Background/Objectives: Low back pain (LBP) is associated with central alterations, but convergence across structural, functional, and network measures remains unclear. We characterized multimodal differences. Methods: Resting-state fMRI included 69 participants (37 patients, 32 controls); VBM retained 23 patients and 32 controls after structural-image quality control. Structural, local functional, and thalamic-connectivity measures were assessed. Motion control used realignment-based exclusion and Friston-24 nuisance regression. Mean Power framewise displacement was additionally calculated for all participants and compared between groups, and VBM-retained and excluded patients were compared. Models adjusted for age and sex, plus total intracranial volume for VBM. Directional maps underwent one-tailed Gaussian random field correction (voxel p < 0.001; cluster p < 0.05), without cross-direction or cross-family correction. Extracted-value and imaging-clinical analyses were exploratory. Results: Mean framewise displacement did not differ between groups. Patients showed lower gray matter volume in thalamic-hippocampal regions and right cerebellar lobule VIII and lower local functional measures in thalamic, orbitofrontal-striatal, and right temporal regions. Thalamic connectivity with sensorimotor, parietal, supplementary motor, and middle cingulate regions was higher. Nominal analyses showed positive left thalamic connectivity cluster 1-VAS and negative left cluster 1-JOA and right clusters 1/2-JOA; none survived false-discovery-rate correction. Conclusions: Multimodal MRI delineated lower thalamic structural and local functional measures alongside higher thalamo-sensorimotor and thalamo-parietal connectivity. Nominal, directionally coherent clinical associations remain hypothesis-generating. This thalamus-centered pattern warrants replication in prospectively matched, clinically stratified cohorts.

ObjectiveTo report a rare case of acute postoperative epidural hematoma (PEDH) following unilateral biportal endoscopic (UBE) unilateral laminotomy with bilateral decompression (ULBD) for L3–4 spinal stenosis, presumably caused by muscular hemorrhage, and to explore its potential etiology through a review of the literature.MethodsThe clinical data, including pre- and postoperative Visual Analog Scale (VAS) and Japanese Orthopaedic Association (JOA) scores, were recorded at key timepoints: preoperatively, pre-surgical drain removal, post-surgical drain removal, and post-emergency debridement. A literature review was conducted to contextualize the findings.ResultsA 56-year-old male presented with left lower limb pain (VAS 6), intermittent claudication (walking distance: 100 meters), and a JOA score of 10 preoperatively. After undergoing the UBE-ULBD surgery at the L3-4 level, the patient reported significant relief of lower limb neurological symptoms upon regaining consciousness from anesthesia. However, three minutes after drain removal on the 24th hour postoperatively, the patient experienced sudden severe left lower limb pain (VAS 10), which was refractory to routine analgesics. Administration of morphine provided only partial relief (VAS 7). Physical examination disclosed localized swelling at the surgical site, and subsequent MRI imaging confirmed the presence of hematoma signals within the operative channel. Emergency debridement revealed continuous bleeding from a small muscular artery within the operative tract, which had led to hematoma accumulation and subsequent compression of the dural sac and nerve roots. The bleeding artery was successfully ligated, and the hematoma was meticulously evacuated. Following debridement, the patient's pain improved significantly (VAS 3), and he was discharged without any sequelae.ConclusionSpinal postoperative epidural hematomas have been reported in 0.1%–3% of cases, however, this represents the first documented instance following UBE-ULBD surgery. Hemorrhage from the muscular layer is identified as a potential etiology, underscoring the necessity for meticulous intraoperative hemostasis, particularly after restoration of baseline blood pressure prior to wound closure. Routine placement of a drainage tube is therefore recommended. Immediate surgical intervention, preferably within 24 h, is crucial for alleviating neurological compression, as emphasized by expert consensus, and significantly improves functional outcomes.

Background: Infection with Staphylococcus aureus (S. aureus) is an important contributor to intervertebral disc degeneration (IDD). Endoplasmic reticulum stress (ERS) is a major pathway through which bacteria regulate cell fate. The aim of this study was to examine the role of ERS in S. aureus-induced IDD. Methods: We assessed the S. aureus-induced degeneration, apoptosis, and senescence of nucleus pulposus cells (NPCs) in vitro by Western blot, flow cytometry, and staining for β-galactosidase, and in vivo by magnetic resonance imaging/computed tomography (MRI/CT) imaging, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and histological staining. RNA sequencing was conducted to identify differentially expressed genes, while siRNA, lentiviral vectors, and Atf3-knockout (Atf3-KO) mice were utilized to confirm the role of ATF3 in persistent IDD following transient S. aureus infection. Results: Following the eradication of S. aureus in vitro, the expression of Aggrecan and collagen II in NPCs continued to decline, accompanied by an increase in the proportion of apoptotic and senescent cells. Transient S. aureus infection was shown to activate the Activating Transcription Factor 3 (ATF3)-CCAAT/Enhancer-Binding Protein Homologous Protein (CHOP) signaling pathway, leading to sustained swelling of the endoplasmic reticulum in NPCs. In vivo experiments further demonstrated that transient S. aureus infection resulted in progressive IDD, activation of the ATF3-CHOP pathway, increased numbers of TUNEL-positive cells, and elevated P21 expression. Knockdown of ATF3 expression in vitro attenuated the S. aureus-mediated increase in apoptotic and senescent cells, while Atf3-KO mice exhibited milder IDD compared to wild type (WT) mice, with fewer apoptotic cells and reduced P21 expression. Conclusion: Transient S. aureus infection may lead to progressive IDD by triggering sustained ER stress and activating related signaling pathways. The ATF3-CHOP pathway may be an important target for alleviating the sustained disc degeneration caused by transient S. aureus infection.

Purpose:The aim of this study was to explore short-term radiological findings after contiguous two-level ACDF with Zero-P VA devices. Methods:Patients who underwent contiguous two-level anterior cervical discectomy and fusion (ACDF) from C3 to C7 with a Zero-P VA system were followed. Cervical anteroposterior and lateral X-rays and functional outcomes were assessed 3 months after surgery. Results:Overall, 34.9% of patients had prosthesis subsidence and 74.6% screw loosening. Up to 46.8% of the patients with screw loosening also experienced prosthesis subsidence compared with 0 patients without screw loosening (p=0.0005). The screw-loosening rate was 91.7% in patients with poor positioning of the screw/cage and 70.6% in patients without poor positioning of the screw/cage, but no statistical difference was found between the groups (p=0.267). The subsidence rate was 50% in patients with poor positioning of the screw/cage and 31.4% in patients without poor positioning of the screw/cage, but no statistical difference was found between the groups (p=0.314). VAS scores of patients with prosthesis subsidence were much higher than those without (p=0.031), but this difference was not found for patients with or without screw loosening (p=0.116). The NDI scale was much higher in patients regradless of screw loosening or subsidence. Conclusion:Screw loosening and prosthesis subsidence happen frequently after contiguous two-level ACDF with Zero-P VA. Screw loosening seems to be the only risk factor for prosthesis subsidence.

Although an increasing number of investigators confirm the latent infection of Propionibacterium acnes in degenerated nucleus pulposus tissue, the molecular mechanism by which P. acnes evades being eliminated and establishes persistent colonization in the nucleus pulposus (NP) tissue remains unknown. In this study, we ascertained that despite the resistance by nucleus pulposus cells (NPCs) to the invasion of P. acnes through microbicidal phagocytosis, P. acnes is able to nevertheless promote its long-term colonization by inhibiting the sustained bactericidal capability of NPCs. This allows P. acnes to reside in intervertebral discs for an extended period, ultimately inducing chronic infectious intervertebral disc degeneration (IVDD). Mechanistically, P. acnes impairs the mitochondrial biogenesis of NPCs through the AMPK/SIRT-1/PGC-1α signaling pathway. This results in impaired mitochondria that are unable to generate sufficient ATP and deliver mitochondrial reactive oxygen species (mROS) to carry out the bactericidal process effectively, thus hampering the sustained microbicidal function. These findings provide novel insights into how P. acnes evades being phagocytosed and killed by NPCs and may offer potential therapeutic targets for the treatment of infectious IVDD.

Reactive oxygen species (ROS) play a pivotal role in multiple events during the progression of intervertebral disc degeneration (IDD). Hence, the precision treatment targets associated with ROS should be further explored to promote developing effective therapeutic strategies. In this study, by analyzing specimens from patients and RNA sequencing of ROS-induced human primary nucleus pulposus cells (NPCs), osteopontin (OPN) and ferroptosis were identified as critical molecular entities and cellular pathways implicated in ROS-mediated IDD. Subsequent animal models and cellular assays determined that ROS induced upregulation of OPN, which in turn triggered ferroptosis in NPCs and intervertebral discs, consequently leading to IDD. Building upon these findings, a comprehensive screening of molecular drug database revealed that quercetin, an antioxidant molecule compound, possesses the capacity to couple OPN, thereby mitigating OPN-induced ferroptosis and IDD. In addition, the compound of quercetin for targeting OPN was encapsulated in phenylboric acid modified dendrimer (G3-PBA) nanoparticles to improve its solubility, and then embedded in a ROS-degradable and injectable hydrogel, thereby achieving on-demand release of quercetin with the progression of IDD. Collectively, this study not only identified a novel therapeutic target, but also engineered an effective therapeutic strategy intended for the autonomous management of IDD.

PurposeTo evaluate the clinical efficacy of surgery in Kummell's disease (KD) to help us select the optimum surgical strategy.MethodsWe included 67 KD patients who underwent Percutaneous vertebral plasty (PVP), Percutaneous kyphosis plasty (PKP), Percutaneous pedicle screw fixation (PPSF) or Posterior decompression osteotomy fixation (PDOF). The differences in imaging parameters and prognosis changes of pre-operation, post-operative and follow-up endpoint were analyzed.ResultsThe incidence rate of KD was 10.02% (67/668) in vertebral compressibility fracture. 80.60% of patients underwent PVP/PKP, 14.93% underwent PPSF, and 4.47% underwent PDOF. The significant differences between the actual used surgical methods and the classification recommended surgical strategies could be found. In I type, there was no significant difference in total improvement of the radiography data and clinical efficacy between PVP and PKP. In II type, there was a significant correlation between opening and closing sign (OCS) and surgical choice. Compared with PPSF, the positive OCS patients who underwent PVP/PKP suffered a poor prognosis. PDOF is an effective surgical method for type III, but PVP could also achieve a good prognosis for patients with poor condition.ConclusionThe mainstream KD classification system has shortcomings, and completely following its treatment strategy may lead to poor prognosis. Compared to PKP, PVP is a better choice for type I patients. OCS is one of the important factors in surgical selection for type II patients. The Li's type III is mainly treated with PDOF but the overall condition of the body needs to be evaluated.

To evaluate the clinical efficacy of surgery in Kummell’s disease (KD) to help us select the optimum surgical strategy. We included 67 KD patients who underwent Percutaneous vertebral plasty (PVP), Percutaneous kyphosis plasty (PKP), Percutaneous pedicle screw fixation (PPSF) or Posterior decompression osteotomy fixation (PDOF). The differences in imaging parameters and prognosis changes of pre-operation, post-operative and follow-up endpoint were analyzed. The incidence rate of KD was 10.02

Intervertebral disc degeneration (IDD) has been identified as one of the predominant factors leading to persistent low back pain and disability in middle-aged and elderly people. Dysregulation of Prostaglandin E2 (PGE2) can cause IDD, while low-dose celecoxib can maintain PGE2 at the physiological level and activate the skeletal interoception. Here, as nano fibers have been extensively used in the treatment of IDD, novel polycaprolactone (PCL) nano fibers loaded with low-dose celecoxib were fabricated for IDD treatment. In vitro studies demonstrated that the nano fibers had the ability of releasing low-dose celecoxib slowly and sustainably and maintain PGE2. Meanwhile, in a puncture-induced rabbit IDD model, the nano fibers reversed IDD. Furthermore, low-dose celecoxib released from the nano fibers was firstly proved to promote CHSY3 expression. In a lumbar spine instability-induced mouse IDD model, low-dose celecoxib inhibited IDD in CHSY3(wt) mice rather than CHSY3(-/-) mice. This model indicated that CHSY3 was indispensable for low-dose celecoxib to alleviate IDD. In conclusion, this study developed a novel low-dose celecoxib-loaded PCL nano fibers to reverse IDD by maintaining PGE2 at the physiological level and promoting CHSY3 expression.

Background This study was performed to investigate the clinical efficacy of percutaneous kyphoplasty (PKP) for vertebral compression fractures with different bone mineral densities (BMD). Methods We performed a retrospective analysis of 232 patients with single-segment vertebral compression fractures who underwent PKP. Patients were divided into the normal BMD, osteopenia, and osteoporosis groups according to their average lumbar BMD before surgery. The visual analog scale (VAS) was used to compare differences in pain relief before and after surgery in each group. Corrections of the wedge angle and kyphotic angle before and after surgery were observed using anteroposterior and lateral radiographs and compared among the groups, as was the incidence of bone cement leakage. Results Patients were followed up for 6–12 months, with an average follow-up time of 9.12 ± 1.68 months. The VAS score, wedge angle, and kyphotic angle of the three groups of patients decreased significantly at the end of the follow-up ( P < 0.05). The changes in VAS score and wedge angle correction in the osteoporosis group were significantly larger than those in the normal BMD and osteopenia groups ( P < 0.05). There were no significant differences among the three groups in terms of kyphotic angle correction or bone cement leakage rates ( P > 0.05). Conclusions PKP has a positive effect on vertebral compression fractures with different BMD, and is especially suitable for osteoporotic vertebral compression fractures.

Background Low back pain (LBP) is associated with lumbar disc degeneration (LDD) and fatty infiltration of paraspinal muscles. However, there are some controversies about the relationship between LDD and fatty infiltration of paraspinal muscles, and the causation of them is also not clear. Thus, we investigated whether the degree of LDD was associated with fatty infiltration of paraspinal muscles and preliminarily explored the underlying mechanism. Methods A retrospective study was conducted on 109 patients with chronic LBP. The degree of LDD was assessed by the Pfirrmann classification. Total muscle cross-sectional area, L4 vertebral body endplate area, and fat cross-sectional area at axial T2-weighted MRI were measured. Multifidus and lumbar disc specimens were taken from eight individuals undergoing discectomy for disc herniation. Gene and protein expression levels of TNF were quantified through qPCR assays and ELISA, respectively. Results The relative cross-sectional area, total muscle cross-sectional area, and muscle cross-sectional area asymmetry were not related to LDD. Pfirrmann grades correlated strongly with fatty infiltration of the multifidus and moderately with fatty infiltration of the erector spinae and the psoas muscles. Linear regression analysis suggested that Pfirrmann grades were most associated with fatty infiltration of the multifidus. Compared with II-degree degeneration discs (mild-degeneration group), fatty infiltration of the multifidus in IV-degree degeneration discs (severe-degeneration group) significantly increased, accompanied by increased mRNA expression of TNF. Meanwhile, the protein expression levels of TNF (pg/g protein) in discs (16.62 ± 4.33) and multifidus (13.10 ± 2.76) of the severe-degeneration group were higher than those in the mild-degeneration group (disc: 9.75 ± 2.18; multifidus: 7.84 ± 2.43). However, the mRNA expression of TNF in the multifidus was not significantly different between the two groups. Conclusions The results suggest that LDD is associated with fatty infiltration of the multifidus. The possible underlying mechanism is that LDD induces fatty infiltration by inflammation. Furthermore, compared with the erector spinae and the psoas muscles, fatty infiltration of the multifidus shows an optimal correlation with LDD, which may contribute to further understanding of LDD pathology.

Sensory nerves are long being recognized as collecting units of various outer stimuli; recent advances indicate that the sensory nerve also plays pivotal roles in maintaining organ homeostasis. Here, this study shows that sensory nerve orchestrates intervertebral disc (IVD) homeostasis by regulating its extracellular matrix (ECM) metabolism. Specifically, genetical sensory denervation of IVD results in loss of IVD water preserve molecule chondroitin sulfate (CS), the reduction of CS bio-synthesis gene chondroitin sulfate synthase 1 (CHSY1) expression, and dysregulated ECM homeostasis of IVD. Particularly, knockdown of sensory neuros calcitonin gene-related peptide (CGRP) expression induces similar ECM metabolic disorder compared to sensory nerve denervation model, and this effect is abolished in CHSY1 knockout mice. Furthermore, in vitro evidence shows that CGRP regulates nucleus pulposus cell CHSY1 expression and CS synthesis via CGRP receptor component receptor activity-modifying protein 1 (RAMP1) and cyclic AMP response element-binding protein (CREB) signaling. Therapeutically, local injection of forskolin significantly attenuates IVD degeneration progression in mouse annulus fibrosus puncture model. Overall, these results indicate that sensory nerve maintains IVD ECM homeostasis via CGRP/CHSY1 axis and promotes IVD repair, and this expands the understanding concerning how IVD links to sensory nerve system, thus shedding light on future development of novel therapeutical strategy to IVD degeneration.

Background:Most patients with osteoporotic vertebral compression fracture (OVCF) obtain pain relief after vertebral augmentation, but some will experience residual back pain (RBP) after surgery. Although several risk factors of RBP have been reported, it is still difficult to estimate the risk of RBP preoperatively. Radiomics is helpful for disease diagnosis and outcome prediction by establishing complementary relationships between human-recognizable and computer-extracted features. However, musculoskeletal radiomics investigations are less frequently reported.Objective:This study aims to establish a radiomics score (rad-score) based nomogram for the preoperative prediction of RBP in OVCF patients.Methods:The training cohort of 731 OVCF patients was used for nomogram development, and the validation cohort was utilized for performance test. RBP was determined as the score of visual analogue scale ≥ 4 at both 3 and 30 days following surgery. After normalization, the RBP-related radiomics features were selected to create rad-scores. These rad-scores, along with the RBP predictors initially identified by univariate analyses, were included in the multivariate analysis to establish a nomogram for the assessment of the RBP risk in OVCF patients preoperatively.Results:A total of 81 patients (11.2%) developed RBP postoperatively. We finally selected 8 radiomics features from 1316 features extracted from each segmented image to determine the rad-score. Multivariate analysis revealed that the rad-score plus bone mineral density, intravertebral cleft, and thoracolumbar fascia injury were independent factors of RBP. Our nomograms based on these factors demonstrated good discrimination, calibration, and clinical utility in both training and validation cohorts. Furthermore, it achieved better performance than the rad-score itself, as well as the nomogram only incorporating regular features.Conclusion:We developed and validated a nomogram incorporating the rad-score and regular features for preoperative prediction of the RBP risk in OVCF patients, which contributed to improved surgical outcomes and patient satisfaction.

Propionibacterium acnes infection in intervertebral discs (IVDs) is a newly identified cause of low back pain (LBP). In the present study, we aimed to determine whether the nerve growth factor (NGF), a critical pro-algesic factor, is involved in P. acnes-induced LBP. After co-culturing with P. acnes, nucleus pulposus cells (NPCs) produced NGF, which was upregulated after inoculation of P. acnes into IVDs of rats. In addition, administration of P. acnes into rat IVDs leads to significant mechanical allodynia and cold hyperreflexia, and significant upregulation of the pain-related factors, including substance P (SP), calcitonin gene-related peptide (CGRP), and Transient Receptor Potential Vanilloid 1 (TRPV1), in rat dorsal root ganglia (DRG), suggesting that P. acnes-inoculated rats had obvious discogenic LBP. However, inhibition of NGF bioactivity significantly ameliorated P. acnes-induced discogenic LBP, suggesting that P. acnes induced LBP via NGF. Finally, an in vitro mechanism study demonstrated that P. acnes stimulated NPCs to secrete NGF via TLR-2 receptor and NF-κB p65/JNK pathway, or ROS-related pathway. Therefore, P. acnes had a strong association with LBP by stimulating NPCs to secrete NGF via the TLR2-NF- κB/JNK or ROS-related pathway. These findings propose a novel potential therapeutic strategy for LBP.

腰椎退行性疾病是脊柱外科常见病和多发病,是引起下腰痛的主要原因[1],下腰痛是以腰骶、臀部伴/不伴下肢疼痛为主要症状的综合征[2].有研究[3-4]发现,下腰痛的发生、发展与脊柱稳定性的失衡密切相关.椎旁肌是脊柱邻近肌群的总称,分为前群(髂腰肌、腰方肌、腰大肌)和后群(多裂肌、竖脊肌等).椎旁肌良好的功能状态对脊柱稳定性起着重要作用.多裂肌作为腰椎稳定性的重要来源,其萎缩与腰椎椎间盘突出症、腰椎椎管狭窄症、腰椎滑脱症等腰椎退行性疾病关系密切[5-6].本文通过查阅多裂肌萎缩与腰椎退行性疾病的相关文献,对多裂肌萎缩的影像学变化、多裂肌萎缩与腰椎退行性疾病的关系及多裂肌的保护与治疗等方面进行分析梳理,综述如下.

A bacterial strain, Gram-stain negative, rod-shaped, aerobic and cellulose-degrading, designated NEAU-DD11T, was isolated from rhizosphere soil of rice collected from Northeast Agricultural University in Harbin, Heilongjiang Province, North-east China. Base on 16S rRNA gene sequence analysis, strain NEAU-DD11T belongs to the genus Massilia and shared high sequence similarities with Massilia phosphatilytica 12-OD1T (98.46%) and Massilia putida 6NM-7 T (98.41%). Phylogenetic analysis based on the 16S rRNA gene and whole genome sequences indicated that strain NEAU-DD11T formed lineage related to M. phosphatilytica 12-OD1T and M. putida 6NM-7 T. The major fatty acids of the strain were C16:0, C17:0-cyclo and C16:1ω7c. The respiratory quinone was Q-8. The polar lipids profile of the strain showed the presence of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified polar lipid and an unidentified phospholipid. In addition, the digital DNA-DNA hybridization values between strain NEAU-DD11T and M. phosphatilytica 12-OD1T and M. putida 6NM-7 T were 45.4 and 35.6%, respectively, which are lower than the accepted threshold value of 70%. The DNA G + C content of strain NEAU-DD11T was 66.2%. The whole genome analysis showed the strain contained carbohydrate enzymes such as glycoside hydrolase and polysaccharide lyase, which enabled the strain to have the function of degrading cellulose. On the basis of the phenotypic, genotypic and chemotaxonomic characteristics, we conclude that strain NEAU-DD11T represents a novel species of the genus Massilia, for which the name Massilia cellulosiltytica sp. nov. is proposed. The type strain is NEAU-DD11T (= CCTCC AB 2019141 T = DSM 109721 T).

目的 评估腰椎侧路椎体间融合术是否会减少退变性脊柱侧凸患者固定融合节段.方法 选取2014年1月至2018年9月,33例在我院行微创矫形术的退变性脊柱侧凸患者,其中女21例,男12例,年龄58～82岁,平均(72.8±4.5)岁.9例采用经腰大肌腰椎侧方椎间融合术(lateral lumbar interbody fusion,LLIF),24例采用斜外侧腰椎椎体间融合术(oblique lumbar interbody fusion,OLIF).所有患者均采取分期微创手术的方式进行,第一期从侧方植入LLIF/OLIF融合器,第二期从后路植入经皮椎弓根螺钉或经Wiltse入路行腰椎椎弓根内固定术.所有患者在两次手术前后均使用EOS系统摄站立位脊柱全长X线片,应用EOS软件系统测量、评估患者的矢状面平衡参数包括骨盆入射角(pelvic incidence,PI),骨盆倾斜角(pelvic tilt,PT),腰椎前凸角(lumbar lordosis,LL),矢状面垂直轴(sagittal vertical axis,SVA)以及冠状面Cobb's角.并在第一期手术前后由一组资深医师评估、计划固定融合范围.在术前、第二期术后3个月和末次随访时评估患者的Oswestry功能障碍指数(oswestry disability index,ODI)和疼痛视觉模拟评分(visual analogue scale,VAS).结果 本组随访时间24～66个月,平均35.1个月.第一期手术后,患者侧凸Cobb's角较术前明显改善;LL、SVA、PT均较术前明显改善.患者末次随访时腰痛VAS评分、ODI也显著改善.LLIF/OLIF术后需固定节段数量较术前明显减少,有51.5％ 的患者(17/33)经评估可以缩短固定节段.结论 腰椎侧路椎体间融合术可以改善退变性脊柱侧凸的冠状面和矢状面平衡,从而可能缩短固定融合的节段.

目的:初步探究炎症相关分泌蛋白CHI3L1在椎间盘退变（IDD）中的作用及机制。方法:通过收集腰椎间盘突出症患者手术中的椎间盘样本作为退变组,同时收集腰椎外伤患者手术中的椎间盘样本作为对照组（根据Pfirrmann分级进行收集）,通过免疫组化检测两组样本髓核细胞中CHI3L1的表达水平。在体外通过炎症因子IL-1β构建退变模型,利用质粒转染过表达或者siRNA干预CHI3L1的表达水平并检测髓核细胞基质代谢相关基因的表达水平变化。通过不同浓度的CHI3L1重组蛋白干预髓核细胞,并检测其在IL-1β诱导下对髓核退变的影响。利用Transwell实验验证CHI3L1对髓核细胞基质代谢的实际作用。结果:通过免疫组化检测发现CHI3L1主要表达于椎间盘的髓核区域,且正常髓核细胞均有表达,而退变髓核细胞表达显著上调。体外细胞实验显示,过表达CHI3L1后髓核细胞基质合成相关基因ACAN、COL2、CHSY的表达均显著高于对照组（均P＜0.05）,而炎症相关基因MMP1、MMP3、MMP13、ADAMTS4以及ADAMTS5的表达均显著低于对照组（均P＜0.05）。干扰CHI3L1表达后结果出现明显反向变化（均P＜0.05）。通过添加不同量CHI3L1的重组蛋白,炎症刺激下髓核细胞基质合成相关基因的表达随着剂量增加而逐渐上升,但其存在最大效应浓度。同时通过Transwell小室侵袭实验发现,过表达CHI3L1显著抑制了IL-1β致髓核细胞分泌降解细胞外基质因子的能力,使得穿膜细胞显著减少（P＜0.05）,而干扰CHI3L1后则出现相反结果（P＜0.05）。结论:炎症相关基因CHI3L1具有髓核特异性,是在炎症刺激下上调的能够保护髓核细胞抵抗IL-1β的诱导退变作用的分泌性分子,具有保护椎间盘髓核细胞退变的作用。

An ultra-large structure-based virtual screening has discovered iKeap1 as a direct Keap1 inhibitor that can efficiently activate Nrf2 signaling. We here tested its potential effect against hydrogen peroxide (H2O2)-induced oxidative injury in osteoblasts. In primary murine and human osteoblasts, iKeap1 robustly activated Nrf2 signaling at micromole concentrations. iKeap1 disrupted Keap1-Nrf2 association, causing Nrf2 protein stabilization, cytosol accumulation and nuclear translocation in murine and human osteoblasts. The anti-oxidant response elements (ARE) activity and transcription of Nrf2-ARE-dependent genes (including HO1, NQO1 and GCLC) were increased as well. Significantly, iKeap1 pretreatment largely ameliorated H2O2-induced reactive oxygen species production, lipid peroxidation and DNA damage as well as cell apoptosis and programmed necrosis in osteoblasts. Moreover, dexamethasone- and nicotine-induced oxidative injury and apoptosis were alleviated by iKeap1. Importantly, Nrf2 shRNA or CRISPR/Cas9-induced Nrf2 knockout completely abolished iKeap1-induced osteoblast cytoprotection against H2O2. Conversely, CRISPR/Cas9-induced Keap1 knockout induced Nrf2 cascade activation and mimicked iKeap1-induced cytoprotective actions in murine osteoblasts. iKeap1 was ineffective against H2O2 in the Keap1-knockout murine osteoblasts. Collectively, iKeap1 activated Nrf2 signaling cascade to inhibit H2O2-induced oxidative injury and death of osteoblasts.