Recovery Of Hindlimb Function Research Articles

The TGFβ1/SMADs/Snail1 signaling axis mediates pericyte-derived fibrous scar formation after spinal cord injury

AimsThe deposition of fibrous scars after spinal cord injury (SCI) affects axon regeneration and the recovery of sensorimotor function. It has been reported that microvascular pericytes in the neurovascular unit are the main source of myofibroblasts after SCI, but the specific molecular targets that regulate pericyte participation in the formation of fibrous scars remain to be clarified. MethodsIn this study, a rat model of spinal cord dorsal hemisection injury was used. After SCI, epigallocatechin gallate (EGCG) was intraperitoneally injected to block the TGFβ1 signaling pathway or LV-Snail1-shRNA was immediately injected near the core of the injury using a microsyringe to silence Snail1 expression. Western blotting and RT-qPCR were used to analyze protein expression and transcription levels in tissues. Nissl staining and immunofluorescence analysis were used to analyze neuronal cell viability, scar tissue, and axon regeneration after SCI. Finally, the recovery of hind limb function after SCI was evaluated. ResultsThe results showed that targeted inhibition of Snail1 could block TGFβ1-induced pericyte-myofibroblast differentiation in vitro. In vivo experiments showed that timely blockade of Snail1 could reduce fibrous scar deposition after SCI, promote axon regeneration, improve neuronal survival, and facilitate the recovery of lower limb motor function. ConclusionIn summary, Snail1 promotes the deposition of fibrous scars and inhibits axonal regeneration after SCI by inducing the differentiation of pericytes into myofibroblasts. Snail1 may be a promising therapeutic target for SCI.

Decellularized extracellular matrix scaffold seeded with adipose-derived stem cells promotes neurorestoration and functional recovery after spinal cord injury through Wnt/β-catenin signaling pathway regulation

Spinal cord injury (SCI) causes tissue destruction and neuronal apoptosis, which impede neural function recovery. Therefore, promoting neuronal regeneration and neural pathway reconstruction is crucial. In this study, a novel and facile decellularized extracellular matrix (dECM) scaffold seeded with adipose-derived stem cells (ADSCs) (dECM scaffolds/ADSCs) was reported. The dECM scaffold maintained the original three-dimensional network structure of spinal cord tissue and contained various small pores. In vitro studies demonstrated that dECM scaffolds exhibited excellent biocompatibility, facilitated efficient adhesion and proliferation of ADSCs, and promoted the secretion of neurotrophin-3 and neuronal differentiation in the microenvironment after SCI. In vivo studies further showed that dECM scaffolds/ADSCs could alleviate inflammatory and apoptotic reactions, providing a favorable microenvironment for promoting endogenous nerve regeneration rather than glial scars formation, ultimately achieving recovery of hind limb function in rats. Notably, ICG-001 effectively reversed the therapeutic effect of dECM scaffolds/ADSCs, proving that dECM scaffolds/ADSCs promoted functional recovery after SCI by regulating the Wnt/β-catenin signaling pathway. Overall, dECM scaffolds/ADSCs can simulate the physiological characteristics of the spinal cord and exert neurorestorative potential, providing a new therapeutic strategy for SCI.

Pramipexole has a neuroprotective effect in spinal cord injury and upregulates D2 receptor expression in the injured spinal cord tissue in rats.

Spinal cord injury (SCI) has emerged as a prevalent condition with limited effective treatment options. The neuroprotective role of pramipexole (PPX) in inhibiting nerve cell apoptosis in central nervous system injuries is well established. Therefore, we investigated the effects of PPX in SCI. Adult Sprague-Dawley rats were divided into four groups (sham, SCI, PPX-0.25, and PPX-2.0 groups) according to the PPX therapy (n = 24). Then, SCI was induced using the modified Allen method, and PPX was intravenously administered into the tail at dosages of 0.25 or 2.0 mg/kg following the injury. Motor function was evaluated using the Rivlin-modified inclined plate apparatus and the Basso Beattie Bresnahan (BBB) workout scale. Western blotting assay was used to measure protein expression levels of DRD2, NeuN, Bax/Bcl-2, and caspase-3. Furthermore, immunohistochemistry assessed the effect of PPX on the quantity of NeuN-positive cells in the spinal cord tissue after SCI. Our findings revealed that the BBB and slanting board test scores of the PPX-treated model groups were considerably higher for the SCI group and significantly lower for the sham operation group (P < 0.001). Moreover, the PPX-2.0 group exhibited significantly higher NeuN expression levels than the SCI group (P < 0.01). Our findings indicate that PPX exerts a neuroprotective effect in secondary neuronal injury following SCI, facilitating the recovery of hind limb function by downregulating Bax/Bcl-2, caspase-3, and IL-1β.

Opposite modulation of functional recovery following contusive spinal cord injury in mice with oligodendrocyte-selective deletions of Atf4 and Chop/Ddit3

The integrated stress response (ISR)-activated transcription factors ATF4 and CHOP/DDIT3 may regulate oligodendrocyte (OL) survival, tissue damage and functional impairment/recovery in white matter pathologies, including traumatic spinal cord injury (SCI). Accordingly, in OLs of OL-specific RiboTag mice, Atf4, Chop/Ddit3 and their downstream target gene transcripts were acutely upregulated at 2, but not 10, days post-contusive T9 SCI coinciding with maximal loss of spinal cord tissue. Unexpectedly, another, OL-specific upregulation of Atf4/Chop followed at 42 days post-injury. However, wild type versus OL-specific Atf4−/− or Chop−/− mice showed similar white matter sparing and OL loss at the injury epicenter, as well as unaffected hindlimb function recovery as determined by the Basso mouse scale. In contrast, the horizontal ladder test revealed persistent worsening or improvement of fine locomotor control in OL-Atf4−/− or OL-Chop−/− mice, respectively. Moreover, chronically, OL-Atf−/− mice showed decreased walking speed during plantar stepping despite greater compensatory forelimb usage. Therefore, ATF4 supports, while CHOP antagonizes, fine locomotor control during post-SCI recovery. No correlation between those effects and white matter sparing together with chronic activation of the OL ISR suggest that in OLs, ATF4 and CHOP regulate function of spinal cord circuitries that mediate fine locomotor control during post-SCI recovery.

Transplantation of neural stem progenitor cells from different sources for severe spinal cord injury repair in rat.

Neural stem progenitor cell (NSPC) transplantation has been regarded as a promising therapeutic method for spinal cord injury (SCI) repair. However, different NSPCs may have different therapeutic effects, and it is therefore important to identify the optimal NSPC type. In our study, we compared the transcriptomes of human fetal brain-derived NSPCs (BNSPCs), spinal cord-derived NSPCs (SCNSPCs) and H9 embryonic stem-cell derived NSPCs (H9-NSPCs) in vitro and subsequently we transplanted each NSPC type on a collagen scaffold into a T8-9 complete SCI rat model in vivo. In vitro data showed that SCNSPCs had more highly expressed genes involved in nerve-related functions than the other two cell types. In vivo, compared with BNSPCs and H9-NSPCs, SCNSPCs exhibited the best therapeutic effects; in fact, SCNSPCs facilitated electrophysiological and hindlimb functional recovery. This study demonstrates that SCNSPCs may be an appropriate candidate cell type for SCI repair, which is of great clinical significance.

具有毒性醛消除功能的聚多肽用于减轻继发性脊髓损伤

Neuroprotective therapy for traumatic spinal cord injury (SCI) still faces formidable challenges in clinic. Immediately after traumatic SCI, toxic reactive aldehydes are largely produced by lipid peroxidation, which subsequently promotes a vicious cycle of oxidative stress and inflammation in injured spinal cord, leading to the worse secondary injury. Therefore, scavenging of toxic reactive aldehydes has become a promising strategy for treatment of secondary SCI. Here, a drug-free polypeptide (PPAH) containing hydrazide groups on the side chains is designed and synthesized for mitigating secondary SCI through scavenging toxic aldehydes. The prepared PPAH displayed the ability to scavenge reactive aldehydes both in vitro and in vivo. Specifically, PPAH exhibited a protective effect against acrolein-induced damage in neurocytes and the intrathecal injection of PPAH was able to suppress inflammation, protect neurons, inhibit demyelination and improve hindlimb functional recovery in a rat SCI model. Therefore, as an effective toxic aldehyde-scavenging agent, PPAH shows promising perspectives in therapies for SCI.

Erythropoietin inhibits ferroptosis and ameliorates neurological function after spinal cord injury.

Ferroptosis is one of the critical pathological events in spinal cord injury. Erythropoietin has been reported to improve the recovery of spinal cord injury. However, whether ferroptosis is involved in the neuroprotective effects of erythropoietin on spinal cord injury has not been examined. In this study, we established rat models of spinal cord injury by modified Allen's method and intraperitoneally administered 1000 and 5000 IU/kg erythropoietin once a week for 2 successive weeks. Both low and high doses of erythropoietin promoted recovery of hindlimb function, and the high dose of erythropoietin led to better outcome. High dose of erythropoietin exhibited a stronger suppressive effect on ferroptosis relative to the low dose of erythropoietin. The effects of erythropoietin on inhibiting ferroptosis-related protein expression and restoring mitochondrial morphology were similar to those of Fer-1 (a ferroptosis suppressor), and the effects of erythropoietin were largely diminished by RSL3 (ferroptosis activator). In vitro experiments showed that erythropoietin inhibited RSL3-induced ferroptosis in PC12 cells and increased the expression of xCT and Gpx4. This suggests that xCT and Gpx4 are involved in the neuroprotective effects of erythropoietin on spinal cord injury. Our findings reveal the underlying anti-ferroptosis role of erythropoietin and provide a potential therapeutic strategy for treating spinal cord injury.

Assessment of hindlimb motor recovery after severe thoracic spinal cord injury in rats: classification of CatWalk XT® gait analysis parameters.

Assessment of locomotion recovery in preclinical studies of experimental spinal cord injury remains challenging. We studied the CatWalk XT® gait analysis for evaluating hindlimb functional recovery in a widely used and clinically relevant thoracic contusion/compression spinal cord injury model in rats. Rats were randomly assigned to either a T9 spinal cord injury or sham laminectomy. Locomotion recovery was assessed using the Basso, Beattie, and Bresnahan open field rating scale and the CatWalk XT® gait analysis. To determine the potential bias from weight changes, corrected hindlimb (H) values (divided by the unaffected forelimb (F) values) were calculated. Six weeks after injury, cyst formation, astrogliosis, and the deposition of chondroitin sulfate glycosaminoglycans were assessed by immunohistochemistry staining. Compared with the baseline, a significant spontaneous recovery could be observed in the CatWalk XT® parameters max intensity, mean intensity, max intensity at%, and max contact mean intensity from 4 weeks after injury onwards. Of note, corrected values (H/F) of CatWalk XT® parameters showed a significantly less vulnerability to the weight changes than absolute values, specifically in static parameters. The corrected CatWalk XT® parameters were positively correlated with the Basso, Beattie, and Bresnahan rating scale scores, cyst formation, the immunointensity of astrogliosis and chondroitin sulfate glycosaminoglycan deposition. The CatWalk XT® gait analysis and especially its static parameters, therefore, seem to be highly useful in assessing spontaneous recovery of hindlimb function after severe thoracic spinal cord injury. Because many CatWalk XT® parameters of the hindlimbs seem to be affected by body weight changes, using their corrected values might be a valuable option to improve this dependency.

3Dimaging of supraspinal inputs to the thoracic and lumbar spinal cord mapped by retrograde tracing and light‐sheet microscopy

The supraspinal inputs play a major role in tuning the hindlimb locomotion function. While most research on spinal cord injury (SCI) with rodents is based on thoracic segments, the difference in connectivity of the supraspinal centers to the thoracic and lumbar cord is still unknown. Here, we combined retrograde tracing and 3D imaging to map the connectivity of supraspinal neurons projecting to thoracic (T9-vertebral) and lumbar (T13-vertebral) spinal levels in adult female mice. We dissected the difference in connections of corticospinal neurons (CSNs), rubrospinal neurons, and reticulospinal neurons projecting to thoracic and lumbar cords. The ratio of double-labeled neurons is higher in T13-vertebral projection CSNs and parvocellular part of the red nucleus (RPC) than in T9-vertebral projection. Using the Cre-DIO system, we precisely targeted CSNs projecting to T9-vertebral or T13-vertebral. We found that abundant axon branches communicated with the red nucleus and reticular formation and distributed from cervical gray matter to the lumbar cord. Their collateral branches showed a distinct innervation pattern in thoracic and lumbar gray matters and a similar distribution pattern in the cervical spinal cord. These results revealed the difference in connectivity between the thoracic and lumbar projection supraspinal centers and clarified the collateralization of thoracic/lumbar projection CSNs throughout the brain and spinal cord. This study highlights brain-spinal cord neural networks and the complexity of the axon terminals of spinal projection CSNs, which could contribute to the development of targeted therapeutic strategies connecting CST fibers and hindlimb function recovery. Cover Image for this issue: https://doi.org/10.1111/jnc.15414.

Protective Effect of Extended Laminectomy on Spinal Cord Injury Induced by Spinal Shortening.

This study investigates the effect of extended laminectomy (EL) on spinal cord injury (SCI) caused by spinal shortening, and further, the timing and the optimal length of removal. Dogs received spinal column shortening at T13 segment, following which the control group underwent regular laminectomy while other groups underwent laminectomy with an additional 1-lamina length removed 6h after shortening ("1-lamina EL 6 h"), an extra 1.5-lamina length resected at 6 h or 12 h after shortening ("1.5-lamina EL 6 h" and "1.5-lamina EL 12 h"), and an extra 2-lamina length removed at 6 or 12 h after shortening ("2-lamina EL 6 h" and 2-lamina EL 12 h"), respectively. Somatosensory evoked potential (SSEP) and neurological function were recorded periodically; spinal cord blood flow (SCBF) and nerve cell apoptosis were detected. The results showed that resection of an additional 1-lamina length appeared inadequate to relieve the sharp kinking of the spinal cord, whereas the kinking disappeared with an additional 2-lamina length resection. The "1-lamina EL 6 h" and "1.5-lamina EL 12 h" groups showed no significant differences from the control in latency of SSEP, SCBF, hindlimb function and apoptosis. By contrast, significant recovery of SSEP, SCBF and hindlimb function as well as reduction of apoptosis were presented in other three groups. The "2-lamina EL 6 h" group, in particular, showed the most prominent recovery. In conclusion, an additional resection of two laminae at 6 h after shortening showed the best effect in alleviating SCI. Timely and adequately extended laminectomy could be a potential therapeutic strategy for SCI attributable to spinal shortening.

Transplantation of BMP-7 gene-transfected bone marrow mesenchymal stem cells for the treatment of spinal cord injury in rats

Background: Spinal cord injury (SCI) is a serious traumatic disease of the central nervous system, and there is currently no effective treatment for SCI because of its complicated pathophysiology. Bone marrow mesenchymal stem cells (BMSCs) have multidirectional differentiation abilities. Our study aims to explore the effects of bone morphogenetic protein 7 (BMP-7)-modified BMSCs transplantation on the repair of SCI in rats. Methods: In this study, a rat spinal cord injury model was established with the modified Allen method. Then, BMSCs transfected with the BMP7 gene were transplanted to treat the spinal cord injury in rats. Forty Sprague-Dawley rats were randomly divided into the sham operation group (sham group), spinal cord injury group (model group), BMSC treatment group (BMSC group) and LV-BMP7-BMSC treatment group (LV-BMP7-BMSC group). The Basso, Beattie, and Bresnahan (BBB) score was used to evaluate the recovery of hindlimb function in the rats. The levels of neurofilament protein NF-200 (NF-200) and glial fibrillary acidic protein (GFAP) were detected by immunofluorescence, RT-PCR and Western blotting. Results: At 14 d, 21 d, and 28 d after treatment, the BBB score of the rats in the LV-BMP7-BMSC group was higher than that of the rats in the model group and BMSC group. The results showed that NF-200 was expressed at the local spinal cord injury site. Compared with that of the sham group, the NF-200 expression level of the BMSC group and LV-BMP7-BMSC group was increased (P < 0.05). The results showed that the mRNA expression levels of NF-200 in the spinal cord tissue of the BMSC group and LV-BMP7-BMSC group were increased compared with those of the sham group (P < 0.05). The western blotting results further confirmed the PCR results. Conclusion: BMP-7 gene-modified BMSC transplantation can promote the repair of spinal cord functions after SCI in rats.

Limited changes in locomotor recovery and unaffected white matter sparing after spinal cord contusion at different times of day.

The circadian gene expression rhythmicity drives diurnal oscillations of physiological processes that may determine the injury response. While outcomes of various acute injuries are affected by the time of day at which the original insult occurred, such influences on recovery after spinal cord injury (SCI) are unknown. We report that mice receiving moderate, T9 contusive SCI at ZT0 (zeitgeber time 0, time of lights on) and ZT12 (time of lights off) showed similar hindlimb function recovery in the Basso mouse scale (BMS) over a 6 week post-injury period. In an independent study, no significant differences in BMS were observed after SCI at ZT18 vs. ZT6. However, the ladder walking test revealed modestly improved performance for ZT18 vs. ZT6 mice at week 6 after injury. Consistent with those minor effects on functional recovery, terminal histological analysis revealed no significant differences in white matter sparing at the injury epicenter. Likewise, blood-spinal cord barrier disruption and neuroinflammation appeared similar when analyzed at 1 week post injury at ZT6 or ZT18. Therefore, locomotor recovery after thoracic contusive SCI is not substantively modulated by the time of day at which the neurotrauma occurred.

Bone marrow mesenchymal stem cell derived exosomal miR-455-5p protects against spinal cord ischemia reperfusion injury

At present, much more studies have focused on the therapeutic effect of exosome-delivered microRNAs on diseases. Previous study has shown that miR-455-5p is downregulated in ischemic stroke, but little is known about the role of exosome-delivered miR-455-5p in spinal cord ischemia reperfusion (SCIR) injury. Herein, we isolated exosomes from bone marrow mesenchymal stem cells (BMSCs) transfected with lentivirus vectors containing miR-455-5p. SCIR rat model was established after the intrathecal injection of exosomes containing miR-455-5p. The expression level of miR-455-5p was downregulated after SCIR, administration of exosomal miR-455-5p enhanced the level of miR-455-5p in the injured spinal cord. Hind-limb motor function scores indicated that exosomal miR-455-5p improved the recovery of hind-limb function of SCIR rats. HE staining and Nissl staining showed that miR-455-5p enriched exosomes reduced histopathological abnormalities after SCIR. Double immunofluorescence staining revealed that exosomes containing miR-455-5p reduced apoptosis of neurons, and activated autophagy in neurons after SCIR. We observed that the expression of Nogo-A, a direct target of miR-455-5p, was decreased in the spinal cord of exosomal miR-455-5p administrated SCIR rats. Targeting relationship between miR-455-5p and Nogo-A was verified by dual-luciferase reporter assay. In summary, exosomes containing miR-455-5p had the neuroprotective effects on SCIR injury by promoting autophagy and inhibiting apoptosis of neurons.

Effects of methylprednisolone and treadmill training on spinal cord injury in experimental rats.

Methylprednisolone (MP) is widely used to treat clinical spinal cord injury (SCI). Treadmill training is also considered an important treatment after SCI to improve motor function in patients, resulting in an evident improvement. Therefore, the present study was designed to evaluate and contrast the effects of MP and treadmill training administered in combination or alone after SCI in adult rats. A rat spinal cord T10 contusion model was induced in Sprague-Dawley rats using an impact device. A total of 40 rats were divided into four groups (n=10 rats/group): the MP, MP + treadmill training, SCI and sham group. At 30 min after injury, MP sodium succinate was injected into the rats of the MP and MP + treadmill training groups. Treadmill training began on the second week post-trauma and was performed for 8 weeks. The results showed that MP therapy combined with treadmill training significantly ameliorated several parameters of hind limb function compared with those by MP treatment alone (all P<0.05). A significantly reduced immunopositive area of Nogo receptor and chondroitin sulfate proteoglycans and reduced relative expression of these mRNAs were found in the MP + treadmill training group (P<0.05) compared with the findings in the MP group. In conclusion, the present study indicated that combined MP and treadmill training treatment improved the recovery of hind limb function in rats with SCI, thus potentially representing a promising strategy to cure SCI.

The Histopathology of Severe Graded Compression in Lower Thoracic Spinal Cord Segment of Rat, Evaluated at Late Post-injury Phase

Spontaneous recovery of lost motor functions is relative fast in rodent models after inducing a very mild/moderate spinal cord injury (SCI), and this may complicate a reliable evaluation of the effectiveness of potential therapy. Therefore, a severe graded (30 g, 40 g and 50 g) weight-compression SCI at the Th9 spinal segment, involving an acute mechanical impact followed by 15 min of persistent compression, was studied in adult female Wistar rats. Functional parameters, such as spontaneous recovery of motor hind limb and bladder emptying function, and the presence of hematuria were evaluated within 28 days of the post-traumatic period. The disruption of the blood-spinal cord barrier, measured by extravasated Evans Blue dye, was examined 24 h after the SCI, when maximum permeability occurs. At the end of the survival period, the degradation of gray and white matter associated with the formation of cystic cavities, and quantitative changes of glial structural proteins, such as GFAP, and integral components of axonal architecture, such as neurofilaments and myelin basic protein, were evaluated in the lesioned area of the spinal cord. Based on these functional and histological parameters, and taking the animal’s welfare into account, the 40 g weight can be considered as an upper limit for severe traumatic injury in this compression model.

Resveratrol inhibits inflammation after spinal cord injury via SIRT-1/NF-κB signaling pathway

Spinal cord injury (SCI) can cause severe trauma to the central nervous system. Resveratrol has been widely studied for several of its medicinal properties, including anti-inflammatory, anti-aging and anti-oxidative effects. The regulation of SIRT-1 is thought to be related to the effects of resveratrol. As a downstream component of SIRT-1, NF-κB is one of the important signaling pathways that regulate the inflammatory response. Herein, we explored how treatment with resveratrol promoted recovery of motor function after SCI by activating the SIRT-1/NF-κB signaling pathway and inhibiting inflammation in rat models. Recovery of hind limb function was observed using the Basso, Beattie, and Bresnahan locomotor rating scale at different time points after SCI. Western blot analysis, immunofluorescence, Nissl staining and HE staining were utilized to observe the morphological characteristics of spinal cord tissue, as well as the expression of SIRT-1, NF-κB, TNF-α, IL-1β, IL-6 and brain-derived neurotrophic factor. Resveratrol treatment promoted motor function recovery, increased the expression of brain-derived neurotrophic factor, and reduced loss of motor neurons and lesion size among rats after SCI. Meanwhile, inflammatory response was inhibited as the SIRT-1/NF-κB signaling pathway was modulated. These results suggest that resveratrol can help achieve neuroprotective effect by inhibiting inflammation, regulated by the SIRT-1/NF-κB signaling pathway.

E-selectin/AAV2/2 Gene Therapy Prevents Severe Tissue Loss and Improves Recovery of Hindlimb Function in a Murine Gangrene Model

E-selectin/AAV2/2 Gene Therapy Prevents Severe Tissue Loss and Improves Recovery of Hindlimb Function in a Murine Gangrene Model

Intravenous Administration of Heat Shock-Treated MSCs Can Improve Neuroprotection and Neuroregeneration in Canine Spinal Cord Injury Model.

Simple SummaryMesenchymal stem cells (MSCs), which are found in connective tissues, can be used to treat spinal cord injury (SCI) in dogs. These stem cells have the ability to repair damaged tissues and can be transplanted into the injured area. While this is considered a promising treatment, the transplanted cells often do not survive in the injured spinal cord. In this study, we found that heat shock treatment, i.e., exposure to high temperatures, increased the efficacy of MSC treatment for SCI.Transplantation of mesenchymal stem cells (MSCs) is a promising treatment for spinal cord injury (SCI). However, many transplanted cells die within a few days, eventually limiting the efficacy of cellular therapy. To overcome this problem, we focused on the potential of heat shock (HS) proteins in facilitating recovery from cell damage and protecting against cytotoxicity. PCR results showed that the expression of neurotrophic factor, anti-inflammatory, stemness, and homing genes increased in HS-treated MSCs. We investigated whether HS-treated MSCs could promote recovery of hindlimb function in an acute canine SCI model. We compared the effects of intravenous transplantation with (i) lactated Ringer’s solution as a control, (ii) green fluorescent protein-expressing MSCs (MSCs-GFP), and (iii) GFP-expressing and HS-treated MSCs (MSCs-GFP-HS). Spinal cords were harvested at four weeks and used for Western blot and histopathological analyses. The MSCs-GFP-HS group showed significant improvements in hindlimb function from weeks 3 and 4 compared with the other groups. This group also showed higher expression of neural markers, fewer intervening fibrotic changes, and pronounced myelination. These results suggest that induction of an HS response in MSCs could promote neural sparing. In conclusion, transplantation of HS-treated MSCs could improve neuroprotection and neuroregeneration in acute SCI.

PTEN-silencing combined with ChABC-overexpression in adipose-derived stem cells promotes functional recovery of spinal cord injury in rats

The efficiency of cell therapy after spinal cord injury (SCI) depend on the survival of transplanted cells. However, sterile microenvironment and glial scar hyperplasia extremely reduce their numbers. Our previous study found overexpression of ChABC gene is positively correlated to migration ability. Expression of PTEN gene is closely associated with proliferation. However, whether manipulation of PTEN and ChABC on adipose-derived mesenchymal stem cells (ADSCs) promote motor recovery is unknown. This study aimed to promote hindlimb function recovery in SCI rats by enhancing proliferation and migration ability of ADSCs, transiently silencing expression of PTEN following overexpression of ChABC (double-gene modified ADSCs, DG-ADSCs). After PTEN silencing, we observed strong proliferation and accelerated G1-S transition in DG-ADSCs using CCK8 assay and flow cytometry. In addition, we demonstrated that migration numbers of DG-ADSCs were higher than control group using Transwell assay. The protein and mRNA levels of MAP2 and βⅢ-tubulin in DG-ADSCs were increased compared with ADSCs. These results were further confirmed in SCI rats. Increased survival cells and reduction of glial scars were quantitatively analyzed in DG-ADSCs groups, which is definitely correlated to function recovery. Recovery of motor function was observed in DG-ADSCs treatment rats using BBB score, which emphasized that improved viability of transplanted cells and reduction of glial scars were an effective strategy for enhancing recovery of neurological function after SCI.

Repair effect of bFGF combined with bone marrow mesenchymal stem cells on spinal cord injury in rats

To observe the repair effect of bone marrow mesenchymal stem cells (BMSCs) combined with basic fibroblast growth factor (bFGF) on spinal cord injury in rats and explore its mechanism. SD rat BMSCs were obtained by serum culture technique. Eighty healthy 6-week-old male SD rats(weight about 240 g) were randomly divided into 4 groups with 20 each. The sham operation group underwent simple laminectomy without damaging spinal cord and was kept in the same condition as the other 3 groups. The other 3 groups underwent left T9 spinal cord hemisection to establish spinal cord injury model. After 9 days of modeling the local transplantation was performed. The Control group was implanted with gelatin sponge containing normal saline. The BMSCs transplantation group was implanted with gelatin sponge containing BMSCs. The bFGF+BMSCs transplantation group was implanted with gelatin sponge containing bFGF+BMSCs. After 4 and 8 weeks, the expression of NF-200 and GFAP in injured spinal cord tissue was analyzed by Western blotting and the recovery of hind limb function was evaluated by Basso Beattie Bresnahan(BBB) motor function score scale. The BBB scores of BMSCs transplantation group and bFGF+BMSCs transplantation group were better than control group at 4 and 8 weeks after operation (P<0.05) and there was significant difference between bFGF+BMSCs transplantation group and BMSCs transplantation group (P<0.05). After 4 and 8 weeks postoperatively, NF-200 expression was minimal in control group and only a small amount was expressed in BMSCs transplantation group while in bFGF+BMSCs transplantation group NF-200 was highly expressed(P<0.05). GFAP expression was high in control group, middle in BMSCs transplantation group and low in bFGF BMSCs transplantation group(P<0.05). There was significant difference between bFGF+BMSCs transplantation group, BMSCs transplantation group and control group(P<0.05). The combined transplantation of BMSCs and bFGF can repair the spinal cord injury in rats. The mechanism may be related to the decrease of GFAP expression and the increase of NF-200 expression.