the expression of 5-HT_2C receptor (5-HT_2CR) and ΔFosB in the ipsilesional (left) NAc were measured. Correlation was explored by Pearson correlation analysis. Our results indicated that either treatment helped improve the grasp dexterity of the affected limb, motor motivation, and resilience to adverse environment in MCAO rats. The dual treatment with fluoxetine and exercise may hasten the recovery process. The dual treatment helped restore the balance of 5-HT level between the bilateral NAc by significantly increasing its level in the ipsilesional side. Either treatment could resume the expression of 5-HT_2CR in the ipsilesional side of the NAc close to the normal level, which was correlated with motor recovery. The dual treatment significantly increased the expression of ΔFosB in the ipsilesional side of the NAc, which was correlated with the balance of 5-HT in the bilateral NAc, but not directly with motor recovery. In conclusion, the NAc may play an important role in driving physical motivation, which was possibly related to motor recovery after stroke. Fluoxetine may hasten the effectiveness of therapeutic exercise, possibly via regulating 5-HT and its receptors in the NAc.

Early constraint-induced movement therapy affects behavior and neuronal plasticity in ischemia-injured rat brains

Constraint-induced movement therapy is an effective rehabilitative training technique used to improve the restoration of impaired upper extremity movement after stroke. However, whether constraint-induced movement therapy is more effective than conventional rehabilitation in acute or sub-acute stroke remains controversial. The aim of the present study was to identify the optimal time to start constraint-induced movement therapy after ischemic stroke and to explore the mechanisms by which constraint-induced movement therapy leads to post-stroke recovery. Sixty-four adult male Sprague-Dawley rats were randomly divided into four groups: sham-surgery group, cerebral ischemia/reperfusion group, early constraint-induced movement therapy group, and late constraint-induced movement therapy group. Rat models of left middle cerebral artery occlusion were established according to the Zea Longa line embolism method. Constraint-induced movement therapy was conducted starting on day 1 or day 14 in the early constraint-induced movement therapy and late constraint-induced movement therapy groups, respectively. To explore the effect of each intervention time on neuromotor function, behavioral function was assessed using a balance beam walking test before surgery and at 8 and 21 days after surgery. The expression levels of brain-derived neurotrophic factor, nerve growth factor and Nogo receptor were evaluated using real time-polymerase chain reaction and western blot assay to assess the effect of each intervention time. The results showed that the behavioral score was significantly lower in the early constraint-induced movement therapy group than in the cerebral ischemia/reperfusion and late constraint-induced movement therapy groups at 8 days. At 21 days, the scores had significantly decreased in the early constraint-induced movement therapy and late constraint-induced movement therapy groups. At 8 days, only mild pyknosis appeared in neurons of the ischemic penumbra in the early constraint-induced movement therapy group, which was distinctly better than in the cerebral ischemia/reperfusion group. At 21 days, only a few vacuolated cells were observed and no obvious inflammatory cells were visible in late constraint-induced movement therapy group, which was much better than at 8 days. The mRNA and protein expression levels of brain-derived neurotrophic factor and nerve growth factor were significantly higher, but expression levels of Nogo receptor were significantly lower in the early constraint-induced movement therapy group compared with the cerebral ischemia/reperfusion and late constraint-induced movement therapy groups at 8 days. The changes in expression levels at 21 days were larger but similar in both the early constraint-induced movement therapy and late constraint-induced movement therapy groups. Besides, the protein nerve growth factor level was higher in the late constraint-induced movement therapy group than in the early constraint-induced movement therapy group at 21 days. These results suggest that both early (1 day) and late (14 days) constraint-induced movement therapy induces molecular plasticity and facilitates functional recovery after ischemic stroke, as illustrated by the histology. The mechanism may be associated with downregulation of Nogo receptor expression and upregulation of brain-derived neurotrophic factor and nerve growth factor expression.

Early wheel-running promotes functional recovery by improving mitochondria metabolism in olfactory ensheathing cells after ischemic stroke in rats

Olfactory ensheathing cells (OECs) has been widely studied in stroke. The present study was aimed at examining the role of wheel-running treatment (WR) on rat olfactory ensheathing cells (rOECs) functions. Thirty adult male Sprague Dawley rats were randomly divided into two groups: the middle cerebral artery occlusion (MCAO) group and WR + MCAO group. Motor behavior was assessed through the footfault test, and the results showed that WR training markedly improved the neurobehavioral outcome. The glucose metabolic status of the brain was assessed with the micro-PET. This training significantly enhanced the glucose uptake of olfactory bulb in the early stage of WR treatment. The function of rOECs mitochondrial was significantly enhanced after 10 days of treatment. Body weight of rats in both of the two groups decreased and then increased slowly following the days. But the growth trend of the WR + MCAO group was no significantly higher than that of the WR group. This training significantly enhanced the glucose uptake, improved the proliferation of rOECs and increased the expression level of cytochrome C (Cyt-c). The mechanism may be associated with the facilitation of mitochondrial function of rOECs cells. Including facilitation of mitochondrial fusion, fission, and accompanying increased quantities of mitochondria. Obtained results indicate that early WR treatment may exert enhanced function on rOECs in vivo and increased mitochondrial amounts, and improved the expression level of Cyt-c after ischemic stroke.

Constrained-induced movement therapy promotes motor function recovery by enhancing the remodeling of ipsilesional corticospinal tract in rats after stroke

Constraint-induced movement therapy (CIMT), which forces the use of the impaired limb by restraining the unaffected limb, has been used extensively for the recovery of limb motor function after stroke. However, the underlying mechanism of CIMT remains unclear. Diffusion tensor imaging (DTI) is a well-known neuroimaging technique that reflects the microstructure of white matter tracts and potential changes associated with different treatments. The aim of this study is to use DTI imaging to determine how corticospinal tract (CST) fibers remodel in ischemic rats with CIMT. In the present study, rats were randomly divided into three groups: a middle cerebral artery occlusion group (MCAO), a therapeutic group (MCAO + CIMT), and a sham-operated group (sham). A plaster cast was used to restrict the unaffected limb of the rats in the MCAO + CIMT group for 14 days. The Catwalk system was used to assess the limb motor function of rats. Fractional anisotropy (FA) and the average diffusion coefficient (ADC) of the CST were quantified through DTI. The expression of the c-Jun-N-terminal kinase signaling pathway (JNK) was examined after 14 days of CIMT. We found that CIMT could accelerate and enhance motor function recovery, and the MCAO + CIMT group showed significantly increased FA values in the ipsilesional posterior limb of internal capsule (PLIC) compared with the MCAO group. In addition, we found no significant difference in the ratio of phosphorylated-JNK/total-JNK among the three groups, whereas the expression of P-JNK decreased significantly in the chronic phase of stroke. In conclusion, CIMT-induced functional recovery following ischemic stroke through facilitation of the remodeling of ipsilesional CST, and restoration after ischemic stroke may be associated with the declining value of the ratio of P-JNK/JNK.

Remote limb ischemic postconditioning promotes motor function recovery in a rat model of ischemic stroke via the up-regulation of endogenous tissue kallikrein

AIMS

Remote ischemic conditionings, such as pre- and per-conditioning, are known to provide cardioprotection in animal models of ischemia. However, little is known about the neuroprotection effect of postconditioning after cerebral ischemia. In this study, we aim to evaluate the motor function rescuing effect of remote limb ischemic postconditioning (RIPostC) in a rat model of acute cerebral stroke.

METHODS

Left middle cerebral artery occlusion (MCAO) was performed to generate the rat model of ischemic stroke, followed by daily RIPostC treatment for maximum 21 days. The motor function after RIPostC was assessed with foot fault test and balance beam test. Local infarct volume was measured through MRI scanning. Neuronal status was evaluated with Nissl's, HE, and MAP2 immunostaining. Lectin immunostaining was performed to evaluate the microvessel density and area.

RESULTS

Daily RIPostC for more than 21 days promoted motor function recovery and provided long-lasting neuroprotection after MCAO. Reduced infarct volume, rescued neuronal loss, and enhanced microvessel density and size in the injured areas were observed. In addition, the RIPostC effect was associated with the up-regulation of endogenous tissue kallikrein (TK) level in circulating blood and local ischemic brain regions. A TK receptor antagonist HOE-140 partially reversed RIPostC-induced improvements, indicating the specificity of endogenous TK mediating the neuroprotection effect of RIPostC.

CONCLUSION

Our study demonstrates RIPostC treatment as an effective rehabilitation therapy to provide motor function recovery and alleviate brain impairment in a rat model of acute cerebral ischemia. We also for the first time provide evidence showing that the up-regulation of endogenous TK from remote conditioning regions underlies the observed effects of RIPostC.

Understanding the Mechanisms of Recovery and/or Compensation following Injury

Injury due to stroke and traumatic brain injury result in significant long-term effects upon behavioral functioning. One central question to rehabilitation research is whether the nature of behavioral improvement observed is due to recovery or the development of compensatory mechanisms. The nature of functional improvement can be viewed from the perspective of behavioral changes or changes in neuroanatomical plasticity that follows. Research suggests that these changes correspond to each other in a bidirectional manner. Mechanisms surrounding phenomena like neural plasticity may offer an opportunity to explain how variables such as experience can impact improvement and influence the definition of recovery. What is more, the intensity of the rehabilitative experiences may influence the ability to recover function and support functional improvement of behavior. All of this impacts how researchers, clinicians, and medical professionals utilize rehabilitation.

Constraint-induced movement therapy in treatment of acute and sub-acute stroke: a meta-analysis of 16 randomized controlled trials

OBJECTIVE:

The aim of this meta-analysis was to evaluate the clinical efficacy of constraint-induced movement therapy in acute and sub-acute stroke.

DATA SOURCES:

The key words were stroke, cerebrovascular accident, constraint-induced therapy, forced use, and randomized controlled trial. The databases, including China National Knowledge Infrastructure, WanFang, Weipu Information Resources System, Chinese Biomedical Literature Database, PubMed, Medline, Embase, the Cochrane Central Register of Controlled Trials, and the Cochrane Database of Systematic Reviews, were searched for studies on randomized controlled trials for treating acute or sub-acute stroke published before March 2016.

DATA SELECTION:

We retrieved relevant randomized controlled trials that compared constraint-induced movement therapy in treatment of acute or sub-acute stroke with traditional rehabilitation therapy (traditional occupational therapy). Patients were older than 18 years, had disease courses less than 6 months, and were evaluated with at least one upper extremity function scale. Study quality was evaluated, and data that met the criteria were extracted. Stata 11.0 software was used for the meta-analysis.

OUTCOME MEASURES:

Fugl-Meyer motor assessment of the arm, the action research-arm test, a motor activity log for amount of use and quality of movement, the Wolf motor function test, and a modified Barthel index.

RESULTS:

A total of 16 prospective randomized controlled trials (379 patients in the constraint-induced movement-therapy group and 359 in the control group) met inclusion criteria. Analysis showed significant mean differences in favor of constraint-induced movement therapy for the Fugl–Meyer motor assessment of the arm (weighted mean difference (WMD) = 10.822; 95% confidence intervals (95% CI): 7.419–14.226), the action research-arm test (WMD = 10.718; 95% CI: 5.704–15.733), the motor activity log for amount of use and quality of movement (WMD = 0.812; 95% CI: 0.331–1.293) and the modified Barthel index (WMD = 10.706; 95% CI: 4.417–16.966).

CONCLUSION:

Constraint-induced movement therapy may be more beneficial than traditional rehabilitation therapy for improving upper limb function after acute or sub-acute stroke.