Dual-responsive PDA-HP hydrogel enables mitochondria-targeted mild photothermal therapy for spinal cord repair.

Axonal degeneration is a common pathological feature in many acute and chronic neurological diseases such as spinal cord injury (SCI). SARM1 (sterile alpha and TIR motif-containing 1), the fifth TLR (Toll-like receptor) adaptor, has diverse functions in the immune and nervous systems, and recently has been identified as a key mediator of Wallerian degeneration (WD). However, the detailed functions of SARM1 after SCI still remain unclear.Methods: Modified Allen's method was used to establish a contusion model of SCI in mice. Furthermore, to address the function of SARM1 after SCI, conditional knockout (CKO) mice in the central nervous system (CNS), SARM1Nestin-CKO mice, and SARM1GFAP-CKO mice were successfully generated by Nestin-Cre and GFAP-Cre transgenic mice crossed with SARM1flox/flox mice, respectively. Immunostaining, Hematoxylin-Eosin (HE) staining, Nissl staining and behavioral test assays such as footprint and Basso Mouse Scale (BMS) scoring were used to examine the roles of SARM1 pathway in SCI based on these conditional knockout mice. Drugs such as FK866, an inhibitor of SARM1, and apoptozole, an inhibitor of heat shock protein 70 (HSP70), were used to further explore the molecular mechanism of SARM1 in neural regeneration after SCI.Results: We found that SARM1 was upregulated in neurons and astrocytes at early stage after SCI. SARM1Nestin-CKO and SARM1GFAP-CKO mice displayed normal development of the spinal cords and motor function. Interestingly, conditional deletion of SARM1 in neurons and astrocytes promoted the functional recovery of behavior performance after SCI. Mechanistically, conditional deletion of SARM1 in neurons and astrocytes promoted neuronal regeneration at intermediate phase after SCI, and reduced neuroinflammation at SCI early phase through downregulation of NF-κB signaling after SCI, which may be due to upregulation of HSP70. Finally, FK866, an inhibitor of SARM1, reduced the neuroinflammation and promoted the neuronal regeneration after SCI.Conclusion: Our results indicate that SARM1-mediated prodegenerative pathway and neuroinflammation promotes the pathological progress of SCI and anti-SARM1 therapeutics are viable and promising approaches for preserving neuronal function after SCI.

Complement Plays an Important Role in Spinal Cord Injury and Represents a Therapeutic Target for Improving Recovery following Trauma

To investigate the changes of Cold-Inducible RNA-Binding Protein (CIRBP) expression in mouse spinal cord injury model. Seventy-five female C57BL/6 mice were randomly divided into five groups, 15 mice per group. According to different degrees of spinal cord injury, they were divided into Mild spinal cord injury, Moderate spinal cord injury, Severe spinal cord injury, Spinal cord amputation group, and Sham surgery group, all constructed with spinal cord percussion. All groups were dissected 1, 3, 5, 14, and 21 days after modeling. HE staining was used to observe the pathological changes in the spinal cord, The Basso mouse scale (BMS) was used for motor function scoring, and immunofluorescence was used to detect the expression of NeuN, IBA-1, and CIRBP in spinal cord tissues. HE results showed that inflammation was more pronounced in moderate, severe, and amputation injuries compared to the Sham surgery group. Moderate injury group and Severe injury group inflammation increased consistently over time. The severe injury group had severe tissue structure destruction and increased astrocytes significantly. Combined with the mouse BMS motor function score, the mouse severe injury group model was more stable. Compared with the Sham surgery group, there was a significant decrease in NeuN over time (P < 0.01) and a significant increase in IBA-1 and CIRBP (P < 0.01) in the severe injury group. Moreover, IBA-1 has significant co-localization with CIRBP. CIRBP expression is significantly elevated in a mouse spinal cord injury model, Which may be related to the proliferation of microglia during spinal cord injury.

Long noncoding RNAs (LncRNAs) play a crucial role in cell growth, development, and various diseases related to the central nervous system. However, LncRNA differential expression profiles in spinal cord injury are yet to be reported. In this study, we profiled the expression pattern of LncRNAs using a microarray method in a contusion spinal cord injury (SCI) mouse model. Compared with a spinal cord without injury, few changes in LncRNA expression levels were noted 1 day after injury. The differential changes in LncRNA expression peaked 1 week after SCI and subsequently declined until 3 weeks after injury. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to validate the reliability of the microarray, demonstrating that the results were reliable. Gene ontology (GO) analysis indicated that differentially expressed mRNAs were involved in transport, cell adhesion, ion transport, and metabolic processes, among others. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that the neuroactive ligand-receptor interaction, the PI3K-Akt signaling pathway, and focal adhesions were potentially implicated in SCI pathology. We constructed a dynamic LncRNA-mRNA network containing 264 LncRNAs and 949 mRNAs to elucidate the interactions between the LncRNAs and mRNAs. Overall, the results from this study indicate for the first time that LncRNAs are differentially expressed in a contusion SCI mouse model.

Context/objective Spinal cord injury (SCI) is a severe condition characterized by neuronal apoptosis and inflammation, with limited therapeutic options. This study aimed to assess the effects of platelet-rich plasma (PRP)-derived exosomes (Exo), Cerebrolysin (CBL), and Cerebrolysin-loaded exosomes (CLE) on inflammation, apoptosis, tissue organization, and motor function recovery in a mouse model of compression SCI. Design An experimental study using a mouse model of SCI, investigating the effects of Exo, CBL, and CLE treatments. Setting Laboratory-based research in a controlled environment. Participants Sixty healthy adult female BALB/c mice, aged 8–10 weeks, weighing 24 ± 2 g were used. SCI was induced via compression to model SCI. Interventions Mice with induced SCI were treated with Exo, CBL, or CLE. Apoptosis was assessed by Bax and Bcl2 expression. Inflammatory markers TNF-α and IL-10 were measured. Histological analysis examined tissue organization, and motor function recovery was evaluated using the Basso-Beattie-Bresnahan (BBB) locomotor scale. Outcome measures The study measured Bax and Bcl2 expression, TNF-α and IL-10 levels, tissue organization, and motor function recovery. Results CLE treatment significantly modulated Bax and Bcl2 expression, reducing apoptosis and enhancing neuronal survival. TNF-α levels decreased, indicating reduced inflammation, while IL-10 levels increased, showing anti-inflammatory effects. Histological assessment revealed improved tissue organization, and motor function recovery was significantly enhanced as measured by BBB scores. Conclusion CLE showed neuroprotective and anti-inflammatory effects, reducing apoptosis and inflammation while promoting tissue repair and motor function recovery in SCI, making it a promising therapeutic candidate.

Gypenoside XVII (GP-17), one of the dominant active components of Gynostemma pentaphyllum, has been studied extensively and found to have a variety of pharmacological effects, including neuroprotective properties. However, the neuroprotective effects of GP-17 against spinal cord injury (SCI), as well as its underlying mechanisms of action remain unknown. The present study aimed to investigate the effects of GP-17 on motor recovery and histopathological changes following SCI and to elucidate the mechanisms underlying its neuroprotective effects in a mouse model of SCI. Motor recovery was evaluated using the Basso, Beattie and Bresnahan (BBB) locomotor rating scale. Spinal cord edema was detected by the wet/dry weight method. H&E staining was performed to examine the effect of GP-17 on spinal cord damage. Inflammatory response production was assessed by ELISA. Candidate miRNAs were identified following the integrated analysis of the Gene Expression Omnibus (GEO) dataset GSE67515. Western blot analysis was also performed to detect the expression levels of associated proteins. The results revealed that GP-17 treatment improved functional recovery, and suppressed neuronal apoptosis and the inflammatory response in the mouse model of SCI. Moreover, it was observed that miR-21 expression was downregulated following SCI, whereas it was upregulated following the administration of GP-17. The inhibition of miR-21 eliminated the protective effects of GP-17 on SCI-induced neuronal apoptosis and the inflammatory response. In addition, phosphatase and tensin homologue (PTEN), a key molecule in the activation of the protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway, was identified as a target of miR-21, and PTEN expression was downregulated by GP-17 through miR-21. Furthermore, the PTEN/AKT/mTOR pathway was inactivated by SCI, whereas it was re-activated by GP-17 through the regulation of miR-21 in mice with SCI. On the whole, the findings of the present study suggest that GP-17 plays a protective role in SCI via regulating the miR-21/PTEN/AKT/mTOR pathway.

A previous study from our team found that hyperbaric oxygen (HBO) pretreatment attenuated decompression sickness (DCS) spinal cord injury by upregulating heat shock protein 32 (HSP32) via the ROS/p38 MAPK pathway. Meanwhile, a MEK1/2-negative regulatory pathway was also activated to inhibit HSP32 overexpression. The purpose of this study was to determine if normobaric oxygen (NBO) might effectively induce HSP32 while concurrently inhibiting MEK1/2 and to observe any protective effects on spinal cord injury in DCS rats. The expression of HSP32 in spinal cord tissue was measured at 6, 12, 18, and 24 h following NBO and MEK1/2 inhibitor U0126 pretreatment. The peak time of HSP32 was observed at 12 h after simulated air diving. Subsequently, signs of DCS, hindlimb motor function, and spinal cord and serum injury biomarkers were recorded. NBO-U0126 pretreatment significantly decreased the incidence of DCS, improved motor function, and attenuated oxidative stress, inflammatory response, and apoptosis in both the spinal cord and serum. These results suggest that pretreatment with NBO and U0126 combined can effectively alleviate DCS spinal cord injury in rats by upregulating HSP32. This may lead to a more convenient approach for DCS injury control, using non-pressurized NBO instead of HBO.

The purpose of this study was to investigate whether microRNA-204-5p can regulate the inflammatory response of spinal cord injury (SCI) by targeting SOX11. Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was used to detect the expression of microRNA-204-5p in patients with SCI. The mouse SCI model was established to detect the recovery of the grip strength of the upper and lower limbs. Then, the expression of microRNA-204-5p in these mice with SCI was detected by qRT-PCR, and the levels of the inflammatory factors Toll-like receptor 4 (TLR4) and iNOS were examined by Western blot. Subsequently, microRNA- 204-5p was overexpressed in the mouse SCI model using lentivirus, and the changes in mouse grip strength and the inflammatory factor levels were observed. SOX11 was then searched as the target gene of microRNA-204-5p through bioinformatics analysis, and its expression in patients or mice with SCI was examined using qRT-PCR. SOX11 expression was again detected after the overexpression or knockdown of microRNA-204-5p in cells. The binding of microRNA-204-5p to SOX11 was verified by dual-luciferase reporting assay. After microRNA-204-5p and SOX11 were co-overexpressed in cells, the levels of TLR4 and iNOS were analyzed. Furthermore, the changes in the grip strength were observed in mice with SCI after simultaneous up-regulation of microRNA-204-5p and SOX11. Micro-204-5p level was conspicuously decreased in the population with SCI. And the SCI mouse model showed that the upper and lower limb strength conspicuously decreased and began to recover after 7 days. During the seven days, microRNA-204-5p level in the SCI mice decreased with time, while the levels of the inflammatory cytokines TLR4 and iNOS conspicuously increased. After microRNA-204-5p was overexpressed in SCI mice, their upper and lower limb strength was conspicuously restored, while the levels of TLR4 and iNOS were also remarkably decreased. The bioinformatics analysis revealed that there exist some binding sites between microRNA-204-5p and SOX11, and we found that SOX11 expression was conspicuously enhanced in the plasma of the SCI patients. Meanwhile, the SOX11 level in SCI mice was also conspicuously increased, and it was time-dependent. The expression of SOX11 was decreased after the upregulation of microRNA-204-5p, while the opposite result was observed after the downregulation of microRNA-204-5p. In addition, the result of the dual-luciferase reporter gene assay revealed that microRNA-204-5p could bind to SOX11 in a targeted manner. Meanwhile, the up-regulation of SOX11 was partially relieved by the inhibitory effect of microRNA-204-5p on TLR4 and iNOS. Moreover, the simultaneous overexpression of SOX11 and microRNA-204-5p partially reversed the impact of the up-regulated microRNA-204-5p alone on the recovery of the upper and lower limb strength in SCI mice. The low expression of microRNA-204-5p in patients with SCI can affect the levels of the inflammatory cytokines TLR4 and iNOS and improve SCI by targeting SOX11.

The spinal cord injury (SCI) refers to different degrees of injuries in the structure or function of spinal cord caused by different factors. The prevalence rate of SCI in the population under 40 years reaches 80%. SCI causes certain injury to both physiology and psychology of patients. An important factor leading to SCI is the rupture of nerve fibers. Bone marrow mesenchymal stem cells (BMMSCs) have the functions of inducing and supporting hematopoietic stem cells in bone marrow. In this study, SCI mouse model was established to assess the effect of BM-MSCs on SCI. A total of 30 SCI mouse model were established and assigned into transplantation group (15 mice) and control group (15 mice) according to random number table method. The mice in transplantation group were treated with BM-MSCs transplantation at SCI site, while mice in control group were treated with normal saline at SCI site. The bone marrow pathological changes were measured by HE staining and neural cells were assessed by Pischingert's methylene blue staining along with measuring SRY level by immunohistochemistry. The motor abilities of mice in transplantation group at the 2nd, 4th, 6th and 8th weeks were significantly higher than mice in control group (P &lt; 0 05). A few vacuoles appeared in mice in transplantation group. The number of cells in mouse spinal cord tissues in transplantation group was increased significantly over time, but a large number of vacuoles appeared in mouse spinal cord tissues in control group with necrosis of a vast amount of nerve fibers (P &lt; 0 05). The number and volume of Nissl bodies in mice in transplantation group was increased significantly at 2 weeks after treatment and degeneration status of nerve cells in transplantation group was significantly better than control group (P &lt; 0 05). The SRY genes were expressed in transplantation group for a long term but not in control group (P &lt; 0 05). The number of adherent cells increased significantly in transplantation group at 48 hours after treatment. BMMSCs transplantation can effectively promotes the recovery of SCI mice, indicating that it is worthy of clinical promotion and application.

Recovery from spinal cord injury via M2 microglial polarization induced by Polygalae Radix

Background Spinal cord injury (SCI) is a refractory neurodegenerative disease caused by inflammation. M1 microglia induce inflammation, whereas M2 suppress inflammation and exhibit neuroprotective effects. Following SCI, M1 cells are more predominant than M2 cells, and hence, increasing the predominance of M2 microglia may improve SCI. Purpose We aimed to evaluate the active constituents of herbal medicine that induce M2 predominance and to investigate their effects using SCI model mice. Methods Herbal medicine inducing M2 were screened using cultured microglia. After orally administering the active herbal medicine, Polygalae Radix (PR), to SCI model mice, motor function was evaluated. Compounds in the spinal cord following treatment were assessed using liquid chromatography-mass spectrometry. The effects of compounds detected in the spinal cord were investigated in cultured microglia. Results PR induced M2 predominance in cultured microglia, improved motor function in SCI model mice, and showed a tendency to increase M2 microglia and protect against axonal degeneration in the inured spinal cord. Sibiricose A5 and 3,6′-disinapoyl sucrose were identified as active constituents in PR. Conclusion PR may be a promising candidate for the treatment of SCI by inducing M2 predominance.

Objective To observe the effects of ischemic preconditioning of hindlimb (HIP) on the expressions of heat shock protein70 (HSP70) in spinal cord of rats after spinal cord injury (SCI). Method Sprague Dawleys rats were randomly( random number) divided into three groups (20 rats in each group).In sham injury group, rats received laminectomy without SCI; while in the SCI group, rats received traumatic SCI. In HIP group, rats received HIP 8 h before SCI. The SCI animal models were made by using modified Allen's weight-drop device (50 g·cm) on L3-L4 vertebrae. HIP was induced by compressing the two lower limbs of rats alternately with a tourniquet for three cycles of ten-minute ischaemia followed by ten-minute reperfusion. Rats were sacrificed 24 h and 48 h after injury separately. The protein and mRNA of HSP70 of involved spinal cord segments were determined by using RT-PCR, hybridization in situ and immunohistochemistry. Results There was weak expression of HSP70 mRNA in rats of sham injury group, and sporadic positive cells in spinal tissue were found by using immunohistochemistry. The expressions of HSP70 mRNA 24 h and48 hours after SCI in HIP group[(22.18±3.69) and (14.15 ±4.18)] were higher than those in SCI group[(13.97±4.46) and ( 8.73 ± 3.55 )], and the differences were statistically significant (F=16.06, P = 0.005 and F = 7.43, P = 0. 028). The protein levels of HSP70 24 h and 48 hours after SCI in HIP group [(16.71±4.02) and (9.85±2.20)] were higher than those in SCI group [( 14.85 ± 3.73)and (8.78 ±2.05)], and the differences were statistically significant (F =90. 13, P =0.032 and F=34.70, P = 0. 036). Conclusions HIP can increase the transcription and expression of HSP70 in spinal cord of rats following SCI and may have the protective effects on neural tissue. Key words: Spinal cord injury; Heat shock protein70; Hybridization in situ; Immunohistochemistry; Hindlimb ischaemic preconditioning; RT-PCR

Hydralazine plays an immunomodulation role of pro-regeneration in a mouse model of spinal cord injury

Spatial and temporal expression levels of specific microRNAs in a spinal cord injury mouse model and their relationship to the duration of compression

DOCK2 deficiency alleviates neuroinflammation and affords neuroprotection after spinal cord injury