Spinal Rats Research Articles

KDM2B and its peptides promote the stem cells from apical papilla mediated nerve injury repair in rats by intervening EZH2 function.

How to improve the neurogenic potential of mesenchymal stem cells (MSCs) and develop biological agent based on the underlying epigenetic mechanism remains a challenge. Here, we investigated the effect of histone demethylase Lysine (K)-specific demethylase 2B (KDM2B) on neurogenic differentiation and nerve injury repair by using MSCs from dental apical papilla (SCAP). We found that KDM2B promoted the neurogenic indicators expression and neural spheres formation in SCAP, and modified the Histone H3K4 trimethylation (H3K4me3) methylation on neurogenesis-related genes. KDM2B improved the SCAP mediated recovery of motor ability at the early healing stage of spinal cord injury rats. Meanwhile, KDM2B acted as a negative regulator to its partner EZH2 during neurogenic differentiation, enhancer of zeste homologue 2 (EZH2) suppressed the neurogenic ability of SCAP. Further, the protein interaction between KDM2B and EZH2 was identified which decreased during neurogenic differentiation. On this basis, we revealed seven key protein binding sequences of KDM2B to EZH2, and synthesized KDM2B-peptides based on these sequences. By the usage of KDM2B-peptides, EZH2 function was effectively intervened and the neurogenic ability of SCAP was promoted. More, KDM2B-peptides significantly improved the SCAP mediated functional recovery at SCI early phase. Our study revealed that KDM2B acted as a promotor to neurogenic differentiation ability of dental MSCs through binding and negatively regulating EZH2, and provided the KDM2B-peptides as candidate agents for improving the neurogenic ability of MSCs and nerve injury repair.

Photobiomodulation reduces spinal cord edema by decreasing the expression of AQP4 in the astrocytes of male spinal cord injury rats via the JAK2/STAT3 signaling pathway.

BackgroundSpinal cord swelling commonly occurs following SCI. Previous studies suggest that PBM may reduce inflammation and scar formation after SCI. However, whether PBM can alleviate post-spinal cord injury edema and its underlying mechanisms have not yet been reported. This study aims to investigate the effects of PBM on spinal cord swelling in rats following SCI and explore the underlying mechanisms. MethodsA rat model of SCI was established, and the rats received continuous PBM therapy for two weeks. Tissue hydration, motor function, AQP4 expression, and pathological changes in the spinal cord were evaluated at different time points. In vitro, astrocytes were subjected to PBM and treated with either cucurbitacin I or TGN020 following OGD. ResultsThe results indicate that PBM reduces tissue swelling in rats with SCI, improves motor function recovery, and inhibits the upregulation of AQP4 and GFAP associated with SCI. In vitro, PBM reduces abnormal activation of the JAK2/STAT3 signaling pathway in astrocytes, leading to decreased AQP4 synthesis and astrocyte activation. ConclusionsThese findings suggest that PBM reduces spinal cord swelling in rats after injury. This effect is associated with the inhibition of JAK2/STAT3 signaling pathway activation in astrocytes and the reduction in AQP4 expression.

A biodegradable piezoelectric scaffold promotes spinal cord injury nerve regeneration

Neural repair and regeneration remain one of the greatest challenges in regenerative medicine. The incorporation of intelligent scaffolds with noninvasive in vivo electrical stimulation illustrates considerable potential for tissue repair and regeneration. Nevertheless, the development of biomaterials that possess both biodegradable tissue scaffolds and electrical stimulation capabilities at a high level remains a significant obstacle. In this study, we effectively integrated the organic piezoelectric material poly-L-lactic acid (PLLA) with inorganic piezoelectric nanowires (potassium sodium niobate coated with polydopamine, KNN@PDA) to fabricate PLLA/KNN@PDA piezoelectric composite fibers. These fibers exhibit in-situ electrical stimulation capabilities, rendering them suitable for direct application in living tissues. The PLLA/KNN@PDA piezoelectric composite fibers not only function as biodegradable scaffolds for regenerative tissue engineering and platforms for in-situ electrical stimulation to enhance dorsal root ganglion axon growth, proliferation, and neuronal differentiation but also serve as versatile scaffolds for broader tissue engineering applications. In the complete spinal cord transection rat model, the piezoelectric scaffold enabled the recovery of rat motor function, indicating its significant ability to promote tissue formation and regeneration. Therefore, combining biodegradable piezoelectric tissue scaffolds with in situ electrical stimulation has significant therapeutic advantages for spinal cord injury repair and may be extended to other damaged tissues regeneration.

Berberine attenuates neuronal ferroptosis via the AMPK–NRF2–HO-1-signaling pathway in spinal cord-injured rats

Ferroptosis, characterized by iron-dependent accumulation of lipid peroxides, plays an important role in spinal cord injury (SCI). Berberine (BBR), as a lipid peroxide scavenger, has been widely used in treating other diseases; however, its role in ferroptosis has not been fully elucidated. Therefore, here, to test our hypothesis that BBR can reduce the severity of SCI and promote motor function recovery by inhibiting neuronal ferroptosis, we evaluated the changes in ferroptosis-related indicators after BBR administration by establishing a cellular ferroptosis model and an SCI contusion model. We found that BBR administration significantly reduces lipid peroxidation damage, maintains normal mitochondrial function, reduces excessive accumulation of iron ions, enhances antioxidant capacity, and activates the ferroptosis defense system in vivo and in vitro. Mechanistically, BBR alleviates neuronal ferroptosis by inducing adenosine monophosphate-activated protein kinase (AMPK) phosphorylation and up-regulating nuclear factor erythroid 2-related factor 2 (NRF2) and heme oxygenase-1 (HO-1) protein expression to promote glutathione production. BBR administration also significantly improves motor function recovery in SCI rats. Meanwhile, applying the AMPK inhibitor Compound C blocks the neuroprotective and all other effects of BBR. Collectively, our findings demonstrate that BBR can attenuate neuronal ferroptosis after SCI by activating the AMPK–NRF2–HO-1 pathway.

Sonic Hedgehog reduces inflammatory response, decreases blood-spinal cord barrier permeability, and improves locomotor function recovery in an acute spinal cord injury rat model

BackgroundSonic Hedgehog (Shh), extensively researched for its role in early neurogenesis and brain development, has recently been recognized for its neuroprotective potential following neuronal injuries. This study examines the immediate impact of early administered Shh on the local inflammatory response post-acute spinal cord injury in rats.MethodsThirty-four female Wistar rats underwent either sham surgery (laminectomy; n = 10) or clip compression/contusion spinal cord injury (SCI) at the T9 level. This was followed by implantation of an osmotic pump and a subdural catheter for continuous intrathecal delivery of Shh (n = 12) or placebo (NaCl; n = 12). Locomotor function was assessed at 3- and 7-days post-injury (dpi) using the Basso, Beattie, and Bresnahan (BBB) score and the Gridwalk test. Animals were euthanized after 3 or 7 days for immunohistochemical analysis of the local inflammatory reaction and immune cell migration.ResultsShh-treated rats demonstrated significant hindlimb movement and coordination improvements at 7 days post-injury, compared to controls. This enhancement was accompanied by a significant reduction in both immune cell presence and blood plasma products within spinal cord lesions, suggesting Shh’s dual role in modulating immune cell migration and maintaining the integrity of the blood-spinal cord barrier. Separately, these Shh-treated rats also showed an increase in M(IL-4) polarization of macrophages, further underlining the potential therapeutic impact of Shh in post-injury recovery. Notably, these effects were not evident at three days post-injury.ConclusionShh application at 7 days post-injury showed immunomodulatory effects, possibly via enhanced blood-spinal cord barrier integrity, reduced immune cell migration, and increased anti-inflammatory immune cell differentiation. These mechanisms collectively contribute to enhanced locomotor recovery.

Ischemia-reperfusion injury after spinal cord decompressive surgery-An invivo rat model.

Although decompression surgery is the optimal treatment for patients with severe degenerative cervical myelopathy (DCM), some individuals experience no improvement or even a decline in neurological function after surgery, with spinal cord ischemia-reperfusion injury (SCII) identified as the primary cause. Spinal cord compression results in local ischemia and blood perfusion following decompression is fundamental to SCII. However, owing to inadequate perioperative blood flow monitoring, direct evidence regarding the occurrence of SCII after decompression is lacking. The objective of this study was to establish a suitable animal model for investigating the underlying mechanism of spinal cord ischemia-reperfusion injury following decompression surgery for degenerative cervical myelopathy (DCM) and to elucidate alterations in neurological function and local blood flow within the spinal cord before and after decompression. Twenty-four Sprague-Dawley rats were allocated to three groups: the DCM group (cervical compression group, with implanted compression material in the spinal canal, n = 8), the DCM-D group (cervical decompression group, with removal of compression material from the spinal canal 4 weeks after implantation, n = 8), and the SHAM group (sham operation, n = 8). Von Frey test, forepaw grip strength, and gait were assessed within 4 weeks post-implantation. Spinal cord compression was evaluated using magnetic resonance imaging. Local blood flow in the spinal cord was monitored during the perioperative decompression. The rats were sacrificed 1 week after decompression to observe morphological changes in the compressed or decompressed segments of the spinal cord. Additionally, NeuN expression and the oxidative damage marker 8-oxoG DNA were analyzed. Following spinal cord compression, abnormal mechanical pain worsened, and a decrease in forepaw grip strength was observed within 1-4 weeks. Upon decompression, the abnormal mechanical pain subsided, and forepaw grip strength was restored; however, neither reached the level of the sham operation group. Decompression leads to an increase in the local blood flow, indicating improved perfusion of the spinal cord. The number of NeuN-positive cells in the spinal cord of rats in the DCM-D group exceeded that in the DCM group but remained lower than that in the SHAM group. Notably, a higher level of 8-oxoG DNA expression was observed, suggesting oxidative stress following spinal cord decompression. This model is deemed suitable for analyzing the underlying mechanism of SCII following decompressive cervical laminectomy, as we posit that the obtained results are comparable to the clinical progression of degenerative cervical myelopathy (DCM) post-decompression and exhibit analogous neurological alterations. Notably, this model revealed ischemic reperfusion in the spinal cord after decompression, concomitant with oxidative damage, which plausibly underlies the neurological deterioration observed after decompression.

The effect of repetitive magnetic stimulation on neuronal apoptosis and PI3K/Akt protein expression in rats with incomplete spinal cord injury.

The pathological and physiological process of spinal cord injury is complex, and there is currently no effective treatment method. Magnetic stimulation is an emerging electromagnetic therapy method in recent years, and studies have shown its potential to reduce cell apoptosis. This study used an improved Allen's method to replicate an incomplete spinal cord injury rat model, and repetitive magnetic stimulation (rMS) intervention was performed on the rats for 21 days. The research plan consists of two parts. The first part aims to observe the effects of rMS on motor function and neuronal cell apoptosis in rats. The Basso-Beattie-Bresnahan (BBB) score results indicate that rMS promotes the recovery of motor function in rats; H&E staining showed that rMS improved spinal cord structural damage and inflammatory infiltration; TUNEL and NeuN staining suggest that rMS can reduce cell apoptosis and promote neuronal cell survival. The second part aims to explore the mechanism of action of rMS. Immunofluorescence staining showed that after rMS intervention, the positive counts of PI3K and Akt increased, whereas the positive counts of caspase-3 decreased. Western blot showed that after rMS intervention, the expression of phospho-phosphatidylinositol-3 kinase (p-PI3K)/PI3K, phospho (p)-Akt/Akt, and Bcl-2 increased, whereas the expression of Bcl-2-associated X protein(Bax) and caspase-3 decreased. In summary, rMS can significantly reduce cell apoptosis in the damaged spinal cord and promote neuronal cell survival. Its mechanism of action may be related to promoting the expression of PI3K/Akt pathway proteins, upregulating the antiapoptotic protein Bcl-2, downregulating the proapoptotic protein Bax, and thereby inhibiting the expression of apoptotic protein caspase-3. NEW & NOTEWORTHY Spinal cord injury is a serious disabling central nervous system disease. Recently, research on magnetic stimulation therapy for spinal cord injury has been increasing, and its potential has gradually attracted the attention of experts. This study found that repetitive magnetic stimulation (rMS) can improve motor function and reduce neuronal apoptosis in spinal cord injury rats. The mechanism may be related to increasing the expression of phosphatidylinositol-3 kinase (PI3K)/Akt protein, thereby inhibiting cell apoptosis and promoting neuronal survival.

An Optimized Decellularized Extracellular Matrix from Dental Pulp Stem Cell Sheets Promotes Axonal Regeneration by Multiple Modes in Spinal Cord Injury Rats.

In the field of tissue engineering, the extracellular matrix (ECM) is considered an important element for promoting neural regeneration after spinal cord injury (SCI). Dental pulp stem cells (DPSCs), mesenchymal stem cells that originate from the neural crest, are easy to harvest and culture in vitro, express a variety of neurotrophic factors (NTFs) and deposit a large amount of ECM, making them a good choice for stem cell- or ECM-based treatment of SCI. In the present study, decellularized extracellular matrix (dECM) derived from DPSC sheets is used for the treatment of SCI. Optimization experiments reveal that incubating DPSC sheets with 1% Triton X-100 for 5 min is the best procedure for preparing DPSC dECM. It is found that DPSC dECM promotes nerve repair and regeneration after SCI and restores hindlimb motor function in rats. Mechanistically, DPSC dECM facilitates the migration and neural differentiation of neural stem cells, as well as M2 polarization of microglia, and inhibits the formation of glial scars. This study suggests that the use of DPSC dECM is a potential strategy for the treatment of SCI.

Bi-layered Adipose Mesenchymal Cell Sheets Improve Bladder Compliance in Spinal Cord-Injured Rats.

To improve bladder compliance in patients with low-compliance bladders, augmentation cystoplasty with the intestinal tract is performed. However, the use of the intestinal tract often leads to serious surgical complications. Tissue engineering technologies have the potential to improve bladder compliance without using the intestinal tract. In this study, we fabricated bi-layered adipose-derived mesenchymal cell (AMC) sheets and then determined whether the bi-layered AMC sheets could improve bladder compliance in rats with spinal cord injury (SCI). The abdominal adipose tissues of green fluorescence protein (GFP)-transfected Sprague-Dawley (SD) rats were harvested, and the attached and proliferating cells on type I collagen were used as AMCs. The AMCs were then cultured on temperature-responsive culture dishes. After reaching over-confluence, the AMCs that maintained cell-cell contacts were detached from the dishes and applied to a gelatin hydrogel sheet. Then, another detached AMC monolayer was accumulated on the AMC monolayer-applied gelatin. Prior to 4 weeks of transplantation, the levels of T8-9 in the spinal cords of recipient SD rats were partially transected. After producing the bi-layered AMC sheets and the rats with SCI, the detrusor muscles of the anterior bladder walls of the rats with SCI were incised, and the bi-layered AMC sheet was patch-transplanted onto the exposed bladder epithelium (n = 8). As a control, the sham operation was performed (n = 7). Four weeks after the transplantation, bladder capacity and bladder compliance in AMC sheet-transplanted SCI rats were significantly higher than those in sham-operated control SCI rats. The smooth muscle layers in AMC sheet-transplanted bladders were significantly larger than those in control bladders. In addition, the collagen fibers in the AMC sheet-transplanted bladders were significantly smaller than those in the control bladders. Some GFP-positive transplanted AMCs differentiated into smooth muscle actin- or desmin-positive cells. Furthermore, GFP-positive cells secreted transforming growth factor-β1 or vascular endothelial growth factor. Therefore, this study showed that bi-layered AMC sheets could improve bladder compliance and bladder tissues in SCI rats.

Serotonin (5-HT)2A/2C receptor agonist 2,5-dimethoxy-4-iodophenyl-2-aminopropane hydrochloride improves detrusor sphincter dyssynergia by inhibiting L-type voltage-gated calcium channels in spinal cord injured rats.

To explore the role of voltage-gated calcium channels (VGCC) in 5-HT2A/2C receptor agonist 2,5-dimethoxy-4-iodophenyl-2-aminopropane hydrochloride's improvement of spinal cord injury (SCI) induced detrusor sphincter dyssynergia and the expressions of the 5-hydroxy tryptamine (5-HT) 2A receptors and VGCCs in lumbosacral cord after SCI. Female Sprague-Dawley rats were randomized into normal control group and SCI group (N = 15 each). Cystometrogram (CMG), simultaneous CMG, and external urethral sphincter electromyography (EUS-EMG) were conducted in all groups under urethane anesthesia. Drugs were administered intrathecally during CMG and EUS-EMG. Rats were euthanized and L6-S1 spinal cord were acquired for immunofluorescence. In SCI rats, intrathecal administration of 2,5-dimethoxy-4-iodophenyl-2-aminopropane hydrochloride or L-type VGCC blocker, nifedipine, could significantly increase voiding volume, voiding efficiency, and the number of high-frequency oscillations. They could also prolong EUS bursting activity duration on EUS-EMG. Moreover, the effect of 2,5-dimethoxy-4-iodophenyl-2-aminopropane hydrochloride can be eliminated with the combined administration of L-type VGCC agonist, (±)-Bay K 8644. No significant differences were observed in CMG after intrathecal administration of T-type VGCC blocker TTA-P2. Additionally, immunofluorescence of the lumbosacral cord in control and SCI rats showed that the 5-HT2A receptor and Cav1.2 immunolabeling-positive neurons in the anterior horn of the lumbosacral cord were increased in SCI rats. Our study demonstrated that 5-HT2A/2C agonist 2,5-dimethoxy-4-iodophenyl-2-aminopropane hydrochloride may improve SCI-induced DSD by inhibiting the L-type voltage-gated calcium channel in lumbosacral cord motoneurons.

Effects of low-intensity extracorporeal shock wave on bladder and urethral dysfunction in spinal cord injured rats.

To investigate the effects of low-intensity extracorporeal shock wave therapy (LiESWT) on bladder and urethral dysfunction with detrusor overactivity and detrusor sphincter dyssynergia (DSD) resulting from spinal cord injury (SCI). At 3 weeks after Th9 spinal cord transection, LiESWT was performed on the bladder and urethra of adult female Sprague Dawley rats with 300 shots of 2Hz and an energy flux density of 0.12mJ/mm2, repeated four times every 3 days, totaling 1200 shots. Six weeks postoperatively, a single cystometrogram (CMG) and an external urethral sphincter electromyogram (EUS-EMG) were simultaneously recorded in awake animals, followed by histological evaluation. Voiding efficiency significantly improved in the LiESWT group (71.2%) compared to that in the control group (51.8%). The reduced EUS activity ratio during voiding (duration of reduced EUS activity during voiding/EUS contraction duration with voiding + duration of reduced EUS activity during voiding) was significantly higher in the LiESWT group (66.9%) compared to the control group (46.3%). Immunohistochemical examination revealed that fibrosis in the urethral muscle layer was reduced, and S-100 stained-positive area, a Schwann cell marker, was significantly increased in the urethra of the LiESWT group. LiESWT targeting the urethra after SCI can restore the EUS-EMG tonic activity during voiding, thereby partially ameliorating DSD. Therefore, LiESWT is a promising approach for treating bladder and urethral dysfunction following SCI.

Characterization of the Expressions and m6A Methylation Modification Patterns of mRNAs and lncRNAs in a Spinal Cord Injury Rat Model.

Spinal cord injury (SCI) is a serious central nervous system disease with no effective treatment strategy presently due to its complex pathogenic mechanism. N6-methyladenosine (m6A) methylation modification plays an important role in diverse physiological and pathological processes. However, our understanding of the potential mechanisms of messenger RNA (mRNA) and long non-coding RNAs (lncRNA) m6A methylation in SCI is currently limited. Here, comprehensive m6A profiles and gene expression patterns of mRNAs and lncRNAs in spinal cord tissues after SCI were identified using microarray analysis of immunoprecipitated methylated RNAs. A total of 3745 mRNAs (2343 hypermethylated and 1402 hypomethylated) and 738 lncRNAs (488 hypermethylated and 250 hypomethylated) were differentially methylated with m6A modifications in the SCI and sham rats. Functional analysis revealed that differentially m6A-modified mRNAs were mainly involved in immune inflammatory response, nervous system development, and focal adhesion pathway. In contrast, differentially m6A-modified lncRNAs were mainly related to antigen processing and presentation, the apoptotic process, and the mitogen-activated protein kinases (MAPKs) signaling pathway. In addition, combined analysis of m6A methylation and RNA expression results revealed that 1636 hypermethylated mRNAs and 262 hypermethylated lncRNAs were up-regulated, and 1571 hypomethylated mRNAs and 204 lncRNAs were down-regulated. Furthermore, we validated the altered levels of m6A methylation and RNA expression of five mRNAs (CD68, Gpnmb, Lilrb4, Lamp5, and Snap25) and five lncRNAs (XR_360518, uc.393 + , NR_131064, uc.280 - , and XR_597251) using MeRIP-qPCR and qRT-PCR. This study expands our understanding of the molecular mechanisms underlying m6A modification in SCI and provides novel insights to promote functional recovery after SCI.

Combination of induced pluripotent stem cell-derived motor neuron progenitor cells with irradiated brain-derived neurotrophic factor over-expressing engineered mesenchymal stem cells enhanced restoration of axonal regeneration in a chronic spinal cord injury rat model

BackgroundSpinal cord injury (SCI) is a disease that causes permanent impairment of motor, sensory, and autonomic nervous system functions. Stem cell transplantation for neuron regeneration is a promising strategic treatment for SCI. However, selecting stem cell sources and cell transplantation based on experimental evidence is required. Therefore, this study aimed to investigate the efficacy of combination cell transplantation using the brain-derived neurotrophic factor (BDNF) over-expressing engineered mesenchymal stem cell (BDNF-eMSC) and induced pluripotent stem cell-derived motor neuron progenitor cell (iMNP) in a chronic SCI rat model.MethodA contusive chronic SCI was induced in Sprague-Dawley rats. At 6 weeks post-injury, BDNF-eMSC and iMNP were transplanted into the lesion site via the intralesional route. At 12 weeks post-injury, differentiation and growth factors were evaluated through immunofluorescence staining and western blot analysis. Motor neuron differentiation and neurite outgrowth were evaluated by co-culturing BDNF-eMSC and iMNP in vitro in 2-dimensional and 3-dimensional.ResultsCombination cell transplantation in the chronic SCI model improved behavioral recovery more than single-cell transplantation. Additionally, combination cell transplantation enhanced mature motor neuron differentiation and axonal regeneration at the injured spinal cord. Both BDNF-eMSC and iMNP played a critical role in neurite outgrowth and motor neuron maturation via BDNF expression.ConclusionsOur results suggest that the combined transplantation of BDNF- eMSC and iMNP in chronic SCI results in a significant clinical recovery. The transplanted iMNP cells predominantly differentiated into mature motor neurons. Additionally, BDNF-eMSC exerts a paracrine effect on neuron regeneration through BDNF expression in the injured spinal cord.Graphical

Oral Administration of a Specific p300/CBP Lysine Acetyltransferase Activator Induces Synaptic Plasticity and Repairs Spinal Cord Injury.

TTK21 is a small-molecule activator of p300/creb binding protein (CBP) acetyltransferase activity, which, upon conjugation with a glucose-derived carbon nanosphere (CSP), can efficiently cross the blood-brain barrier and activate histone acetylation in the brain. Its role in adult neurogenesis and retention of long-term spatial memory following intraperitoneal (IP) administration is well established. In this study, we successfully demonstrate that CSP-TTK21 can be effectively administered via oral gavage. Using a combination of molecular biology, microscopy, and electrophysiological techniques, we systematically investigate the comparative efficacy of oral administration of CSP and CSP-TTK21 in wild-type mice and evaluate their functional effects in comparison to intraperitoneal (IP) administration. Our findings indicate that CSP-TTK21, when administered orally, induces long-term potentiation in the hippocampus without significantly altering basal synaptic transmission, a response comparable to that achieved through IP injection. Remarkably, in a spinal cord injury model, oral administration of CSP-TTK21 exhibits efficacy equivalent to that of IP administration. Furthermore, our research demonstrates that oral delivery of CSP-TTK21 leads to improvements in motor function, histone acetylation dynamics, and increased expression of regeneration-associated genes (RAGs) in a spinal injury rat model, mirroring the effectiveness of IP administration. Importantly, no toxic and mutagenic effects of CSP-TTK21 are observed at a maximum tolerated dose of 1 g/kg in Sprague-Dawley (SD) rats via the oral route. Collectively, these results underscore the potential utility of CSP as an oral drug delivery system, particularly for targeting the neural system.

Rapid-Onset, Short-Duration Induction of Colorectal Contractions in Anesthetized, Adult, Male Rats.

Substantial clinical and preclinical evidence indicates that transient receptor potential vanilloid 1 (TRPV1) receptors are expressed on terminals of colorectal chemoreceptors and mechanoreceptors and are involved in various rectal hypersensitivity disorders with common features of colorectal overactivity. These stimulatory properties of TRPV1 receptors on colorectal function suggested that brief stimulation of TRPV1 might provide a means of pharmacologically activating the colorectum to induce defecation in patients with an "unresponsive" colorectum. The current studies explored the basic features of TRPV1 receptor-induced contractions of the colorectum in anesthetized rats with and without acute spinal cord injury (aSCI). Cumulative concentration-response curves to intrarectal (IR) capsaicin (CAP) solutions (0.003%-3.0%) were performed in anesthetized aSCI and spinal intact rats. CAP produced an "inverted U," cumulative concentration-response curve with a threshold for inducing colorectal contractions at 0.01% and a peak response at 0.1% and slight decreases in responses up to 3%. Decreases in responses with concentrations >0.1% are due to a rapid desensitization (i.e., ≤30 minutes) of TRPV1 receptors to each successive dose. Desensitization appeared fully recovered within 24 hours in spinal intact rats. Colorectal contractions were completely blocked by atropine, indicating a reflexogenic activation of parasympathetic neurons, and responses were completely unaffected by a neurokinin 2 receptor antagonist, indicating that release of neurokinin A from afferent terminals and subsequent direct contractions of the smooth muscle was not involved. IR administration of three other TRPV1 receptor agonists produced similar results as CAP. SIGNIFICANCE STATEMENT: Individuals with spinal cord injury often lose control of defecation. Time-consuming bowel programs using digital stimulation of the rectum are used to empty the bowel. This study shows that intrarectal administration of the transient receptor potential vanilloid 1 (TRPV1) receptor agonist, capsaicin, can induce rapid-onset, short-duration colorectal contractions capable of inducing defecation in spinal cord injured and intact rats. Therefore, TRPV1 agonists show promise as potential therapeutics to induce defecation in individuals with neurogenic bowel.

Identification of Key Genes and Pathways in Oxaliplatin-Induced Neuropathic Pain Through Bioinformatic Analysis.

The mechanism of Chemotherapy-induced neuropathic pain (NP) remains obscure. This study was aimed to uncover the key genes as well as protein networks that contribute to Oxaliplatin-induced NP. Oxaliplatin frequently results in a type of Chemotherapy-induced NP that is marked by heightened sensitivity to mechanical and cold stimuli, which can lead to intolerance and discontinuation of medication. We investigated whether these different etiologies lead to similar pathological outcomes by targeting shared genetic targets or signaling pathways. Gene expression data were obtained from the Gene Expression Comprehensive Database (GEO) for GSE38038 (representing differential expression in the spinal nerve ligation model rats) and GSE126773 (representing differential expression among the Oxaliplatin-induced NP model rats). Differential gene expression analysis was performed using GEO2R. Protein-protein interaction (PPI) analysis identified 260 co-differentially expressed genes (co-DEGs). Subsequently, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed three shared pathways involved in both models: Kaposi sarcoma-associated herpesvirus (KSHV) infection, Epstein-Barr virus (EBV) infection, and AGE-RAGE signaling pathway in diabetic complications. Further bioinformatics analysis highlighted eight significantly up-regulated genes in the NP group: Mapk14, Icam1, Cd44, IL6, Cxcr4, Stat1, Casp3 and Fgf2. Our results suggest that immune dysfunction, inflammation-related factors or regulating inflammation factors may also be related to Oxaliplatin-induced NP. Additionally, we analyzed a dataset (GSE145222) involving chronic compression of DRGs (CCD) and control groups. CCD model is a classic model for studying NP. We assessed these hub genes' expression levels. In contrast with the control groups, the hub genes were up-regulated in CCD groups, the difference was statistically significant, except Stat1. Our research significantly contributes to elucidating the mechanisms underlying the occurrence as well as the progression of Oxaliplatin-induced NP. We have identified crucial genes and signaling pathways associated with this condition.

Treadmill training improves lung function and inhibits alveolar cell apoptosis in spinal cord injured rats

Secondary lung injury after SCI is a major cause of patient mortality, with apoptosis playing a key role. This study aimed to explore the impact of treadmill training and miR145-5p on the MAPK/Erk signaling pathway and apoptosis in rats with complete SCI. SD rats were used to establish T10 segmental complete SCI models and underwent treadmill training 3, 7, or 14 days postinjury. Various techniques including arterial blood gas analysis, lung wet/dry weight ratio, HE staining, immunofluorescence staining, immunohistochemical staining, qRT-PCR, and Western blotting were employed to assess alterations in lung function and the expression levels of crucial apoptosis-related factors. In order to elucidate the specific mechanism, the impact of miR145-5p on the MAPK/Erk pathway and its role in apoptosis in lung cells were confirmed through miR145-5p overexpression and knockdown experiments. Following spinal cord injury (SCI), an increase in apoptosis, activation of the MAPK/Erk pathway, and impairment of lung function were observed in SCI rats. Conversely, treadmill training resulted in a reduction in alveolar cell apoptosis, suppression of the MAPK/Erk pathway, and enhancement of lung function. The gene MAP3K3 was identified as a target of miR145-5p. The influence of miR145-5p on the MAPK/Erk pathway and its impact on apoptosis in alveolar cells were confirmed through the manipulation of miR145-5p expression levels. The upregulation of miR145-5p in spinal cord injury (SCI) rats led to a reduction in MAP3K3 protein expression within lung tissues, thereby inhibiting the MAPK/Erk signaling pathway and decreasing apoptosis. Contrarily, rats with miR145-5p knockdown undergoing treadmill training exhibited an increase in miR145-5p expression levels, resulting in the inhibition of MAP3K3 protein expression in lung tissues, suppression of the MAPK/Erk pathway, and mitigation of lung cell apoptosis. Ultimately, the findings suggest that treadmill training may attenuate apoptosis in lung cells post-spinal cord injury by modulating the MAP3K3 protein through miR145-5p to regulate the MAPK/Erk signaling pathway.

Establishment of a bio-industry-need hemisection of spinal cord rat model

Spinal cord injury (SCI) is a severe central nervous system disorder, and due to its complex pathophysiology, effective treatment strategies are currently lacking, posing a significant challenge in the field of medicine. While research into the fundamentals of SCI continues to advance and innovate, there exists a gap between basic research and clinical applications, hindering the translation of basic research findings into clinical practice. One of the reasons for this gap is the use of non-standardized animal models for SCI, which leads to inaccuracies in research results and reduces the guidance value of basic research for clinical treatment. This study provides a SCI rat model for R&D of SCI medicine target research and therapeutic strategy designs.

Effect of electroacupuncture of Governor Vessel on mitochondrial fusion and proliferation and differentiation of neural stem cells in spinal cord injury rats.

To observe the effect of electroacupuncture (EA) at "Dazhui" (GV14) and "Jizhong"(GV6) of the Governor Vessel (GV) on mitochondrial fusion and neural stem cell (NSC) proliferation and differentiation in the spinal cord of rats with spinal cord injury (SCI), so as to investigate its mechanisms underlying improvement of SCI. SD rats were randomly divided into sham operation, model and EA groups, with 15 rats in each group. The SCI model was established by using a precision impactor. EA (20 Hz/100 Hz, 1-2 mA) was applied to GV14 and GV6 for 30 min, once daily for 14 days. The rats' hindlimb locomotor function in each group was assessed using the Basso-Beattie-Bresnahan (BBB) locomotor scale. Histopathological changes of the injured spinal cord tissue and the number of neurons were evaluated after H.E. staining and Nissl staining. The expressions of Nestin, mitochondrial fusion-related protein optic atrophy-1 (OPA1) and NSC markers sex-determining region Y-box 2 (SOX2) in the injured spinal cord tissue were detected by immunofluorescence staining. The protein and mRNA expression levels of Nestin in the spinal cord tissue were detected by quantitative real-time PCR and Western blot, separately. Compared with the sham operation group, the BBB scores after modeling, and the number of neurons were significantly decreased (P<0.001), while the mean fluorescence intensity values of Nestin, SOX2 and OPA1, and the expressions of Nestin mRNA and protein considerably increased (P<0.001, P<0.01, P<0.05) in the model group. After EA intervention and in comparison with the model group, the BBB scores at the 7th and 14th day, the number of neurons, the mean fluorescence intensity values of Nestin, SOX2 and OPA1, and the expressions of Nestin mRNA and protein were strikingly increased (P<0.05, P<0.01, P<0.001) in the EA group. H.E. staining showed swollen, ruptured and necrotic neurons of the spinal cord, with a large number of vacuoles and severe inflammatory cell infiltration after modeling, which was relatively milder in the EA group. EA stimulation of GV14 and GV6 can promote the recovery of motor function in rats with SCI, which may be related to its effects in promoting mitochondrial fusion and enhancing the proliferation and differentiation of NSCs.

Effect of robotic gait training on muscle and bone characteristics in spinal cord transected rats.

Osteoporosis and loss of muscle mass are secondary issues with spinal cord injury. Robotic gait training has provided evidence of increasing bone density and muscle mass, but its effect on bone strength is undetermined. The purpose of this study was to determine the effect of a 6-week robotic locomotion training program on skeletal muscle mass and bone characteristics. Twelve female Sprague-Dawley rats received a mid-thoracic spinal cord transection at 5 days old and at 3 weeks old were assigned to a Control or Trained Group. The Trained Group performed 5-min sessions on the Rat Stepper 5 days a week for 6 weeks with 90% of body weight supported. At the end of the 6 weeks, body mass was obtained and right femurs and four lower extremity muscles were harvested. Femur bone mineral density was measured with DXA and mechanical characteristics of the femur were determined via 3-point bending testing. Independent t-tests, effects sizes and percent differences were computed between the two groups (p < 0.05). The Trained Group had significantly larger normalized femur mass (p = 0.007) and normalized soleus muscle mass (p = 0.033) when compared to the Control Group. There was a medium or large effect size with the Trained Groups' femurs having larger mass, bone mineral density, rupture loads, cortical wall thickness, shaft cross sectional area, soleus mass, normalized gastrocnemius mass, and smaller shaft inner diameters compared to the Control Group. These changes may contribute to decreasing osteoporosis and fracture risk in those with spinal cord injuries.