椎间盘退变动物模型的研究进展

椎间盘退变是腰痛发生的主要原因,严重影响了人们的生活和工作。尽管具体发病机制尚不明确,但近年来其相关动物模型的研究有了很大的进步。造模方法包括结构损伤、应力改变及基因敲除等,本文综述并讨论了这些方法的优缺点和应用方向,以期为后续的研究奠定理论基础。     

压应力对软骨细胞的影响

骨关节炎(osteoarthritis, OA)是一种以关节软骨退变、软骨下骨重塑、骨赘形成、关节内滑膜炎症反应和广泛血管生成为特征的慢性退行性疾病。其发生受遗传、环境、代谢、生物化学和机械应力等诸多因素的共同影响,其中机械应力异常为主要诱因。在机械应力异常导致OA的过程中,软骨组织的稳定状态被打破,软骨细胞作为软骨组织中唯一的细胞也会发生相应的变化。压应力是机械应力的一种,最新研究表明,压应力可对软骨细胞的形态、代谢状态、表型、细胞活性产生影响。因此,该文综述了近年来压应力对软骨细胞影响的相关文献,为OA的机制和治疗有关研究提供理论基础。     

氧化应激介导的NF-κB信号转导通路在椎间盘退变中的作用

椎间盘位于两个椎体之间,在脊柱中发挥着连接、减震和固定作用,其发生退变可以引起一系列椎间盘退变性疾病,是多数脊柱疾病发病的根本原因,探索椎间盘的退变机制是寻找其治疗措施的前提。椎间盘退变机制十分复杂,其最主要的病理基础是椎间盘活性细胞减少以及其引起的细胞外基质合成减少和成分的改变,而NF-κB作为一种普遍存在在真核细胞中的多向性转录因子,通过多种途径在细胞增殖、分化及凋亡方面起着关键的作用,研究表明,抑制NF-κB信号通路可以有效的缓解椎间盘退变;而引起NF-κB信号通路的异常激活的因素很多,其中氧化应激是一个重要的因素,同时研究证实在椎间盘退变中存在着氧化损伤。因此,当年龄、营养、外伤等因素引起的椎间盘细胞中发生氧化应激,进而导致NF-κB信号通路的激活,从而使其转录活性增高,触发凋亡信号,引起髓核细胞的大量凋亡,使其参与到椎间盘退变中。     

细胞衰老与椎间盘退变的相关性研究进展

椎间盘退变(intervertebral disc degeneration,IDD)是导致下腰痛的主要原因之一,严重降低患者生活质量,并给家庭带来沉重的经济负担.细胞衰老是驱动IDD的关键因素,而炎症反应、氧化应激、线粒体功能障碍、端粒缩短、DNA损伤、营养剥夺、机械负荷异常和表观遗传学改变介导了椎间盘细胞的衰老进程...     

NF-κB信号和MAPK通路在椎间盘退变中的研究进展

椎间盘退变涉及诸多因素,其中由细胞外基质分解代谢和合成代谢失衡导致的基质减少发挥了很大的作用,但这些变化的发生还没被全部阐明。由丝裂原活化蛋白激酶（MAPK）和核因子kappaB（NF-κB）通路介导的细胞因子在代谢失衡中发挥重要作用,所以,研究细胞因子产生作用的信号转导通路对深入了解椎间盘退变的原因及为其治疗提供了新的方向。对NF-κB和MAPK信号转导通路及其在椎间盘退变中的作用机制加以综述。     

氧化应激介导的NF-kB 信号转导通路在椎间盘退变中的作用

椎间盘位于两个椎体之间,在脊柱中发挥着连接、减震和固定作用,其发生退变可以引起一系列椎间盘退变性疾病,是多数 脊柱疾病发病的根本原因,探索椎间盘的退变机制是寻找其治疗措施的前提。椎间盘退变机制十分复杂,其最主要的病理基础是 椎间盘活性细胞减少以及其引起的细胞外基质合成减少和成分的改变,而NF-kB 作为一种普遍存在在真核细胞中的多向性转录 因子,通过多种途径在细胞增殖、分化及凋亡方面起着关键的作用,研究表明,抑制NF-kB信号通路可以有效的缓解椎间盘退变; 而引起NF-kB信号通路的异常激活的因素很多,其中氧化应激是一个重要的因素,同时研究证实在椎间盘退变中存在着氧化损 伤。因此,当年龄、营养、外伤等因素引起的椎间盘细胞中发生氧化应激,进而导致NF-资B信号通路的激活,从而使其转录活性增 高,触发凋亡信号,引起髓核细胞的大量凋亡,使其参与到椎间盘退变中。     

Nbn基因神经特异性敲除小鼠海马神经元发育的形态学研究

Nbn基因（又称Nbs1）是DNA断裂损伤修复和端粒长度调控的重要因子,其功能缺失不仅会导致DNA损伤修复异常,也会使端粒难以维持正常的稳定结构,从而影响小鼠中枢神经系统的发育,导致小头畸形、生长障碍、小脑萎缩以及共济失调等。本实验通过观察Nbn基因神经特异性敲除（Nbn-CNS-del）小鼠海马神经元发育的形态学变化,探讨Nbn基因在小鼠海马神经元发育中的作用,     

腰痛相关动物模型的研究进展

腰痛(low back pain,LBP)是影响人类健康的最常见疾病之一,患病率高且治愈率低下。其发病机制尚不清楚,可能与多种因素有关,如椎间盘退变、关节突关节损伤、肌肉筋膜炎症等。建立恰当的动物模型有助于研究和了解LBP的发病机制、探索预防及治疗方法。本文就可诱发腰痛的动物模型研究进展综述如下。     

啮齿类动物糖尿病模型

糖尿病是一类由遗传、环境、免疫等因素引起的、具有明显异质性的急、慢性高血糖及其并发症所组成的综合征。世界范围内大约有两亿多人受到此病困扰,引发了一系列社会经济问题。建立合适的糖尿病动物模型对于研究糖尿病及其并发症的发病机制、治疗和预防等具有重要的作用。既往的糖尿病模型主要包括自发性模型及采用化学、手术、饮食单独或共同诱导型模型。近年来,随着基因工程技术发展,转基因动物、基因敲除动物及组织特异性基因敲除动物被广泛应用于糖尿病研究。本文对目前若干啮齿类动物糖尿病模型的来源、主要特点和应用进行总结。     

线粒体自噬调控椎间盘退变的分子机制研究进展

椎间盘退变是一种常见的慢性退行性关节疾病。椎间盘退变的发病与髓核细胞的功能障碍或丧失密切相关。线粒体作为髓核细胞腺苷三磷酸(adenosine triphosphate, ATP)的主要来源,对维持髓核细胞生存和生理功能至关重要。线粒体自噬是近几年发现的一种重要细胞生理过程,通常被认为是线粒体质量控制的一种主要机制。大量研究显示,线粒体自噬在椎间盘退变的发生和缓解过程中均发挥重要作用。因此,该文通过综述线粒体自噬与椎间盘退变的相关文献,探究sirtuins、Parkin和缺氧诱导因子1α(hypoxia-inducible factor 1-alpha, HIF-1α)等信号分子在线粒体自噬调控椎间盘退变的过程中可能起到的关键作用,总结线粒体自噬对椎间盘退变的具体调控机制,以期为椎间盘退变潜在治疗靶点的相关研究提供参考和依据。     

Emerging role and therapeutic implication of mTOR signalling in intervertebral disc degeneration

Intervertebral disc degeneration (IDD), an important cause of chronic low back pain (LBP), is considered the pathological basis for various spinal degenerative diseases. A series of factors, including inflammatory response, oxidative stress, autophagy, abnormal mechanical stress, nutritional deficiency, and genetics, lead to reduced extracellular matrix (ECM) synthesis by intervertebral disc (IVD) cells and accelerate IDD progression. Mammalian target of rapamycin (mTOR) is an evolutionarily conserved serine/threonine kinase that plays a vital role in diverse degenerative diseases. Recent studies have shown that mTOR signalling is involved in the regulation of autophagy, oxidative stress, inflammatory responses, ECM homeostasis, cellular senescence, and apoptosis in IVD cells. Accordingly, we reviewed the mechanism of mTOR signalling in the pathogenesis of IDD to provide innovative ideas for future research and IDD treatment.     

Enhancing intervertebral disc repair and regeneration through biology: platelet-rich plasma as an alternative strategy

Intervertebral disc degeneration (IDD) is a common orthopedic disease associated with mechanical changes that may result in significant pain. Current treatments for IDD mainly depend on conservative therapies and spinal surgeries that are only able to relieve the symptoms but do not address the cause of the degeneration and even accelerate the degeneration of adjacent segments. This has prompted research to improve our understanding of the biology of intervertebral disc healing and into methods to enhance the regenerative process. Recently, biological therapies, including active substances, gene therapy and tissue engineering based on certain cells, have been attracting more attention in the field of intervertebral disc repair and regeneration. Early selection of suitable biological treatment is an ideal way to prevent or even reverse the progressive trend of IDD. Growth factors have been enjoying more popularity in the field of regeneration of IDD and many have been proved to be effective in reversing the degenerative trend of the intervertebral disc. Identification of these growth factors has led to strategies to deliver platelet-derived factors to the intervertebral disc for regeneration. Platelet-rich plasma (PRP) is the latest technique to be evaluated for promoting intervertebral disc healing. Activation of the PRP leads to the release of growth factors from the α-granules in the platelet cytoplasm. These growth factors have been associated with the initiation of a healing cascade that leads to cellular chemotaxis, angiogenesis, synthesis of collagen matrix, and cell proliferation. This review describes the current understanding of IDD and related biological therapeutic strategies, especially the promising prospects of PRP treatment. Future limitations and perspectives of PRP therapy for IDD are also discussed.     

Disc cell senescence in intervertebral disc degeneration: Causes and molecular pathways

The accumulation of senescent disc cells in degenerative intervertebral disc (IVD) suggests the detrimental roles of cell senescence in the pathogenesis of intervertebral disc degeneration (IDD). Disc cell senescence decreased the number of functional cells in IVD. Moreover, the senescent disc cells were supposed to accelerate the process of IDD via their aberrant paracrine effects by which senescent cells cause the senescence of neighboring cells and enhance the matrix catabolism and inflammation in IVD. Thus, anti-senescence has been proposed as a novel therapeutic target for IDD. However, the development of anti-senescence therapy is based on our understanding of the molecular mechanism of disc cell senescence. In this review, we focused on the molecular mechanism of disc cell senescence, including the causes and various molecular pathways. We found that, during the process of IDD, age-related damages together with degenerative external stimuli activated both p53-p21-Rb and p16-Rb pathways to induce disc cell senescence. Meanwhile, disc cell senescence was regulated by multiple signaling pathways, suggesting the complex regulating network of disc cell senescence. To understand the mechanism of disc cell senescence better contributes to developing the anti-senescence-based therapies for IDD.     

MicroRNA-181a exerts anti-inflammatory effects via inhibition of the ERK pathway in mice with intervertebral disc degeneration

Enzymatic decomposition of extracellular matrix and possibly local inflammation may cause intervertebral disc degeneration (IDD). MicroRNAs have been reported to correlate with the development of IDD. In this experiment, we aim at finding out the role of miR-181a in the inflammation of IDD and the underlying mechanism. The targeting relationship between miR-181a and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) was verified. Following the establishment of IDD mouse models, disc height index (DHI) and the change of DHI (%DHI) were measured. The functional role of miR-181a in IDD was determined using ectopic expression and depletion and reporter assay experiments. Expression of miR-181a, TRAIL, extracellular signal-regulated kinase (ERK) pathway-related genes and inflammatory factors was evaluated. Also, the expression of collagen I and collagen II was observed. miR-181a directly targeted TRAIL. IDD mice exhibited significant degeneration of the intervertebral disc. miR-181a was downregulated while TRAIL was upregulated in mice with IDD. miR-181a upregulation and the ERK pathway inhibition could reduce expression of TRAIL, ERK pathway-related genes, inflammatory factors, and collagen I, but promote collagen II expression. Our results reveal that upregulation of miR-181a protects against inflammatory response by inactivating the ERK pathway via suppression of TRAIL in IDD mice. These results point to miR-181a as a potential therapeutic target for the clinical management of IDD.     

BMP13 Prevents the Effects of Annular Injury in an Ovine Model

Chronic back pain is a global health problem affecting millions of people worldwide and carries significant economic and social morbidities. Intervertebral disc damage and degeneration is a major cause of back pain, characterised by histological and biochemical changes that have been well documented in animal models. Recently there has been intense interest in early intervention in disc degeneration using growth factors or stem cell transplantation, to replenish the diseased tissues. Bone Morphogenetic Proteins (BMPs) have been approved for clinical use in augmenting spinal fusions, and may represent candidate molecules for intervertebral disc regeneration.     

Down‐regulation of insulin‐like growth factor binding protein 5 is involved in intervertebral disc degeneration via the ERK signalling pathway

It is obvious that epigenetic processes influence the evolution of intervertebral disc degeneration (IDD). However, its molecular mechanisms are poorly understood. Therefore, we tested the hypothesis that IGFBP5, a potential regulator of IDD, modulates IDD via the ERK signalling pathway. We showed that IGFBP5 mRNA was significantly down‐regulated in degenerative nucleus pulposus (NP) tissues. IGFBP5 was shown to significantly promote NP cell proliferation and inhibit apoptosis in vitro, which was confirmed by MTT, flow cytometry and colony formation assays. Furthermore, IGFBP5 was shown to exert its effects by inhibiting the ERK signalling pathway. The effects induced by IGFBP5 overexpression on NP cells were similar to those induced by treatment with an ERK pathway inhibitor (PD98059). Moreover, qRT‐PCR and Western blot analyses were performed to examine the levels of apoptosis‐related factors, including Bax, caspase‐3 and Bcl2. The silencing of IGFBP5 up‐regulated the levels of Bax and caspase‐3 and down‐regulated the level of Bcl2, thereby contributing to the development of human IDD. Furthermore, these results were confirmed in vivo using an IDD rat model, which showed that the induction of Igfbp5 mRNA expression abrogated the effects of IGFBP5 silencing on intervertebral discs. Overall, our findings elucidate the role of IGFBP5 in the pathogenesis of IDD and provide a potential novel therapeutic target for IDD.     

Intervertebral disc viscoelastic parameters and residual mechanics spatially quantified using a hybrid confined/in situ indentation method

With advancing age, injury, musculoskeletal pathology or a combination of these, a degenerative cascade of biomechanical, biochemical, and nutritional alterations diminish the intervertebral discs' ability to maintain its structure and function. While the biomechanics of isolated disc tissues has been investigated across this degenerative spectrum, none have attempted to retain the in situ disc-endplate morphology during compressive tissue characterization. The objective of this study was to spatially quantify the viscoelastic parameters of the intervertebral disc throughout degeneration, including the as yet unreported residual stress/strain. This required the development of a hybrid confined/in situ indentation methodology, which preserves the disc structural morphology. At four locations of the disc (anterior-AF, right and left lateral AF, and NP) stress-relaxation tests were performed using the hybrid confined/in situ indentation method, which utilizes the vertebral endplate as the porous indenter tip. This method allows the endplate to remain interwoven with the disc tissue, retaining its native orientation. Healthy disc tissue exhibited significantly higher residual stress values compared to both moderate and severe degeneration in all locations (p<0.0156). Furthermore, the equilibrium stress at 15% strain (stress relaxation) was significantly diminished with advancing disc degeneration (p<0.0241). The equilibrium viscoelastic parameters show healthy discs encounter higher forces at the same strain level, and are able to maintain this force, where degenerated discs are unable to maintain this force throughout time. This morphology-conserved method provides insight into the spatial compressive mechanical properties of the intervertebral disc across the degeneration spectrum and will aid in modeling these tissue changes.     

What have we learned from finite element model studies of lumbar intervertebral discs in the past four decades?

Finite element analysis is a powerful tool routinely used to study complex biological systems. For the last four decades, the lumbar intervertebral disc has been the focus of many such investigations. To understand the disc functional biomechanics, a precise knowledge of the disc mechanical, structural and biochemical environments at the microscopic and macroscopic levels is essential. In response to this need, finite element model studies have proven themselves as reliable and robust tools when combined with in vitro and in vivo measurements.     

Therapeutic potential of melatonin in the intervertebral disc degeneration through inhibiting the ferroptosis of nucleus pulpous cells

Ferroptosis, a novel type of cell death mediated by the iron-dependent lipid peroxidation, contributes to the pathogenesis of the intervertebral disc degeneration (IDD). Increasing evidence demonstrated that melatonin (MLT) displayed the therapeutic potential to prevent the development of IDD. Current mechanistic study aims to explore whether the downregulation of ferroptosis contributes to the therapeutic capability of MLT in IDD. Current studies demonstrated that conditioned medium (CM) from the lipopolysaccharide (LPS)-stimulated macrophages caused a series of changes about IDD, including increased intracellular oxidative stress (increased reactive oxygen species and malondialdehyde levels, but decreased glutathione levels), upregulated expression of inflammation-associated factors (IL-1β, COX-2 and iNOS), increased expression of key matrix catabolic molecules (MMP-13, ADAMTS4 and ADAMTS5), reduced the expression of major matrix anabolic molecules (COL2A1 and ACAN), and increased ferroptosis (downregulated GPX4 and SLC7A11 levels, but upregulated ACSL4 and LPCAT3 levels) in nucleus pulposus (NP) cells. MLT could alleviate CM-induced NP cell injury in a dose-dependent manner. Moreover, the data substantiated that intercellular iron overload was involved in CM-induced ferroptosis in NP cells, and MLT treatment alleviated intercellular iron overload and protected NP cells against ferroptosis, and those protective effects of MLT in NP cells further attenuated with erastin and enhanced with ferrostatin-1(Fer-1). This study demonstrated that CM from the LPS-stimulated RAW264.7 macrophages promoted the NP cell injury. MLT alleviated the CM-induced NP cell injury partly through inhibiting ferroptosis. The findings support the role of ferroptosis in the pathogenesis of IDD, and suggest that MLT may serve as a potential therapeutic approach for clinical treatment of IDD.     

MicroRNA in intervertebral disc degeneration

Aetiology of intervertebral disc degeneration (IDD) is complex, with genetic, developmental, biochemical and biomechanical factors contributing to the disease process. It is becoming obvious that epigenetic processes influence evolution of IDD as strongly as the genetic background. Deregulated phenotypes of nucleus pulposus cells, including differentiation, migration, proliferation and apoptosis, are involved in all stages of progression of human IDD. Non‐coding RNAs, including microRNAs, have recently been recognized as important regulators of gene expression. Research into roles of microRNAs in IDD has been very active over the past 5 years. Our review summarizes current research enlightenment towards understanding roles of microRNAs in regulating nucleus pulposus cell functions in IDD. These exciting findings support the notion that specific modulation of microRNAs may represent an attractive approach for management of IDD.