Promote Motor Function Recovery Research Articles

Delayed metformin treatment improves functional recovery following traumatic brain injury via central AMPK-dependent brain tissue repair

Accumulating evidence suggests that chronic metformin posttreatment offers potent neuroreparative effects against acute brain injury. However, in previous studies, metformin was not initially administered beyond 24 h postinjury, and the effects of delayed metformin treatment in traumatic brain injury (TBI) and other types of acute brain injury and the related mechanisms are unclear. To test this, male C57BL/6 mice received once daily metformin treatment (20, 50 or 100 mg/kg/d, i.p.) at day 1–14, day 1–2, day 1–10, day 3–10, day 5–12 or day 5–28 after cryogenic TBI (cTBI). The results showed that 100 mg/kg/d metformin administered at day 1–14 postinjury significantly promoted motor functional recovery in the beam walking and gait tests and reduced the infarct volume. Metformin (100 mg/kg/d) administered at day 1–10 or day 3–10 but not day 1–2 or day 5–12 after cTBI significantly improved motor functional outcomes at day 7 and 14, and reduced the infarct volume at day 14. Interestingly, the therapeutic time window was further expanded when the duration of metformin treatment starting at day 5 postinjury was extended to 2 weeks. Furthermore, compared with cTBI, the administration of metformin at day 3–10 or day 5–28 after cTBI significantly elevated the expression of phosphorylated adenosine monophosphate-activated protein kinase (AMPK) and growth associated protein 43 (an axonal regeneration marker) and the number of vascular branch points and decreased the area of glial scar and the number of amoeboid microglia in the peri-infarct area at day 14 or 28 postinjury. The above beneficial effects of metformin were blocked by the intracerebroventricular injection of the AMPK inhibitor compound C (40 μg/mouse/d). Our data provide the first evidence that metformin has a wide therapeutic time window for at least 5 days after cTBI, during which it can improve functional recovery by promoting tissue repair and inhibiting glial scar formation and microglial activation in a central AMPK-dependent manner.

Total flavonoids of hawthorn leaves promote motor function recovery via inhibition of apoptosis after spinal cord injury.

Flavonoids have been reported to have therapeutic potential for spinal cord injury. Hawthorn leaves have abundant content and species of total flavonoids, and studies of the effects of the total flavonoids of hawthorn leaves on spinal cord injury have not been published in or outside China. Therefore, Sprague-Dawley rats were used to establish a spinal cord injury model by Allen's method. Rats were intraperitoneally injected with 0.2 mL of different concentrations of total flavonoids of hawthorn leaves (5, 10, and 20 mg/kg) after spinal cord injury. Injections were administered once every 6 hours, three times a day, for 14 days. After treatment with various concentrations of total flavonoids of hawthorn leaves, the Basso, Beattie, and Bresnahan scores and histological staining indicated decreases in the lesion cavity and number of apoptotic cells of the injured spinal cord tissue; the morphological arrangement of the myelin sheath and nerve cells tended to be regular; and the Nissl bodies in neurons increased. The Basso, Beattie, and Bresnahan scores of treated spinal cord injury rats were increased. Western blot assays showed that the expression levels of pro-apoptotic Bax and cleaved caspase-3 were decreased, but the expression level of the anti-apoptotic Bcl-2 protein was increased. The improvement of the above physiological indicators showed a dose-dependent relationship with the concentration of total flavonoids of hawthorn leaves. The above findings confirm that total flavonoids of hawthorn leaves can reduce apoptosis and exert neuroprotective effects to promote the recovery of the motor function of rats with spinal cord injury. This study was approved by the Ethics Committee of the Guangxi Medical University of China (approval No. 201810042) in October 2018.

Promoting 3D neuronal differentiation in hydrogel for spinal cord regeneration

Spinal cord injury (SCI) affects millions of people worldwide, and results in the loss of neurons and limited recovery of functions. Bone mesenchymal stem cells (BMSCs) and neural stem cells (NSCs) can proliferate or differentiate into other specific cell types. These cells represent potential treatments for SCIs. However, recent studies have shown that NSCs mainly differentiate into astrocytes, rather than neurons, in the microenvironment of an SCI. BMSCs have been reported to promote neuronal differentiation of NSCs and reduce the formation of astrocytes. Furthermore, three-dimensional (3D) gelatin methacryloyl (GelMA) provides superior mechanical properties and functional characteristics for cell proliferation, migration, and differentiation. In this study, we proposed a functional scaffold developed by loading BMSCs and NSCs into 3D GelMA hydrogel. BMSCs and NSCs that were photo-encapsulated in the 3D GelMA hydrogel survived and demonstrated good proliferation in vitro. The NSCs differentiated more toward neurons and oligodendrocytes than toward astrocytes, a phenomenon more noticeable in low-modulus hydrogels. When functional hydrogel scaffolds, loaded with BMSCs and NSCs, were implanted into the hemisection site of the rat spinal cord, they could significantly promote motor function recovery and neuronal differentiation, and decrease glial scarring, fibrotic scarring, and inflammatory responses. The immense therapeutic potential of this system to promote axonal regeneration was thereby demonstrated. Taken together, loading of the GelMA scaffold with BMSCs and NSCs is a promising therapeutic strategy to trigger functional regeneration of the spinal cord.

GRP78-Mediated Signaling Contributes to Axonal Growth Resulting in Motor Function Recovery in Spinal Cord-Injured Mice.

Promoting axonal growth is essential for repairing damaged neuronal connections and motor function in spinal cord injury (SCI). Neuroleukin (NLK) exerts axonal growth activity in vitro and in vivo, but the mechanism remains unclear. This study reveals that the 78-kDa glucose-regulated protein (GRP78) is a NLK neuronal receptor that contributes to recovery from SCI. Binding and immunoprecipitation assays indicated that NLK binds to GRP78. Pretreatment to cultured neurons with a GRP78-neutralizing antibody suppressed NLK-induced axonal growth. Blocking cell surface GRP78 inhibited neuronal NLK-induced Akt activation. Treatment with an Akt inhibitor suppressed NLK-induced axonal growth. Continuous administration of NLK into the lateral ventricle of SCI mice increased axonal density in the injured region and restored motor function, which was not observed when NLK was simultaneously administered with a GRP78-neutralizing antibody. These results indicate that GRP78 regulates the NLK-induced axonal growth activity; NLK-GRP78 signaling promotes motor function recovery in SCI, presenting as a potential therapeutic target.

MicroRNA-421-3p-abundant small extracellular vesicles derived from M2 bone marrow-derived macrophages attenuate apoptosis and promote motor function recovery via inhibition of mTOR in spinal cord injury

BackgroundSpinal cord injury (SCI) has a very disabling central nervous system impact but currently lacks effective treatment. Bone marrow-derived macrophages (BMDMs) are recruited to the injured area after SCI and participate in the regulation of functional recovery with microglia. Previous studies have shown that M2 microglia-derived small extracellular vesicles (SEVs) have neuroprotective effects, but the effects of M2 BMDM-derived sEVs (M2 BMDM-sEVs) have not been reported in SCI treatment.ResultsIn this study, we investigated the role of M2 BMDM-sEVs in vivo and in vitro for SCI treatment and its mechanism. Our results indicated that M2 BMDM-sEVs promoted functional recovery after SCI and reduced neuronal apoptosis in mice. In addition, M2 BMDM-sEVs targeted mammalian target of rapamycin (mTOR) to enhance the autophagy level of neurons and reduce apoptosis. MicroRNA-421-3P (miR-421-3p) can bind to the 3′ untranslated region (3′UTR) of mTOR. MiR-421-3p mimics significantly reduced the activity of luciferase-mTOR 3′UTR constructs and increased autophagy. At the same time, tail vein injection of inhibitors of SEVs (Inh-sEVs), which were prepared by treatment with an miR-421-3p inhibitor, showed diminished protective autophagy of neuronal cells in vivo.ConclusionsIn conclusion, M2 BMDM-sEVs inhibited the mTOR autophagy pathway by transmitting miR-421-3p, which reduced neuronal apoptosis and promoted functional recovery after SCI, suggesting that M2 BMDM-sEVs may be a potential therapy for SCI.

A chitosan-based thermosensitive scaffold loaded with bone marrow-derived mesenchymal stem cells promotes motor function recovery in spinal cord injured mice

Spinal cord injury is a devastating trauma with high mortality and disability, for which there is no effective treatment. Stem cell-based tissue engineering has been reported to promote functional neural recovery. At present, building a neural scaffold with excellent biocompatibility for cells and tissues is still challenging. In this study, a new thermosensitive composite hydrogel based on chitosan, hydroxyethyl cellulose, collagen and β-phosphoglycerate (CS-HEC-Col/GP hydrogel) is developed to encapsulate murine bone marrow-derived mesenchymal stem cells (BMSCs) to improve therapeutic efficacy in spinal cord injured mice. This composite hydrogel possesses a good cytocompatibility to mouse BMSCs by live/dead staining, minimized inflammatory reaction in vivo by hematoxylin and eosin staining and suitable rheological behavior similar to neural tissue, ranging from 100 to 1000 Pa. Furthermore, the data from animal experiments indicated that BMSC-loaded CS-HEC-Col/GP hydrogel could enhance the survival or proliferation of endogenous nerve cells, probably by secreting neurotrophic factors and inhibiting apoptosis, and thereby promote the recovery of motor function in the hindlimbs of a murine spinal cord injury model.

Curcumin Promotes Recovery of Motor Function After Spinal Cord Injury in Rats Through Mammalian Target of Rapamycin (mTOR)-Signal Transducer and Activator of Transcription 3 (STAT3) Signaling Pathway

Objective: Curcumin possesses extensive therapeutic effects on several diseases and tumor cells, which has inhibitory effects on mammalian target of rapamycin (mTOR)-STAT3 signaling. Our study aims to explore the influences of curcumin on promoting the recovery of motor function after spinal cord injury (SCI) in rats through the mTOR-STAT3 signaling pathway. Methods : SCI rats were treated with rapamycin and curcumin followed by establishing rat models of SCI. The influences of rapamycin and curcumin on the protein expressions of PTEN, Akt, phosphorylated S6 and chondroitin sulphate proteoglycans (CSPGs) were measured by western blot. Means of Basso, Beattie and Bresnahan (BBB) locomotor rating scale was used to assess motor function. Results: After SCI, curcumin promoted the expression of PTEN, reduced the proliferation of neuroglia cells, affected the expressions of CSPGs and improved the motor function. Conclusion: Curcumin can promote motor function recovery after SCI which is possibly by up-regulating the PTEN expression via the mTOR-STAT3 signaling pathway.

Experimental Study on the Role of Apelin-13 in Alleviating Spinal Cord Ischemia Reperfusion Injury Through Suppressing Autophagy.

BackgroundThis study aimed to explore the effect of Apelin-13 in protecting rats against spinal cord ischemia reperfusion injury (SCIR), as well as the related molecular mechanisms.MethodsOne week prior to the experiment, experimental Sprague–Dawley rats were injected with Apelin-13 and the autophagy activator rapamycin through the tail vein once a day for 7 consecutive days. The SCIR rat model was prepared through the abdominal aorta clamping method. At 72 h after injury, the spinal cord tissue water content, infarct volume, and normal neuron count were determined to evaluate the degree of spinal cord tissue injury in the rats. The Basso–Beattie–Bresnahan scoring standard was adopted for functional scoring of the rat hind leg, to reflect the post-injury motor function. At 72 h after injury, changes in mitochondrial membrane potential, reactive oxygen species content, and mitochondrial ATP were detected. ELISA was carried out to detect the malonaldehyde content, as well as catalase, superoxide dismutase, and glutathione catalase activities in spinal cord tissues at 72 h after injury. Quantitative chemistry was conducted to examine the contents of nitric oxide (NO) and endothelial nitric oxide synthase (eNOS) in spinal cord tissues. Finally, the expression of autophagy-related proteins, Beclin1, ATG5, and LC3, in spinal cord tissues was detected through the Western blotting assay.ResultsApelin-13 pretreatment alleviated SCIR, promoted motor function recovery, suppressed mitochondrial dysfunction, resisted oxidative stress, and inhibited autophagy in spinal cord tissues following ischemia reperfusion injury.ConclusionApelin-3 exerts protection against SCIR by suppressing autophagy.

Restoring Cellular Energetics Promotes Axonal Regeneration and Functional Recovery after Spinal Cord Injury

Axonal regeneration in the central nervous system (CNS) is a highly energy-demanding process. Extrinsic insults and intrinsic restrictions lead to an energy crisis in injured axons, raising the question of whether recovering energy deficits facilitates regeneration. Here, we reveal that enhancing axonal mitochondrial transport by deleting syntaphilin (Snph) recovers injury-induced mitochondrial depolarization. Using three CNS injury mouse models, we demonstrate that Snph-/- mice display enhanced corticospinal tract (CST) regeneration passing through a spinal cord lesion, accelerated regrowth of monoaminergic axons across a transection gap, and increased compensatory sprouting of uninjured CST. Notably, regenerated CST axons form functional synapses and promote motor functional recovery. Administration of the bioenergetic compound creatine boosts CST regenerative capacity in Snph-/- mice. Our study provides mechanistic insights into intrinsic regeneration failure in CNS and suggests that enhancing mitochondrial transport and cellular energetics are promising strategies to promote regeneration and functional restoration after CNS injuries.

Zinc promotes functional recovery after spinal cord injury by activating Nrf2/HO-1 defense pathway and inhibiting inflammation of NLRP3 in nerve cells

AimsTo study the specific therapeutic effect of zinc on spinal cord injury (SCI) and its specific protective mechanism. Main methodsThe effects of zinc ions on neuronal cells were examined in a mouse SCI model and in vitro. In vivo, neurological function was assessed by Basso Mouse Scaleat (BMS) at 1, 3, 5, 7, 10, 14, 21, and 28 days after spinal cord injury. The number of neurons and histomorphology were observed by nissl staining and hematoxylin-eosin staining (HE). The chromatin and mitochondrial structure of neurons were detected by transmission electron microscopy (TEM). The expression of nuclear factor erythroid 2 related factor 2 (Nrf2)-related antioxidant protein and NLRP3 inflammation-related protein were detected in vivo and in vitro by western blot (WB) and immunofluorescence (IF), respectively. Key findingsZinc treatment promoted motor function recovery on days 3, 5, 7, 14, 21 and 28 after SCI. In addition, zinc reduces the mitochondrial void rate in spinal neuronal cells and promotes neuronal recovery. At the same time, zinc reduced the levels of reactive oxygen species (ROS) and malondialdehyde in spinal cord tissue after SCI, while increasing superoxide dismutase activity and glutathione peroxidase production. Zinc treatment resulted in up-regulation of Nrf2/Ho-1 levels and down-regulation of nlrp3 inflammation-associated protein expression in vitro and in vivo. SignificanceZinc has a protective effect on spinal cord injury by inhibiting oxidative damage and nlrp3 inflammation. Potential mechanisms may include activation of the Nrf 2/Ho-1 pathway to inhibit nlrp3 inflammation following spinal cord injury. Zinc has the potential to treat SCI.

Role of argatroban in repair of spinal cord injury in rats

Objective To investigate the effect of argatroban in repair of spinal cord injury in rats. Methods A total of 54 female Wistar rats were selected and divided into three groups according to the random number table: sham group, injury group and Argatroban group, with 18 rats in each group. The sham group only took the T10lamina; the injury group used the spinal cord injury device to make the rat spinal cord injury model; the Argatroban group received Argatroban treatment after spinal cord injury. The recovery of hindlimb motor function was evaluated by BBB score and clined plate test before injury and 7, 14, 21, 28, 35 and 42 days after injury. The sensory evoked potentials (SEP) and motor evoked potentials (MEP) were detected 42 days after operation. HE staining was used to compare the size of the cavity in the local region 42 days after injury. Results At day 7 after injury, the BBB score was (3.7±0.5)points and the inclined plane test was (28.0±2.6)° in the Argatroban group, which were better than those in the injury group [(3.3±0.5)points, (24.3±1.9)°] (P<0.05). At day 42 after injury, the BBB score was (13.0±0.8)points and inclined plane test was (50.7±2.7)° in the Argatroban group, which were significantly better than those in the injury group [(9.7±1.3) points, (40.5±2.7)°] (P<0.05). But all the above values in the Argatroban group were significantly lower than those in the sham group [(21.0±0.0)points, (60.0±0.0)°](P<0.05). At day 42 after operation, the SEP latency [(25.0±0.9)ms] in the Argatroban group was significantly shorter than that in the injury group [(31.5±1.9) ms]; the amplitude [(2.1±0.1)μV] in the Argatroban group was lower than that in the injury group [(0.5±0.1)μV] (P<0.05). The MEP latency [(11.5±1.0)ms] in the Argatroban group was significantly shorter than that in the injury group [(17.5±1.1)ms], and the amplitude [(4.8±0.8)μV] in the Argatroban group was lower than that in the injury group [(2.8±0.7)μV] (P<0.05). And the SEP or MEP latency and amplitude in the Argatroban group showed significant differences compared to the sham group [(7.5±1.0)ms, (7.5±1.0)μV](P<0.05). HE staining showed that the central area of the lesion in the Argatroban group [(0.35±0.04)mm2] was significantly smaller than that in the injury group [(0.71±0.05)mm2]. Conclusion After spinal cord injury, argatroban can protect the spinal cord tissue effectively in the injured area and promote recovery of sensory and motor function in the hind limbs of rats. Key words: Spinal cord injuries; Argatroban; Inflammation; Thrombin

Neuroprotective effects of a ketogenic diet in combination with exogenous ketone salts following acute spinal cord injury.

We have previously shown that induction of ketosis by ketogenic diet (KD) conveyed neuroprotection following spinal cord injury in rodent models, however, clinical translation may be limited by the slow raise of ketone levels when applying KD in the acute post-injury period. Thus we investigated the use of exogenous ketone supplementation (ketone sodium, KS) combined with ketogenic diet as a means rapidly inducing a metabolic state of ketosis following spinal cord injury in adult rats. In uninjured rats, ketone levels increased more rapidly than those in rats with KD alone and peaked at higher levels than we previously demonstrated for the KD in models of spinal cord injury. However, ketone levels in KD + KS treated rats with SCI did not exceed the previously observed levels in rats treated with KD alone. We still demonstrated neuroprotective effects of KD + KS treatment that extend our previous neuroprotective observations with KD only. The results showed increased neuronal and axonal sparing in the dorsal corticospinal tract. Also, better performance of forelimb motor abilities were observed on the Montoya staircase (for testing food pellets reaching) at 4 and 6 weeks post-injury and rearing in a cylinder (for testing forelimb usage) at 6 and 8 weeks post-injury. Taken together, the findings of this study add to the growing body of work demonstrating the potential benefits of inducing ketosis following neurotrauma. Ketone salt combined with a ketogenic diet gavage in rats with acute spinal cord injury can rapidly increase ketone body levels in the blood and promote motor function recovery. This study was approved by the Animal Care Committee of the University of British Columbia (protocol No. A14-350) on August 31, 2015.

A combination of mesenchymal stem cells and scaffolds promotes motor functional recovery in spinal cord injury: a systematic review and meta-analysis.

There is controversy about the role of scaffolds as an adjunctive therapy to mesenchymal stem cell (MSC) transplantation in spinal cord injury (SCI). Thus, the authors aimed to design a meta-analysis on preclinical evidence to evaluate the effectiveness of combination therapy of scaffold + MSC transplantation in comparison with scaffolds alone and MSCs alone in improving motor dysfunction in SCI. Electronic databases including Medline, Embase, Scopus, and Web of Science were searched from inception until the end of August 2018. Two independent reviewers screened related experimental studies. Animal studies that evaluated the effectiveness of scaffolds and/or MSCs on motor function recovery following experimental SCI were included. The findings were reported as standardized mean difference (SMD) and 95% confidence interval (CI). A total of 34 articles were included in the meta-analysis. Analyses show that combination therapy in comparison with the scaffold group alone (SMD 2.00, 95% CI 1.53-2.46, p < 0.0001), the MSCs alone (SMD 1.58, 95% CI 0.84-2.31, p < 0.0001), and the nontreated group (SMD 3.52, 95% CI 2.84-4.20, p < 0.0001) significantly improved motor function recovery. Co-administration of MSCs + scaffolds only in the acute phase of injury (during the first 3 days after injury) leads to a significant recovery compared to scaffold alone (SMD 2.18, p < 0.0001). In addition, the cotransplantation of scaffolds with bone marrow-derived MSCs (SMD 1.99, p < 0.0001) and umbilical cord-derived MSCs (SMD 1.50, p = 0.001) also improved motor function following SCI. The findings showed that scaffolds + MSCs is more effective than scaffolds and MSCs alone in improving motor function following SCI in animal models, when used in the acute phase of injury.

Epidural Spinal Cord Stimulation Promotes Motor Functional Recovery by Enhancing Oligodendrocyte Survival and Differentiation and by Protecting Myelin after Spinal Cord Injury in Rats.

Epidural spinal cord stimulation (ESCS) markedly improves motor and sensory function after spinal cord injury (SCI), but the underlying mechanisms are unclear. Here, we investigated whether ESCS affects oligodendrocyte differentiation and its cellular and molecular mechanisms in rats with SCI. ESCS improved hindlimb motor function at 7 days, 14 days, 21 days, and 28 days after SCI. ESCS also significantly increased the myelinated area at 28 days, and reduced the number of apoptotic cells in the spinal white matter at 7 days. SCI decreased the expression of 2',3'-cyclic-nucleotide 3'-phosphodiesterase (CNPase, an oligodendrocyte marker) at 7 days and that of myelin basic protein at 28 days. ESCS significantly upregulated these markers and increased the percentage of Sox2/CNPase/DAPI-positive cells (newly differentiated oligodendrocytes) at 7 days. Recombinant human bone morphogenetic protein 4 (rhBMP4) markedly downregulated these factors after ESCS. Furthermore, ESCS significantly decreased BMP4 and p-Smad1/5/9 expression after SCI, and rhBMP4 reduced this effect of ESCS. These findings indicate that ESCS enhances the survival and differentiation of oligodendrocytes, protects myelin, and promotes motor functional recovery by inhibiting the BMP4-Smad1/5/9 signaling pathway after SCI.

Ginsenoside Rb1 Promotes Motor Functional Recovery and Axonal Regeneration in Post-stroke Mice through cAMP/PKA/CREB Signaling Pathway

The central nervous system (CNS) has a poor self-repairing capability after injury because of the inhibition of axonal regeneration by many myelin-associated inhibitory factors. Therefore, ischemic stroke usually leads to disability. Previous studies reported that Ginsenoside Rb1 (GRb1) plays a role in neuronal protection in acute phase after ischemic stroke, but its efficacy in post-stroke and the underlying mechanism are not clear. Recent evidences demonstrated GRb1 promotes neurotransmitter release through the cAMP-depend protein kinase A (PKA) pathway, which is related to axonal regeneration. The present study aimed to determine whether GRb1 improves long-term motor functional recovery and promotes cortical axon regeneration in post-stroke. Adult male C57BL/6 mice were subjected to distal middle cerebral artery occlusion (dMCAO). GRb1 solution (5 mg/ml) or equal volume of normal saline was injected intraperitoneally for the first time at 24 h after surgery, and then daily injected until day 14. Day 3, 7, 14 and 28 after dMCAO were used as observation time points. Motor functional recovery was assessed with Rota-rod test and grid walking task. The expression of growth-associated protein 43 (GAP43) and biotinylated dextran amine (BDA) was measured to evaluate axonal regeneration. The levels of cyclic AMP (cAMP) and PKA were measured by Elisa, PKAc and phosphorylated cAMP response element protein (pCREB) were determined by western blot. Our results shown that GRb1 treatment improved motor function and increased the expression of GAP43 and BDA in ipsilesional and contralateral cortex. GRb1 significantly elevated cAMP and PKA, increased the protein expression of PKAc and pCREB. However, the effects of GRb1 were eliminated by H89 intervention (a PKA inhibitor). These results suggested that GRb1 improved functional recovery in post-stroke by stimulating axonal regeneration and brain repair. The underlying mechanism might be up-regulating the expression of cAMP/PKA/CREB pathway.

Isoquercitrin promotes peripheral nerve regeneration through inhibiting oxidative stress following sciatic crush injury in mice.

Oxidative stress has been recognized to play a crucial role in the pathogenesis of peripheral nerve injury. Isoquercitrin (quercetin-3-glucoside) is a flavonoid that exhibited many biological activities, including anti-oxidative effect. However, it is unclear whether isoquercitrin has protective effects on peripheral nerve injury. Mice treated by isoquercitrin were used as a case group, and mice injected with saline was the control group. Sciatic behavioral function was assessed using SFI and CMAPs were measured by electrophysiology. Schwann cells proliferation and migration were tested using EdU staining and Transwell migration chambers respectively. The expression of oxidative stress related factors were detected by qRT-PCR and Western blotting. In present study, our results demonstrated that isoquercitrin (20 mg/kg/day) treatment achieved significantly higher SFI and higher amplitude of CMAP, promoted the nerve regeneration and remyelination, increased the production of GAP43, NF200, MAG and PMP22, alleviated target muscle atrophy and autophagy, and suppressed the expression of ATG7, PINK1 and Beclin1 in soleus muscles after sciatic nerve crush. In vitro studies found that isoquercitrin promoted the axonal regeneration of DRGs neurons, the proliferation and migration of Schwann cells, and the expression of proliferating cell nuclear antigen (PCNA) in Schwann cells. The administration of isoquercitrin at 40 and 320 µM showed a dose dependent, and high doses of isoquercitrin (160 and 320 µM) showed better performance in promoting axonal regeneration of DRGs neurons, and the proliferation and migration of Schwann cells than low dose of isoquercitrin (40 µM). Furthermore, isoquercitrin significantly inhibited oxidative stress through reducing the production of Nox4 and Duox1, and promoting the expression of Nrf2 and SOD2 in soleus muscles after sciatic nerve crush. Isoquercitrin may promote motor functional recovery and nerve regeneration following peripheral nerve injury though inhibition of oxidative stress, which highlighted the therapeutic values of isoquercitrin as a neuroprotective drug for peripheral nerve repair applications.

The effects of early treadmill training combined with ultrashort wave irradiation on functional recovery from spinal cord injury

Objective To investigate the effect of early-stage training combined with the ultrashort wave therapy on the functional recovery of rats after a spinal cord injury, and to observe the expression of aquaporin protein-4 (AQP-4) and glial fibrillary acidic protein (GFAP). Methods Fifty female Sprague-Dawley rats had spinal cord injury (SCI) induced using the modified Allen′s method. After successful modeling, 40 were randomly divided into a sham operation group, a control group, an ultrashort wave group, a treadmill group and a combined group, each of 8. Motor function in their hind limbs was evaluated 4 weeks after the operation using BBB scoring. GFAP and AQP-4 immunohistochemical staining were used to determine the integral optical density (IOD) of the protein expression. Results The average BBB score of the sham operation group was 21, while the other four groups averages were all less than 1 on the 1st day after the operation. They gradually increased with time, and by 4 weeks the increases were significant. Compared with the control group at the same time point, the average BBB scores of the treadmill and the combined groups were significantly higher. Compared with the ultrashort wave group, the average BBB score of the treadmill group was higher after 4 weeks, and the combined group′s average was significantly higher at 2, 3 and 4 weeks after the operation. Four weeks after the SCI modeling, the average AQP-4 IOD and GFAP IOD levels of the ultrashort wave group, the treadmill group and the combined group were lower than that of the control group, while the average AQP-4 and GFAP IOD levels of the combined group were significantly lower than those of the ultrashort wave group. Compared with the treadmill group, the combined group had a significantly lower average GFAP level. Conclusions Both treadmill training and ultrashort wave treatment promote motor function recovery after a spinal cord injury. The mechanism may be related to downregulation of AQP-4 and GFAP expression at the injured site. Combining the two treatments gives better effects. Key words: Spinal cord injury; Treadmill training; Ultrashort wave irradiation; Auaporin protein-4; Glial fibrillary acidic protein

Effect of docosahexaenoic acid on the recovery of motor function in rats with spinal cord injury: a meta-analysis.

Objective:Studies have shown that docosahexaenoic acid (DHA) has a beneficial effect in the treatment of spinal cord injury. A meta-analysis was used to study the effect of DHA on the neurological recovery in the rat spinal cord injury model, and the relationship between the recovery of motor function after spinal cord injury and the time and method of administration and the dose of DHA.Data source:Published studies on the effect of DHA on spinal cord injury animal models from seven databases were searched from their inception to January 2019, including PubMed, MEDLINE, EMBASE, the China National Knowledge Infrastructure, Wanfang, VIP, and SinoMed databases. The search terms included “spinal cord injury” “docosahexaenoic acid”, and “rats”.Data selection:Studies that evaluated the influence of DHA in rat models of spinal cord injury for locomotor functional recovery were included. The intervention group included any form of DHA treatment and the control group included treatment with normal saline, vehicle solution or no treatment. The Systematic Review Centre for Laboratory animal Experimentation’s risk of bias assessment tool was used for the quality assessment of the included studies. Literature inclusion, quality evaluation and data extraction were performed by two researchers. Meta-analysis was then conducted on all studies that met the inclusion criteria. Statistical analysis was performed on the data using RevMan 5.1.2. software.Outcome measures:The primary outcome measure was the score on the Basso, Beattie, and Bresnahan scale. Secondary outcome measures were the sloping plate test, balance beam test, stair test and grid exploration test.Results:A total of 12 related studies were included, 3 of which were of higher quality and the remaining 9 were of lower quality. The highest mean Basso, Beattie, and Bresnahan scale score occurred at 42 days after DHA treatment in spinal cord injury rats. At 21 days after treatment, the mean difference in Basso, Beattie, Bresnahan scores between the DHA group and the control group was the most significant (pooled MD = 4.14; 95% CI = 3.58–4.70; P < 0.00001). In the subgroup analysis, improvement in the Basso, Beattie, and Bresnahan scale score was more significant in rats administered DHA intravenously (pooled MD = 2.74; 95% CI = 1.41–4.07; P < 0.0001) and subcutaneously (pooled MD = 2.99; 95% CI = 2.29–3.69; P < 0.00001) than in the groups administered DHA orally (pooled MD = 3.04; 95% CI = –1.01 to 7.09; P = 0.14). Intravenous injection of DHA at 250 nmol/kg (pooled MD = 2.94; 95% CI = 2.47–3.41; P < 0.00001] and 1000 nmol/kg [pooled MD = 3.60; 95% CI = 2.66–4.54; P < 0.00001) significantly improved the Basso, Beattie, and Bresnahan scale score in rats and promoted the recovery of motor function.Conclusion:DHA can promote motor functional recovery after spinal cord injury in rats. The administration of DHA by intravenous or subcutaneous injection is more effective than oral administration of DHA. Intravenous injection of DHA at doses of 250 nmol/kg or 1000 nmol/kg is beneficial. Because of the small number and the low quality of the included studies, more high-quality research is needed in future to substantiate the results.

Brilliant Blue G Inhibits Inflammasome Activation and Reduces Disruption of Blood-Spinal Cord Barrier Induced by Spinal Cord Injury in Rats.

BackgroundBrilliant blue G (BBG) is a P2X7 receptor inhibitor that has been reported to improve spinal cord injury (SCI) in previous studies, but the specific mechanism has been unclear. In this study, we investigated the effects of BBG on inflammasomes and blood–spinal cord barrier (BSCB) permeability after SCI.Material/MethodsThe experimental rats were randomly divided into 3 groups: sham, SCI, and SCI+BBG. The expression of P2X7 and inflammasome-related proteins was measured by Western blot and immunohistochemistry, while IL-1β and IL-18 levels were measured by using an enzyme-linked immunosorbent assay (ELISA) kit. The permeability of the BSCB was evaluated by Evans Blue (EB) exosmosis, and histological alterations were observed by hematoxylin-eosin staining. Motor function recovery was assessed by the Basso, Beattie, Bresnahan (BBB) scale after SCI.ResultsThe expression levels of P2X7, NLRP3, ASC, cleaved XIAP, caspase-1, caspase-11, IL-1β, and IL-18 were increased significantly after SCI, and BBG administration inhibited this increase at 72 h after SCI. BBG administration significantly reduced EB leakage at 24 h after SCI. Furthermore, treatment with BBG significantly attenuated histological alterations and improved motor function recovery after SCI.ConclusionsBBG administration promoted motor function recovery and alleviated tissue injury, and these effects might be related to the suppression of inflammasomes and the maintenance of BSCB integrity.

Exosomes from Bone Marrow Mesenchymal Stem Cells Inhibit Neuronal Apoptosis and Promote Motor Function Recovery via the Wnt/β-catenin Signaling Pathway

Severe spinal cord injury (SCI) is caused by external mechanical injury, resulting in unrecoverable neurological injury. Recent studies have shown that exosomes derived from bone marrow mesenchymal stem cells (BMSCs-Exos) might be valuable paracrine molecules in the treatment of SCI. In this study, we designed SCI models in vivo and in vitro and then investigated the possible mechanism of successful repair by BMSCs-Exos. In vivo, we established one Sham group and two SCI model groups. The Basso, Beattie, Bresnahan (BBB) scores showed that BMSCs-Exos could effectively promote the recovery of spinal cord function. The results of the Nissl staining, immunohistochemistry, and TUNEL/NeuN/DAPI double staining showed that BMSCs-Exos inhibited neuronal apoptosis. Western blot analysis showed that the protein expression level of Bcl-2 was significantly increased in the BMSCs-Exos group compared with the PBS group, while the protein expression levels of Bax, cleaved caspase-3, and cleaved caspase-9 were significantly decreased. The results of western bolt and qRT-PCR demonstrated that BMSCs-Exos could activate the Wnt/β-catenin signaling pathway effectively. In vitro, we found that inhibition of the Wnt/β-catenin signaling pathway could promote neuronal apoptosis following lipopolysaccharide (LPS) induction. These results demonstrated that BMSCs-Exos may be a promising therapeutic for SCI by activating the Wnt/β-catenin signaling pathway.