Constraint-induced movement therapy enhances angiogenesis and neurogenesis after cerebral ischemia/reperfusion

rESWT promoted angiogenesis via Bach1/Wnt/β-catenin signaling pathway

Previous reports have established that rESWT fosters angiogenesis, yet the mechanism by which rESWT promotes cerebral angiogenesis remains elusive. rESWT stimulated HUVECs proliferation as evidenced by the CCK-8 test, with an optimal dosage of 2.0 Bar, 200 impulses, and 2 Hz. The tube formation assay of HUVECs revealed that tube formation peaked at 36 h post-rESWT treatment, concurrent with the lowest expression level of Bach1, as detected by both Western blot and immunofluorescence. The expression level of Wnt3a, β-catenin, and VEGF also peaked at 36 h. A Bach1 overexpression plasmid was transfected into HUVECs, resulting in a decreased expression level of Wnt3a, β-catenin, and VEGF. Upon treatment with rESWT, the down-regulation of Wnt3a, β-catenin, and VEGF expression in the transfected cells was reversed. The Wnt/β-catenin inhibitor DKK-1 was utilized to suppress Wnt3a and β-catenin expression, which led to a concurrent decrease in VEGF expression. However, rESWT treatment could restore the expression of these three proteins, even in the presence of DKK-1. Moreover, in the established OGD model, it was observed that rESWT could inhibit the overexpression of Bach1 and enhance VEGF and VEGFR-2 expression under the OGD environment.

Constraint-Induced Movement Therapy Modulates Neuron Recruitment and Neurotransmission Homeostasis of the Contralesional Cortex to Enhance Function Recovery after Ischemic Stroke

Stroke often results in long-term and severe limb dysfunction for a majority of patients, significantly limiting their activities and social participation. Constraint-induced movement therapy (CIMT) is a rehabilitation approach aimed explicitly at enhancing upper limb motor function following a stroke. However, the precise mechanism remains unknown. This study explores how CIMT may alleviate forelimb paralysis in ischemic mice, potentially through structural and functional remodeling of brain regions beyond the infarct area, especially the contralateral cortex. We demonstrated that CIMT recruits neurons from the contralesional cortex into the network that innervates the affected forelimb, as evidenced by PRV retrograde nerve tracing. Additionally, we investigated how CIMT influences synaptic plasticity in the contralateral cortex by evaluating synaptic growth marker levels and neurotransmission's homeostatic regulation. Our findings uncover a rehabilitative mechanism by which CIMT treats ischemic stroke, characterized by increased recruitment of neurons from the contralateral cortex into the network that innervates the affected forelimb, facilitated by homeostatic regulation of neurotransmission.

Constraint-Induced Movement Therapy Promotes Myelin Remodeling and Motor Function by Mediating Sox2/Fyn Signals in Rats With Hemiplegic Cerebral Palsy

OBJECTIVE

Hypoxic-ischemic brain injury in infants often leads to hemiplegic motor dysfunction. The mechanism of their motor dysfunction has been attributed to deficiencies of the transcription factor sex-determining region (SRY) box 2 (Sox2) or the non-receptor-type tyrosine kinase Fyn (involved in neuronal signal transduction), which causes a defect in myelin formation. Constraint-induced movement therapy (CIMT) following cerebral hypoxia-ischemia may stimulate myelin growth by regulating Sox2/Fyn, Ras homolog protein family A (RhoA), and rho-associated kinase 2 (ROCK2) expression levels. This study investigated how Sox2/Fyn regulates myelin remodeling following CIMT to improve motor function in rats with hemiplegic cerebral palsy (HCP).

METHODS

To investigate the mechanism of Sox2 involvement in myelin growth and neural function in rats with HCP, Lentivirus (Lenti)-Sox2 adeno-associated virus and negative control-Lenti-Sox2 (LS) adeno-associated virus were injected into the lateral ventricle. The rats were divided into a control group and an HCP group with different interventions (CIMT, LS, or negative control-LS [NS] treatment), yielding the HCP, HCP plus CIMT (HCP + CIMT), HCP + LS, HCP + LS + CIMT, HCP + NS, and HCP + NS + CIMT groups. Front-limb suspension and RotaRod tests, Golgi-Cox staining, transmission electron microscopy, immunofluorescence staining, western blotting, and quantitative polymerase chain reaction experiments were used to analyze the motor function, dendrite/axon area, myelin ultrastructure, and levels of expression of oligodendrocytes and Sox2/Fyn/RhoA/ROCK2 in the motor cortex.

RESULTS

The rats in the HCP + LS + CIMT group had better values for motor function, dendrite/axon area, myelin ultrastructure, oligodendrocytes, and Sox2/Fyn/RhoA/ROCK2 expression in the motor cortex than rats in the HCP and HCP + NS groups. The improvement of motor function and myelin remodeling, the expression of oligodendrocytes, and the expression of Sox2/Fyn/RhoA/ROCK2 in the HCP + LS group were similar to those in the HCP + CIMT group.

CONCLUSION

CIMT might overcome RhoA/ROCK2 signaling by upregulating the transcription of Sox2 to Fyn in the brain to induce the maturation and differentiation of oligodendrocytes, thereby promoting myelin remodeling and improving motor function in rats with HCP.

IMPACT

The pathway mediated by Sox2/Fyn could be a promising therapeutic target for HCP.

Effects of combined electroacupuncture and medication therapy on the RhoA/ROCK-2 signaling pathway in the striatal region of rats afflicted by cerebral ischemia

OBJECTIVE

To investigate the effects of electroacupuncture(EA), gastrodin(Gas), and their combination on the signaling pathways involving Ras homologous gene family member A (RhoA) and Rho-associated frizzled helix protein kinase (ROCK-2) within the striatal region of rats subjected to cerebral ischemia. Additionally, we aim to elucidate the therapeutic effects and potential underlying mechanisms associated with the concurrent application of electroacupuncture and medication in the treatment of cerebral ischemia.

METHODS

Rats were randomly assigned to one of five groups, namely, the sham operation (Sham) group, model group, EA group, Gas group, and the EA combined with Gas group (referred to as the "EA+Gas group"). Each group consisted of ten rats. Following the induction of cerebral ischemia, the EA group and EA+Gas group received EA stimulation at the Baihui(GV20) and Zusanli(ST36) acupoints for 30 min per session, administered once daily for 14 consecutive days. The Gas group and EA+Gas group were intraperitoneally injected with Gas at a dosage of 10 mg/kg, also administered once daily for 14 consecutive days. Nissl staining was employed to observe morphological alterations in the striatal nerve cells of rats in each group. Immunohistochemistry and western blot techniques were employed to evaluate the expression levels of striatal RhoA and ROCK-2 proteins.

RESULTS

In comparison to the Sham group, the model group exhibited a substantial reduction in the number of striatal nerve cells on the ischemic side, accompanied by notable changes in cell morphology, characterized by reduced cytoplasm, defective and atrophied cytosol, solidified nuclei, loosely arranged cells, and enlarged intercellular spaces. Additionally, there was a notable increase in the positive expression of RhoA and ROCK-2. In contrast, when compared to the model group, the EA, Gas, and EA+Gas groups demonstrated an elevated number of normal nerve cells within the ischemic striatal region, with a significant improvement in cell count and morphology. Furthermore, positive expression levels of RhoA and ROCK-2 were notably reduced in these groups. Compared with the EA group or the GAS group, the number of normal nerve cells in the striatum on the ischemic side of the EA+GAS group was further increased, and the positive expression level of RhoA and ROCK-2 were both further reduced.

CONCLUSION

The protective mechanism underlying the therapeutic efficacy of EA combined with Gas against cerebral ischemic striatal injury in rats may be associated with the inhibition of the activation of the RhoA/ROCK-2 signaling pathway. Importantly, the therapeutic effects observed with the combination of electroacupuncture and medication were superior to those achieved with EA alone or the sole administration of Gas.

Enriched environment attenuates ferroptosis after cerebral ischemia/reperfusion injury by regulating iron metabolism

Preventing neuronal death after ischemic stroke (IS) is crucial for neuroprotective treatment, yet current management options are limited. Enriched environment (EE) is an effective intervention strategy that promotes the recovery of neurological function after cerebral ischemia/reperfusion (I/R) injury. Ferroptosis has been identified as one of the mechanisms of neuronal death during IS, and inhibiting ferroptosis can reduce cerebral I/R injury. Our previous research has demonstrated that EE reduced ferroptosis by inhibiting lipid peroxidation, but the underlying mechanism still needs to be investigated. This study aims to explore the potential molecular mechanisms by which EE modulates iron metabolism to reduce ferroptosis. The experimental animals were randomly divided into four groups based on the housing environment and the procedure the animals received: the sham-operated + standard environment (SSE) group, the sham-operated + enriched environment (SEE) group, the ischemia/reperfusion + standard environment (ISE) group, and the ischemia/reperfusion + enriched environment (IEE) group. The results showed that EE reduced IL-6 expression during cerebral I/R injury, hence reducing JAK2-STAT3 pathway activation and hepcidin expression. Reduced hepcidin expression led to decreased DMT1 expression and increased FPN1 expression in neurons, resulting in lower neuronal iron levels and alleviated ferroptosis. In addition, EE also reduced the expression of TfR1 in neurons. Our research suggested that EE played a neuroprotective role by modulating iron metabolism and reducing neuronal ferroptosis after cerebral I/R injury, which might be achieved by inhibiting inflammatory response and down-regulating hepcidin expression.

Constraint therapy promotes motor cortex remodeling and functional improvement by regulating c-Jun/miR-182-5p/Nogo - A signals in hemiplegic cerebral palsy mice

BACKGROUND

Our previous study has confirmed that constraint-induced movement therapy (CIMT) could promote neural remodeling in hemiplegic cerebral palsy (HCP) mice through Nogo-A/NgR/RhoA/ROCK signaling, however, the upstream mechanism was still unclear. Therefore, the present study aimed to further explore the mechanism of CIMT regulating the expression of Nogo-A in HCP mice.

METHOD

HCP mice were well established through ligating the left common carotid artery of 7-day-old pups and being placed in a hypoxic box which was filled with a mixture of 8% oxygen and 92% nitrogen. CIMT intervention was conducted by taping to fix the entire arm of the contralateral side (left) to force the mice to use the affected limb (right). Bioinformatics prediction and luciferase experiment were performed to confirm that miR-182-5p was targeted with Nogo-A. The beam test and grip test were applied to examine the behavioral performance under the intervention of c-Jun and CIMT. Also, immunofluorescence, Golgi staining, and transmission electron microscopy were conducted to show that the lenti-expression of c-Jun could increases the expression of myelin, and downregulates the expression of Nogo-A under the CIMT on HCP mice.

RESULT

(1) The beam walking test and grip test experiment results showed that compared with the control group, the HCP + nCIMT group's forelimb grasping ability and balance coordination ability were decreased (P < 0.05). (2) The results of Golgi staining, and transmission electron microscopy showed that the thickness of myelin sheath and the density of dendritic spines in the HCP + nCIMT group were lower than those in the control group (P < 0.05). Compared with the HCP + nCIMT group, the cerebral cortex myelin sheath thickness, dendrite spine density and nerve filament expression were increased in HCP + CIMT group (P < 0.05). (3) Immunofluorescence staining showed that the expression of Nogo-A in the cerebral cortex of the HCP + nCIMT group was higher than that of the HCP + CIMT group (P < 0.05). Compared with the HCP + CIMT group, the expression of Nogo-A in the HCP + LC + CIMT group was decreased and, in the HCP, + SC + CIMT group was significantly increased (P < 0.05). Compared with the HCP + nCIMT group, the expression of c-Jun in the control, HCP + CIMT, HCP + LC + nCIMT and HCP + LC + CIMT groups was significantly increased, and in the HCP + SC + CIMT was decreased (P < 0.05). (4) Real-time quantitative polymerase chain reaction (RT-qPCR) results showed that the expression level of miR-182-5p in the HCP + LC + CIMT group was more increased than that in the HCP + nCIMT group (P < 0.05). The expression level of miR-182-5p in the HCP + LC + CIMT group was higher than that in the HCP + LC + nCIMT group and the HCP + SC + CIMT group (P < 0.05).

CONCLUSION

These data identified that CIMT might stimulate the remodeling of neurons and myelin in the motor cortex by partially inhibiting the c-Jun/miR-182-5p/Nogo-A pathway, thereby facilitating the grasping performance and balance function of HCP mice.

Combination of constraint-induced movement therapy with fasudil amplifies neurogenesis after focal cerebral ischemia/reperfusion in rats

PURPOSE

Spontaneous axonal plasticity and functional restoration after stroke may be limited by Nogo-A, a myelin-associated inhibitor, via activation of the Rho/Rho-associated protein kinase (ROCK) pathway. Constraint-induced movement therapy (CIMT) is a rehabilitation technique based on neuroplasticity and neural recombination. We recently reported that CIMT promoted neurogenesis after cerebral ischemia/reperfusion in part by inhibiting the Nogo-A-RhoA-ROCK pathway. Here, we examine the hypothesis that CIMT combined with the ROCK inhibitor fasudil further amplifies neurogenesis during stroke recovery.

METHODS

Four groups of rats were randomized as follows: Cerebral ischemia-reperfusion (IR), Fasudil, CIMT and CIMT + Fasudil. Seven days after stroke, CIMT and/or intraperitoneal infusion of fasudil were initiated and continued for 3 weeks. The behavioral outcomes and immunohistochemical markers of neurogenesis were quantified.

RESULTS

Compared with other groups, the combination of CIMT with fasudil after IR significantly improved motor and memory function recovery. In addition, BrdU, BrdU/doublecortin and BrdU/GFAP all increased significantly in the brain tissue of the combined treatment group compared to the CIMT or Fasudil group.

CONCLUSION

These results suggest that the effects of CIMT on neurogenesis are amplified by fasudil during the recovery phase after stroke.

Molecular mediators of angiogenesis and neurogenesis after ischemic stroke

The mechanisms governing neurological and functional recovery after ischemic stroke are incompletely understood. Recent advances in knowledge of intrinsic repair processes of the CNS have so far translated into minimal improvement in outcomes for stroke victims. Better understanding of the processes underlying neurological recovery after stroke is necessary for development of novel therapeutic approaches. Angiogenesis and neurogenesis have emerged as central mechanisms of post-stroke recovery and potential targets for therapeutics. Frameworks have been developed for conceptualizing cerebral angiogenesis and neurogenesis at the tissue and cellular levels. These models highlight that angiogenesis and neurogenesis are linked to each other and to functional recovery. However, knowledge of the molecular framework linking angiogenesis and neurogenesis after stroke is limited. Studies of potential therapeutics typically focus on one mediator or pathway with minimal discussion of its role within these multifaceted biochemical processes. In this article, we briefly review the current understanding of the coupled processes of angiogenesis and neurogenesis after stroke. We then identify the molecular mediators and signaling pathways found in pre-clinical studies to upregulate both processes after stroke and contextualizes them within the current framework. This report thus contributes to a more-unified understanding of the molecular mediators governing angiogenesis and neurogenesis after stroke, which we hope will help guide the development of novel therapeutic approaches for stroke survivors.

Deep Learning Reconstruction Algorithm-Based MRI Image Evaluation of Edaravone in the Treatment of Lower Limb Ischemia-Reperfusion Injury

This research aimed to evaluate the therapeutic effect of edaravone on lower limb ischemia-reperfusion injury by MRI images of graph patch-based directional curvelet transform (GPBDCT), compression reconstruction algorithm. 200 patients with lower limb ischemia-reperfusion injury after replantation of severed limb were randomly divided into the observation group (edaravone treatment) and control group (Mailuoning injection treatment), with 100 cases in each group. MRI scanning and image processing using the GPBDCT algorithm were used to evaluate the therapeutic effect of the two groups of patients. The results showed that the signal noise ratio (SNR) (22.01), relative $l_2$ norm error (RLNE) (0.0792), and matching degree $\gamma$ (0.9997) of the compression and reconstruction algorithm based on GPBDCT were superior to those of the conventional compression and reconstruction algorithm ( $P<0.05$ ). MRI examination showed that the decrease of bleeding signal after treatment in the observation group was superior to that in the control group. The levels of superoxide dismutase (SOD) (15 ± 2.02), malondialdehyde (MDA) (2.27 ± 1.02), B cell lymphoma-2 (Bcl-2) (8.5 ± 1.02), Bcl-2-associated X (Bax) (3.7 ± 0.42), and Caspase-3 protein (35.9 ± 5.42) in the observation group before and after treatment were significantly higher than those in the control group ( $P<0.05$ ). In conclusion, the GPBDCT-based compression reconstruction algorithm has a better effect on MRI image processing, and edaravone can better remove free radicals and alleviate apoptosis.

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.

Rho-Kinase Inhibition Improves the Outcome of Focal Subcortical White Matter Lesions

BACKGROUND

Subcortical white matter lesions are exceedingly common in cerebral small vessel disease and lead to significant cumulative disability without an available treatment. Here, we tested a rho-kinase inhibitor on functional recovery after focal white matter injury.

METHODS

A focal corpus callosum lesion was induced by stereotactic injection of N⁵-(1-iminoethyl)-L-ornithine in mice. Fasudil (10 mg/kg) or vehicle was administered daily for 2 weeks, starting one day after lesion induction. Resting-state functional connectivity and grid walk performance were studied longitudinally, and lesion volumes were determined at one month.

RESULTS

Resting-state interhemispheric functional connectivity significantly recovered between days 1 and 14 in the fasudil group (P<0.001), despite worse initial connectivity loss than vehicle before treatment onset. Grid walk test revealed an increased number of foot faults in the vehicle group compared with baseline, which persisted for at least 4 weeks. In contrast, the fasudil arm did not show an increase in foot faults and had smaller lesions at 4 weeks. Immunohistochemical examination of reactive astrocytosis, synaptic density, and mature oligodendrocytes did not reveal a significant difference between treatment arms.

CONCLUSIONS

These data show that delayed fasudil posttreatment improves functional outcomes after a focal subcortical white matter lesion in mice. Future work will aim to elucidate the mechanisms.

Aerobic Physical Exercise as a Non-medical Intervention for Brain Dysfunction: State of the Art and Beyond

Brain disorders, including stroke, Alzheimer's disease, depression, and chronic pain, are difficult to effectively treat. These major brain disorders have high incidence and mortality rates in the general population, and seriously affect not only the patient's quality of life, but also increases the burden of social medical care. Aerobic physical exercise is considered an effective adjuvant therapy for preventing and treating major brain disorders. Although the underlying regulatory mechanisms are still unknown, systemic processes may be involved. Here, this review aimed to reveal that aerobic physical exercise improved depression and several brain functions, including cognitive functions, and provided chronic pain relief. We concluded that aerobic physical exercise helps to maintain the regulatory mechanisms of brain homeostasis through anti-inflammatory mechanisms and enhanced synaptic plasticity and inhibition of hippocampal atrophy and neuronal apoptosis. In addition, we also discussed the cross-system mechanisms of aerobic exercise in regulating imbalances in brain function, such as the “bone-brain axis.” Furthermore, our findings provide a scientific basis for the clinical application of aerobic physical exercise in the fight against brain disorders.

Effect of Pericytes on Cerebral Microvasculature at Different Time Points of Stroke

Pericyte, as an important component of the blood-brain barrier, has received increasing attention in the study of cerebrovascular diseases. However, the mechanism of pericytes after the occurrence of cerebral ischemia is controversial. On the one hand, the expression of pericytes increases after cerebral ischemia, constricting the blood vessels to restrict blood supply and aggravating the damage caused by ischemia; on the other hand, pericytes participate in capillary angiogenesis in the ischemic area, which facilitates the repair of the ischemic injury area. The multifunctionality of pericytes is an important reason for this phenomenon, but the different time points of observation for the outcome indicators in each study are also an important factor that leads to the controversy of pericytes. Based on the review of a large database of original studies, the authors' team summarized the effects of pericytes on cerebral microvasculature at different time points after stroke, searched the possible markers, and explored possible therapeutic.

Different training patterns at recovery stage improve cognitive function in ischemic stroke rats through regulation of the axonal growth inhibitor pathway

Running wheel exercise training (RWE) and skilled reaching training (SRT) are physical training approaches with positive effects on cognitive function. However, few studies have compared the different effects of these exercises on long-term memory, and their mechanism remains unknown. This study investigated the effects of SRT and RWE, at the recovery stage, on the cognitive function of transient middle cerebral artery occlusion (tMCAO) rats and explored their association with NgR1/Rho-A/ROCK/LOTUS/LGI1 signaling. Adult Sprague-Dawley rats (n = 55) were divided into four groups after pretraining: SRT, RWE, tMCAO, and Sham. Rats were subjected to modified neurological severity score (mNSS) measurements and forelimb grip strength and the Morris water maze tests. Using immunofluorescence and western blotting, we evaluated axonal growth inhibitor expression in the peri-infarct cortex on days 28 and 56 after tMCAO. Results showed the mNSS reduced, whereas the grip strengths improved in RWE and SRT groups. The escape latency in the Morris water maze test was shorter, whereas the number of times of crossing the platform was higher in both the SRT and RWE groups than in the tMCAO group on day 56; furthermore, the parameters in the SRT group improved compared to those in the RWE group. Physical exercise training could improve cognitive functions by reducing the expression of the NgR1/RhoA/ROCK axon growth inhibitors and increasing the expression of the endogenous antagonists LOTUS/LGI1. Exercise training beginning at the recovery stage could improve the cognitive function in tMCAO rats through a mechanism probably associated with the axonal growth inhibitor pathway.

Angiogenesis effects of 4-methoxy benzyl alcohol on cerebral ischemia-reperfusion injury via regulation of VEGF-Ang/Tie2 balance

Angiogenesis facilitates the formation of microvascular networks and promotes neurological deficit recovery after cerebral ischemia-reperfusion injury (CIRI). This study investigated the angiogenesis effects of 4-methoxy benzyl alcohol (4-MA) on CIRI. The angiogenesis effects of 4-MA and the potential underlying mechanisms were assessed based on a middle cerebral artery occlusion/reperfusion (MCAO/R) rat model and a hind limb ischemic (HLI) mouse model. Immunofluorescence was conducted to detect microvessel density, and Western blotting and polymerase chain reaction were performed to determine the expression of angiogenesis-promoting factors. In addition, we investigated whether the angiogenesis effects of 4-MA caused damage to the blood-brain barrier (BBB). After treatment with 4-MA (20 mg/kg) for 7 days, the neurological deficits recovered and microvessel density in the cerebral cortex increased in the MCAO/R rats. Additionally, 4-MA also regulated the expression of angiogenesis factors, with an increase in vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor 2 (VEGFR-2) expression and a decrease in angiopoietin 1 (Ang-1), Ang-2, and Tie-2 expression in both MCAO/R rats and HLI mice. Moreover, 4-MA increased the expression of angiogenesis-promoting factors without exacerbating BBB cascade damage in MCAO/R rats. Our results indicated that 4-MA may contribute to the formation of microvascular networks, thus promoting neurological deficit recovery after CIRI.

PLGA-PEG-PLGA hydrogel with NEP1-40 promotes the functional recovery of brachial plexus root avulsion in adult rats

Adult brachial plexus root avulsion can cause serious damage to nerve tissue and impair axonal regeneration, making the recovery of nerve function difficult. Nogo-A extracellular peptide residues 1-40 (NEP1-40) promote axonal regeneration by inhibiting the Nogo-66 receptor (NgR1), and poly (D, L-lactide-co-glycolide)-poly (ethylene glycol)-poly (D, L-lactide-co-glycolide) (PLGA-PEG-PLGA) hydrogel can be used to fill in tissue defects and concurrently function to sustain the release of NEP1-40. In this study, we established an adult rat model of brachial plexus nerve root avulsion injury and conducted nerve root replantation. PLGA-PEG-PLGA hydrogel combined with NEP1-40 was used to promote nerve regeneration and functional recovery in this rat model. Our results demonstrated that functional recovery was enhanced, and the survival rate of spinal anterior horn motoneurons was higher in rats that received a combination of PLGA-PEG-PLGA hydrogel and NEP1-40 than in those receiving other treatments. The combined therapy also significantly increased the number of fluorescent retrogradely labeled neurons, muscle fiber diameter, and motor endplate area of the biceps brachii. In conclusion, this study demonstrates that the effects of PLGA-PEG-PLGA hydrogel combined with NEP1-40 are superior to those of other therapies used to treat brachial plexus nerve root avulsion injury. Therefore, future studies should investigate the potential of PLGA-PEG-PLGA hydrogel as a primary treatment for brachial plexus root avulsion.

Rho/ROCK Pathway and Noncoding RNAs: Implications in Ischemic Stroke and Spinal Cord Injury

Ischemic strokes (IS) and spinal cord injuries (SCI) are major causes of disability. RhoA is a small GTPase protein that activates a downstream effector, ROCK. The up-regulation of the RhoA/ROCK pathway contributes to neuronal apoptosis, neuroinflammation, blood-brain barrier dysfunction, astrogliosis, and axon growth inhibition in IS and SCI. Noncoding RNAs (ncRNAs), such as microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), were previously considered to be non-functional. However, they have attracted much attention because they play an essential role in regulating gene expression in physiological and pathological conditions. There is growing evidence that ROCK inhibitors, such as fasudil and VX-210, can reduce injury in IS and SCI in animal models and clinical trials. Recently, it has been reported that miRNAs are decreased in IS and SCI, while lncRNAs are increased. Inhibiting the Rho/ROCK pathway with miRNAs alleviates apoptosis, neuroinflammation, oxidative stress, and axon growth inhibition in IS and SCI. Further studies are required to explore the significance of ncRNAs in IS and SCI and to establish new strategies for preventing and treating these devastating diseases.

MiR-615 Agomir Encapsulated in Pluronic F-127 Alleviates Neuron Damage and Facilitates Function Recovery After Brachial Plexus Avulsion

Brachial plexus avulsion (BPA) is a devastating traumatic peripheral nerve injury complicated with paralysis of the upper extremity. We previously reported that leucine-rich repeat and immunoglobulin-like domain-containing NOGO receptor-interacting protein 1 (LINGO-1) has a potent role in inhibiting neuron survival and axonal regeneration after the central nervous system (CNS) damage and miR-615 is a potential microRNA (miRNA) negatively regulated LINGO-1. However, the effect of miR-615 in BPA remains to be elucidated. Accumulating evidence indicates that pluronic F-127 (PF-127) hydrogel could serve as a promising vehicle for miRNA encapsulation. Thus, to further explore the potential role of hydrogel-miR-615 in BPA-reimplantation, the present study established the BPA rat model and injected miR-615 agomir encapsulated by PF-127 hydrogel into the reimplantation site using a microsyringe. In this study, results indicated that hydrogel-miR-615 agomir effectively alleviated motoneuron loss by LINGO-1 inhibition, promoted musculocutaneous nerve regeneration and myelination, reduced astrocytes activation, promoted angiogenesis and attenuated peripheral amyotrophy, leading to improved motor functional rehabilitation of the upper extremity. In conclusion, our findings demonstrate that miR-615-loaded PF-127 hydrogel may represent a novel therapeutic strategy for BPA treatment.

Deregulated Protein Kinases: Friend and Foe in Ischemic Stroke

Ischemic stroke is the third leading cause of mortality worldwide, but its medical management is still limited to the use of thrombolytics as a lifesaving option. Multiple molecular deregulations of the protein kinase family occur during the period of ischemia/reperfusion. However, experimental studies have shown that alterations in the expression of essential protein kinases and their pharmacological modulation can modify the neuropathological milieu and hasten neurophysiological recovery. This review highlights the role of key protein kinase members and their implications in the evolution of stroke pathophysiology. Activation of ROCK-, MAPK-, and GSK-3β-mediated pathways following neuronal ischemia/reperfusion injury in experimental conditions aggravate the neuropathology and delays recovery. Targeting ROCK, MAPK, and GSK-3β will potentially enhance myelin regeneration, improve blood-brain barrier (BBB) function, and suppress inflammation, which ameliorates neuronal survival. Conversely, protein kinases such as PKA, Akt, PKCα, PKCε, Trk, and PERK salvage neurons post-ischemia by mechanisms including enhanced toxin metabolism, restoring BBB integrity, neurotrophic effects, and apoptosis suppression. Certain protein kinases such as ERK1/2, JNK, and AMPK have favourable and unfavourable effects in salvaging ischemia-injured neurons. Targeting multiple protein kinase-mediated pathways simultaneously may improve neuronal recovery post-ischemia.

Adult Neurogenesis and Stroke: A Tale of Two Neurogenic Niches

In the aftermath of an acute stroke, numerous signaling cascades that reshape the brain both in the perilesional zone as well as in more distal regions are activated. Despite continuous improvement in the acute treatment of stroke and the sustained research efforts into the pathophysiology of stroke, we critically lag in our integrated understanding of the delayed and chronic responses to ischemic injury. As such, the beneficial or maladaptive effect of some stroke-induced cellular responses is unclear, restricting the advancement of therapeutic strategies to target long-term complications. A prominent delayed effect of stroke is the robust increase in adult neurogenesis, which raises hopes for a regenerative strategy to counter neurological deficits in stroke survivors. In the adult brain, two regions are known to generate new neurons from endogenous stem cells: the subventricular zone (SVZ) and the dentate subgranular zone (SGZ) of the hippocampus. While both niches respond with an increase in neurogenesis post-stroke, there are significant regional differences in the ensuing stages of survival, migration, and maturation, which may differently influence functional outcome. External interventions such as rehabilitative training add a further layer of complexity by independently modulating the process of adult neurogenesis. In this review we summarize the current knowledge regarding the effects of ischemic stroke on neurogenesis in the SVZ and in the SGZ, and the influence of exogenous stimuli such as motor activity or enriched environment (EE). In addition, we discuss the contribution of SVZ or SGZ post-stroke neurogenesis to sensory, motor and cognitive recovery.

Constraint-Induced Movement Therapy Promotes Neural Remodeling and Functional Reorganization by Overcoming Nogo-A/NgR/RhoA/ROCK Signals in Hemiplegic Cerebral Palsy Mice

Background. Little is known about the induction of functional and brain structural reorganization in hemiplegic cerebral palsy (HCP) by constraint-induced movement therapy (CIMT). Objective. We aimed to explore the specific molecular mechanism of functional and structural plasticity related to CIMT in HCP. Methods. The mice were divided into a control group and HCP groups with different interventions (unconstraint-induced movement therapy [UNCIMT], CIMT or siRNA-Nogo-A [SN] treatment): the HCP, HCP+UNCIMT, HCP+CIMT, HCP+SN, and HCP+SN+CIMT groups. Rotarod and front-limb suspension tests, immunohistochemistry, Golgi-Cox staining, transmission electron microscopy, and Western blot analyses were applied to measure motor function, neurons and neurofilament density, dendrites/axon areas, myelin integrity, and Nogo-A/NgR/RhoA/ROCK expression in the motor cortex. Results. The mice in the HCP+CIMT group had better motor function, greater neurons and neurofilament density, dendrites/axon areas, myelin integrity, and lower Nogo-A/NgR/RhoA/ROCK expression in the motor cortex than the HCP and HCP+UNCIMT groups (P < .05). Moreover, the expression of Nogo-A/NgR/RhoA/ROCK, the improvement of neural remodeling and motor function of mice in the HCP+SN group were similar to those in the HCP+CIMT group (P > .05). The neural remodeling and motor function of the HCP+SN+CIMT group were significantly greater than those in the HCP+SN and HCP+CIMT groups (P < .05). Motor function were positively correlated with the density of neurons (r = 0.450 and 0.309, respectively; P < .05) and neurofilament (r = 0.717 and 0.567, respectively; P < .05). Conclusions. CIMT might promote the remodeling of neurons, neurofilament, dendrites/axon areas, and myelin in the motor cortex by partially inhibiting the Nogo-A/NgR/RhoA/ROCK pathway, thereby promoting the improvement of motor function in HCP mice.

Environmental enrichment combined with fasudil treatment inhibits neuronal death in the hippocampal CA1 region and ameliorates memory deficits

Currently, no specific treatment exists to promote recovery from cognitive impairment after a stroke. Dysfunction of the actin cytoskeleton correlates well with poststroke cognitive declines, and its reorganization requires proper regulation of Rho-associated kinase (ROCK) proteins. Fasudil downregulates ROCK activation and protects neurons against cytoskeleton collapse in the acute phase after stroke. An enriched environment can reduce poststroke cognitive impairment. However, the efficacy of environmental enrichment combined with fasudil treatment remains poorly understood. A photothrombotic stroke model was established in 6-week-old male C57BL/6 mice. Twenty-four hours after modeling, these animals were intraperitoneally administered fasudil (10 mg/kg) once daily for 14 successive days and/or provided with environmental enrichment for 21 successive days. After exposure to environmental enrichment combined with fasudil treatment, the number of neurons in the hippocampal CA1 region increased significantly, the expression and proportion of p-cofilin in the hippocampus decreased, and the distribution of F-actin in the hippocampal CA1 region increased significantly. Furthermore, the performance of mouse stroke models in the tail suspension test and step-through passive avoidance test improved significantly. These findings suggest that environmental enrichment combined with fasudil treatment can ameliorate memory dysfunction through inhibition of the hippocampal ROCK/cofilin pathway, alteration of the dynamic distribution of F-actin, and inhibition of neuronal death in the hippocampal CA1 region. The efficacy of environmental enrichment combined with fasudil treatment was superior to that of fasudil treatment alone. This study was approved by the Animal Ethics Committee of Fudan University of China (approval No. 2019-Huashan Hospital JS-139) on February 20, 2019.

Modified constraint-induced movement therapy alters synaptic plasticity of rat contralateral hippocampus following middle cerebral artery occlusion

Modified constraint-induced movement therapy is an effective treatment for neurological and motor impairments in patients with stroke by increasing the use of their affected limb and limiting the contralateral limb. However, the molecular mechanism underlying its efficacy remains unclear. In this study, a middle cerebral artery occlusion (MCAO) rat model was produced by the suture method. Rats received modified constraint-induced movement therapy 1 hour a day for 14 consecutive days, starting from the 7^th day after middle cerebral artery occlusion. Day 1 of treatment lasted for 10 minutes at 2 r/min, day 2 for 20 minutes at 2 r/min, and from day 3 onward for 20 minutes at 4 r/min. CatWalk gait analysis, adhesive removal test, and Y-maze test were used to investigate motor function, sensory function as well as cognitive function in rodent animals from the 1^st day before MCAO to the 21^st day after MCAO. On the 21^st day after MCAO, the neurotransmitter receptor-related genes from both contralateral and ipsilateral hippocampi were tested by micro-array and then verified by western blot assay. The glutamate related receptor was shown by transmission electron microscopy and the glutamate content was determined by high-performance liquid chromatography. The results of behavior tests showed that modified constraint-induced movement therapy promoted motor and sensory functional recovery in the middle cerebral artery-occluded rats, but had no effect on cognitive function. The modified constraint-induced movement therapy upregulated the expression of glutamate ionotropic receptor AMPA type subunit 3 (Gria3) in the hippocampus and downregulated the expression of the beta3-adrenergic receptor gene Adrb3 and arginine vasopressin receptor 1A, Avpr1a in the middle cerebral artery-occluded rats. In the ipsilateral hippocampus, only Adra2a was downregulated, and there was no significant change in Gria3. Transmission electron microscopy revealed a denser distribution the more distribution of postsynaptic glutamate receptor 2/3, which is an α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor, within 240 nm of the postsynaptic density in the contralateral cornu ammonis 3 region. The size and distribution of the synaptic vesicles within 100 nm of the presynaptic active zone were unchanged. Western blot analysis showed that modified constraint-induced movement therapy also increased the expression of glutamate receptor 2/3 and brain-derived neurotrophic factor in the hippocampus of rats with middle cerebral artery occlusion, but had no effect on Synapsin I levels. Besides, we also found modified constraint-induced movement therapy effectively reduced glutamate content in the contralateral hippocampus. This study demonstrated that modified constraint-induced movement therapy is an effective rehabilitation therapy in middle cerebral artery-occluded rats, and suggests that these positive effects occur via the upregulation of the postsynaptic membrane α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor expression. This study was approved by the Institutional Animal Care and Use Committee of Fudan University, China (approval No. 201802173S) on March 3, 2018.

miR‑126a‑5p‑Dbp and miR‑31a‑Crot/Mrpl4 interaction pairs crucial for the development of hypertension and stroke

The present study aimed to integrate the mRNA and microRNA (miRNA) expression profiles of spontaneously hypertensive rats (SHR rats) and stroke-prone spontaneously hypertensive rats (SHRSP rats) to screen for potential therapeutic targets for hypertension and stroke. The datasets GSE41452, GSE31457, GSE41453 and GSE53363 were collected from the Gene Expression Omnibus (GEO) database to screen differentially expressed genes (DEGs). The GSE53361 dataset was obtained to analyze differentially expressed miRNAs (DEMs). The DEGs and DEMs were identified between SHR (or SHRSP) rats and normotensive Wistar-Kyoto (WKY) rats using the Linear Models for Microarray (limma) data method. Venn diagrams were used to show the SHR-specific, SHRSP-specific and SHR-SHRSP shared DEGs and DEMs, and these were utilized to construct the protein-protein interaction (PPI) and miRNA-mRNA regulatory networks. The Database for Annotation, Visualization and Integrated Discovery (DAVID) was used to explore the function of the genes. Subsequently, the connectivity Map (CMAP) database was searched to identify small-molecule drugs. Comparisons between the GSE41452-GSE31457-GSE41453 merged and GSE53363 datasets identified 2 SHR-specific, 8 SHRSP-specific and 15 SHR-SHRSP shared DEGs. Function enrichment analysis showed that SHRSP-specific D-box binding PAR bZIP transcription factor (Dbp) was associated with circadian rhythm, and SHR-SHRSP shared carnitine O-octanoyltransferase (Crot) was involved in fatty acid metabolic processes or the inflammatory response via interacting with epoxide hydrolase 2 (EPHX2). SHR-SHRSP shared mitochondrial ribosomal protein L4 (Mrpl4) may exert roles by interacting with the threonine-tRNA ligase, TARS2. The miRNA regulatory network predicted that upregulated Dbp could be regulated by rno-miR-126a-5p, whereas downregulated Crot and Mrpl4 could be modulated by rno-miR-31a. The CMAP database predicted that small-molecule drugs, including botulin, Gly-His-Lys, and podophyllotoxin, may possess therapeutic potential. In conclusion, the present study has identified Dbp, Crot and Mrpl4 as potential targets for the treatment of hypertension and stroke. Furthermore, the expression of these genes may be reversed by the above miRNAs or drugs.

Functions of subventricular zone neural precursor cells in stroke recovery

The proliferation and ectopic migration of neural precursor cells (NPCs) in response to ischemic brain injury was first reported two decades ago. Since then, studies of brain injury-induced subventricular zone cytogenesis, primarily in rodent models, have provided insight into the cellular and molecular determinants of this phenomenon and its modulation by various factors. However, despite considerable correlational evidence-and some direct evidence-to support contributions of NPCs to behavioral recovery after stroke, the causal mechanisms have not been identified. Here we discuss the subventricular zone cytogenic response and its possible roles in brain injury and disease, focusing on rodent models of stroke. Emerging evidence suggests that NPCs can modulate harmful responses and enhance reparative responses to neurologic diseases. We speculatively identify four broad functions of NPCs in the context of stroke: cell replacement, cytoprotection, remodeling of residual tissue, and immunomodulation. Thus, NPCs may have pleiotropic functions in supporting behavioral recovery after stroke.