Tetramethylpyrazine-loaded electroconductive hydrogels promote tissue repair after spinal cord injury by protecting the blood-spinal cord barrier and neurons.

Spinal cord injury (SCI) usually induces profound microvascular dysfunction. It disrupts the integrity of the blood-spinal cord barrier (BSCB), which could trigger a cascade of secondary pathological events that manifest as neuronal apoptosis and axonal demyelination. These events can further lead to irreversible neurological impairments. Thus, reducing the permeability of the BSCB and maintaining its substructural integrity are essential to promote neuronal survival following SCI. Tetramethylpyrazine (TMP) has emerged as a potential protective agent for treating the BSCB after SCI. However, its therapeutic potential is hindered by challenges in the administration route and suboptimal bioavailability, leading to attenuated clinical outcomes. To address this challenge, traditional Chinese medicine, TMP, was used in this study to construct a drug-loaded electroconductive hydrogel for synergistic treatment of SCI. A conductive hydrogel combined with TMP demonstrates good electrical and mechanical properties as well as superior biocompatibility. Furthermore, it also facilitates sustained local release of TMP at the implantation site. Furthermore, the TMP-loaded electroconductive hydrogel could suppress oxidative stress responses, thereby diminishing endothelial cell apoptosis and the breakdown of tight junction proteins. This concerted action repairs BSCB integrity. Concurrently, myelin-associated axons and neurons are protected against death, which meaningfully restore neurological functions post spinal cord injury. Hence, these findings indicate that combining the electroconductive hydrogel with TMP presents a promising avenue for potentiating drug efficacy and synergistic repair following SCI.

Tetramethylpyrazine inhibits the inflammatory response by downregulating the TNFR1/IκB-α/NF-κB p65 pathway after spinal cord injury.

Previous studies have demonstrated that tetramethylpyrazine (TMP) can enhance the recovery of motor function in spinal cord injury (SCI) rats. However, the underlying mechanism involved in this therapeutic effect remains to be elucidated. We conducted RNA sequencing with a network pharmacology strategy to predict the targets and mechanism of TMP for SCI. The modified Allen's weight-drop method was used to construct an SCI rat model. The results indicated that the nuclear transfer factor-κB (NF-κB) pathway was identified through the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, and an inflammatory response was identified through the Gene Ontology (GO) enrichment analysis. Tumor necrosis factor (TNF) was identified as a crucial target. Western blotting revealed that TMP decreased the protein expression of TNF superfamily receptor 1 (TNFR1), inhibitor κB-α (IκB-α), and NF-κB p65 in spinal cord tissues. Enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) demonstrated that TMP inhibited TNF-α, interleukin-1ß (IL-1ß), reactive oxygen species (ROS), and malondialdehyde (MDA) expression and enhanced superoxide dismutase (SOD) expression. Histopathological observation and behavior assessments showed that TMP improved morphology and motor function. In conclusion, TMP inhibits inflammatory response and oxidative stress, thereby exerting a neuroprotective effect that may be related to the regulation of the TNFR1/IκB-α/NF-κB p65 signaling pathway.

[Experimental study of tetramethylpyrazine-loaded electroconductive hydrogel on angiogenesis and neuroprotection after spinal cord injury].

Objective: To explore the mechanisms for repairing spinal cord injury (SCI) with tetramethylpyrazine-loaded electroconductive hydrogel (hereinafter referred to as "TGTP"). Mehtods: A total of 72 female Sprague-Dawley rats were randomly divided into 4 groups: sham operation group (group A), SCI group (group B), SCI+electroconductive hydrogel group (group C), and SCI+TGTP group (group D). Only the vertebral plate was removed in group A, while the remaining groups were subjected to a whole transection model of spinal cord with a 2 mm gap in the lesions. The recovery of hindlimb motor function was evaluated by Basso, Beattie, Bresnahan (BBB) score and modified Rivlin-Tator inclined plate test before operation and at 1, 3, 7, 14, and 28 days after operation, respectively. Animals were sacrificed at 7 days and 28 days after modeling. Neovascularisation was observed by immunofluorescence staining of CD31 and the expression levels of angiopoietin 1 (Ang-1) and Tie-2 were assessed by Western blot assay. At 28 days postoperatively, the expression levels of pro-angiogenic related proteins, including platelet-derived growth factor B (PDGF-B), PDGF receptor ß (PDGFR-ß), vascular endothelial growth factor A (VEGF-A), and VEGF receptor 2 (VEGFR-2), were also assessed by Western blot. The fibrous scar in the injured area was assessed using Masson staining, while neuronal survival was observed through Nissl staining. Furthermore, LFB staining was utilized to detect myelin distribution and regeneration. Immunofluorescence and Western blot assay were employed to evaluate the expression of neurofilament 200 (NF200). Results: The hindlimb motor function of rats in each group gradually recovered from the 3rd day after operation. The BBB score and climbing angle in group D were significantly higher than those in group B from 3 to 28 days after operation, and significantly higher than those in group C at 14 days and 28 days after operation ( P<0.05). Masson staining showed that the collagen volume fraction in groups B-D were significantly higher than that in group A, and that in group D was significantly lower than that in groups B and C ( P<0.05); a small amount of black conductive particles were scattered at the broken end in group D, and the surrounding collagen fibers were less than those in group C. Nissl and LFB staining showed that the structure of neurons and myelin sheath in the injured area of spinal cord in group D was relatively complete and continuous, and the number of Nissl bodies and the positive area of myelin sheath in group D were significantly better than those in groups B and C ( P<0.05). NF200 immunofluorescence staining and Western blot assay results showed that the relative expression of NF200 protein in group D was significantly higher than that in groups B and C ( P<0.05). CD31 immunofluorescence staining showed that the fluorescence intensity of group D was better than that of groups B and C at 28 days after operation, and tubular or linear neovascularization could be seen. The relative expressions of Ang-1 and Tie-2 proteins in group D were significantly higher than those in groups B and C at 7 and 28 days after operation ( P<0.05). The relative expressions of PDGF-B and PDGFR-ß proteins in group D were significantly higher than those in groups B and C, and group B was significantly higher than group C at 28 days after operation ( P<0.05). The relative expressions of VEGF-A and VEGFR2 proteins in group D were higher than those in groups B and C, showing significant difference when compared with group B ( P<0.05), but only the expression of VEGF-A protein was significantly higher than that in group C ( P<0.05). There was significant difference only in VEGFR-2 protein between groups B and C ( P<0.05). Conclusion: TGTP may enhance the revascularization of the injured area and protect the neurons, thus alleviating the injury of spinal cord tissue structure and promoting the recovery of neurological function after SCI in rats.

Effect of use of NSAIDs or steroids during the acute phase of pain on the incidence of chronic pain: a systematic review and meta-analysis of randomised trials.

BACKGROUND: This study is the first to summarize the evidence on how the use of anti-inflammatory drugs during acute pain has an impact on the development of chronic pain. METHODS: Randomized controlled trials retrieved from nine databases included anti-inflammatory drugs (NSAIDs or steroids) versus non-anti-inflammatory drugs in patients with acute pain and reported the incidence of chronic pain. No specified date, age, sex, or language restrictions. Subgroup analyses were performed according to pain classification, follow-up time, and medication. The GRADE method was used to evaluate quality of evidence. RESULTS: A total of 29 trials (5220 patients) were included. Steroids or NSAIDs did not reduce the incidence of chronic nociceptive pain. Steroid use in acute phase significantly reduced the incidence of chronic neuropathic pain. In subgroup analysis, benefits were observed for methylprednisolone and dexamethasone, with some adverse effects. Steroids or NSAIDs were statistically significant in reducing pain intensity over 1 year, but the effect size was too small, and whether the long-term effect is clinically relevant needs to be further studied. CONCLUSION: Quality of the evidence was low to moderate. No drug can be recommended to prevent chronic nociceptive pain. Injections of steroids (methylprednisolone or dexamethasone) during the acute phase reduce the incidence of chronic neuropathic pain, but most included studies also used local anesthetics. The results are indirect and need to be interpreted with caution. The pooled data effect sizes for pain intensity were small, so the clinical relevance was unclear. Study registration PROSPERO (CRD42022367030).

Temporal profiling and validation of oxidative stress-related genes in spinal cord injury.

Oxidative stress (OS) plays a pivotal role in the pathogenesis of spinal cord injury (SCI), yet its underlying mechanisms remain elusive. In this study, we explored the OS phenotype in a rat model of SCI. Subsequently, comprehensive bioinformatic analyses were conducted on microarray data pertaining to SCI (GSE45006). Notably, KEGG enrichment analysis revealed a pronounced enrichment of pivotal pathways, namely MAPK, FoxO, Apoptosis, NF-κB, TNF, HIF-1, and Chemokine across distinct phases of SCI. Furthermore, GO enrichment analysis highlighted the significance of biological processes including response to hypoxia, response to decrease oxygen levels, response to reactive oxygen species, cellular response to oxidative stress, reactive oxygen species metabolic process, and regulation of neuron death in the context of OS following SCI. Notably, our study underscores the prominence of nine genes, namely Itgb1, Itgam, Fn1, Icam1, Cd44, Cxcr4, Ptprc, Tlr4, and Tlr2 as OS key genes in SCI, consistently expressed in both the acute phase (1, 3, 7 days) and sub-acute phase (14 days). Subsequently, the relative mRNA expression of these key genes in different time points (1, 3, 7, 14 days) post-SCI. Finally, leveraging the DsigDB database, we predicted ten potential compounds potentially targeting OS and facilitating the repair of SCI, thus providing novel insights into the mechanisms underlying OS and identifying potential therapeutic targets for SCI.

3D Printing Model of a Patient's Specific Lumbar Vertebra.

Selective dorsal rhizotomy (SDR) is a difficult, risky, and sophisticated operation, in which a laminectomy should not only expose an adequate surgical field of view but also protect the patient's spinal nerves from injury. Digital models play an important role in the pre-and intra-operation of SDR, because they can not only make doctors more familiar with the anatomical structure of the surgical site, but also provide precise surgical navigation coordinates for the manipulator. This study aims to create a 3D digital model of a patient-specific lumbar vertebra that can be used for planning, surgical navigation, and training of the SDR operation. The 3D printing model is also manufactured for more effective work during these processes. Traditional orthopedic digital models rely almost entirely on computed tomography (CT) data, which is less sensitive to soft tissues. Fusion of the bone structure from CT and the neural structure from magnetic resonance imaging (MRI) is the key element for the model reconstruction in this study. The patient's specific 3D digital model is reconstructed for the real appearance of the surgical area and shows the accurate measurement of inter-structural distances and regional segmentation, which can effectively help in the preoperative planning and training of SDR. The transparent bone structure material of the 3D-printed model allows surgeons to clearly distinguish the relative relationship between the spinal nerve and the vertebral plate of the operated segment, enhancing their anatomical understanding and spatial sense of the structure. The advantages of the individualized 3D digital model and its accurate relationship between spinal nerve and bone structures make this method a good choice for preoperative planning of SDR surgery.

[Relationship between the gross motor function classification system and hip and lumbar spine development in children with spastic cerebral palsy].

OBJECTIVE: To investigate the relationship among the gross motor function classification system (GMFCS)and the development of hip joint and lumbar spine in children with spastic cerebral palsy. METHODS: The clinical data of 125 children with spastic cerebral palsy admitted from January 2018 to July 2021 were retrospectively analyzed. There were 85 males and 40 females, aged from 4 to 12 years old with an average of (8.4±2.9) years. According to GMFCS, the patients were divided into gradeⅠ, Ⅱ, Ⅲ and Ⅳ groups. There were 27 cases in gradeⅠgroup, 40 cases in gradeⅡgroup, 35 cases in grade Ⅲ group and 23 cases in grade Ⅳ group. The migration percentage(MP), central edge angle(CE), neck-shaft angle(NSA), acetabular index(AI) were measured by the radiograph of pelvis, abnormal parameters were selected to evaluate the relationship between different GMFCS grades and hip joint development. Lumbar sagittal Cobb angle, lumbar sacral angle, lumbar lordosis index and apical distance were measured by lateral lumbar radiographs to evaluate the relationship between different GMFCS grades and lumbar spine development. RESULTS: ①Among the 125 spastic cerebral palsy children, there were 119 cases of pelvic radiographs that met the measurement standards. In the four groups with gradeⅠ, Ⅱ, Ⅲ, Ⅳ, MP was (22.72±3.88), (26.53±4.36), (33.84±4.99), and (49.54±7.87)%, CE was(30.10±6.99) °, ( 22.92±4.19) °, ( 17.91±5.50) °, and (-0.70±17.33)°, AI was (16.41±2.77) °, (20.46±4.63) °, (23.76±5.10) °, and ( 29.15±7.35)°, respectively, there were significant differences between the two comparisons (P<0.05). And the higher GMFCS grade, the greater MP and AI, and the smaller CE.The NSA was(142.74±10.03) °, (148.66±9.09) °, (151.66±10.52) °, and (153.70±8.05)° in four groups with gradeⅠ, Ⅱ, Ⅲ, Ⅳ, respectively. The differences between the two comparisons of the GMFCS gradeⅠgroup and the other three groups were statistically significant (P<0.05). NSA of GMFCSⅠgroup was significantly lower than that of the others, there was no significant difference among other groups(P>0.05). ② Among the 125 spastic cerebral palsy children, there were 88 cases of lumbar spine radiographs that met the measurement standards. ③The lumbar sagittal Cobb angle was(32.62±11.10) °, (29.86±9.90) °, (31.70±11.84) °, and (39.69±6.80)° in the four groups with gradeⅠ, Ⅱ, Ⅲ, Ⅳ, respectively;GMFSS of grade Ⅳ group was significantly higher than that of other three groups, there was significant difference between the two comparisons (P<0.05);there were no significant differences between other groups (P>0.05). In the four groups with gradeⅠ, Ⅱ, Ⅲ, Ⅳ, the lumbosacral angle was (31.02±9.91) °, ( 26.57±9.41) °, (28.08±8.56) °, and ( 27.31±11.50)°, the lumbar lordosis index was (4.14±12.89), (8.83±13.53), (13.00±11.78), and (10.76±9.97) mm, the arch apex distance was (9.50±6.80), (6.68±3.20), (7.16±4.94), and (6.62±4.13) mm, respectively, there were no significant differences between the two comparisons(P>0.05). CONCLUSION: ①In children with GMFCS gradeⅠ-Ⅳ, the higher the GMFCS grade, the worse the hip develops. ② Children with GMFCS grade Ⅲ-Ⅳ may be at greater risk for lumbar kyphosis.

[Experimental study on the repair of spinal cord injury by conducting hydrogel loaded with tetramethylpyrazine sustained-release microparticles].

Objective: To investigate the neuroprotective effect of conducting hydrogel loaded with tetramethylpyrazine sustained-release microparticles (hereinafter referred to as "TGTP hydrogel") on spinal cord injury rats. Methods: Forty-eight adult female Sprague Dawley rats were randomly divided into 4 groups: sham operation group (group A), model group (group B), conductive hydrogel group (group C), and TGTP hydrogel group (group D), with 12 rats in each group. Only laminectomy was performed in group A, and complete spinal cord transection was performed in groups B, C, and D. Basso-Bettie-Bresnahan (BBB) score was used to evaluate the recovery of hind limb motor function of each group before modeling and at 1, 3, 7, 14, and 28 days after modeling, respectively. At 28 days after modeling, the rats were sacrificed for luxol fast blue (LFB) staining to detect myelin regeneration. Nissl staining was used to detect the survival of neurons. Immunohistochemical staining was used to evaluate the expression of inflammation-related factors [nuclear factor кB (NF-кB), tumor necrosis factor α (TNF-α), and interleukin 10 (IL-10)]. Immunofluorescence staining and Western blot were used to evaluate the expression of neurofilament 200 (NF200). Rseults: BBB scores of group A were significantly better than those of the other three groups at all time points after modeling (P<0.05); at 14 and 28 days after modeling, there was no significant difference in BBB scores between groups C and D (P>0.05), but the BBB score of group D was significantly better than that of group B (P<0.05). LFB staining and Nissl staining showed that the structure of neurons and myelin in group A was intact, and the myelin integrity and survival number of neurons in group D were significantly better than those in groups B and C. Immunohistochemical staining showed that the absorbency (A) value of NF-кB and TNF-α in group A were significantly lower than those in groups B and C (P<0.05), the A value of IL-10 was significantly higher than that in the other three groups (P<0.05); the A value of NF-κB in group D was significantly lower than that in groups B and C, the A value of TNF-α in group D was significantly lower than that in group B, while the A value of IL-10 in group D was significantly higher than that in group B (P<0.05). Immunofluorescence staining showed that the structure of neurons and nerve fibers in group A was clear and the fluorescence intensity was high. The fluorescence intensity of NF200 in group D was higher than that in groups B and C, and some nerve fibers could be seen. Western blot analysis showed that the relative expression of NF200 in group A was the highest, and the relative expression of NF200 in group D was significantly higher than that in groups B and C (P<0.05). Conclusion: The TGTP hydrogel can effectively promote the recovery of motor function in rats with spinal cord injury, and its mechanism may be related to the regulation of inflammatory response.

High-precision camera calibration based on a 1D target.

In this paper, the problem of camera 1D calibration is well solved by our proposed high-precision algorithm, which can satisfy actual requirements. We present a viewpoint that the closed-form solution can simply achieve high calibration accuracy in the absence of distortion. So, we abandon the habitual strategy of global nonlinear optimization for all intrinsic and extrinsic parameters. The innovations of the proposed algorithm are three-fold: firstly, cyclic distortion correction method is introduced to ensure that the estimated distortion parameters gradually approach the exact values; secondly, a new criterion for the nonlinear optimization of distortion correction is developed; thirdly, we enhance the anti-noise ability of the closed-form solution by optimally weighting the constraint equations. Extensive experiments prove that the proposed algorithm provides the highest calibration accuracy and robustness, which is comparable to 2D calibration. In addition, our proposed algorithm provides a new approach for desirable distortion correction and an idea for 2D calibration of large field of view.

[Establishment of artificial joint aseptic loosening mouse model by cobalt-chromium particles stimulation].

OBJECTIVE: To explore the feasibility of establishment of a artificial joint aseptic loosening mouse model by cobalt-chromium particles stimulation. METHODS: Twenty-four 8-week-old male severe combined immunodeficient (SCID) mice were divided into experimental group ( n=12) and control group ( n=12). The titanium nail was inserted into the tibial medullary cavity of mouse in the two groups to simulate artificial joint prosthesis replacement. And the cobalt-chromium particles were injected into the tibial medullary cavity of mouse in experimental group. The survival of the mouse was observed after operation; the position of the titanium nail and the bone mineral density of proximal femur were observed by X-ray film, CT, and Micro-CT bone scanning; and the degree of dissolution of the bone tissue around the tibia was detected by biomechanical test and histological staining. RESULTS: Two mice in experimental group died, and the rest of the mice survived until the experiment was completed. Postoperative imaging examination showed that there was no obvious displacement of titanium nails in control group, and there were new callus around the titanium nails. In experimental group, there was obvious osteolysis around the titanium nails. The bone mineral density of the proximal tibia was 91.25%±0.67%, and the maximum shear force at the tibial nail-bone interface was (5.93±0.85) N in experimental group, which were significantly lower than those in control group [102.07%±1.87% and (16.76±3.09) N] ( t=5.462, P=0.041; t=3.760, P=0.046). Histological observation showed that a large number of inflammatory cells could be seen around the titanium nails in experimental group, while there was no inflammatory cells, and obvious bone tissue formation was observed in control group. CONCLUSION: The artificial joint aseptic loosening mouse model can be successfully established by cobalt-chromium particles stimulation.

A minimally invasive incision and loop drainage technique for the treatment of lower limb Morel-Lavallée lesions: Nose ring drainage technique.

Morel-Lavallée lesions (MLLs) are shearing injuries resulting in separation of the skin and subcutaneous tissue from the underlying fascia. They are closed internal degloving injuries. Classical sites of the lesions are around the greater trochanter, pelvis, thigh, knee joint, and on the head, in decreasing order of frequency. This injury is often delayed or misdiagnosed when patients present with soft tissue injury alone or when more obvious injuries distract from its presence in polytrauma patients. There is currently no universally accepted treatment for these lesions. Conservative management often fails and requires surgical intervention. The purpose of this manuscript is to show that nose ring drainage, a minimally invasive incision and loop drainage technique for the treatment of lower limb Morel-Lavallée lesions, is effective and economical.