退变腰椎间盘髓核组织中NDRG2表达的变化及其意义

[目的]研究退变的腰椎间盘髓核组织中NDRG2表达的变化及其在椎间盘退变中的作用。[方法]收集腰椎间盘标本47例,根据Pfirrmann分级分为Ⅰ~Ⅴ级。采用免疫组织化学染色、实时-定量PCR(RT-PCR)和Western-Blotting技术从细胞、蛋白和基因水平分别检测腰椎间盘髓核组织中NDRG2的表达,并与Pfirrmann分级进行相关性分析;通过RT-PCR分析P53 mRNA的表达;采用衰老相关的β-半乳糖苷酶(SA-β-gal)实验检测腰椎间盘髓核组织中衰老髓核细胞比例,并与NDRG2表达量进行相关性分析。[结果]免疫组织化学染色、RT-PCR及Western-Blotting检测示NDRG2表达随椎间盘退变程度加重而增加,且与Pfirrmann分级呈正相关;P53 mRNA在腰椎间盘髓核组织中的相对表达随着椎间盘退变程度加重而增加,且与NDRG2的表达量呈正相关。SA-β-gal阳性细胞比例在椎间盘髓核组织中随退变程度加重而增加,并且与NDRG2阳性细胞比例呈正相关。[结论]NDRG2参与了腰椎间盘退变的病理过程,并且可能通过介导腰椎间盘髓核细胞衰老对椎间盘退变起促进作用。     

兔退变椎间盘中髓核细胞凋亡与BNIP3基因表达的意义

目的髓核细胞凋亡可能与髓核组织代谢障碍产生缺氧,导致BNIP3基因表达有关。通过观察兔退变椎间盘中髓核组织的细胞密度、细胞凋亡率及BNIP3的表达,为进一步了解髓核细胞凋亡机制提供实验依据。方法健康3月龄雄性新西兰大白兔30只,体重(2.3±0.2)kg,随机分为实验组(n=20)及对照组(n=10)。实验组大白兔采用针刺L3、4、L4、5及L5、6椎间盘制备椎间盘退变模型;对照组仅暴露椎间盘后缝合。术后4、8周通过MRI检查评价椎间盘退变情况,采用组织学观察和TUNEL法检查椎间盘髓核组织中凋亡细胞,用免疫组织化学染色法检测兔椎间盘髓核细胞BNIP3的表达。结果 MRI检查示实验组术后4、8周椎间盘髓核信号强度呈逐渐降低趋势。根据Pfirrmann分级标准,实验组术后4、8周椎间盘退变分级比较,差异均有统计学意义(P0.05)。组织学观察及TUNEL检查示:对照组椎间盘髓核中细胞密度高,可见少量散在的凋亡细胞;实验组术后4、8周时椎间盘髓核组织内细胞密度逐渐降低,可见较多凋亡细胞。各时间点实验组细胞密度、TUNEL染色阳性细胞率与对照组比较,以及实验组各指标两时间点间比较,差异均有统计学意义(P0.05)。对照组椎间盘髓核组织细胞中无BNIP3表达;实验组术后4、8周椎间盘髓核组织细胞中BNIP3表达逐渐增多,BNIP3染色阳性细胞率分别为13.45%±1.16%、32.00%±1.82%,BNIP3灰度值分别为194.32±4.65、117.54±2.11,各时间点间比较差异均有统计学意义(P0.05)。结论椎间盘退变与髓核组织中细胞密度下降有关,细胞凋亡是椎间盘髓核细胞减少的原因之一,BNIP3参与了椎间盘髓核细胞凋亡。     

LOX在人体退变椎间盘髓核组织中的表达及临床意义

目的探讨赖氨酰氧化酶(LOX)在人体退变椎间盘髓核组织中的表达及其临床意义。方法选取自2018-01—2018-12诊治的22例腰椎间盘突出症患者作为观察组,将4例同期突发创伤导致腰椎椎体骨折行手术摘除椎间盘的年轻患者作为对照组。按照椎间盘Pfirrmann分级分组,对照组为Ⅰ级(A组);观察组细分为4组,B组为Ⅱ级,C组为Ⅲ级,D组为Ⅳ级,E组为Ⅴ级。取各组椎间盘髓核组织行免疫组化、Western Blot、PT-PCR检测。结果观察组髓核细胞数量及细胞外基质成分明显少于对照组。LOX在髓核细胞中的阳性表达率与Pfirrmann分级、年龄呈负相关。各组LOX蛋白表达量:A组2.69±0.24,B组2.24±0.32,C组1.34±0.19,D组1.30±0.32,E组1.01±0.12。各组LOXmRNA表达量:A组1.06±0.03,B组0.83±0.07,C组0.71±0.09,D组0.53±0.09,E组0.27±0.05。随着椎间盘退变程度加重,髓核组织LOX蛋白表达水平、mRNA表达水平呈逐渐降低趋势。结论 LOX的蛋白及mRNA表达水平随着人体椎间盘退变程度加重而降低,LOX可能参与了人体椎间盘髓核组织退变的发生与发展过程。     

缺氧和营养缺乏对软骨终板干细胞凋亡的影响及相关机制

目的 :观察缺氧和营养缺乏对软骨终板干细胞(cartilage endplate-derived stem cells,CESCs)凋亡的影响,探讨B细胞淋巴瘤/白血病-2/腺病毒E1B 19-k Da结合蛋白3(Bcl-2/adenovirus E1B 19-k Da-interacting protein 3,BNIP3)信号通路在其中的作用。方法 :从临床获取退变椎间盘软骨终板标本,分离培养软骨终板细胞,使用琼脂糖筛选获得CESCs并进行干细胞标志物鉴定,将第三代细胞分别在常氧/完全培养基(对照组)与缺氧和营养缺乏(实验组)条件下培养48h,通过流式细胞术检测细胞凋亡率,CCK-8法检测细胞活性,Western Blot检测BNIP3、Bcl-2关联x蛋白(Bax)、Bcl-2关联k蛋白(Bak)和低氧诱导因子1α(HIF-1α)蛋白表达水平。使用BNIP3小干扰RNA(siRNA)干扰CESCs中BNIP3基因,同时设置阴性干扰对照组(Scramble siRNA),同前分组处理后再次检测细胞凋亡率、细胞活性及BNIP3、Bax、Bak蛋白的表达水平。结果:对5例标本获得的CESCs进行了干细胞标志物鉴定,其中细胞表面粘附分子44(CD44)、CD73、CD90和CD105为阳性,CD34、CD45、CD11b、CD19和HLA-DR为阴性,提示CESCs具有干细胞特性。实验组细胞凋亡率为(29.12±0.65)%显著高于对照组的(14.87±2.03)%(P0.05);实验组的细胞增殖活性明显降低,为对照组的56.18%(P0.05)。与对照组相比,实验组BNIP3、Bax、Bak蛋白的表达均显著上调(P0.05)。使用BNIP3 siRNA干扰后,缺氧和营养缺乏引起的细胞凋亡增加和细胞增殖活力下降均被明显抑制;同时,缺氧和营养缺乏导致CESCs中BNIP3、Bax和Bak的蛋白表达升高也被显著逆转(P0.05)。结论:缺氧和营养缺乏能够诱导CESCs发生凋亡,此过程可能是通过上调BNIP3、Bax和Bak蛋白表达而发挥作用的。     

间隙连接蛋白37在腰椎椎间盘突出症炎性反应中的意义

目的探索间隙连接蛋白37(CX37)在腰椎椎间盘突出症炎性反应中的意义。方法观察10例腰椎椎间盘突出症患者(观察组)及8例腰椎爆裂骨折患者(椎间盘部分损坏无明显退变,对照组)CT与MRI表现差异,采用Pfirrmann分级评估椎间盘退行性变程度。利用PCR方法检测患者椎间盘组织中CX37、白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)的表达,并分析CX37与IL-6、TNF-α表达的相关性。结果对照组影像学资料主要表现为不同程度的椎间盘损伤,观察组主要表现为椎间盘突出、髓核脱垂、髓核突出。对照组Pfirrmann分级Ⅰ级6例,Ⅱ级2例;观察组Ⅲ级3例,Ⅳ级3例,Ⅴ级4例。PCR结果显示观察组CX37、IL-6和TNF-α的m RNA表达水平均高于对照组,差异有统计学意义(P 0.05)。Pearson相关性分析显示,炎症因子IL-6,TNF-α的表达与CX37均呈正相关。结论腰椎椎间盘突出症患者髓核中CX37表达显著高于无椎间盘退行性变病例,且与炎症因子IL-6,TNF-α的表达均呈正相关,CX37可能通过调控炎症因子的表达参与椎间盘突出症的发生、发展。     

NF-κB信号通路的激活与椎间盘退变的关系

[目的]探讨NF-κB信号通路在椎间盘退变中的激活机制及其作用。[方法]按照Pfirrmann椎间盘退变分级系统对患者进行分级,分别收集2012~2013年上海市第一人民医院手术患者的正常和退变椎间盘组织(退变102例,正常9例),生化检测试剂盒测定椎间盘组织中丙二醛(MDA)、髓过氧化物酶(MPO)含量;凝胶迁移试验(EMSA)检测细胞核内NF-κB蛋白结合活性;RT-PCR和Western blotting检测凋亡相关分子CHOP和Caspase-3表达。[结果]椎间盘退变组织中MDA、MPO水平较正常对照组明显增加;EMSA显示髓核细胞核中NF-κB活性增高;RT-PCR和Western blotting结果显示椎间盘退变组织中凋亡相关分子CHOP和Caspase-3水平明显增高。[结论]髓核细胞受氧化应激作用后可通过激活NF-κB通路导致细胞凋亡从而在椎间盘退变中发挥作用。     

1-磷酸鞘氨醇受体在不同退变程度髓核组织中的表达变化

目的 :比较不同退变程度人椎间盘髓核组织中3种1-磷酸鞘氨醇受体(S1PR1/2/3)表达水平的差异,探讨椎间盘中S1PR表达水平与椎间盘退变的关系。方法:收集腰椎间盘退行性病变患者手术切除的椎间盘组织,其中轻度退变(Pfirrmann分级Ⅳ级)22例,严重退变(Pfirrmann分级Ⅴ级)14例;同时取6例无椎间盘退变患者(单纯腰椎椎体骨折,Pfirrmann分级Ⅱ级)手术切除的椎间盘组织作为对照组;通过HE染色以及Saf-O染色观察不同退变程度椎间盘的组织学变化,免疫组化检测不同退变程度组织中的S1PR表达水平;Ⅱ型胶原酶消化分离提取原代髓核细胞,通过Real-time PCR、Western-bolt检测不同退变程度椎间盘髓核细胞中S1PR的表达水平,并通过细胞免疫化学方法对S1PR进行定位。结果:HE染色及Saf-O染色结果显示退变椎间盘的纤维环出现破损,髓核细胞形成明显的集落,细胞外基质减少。免疫组化结果显示正常和轻度退变的髓核组织中3种受体(S1PR1/2/3)都有表达,严重退变的组织中表达极弱;Real-time PCR结果显示对照组髓核细胞中S1PR1/2/3的m RNA表达水平分别是严重退变组的5.34±0.52倍、7.25±0.04倍、1.92±0.06倍,轻度退变组S1PR1/2/3的m RNA表达水平分别是严重退变组的4.35±2.45倍、4.96±3.44倍、2.19±0.82倍;Western-blot发现对照组和轻度退变组髓核细胞中S1PR1/2/3均有表达,严重退变组表达水平较低;免疫细胞化学显示S1PR主要集中在髓核细胞的细胞质和细胞膜上。结论:髓核组织中主要表达S1PR1/2/3,在严重退变的髓核组织和细胞中其表达水平明显下降,S1P及其受体可能参与椎间盘髓核组织的退变过程。     

复方丹参注射液对体外循环后大鼠肺组织Bcl-2和Bax表达的影响

目的探讨复方丹参注射液对体外循环（CPB）后大鼠肺组织凋亡调控基因Bcl-2和Bax表达的影响。方法成年健康雄性SD大鼠24只,年龄12～16周龄,体重400～450 g,随机分为3组（n=8）：对照组、CPB组和丹参组。对照组行假手术,CPB组和丹参组建立体外循环,丹参组在停机前5 min经储血器加入复方丹参注射液1 ml/kg。CPB结束后60 min取肺组织提取总RNA,用RT-PCR方法测定凋亡调控基因Bcl-2、Bax的mRNA表达。取肺组织用多聚甲醛固定,制作石蜡切片,用免疫组织化学方法测定肺组织中Bcl-2、Bax的蛋白表达。结果与对照组相比,CPB组和丹参组肺组织Bcl-2和Bax的mRNA和蛋白表达均增加（P＜0．05或0．01）,CPB组Bax/Bcl-2比值升高（P＜0．05）。与CPB组相比,丹参组肺组织Bax的mRNA表达及Bax/Bcl-2比值均降低（P＜0．05）,肺组织Bcl-2蛋白表达增高,Bax蛋白表达降低（P＜0．01）。结论体外循环可上调凋亡调控基因的表达,复方丹参注射液能下调促凋亡基因Bax的表达,抑制大鼠肺组织的细胞凋亡因而可减轻肺损伤。     

营养剥夺诱导髓核细胞Bcl-2/腺病毒干扰蛋白3表达及线粒体转位的实验研究

目的通过营养剥夺模拟体内髓核细胞退变微环境,检测Bcl-2/腺病毒干扰蛋白3（Bcl-2/adenovirusE1B 19-kDa-interacting protein 3,BNIP3）表达及线粒体转位情况,为进一步探索髓核细胞退变死亡机制提供实验依据。方法成年清洁级SD大鼠2只,雌雄不限,体重150～200 g。体外分离获取鼠尾椎问盘髓核细胞,将传代后细胞分别置入正常环境（对照组:L-DMEM培养基、10%FBS、21%O₂）和营养剥夺环境（实验组:DMEM无糖无血清培养基、1%O₂）培养24、48、72 h后,实时荧光定量PCR、细胞免疫荧光染色及Western blot检测BNIP3基因及蛋白表达,流式细胞仪检测凋亡率及线粒体膜电位。结果实时荧光定量PCR、细胞免疫荧光染色及Western blot检测显示对照组细胞低表达BNIP3;实验组随培养时间延长,BNIP3表达呈上升趋势,且BNIP3与线粒体相结合;除培养后24 h实验组BNIP3基因表达与对照组比较差异无统计学意义（P>0.05）外,其余各时间点实验组BNIP3基因及蛋白表达与对照组比较差异均有统计学意义（P<0.05）。流式细胞仪检测显示,对照组细胞凋亡率较低,且细胞保持较高的线粒体膜电位;而实验组随培养时间延长细胞凋亡率增加、线粒体膜电位降低,与对照组比较差异均有统计学意义（P<0.05）。结论营养剥夺可能通过诱导BNIP3表达增加并结合线粒体导致线粒体功能障碍,最终导致髓核细胞死亡。     

低频超声微泡增强紫杉醇诱导三阴性乳腺癌细胞自噬的作用及机制

目的 探讨低频超声微泡增强紫杉醇诱导三阴性乳腺癌细胞自噬的作用及机制。方法 将MDA-MB-468细胞分为对照组(不进行处理)、紫杉醇组(6μg/ml紫杉醇)、低频超声组(低频超声+6μg/ml紫杉醇)和低频超声微泡组(低频超声+6μg/ml紫杉醇+微泡),检测各组MDA-MB-468细胞增殖情况,凋亡情况,自噬情况,Bcl-2、Bax、Beclin1、LC3Ⅰ、LC3Ⅱ蛋白表达情况。结果 与0μg/ml相比,1、3、6、12、24μg/ml紫杉醇处理下MDA-MB-468细胞增殖抑制率均升高(P 0. 05)。与对照组相比,紫杉醇组MDA-MB-468细胞增殖抑制率、凋亡率、细胞中Bax、Beclin1、LC3Ⅱ蛋白表达水平升高(P 0. 05),细胞中绿色点状物明显增多,细胞中Bcl-2、LC3Ⅰ蛋白表达水平降低(P 0. 05);与紫杉醇组相比,低频超声组MDA-MB-468细胞增殖抑制率、凋亡率、细胞中Bax、Beclin1、LC3Ⅱ蛋白表达水平升高(P 0. 05),细胞中绿色点状物明显增多,细胞中Bcl-2、LC3Ⅰ蛋白表达水平降低(P 0. 05);与低频超声组相比,低频超声微泡组MDA-MB-468细胞增殖抑制率、凋亡率、细胞中Bax、Beclin1、LC3Ⅱ蛋白表达水平升高(P 0. 05),细胞中绿色点状物明显增多,Bcl-2、LC3Ⅰ蛋白表达水平降低(P 0. 05)。结论 低频超声微泡可通过上调Bax、Beclin1、LC3Ⅱ蛋白表达及下调Bcl-2、LC3Ⅰ蛋白表达增强紫杉醇诱导三阴性乳腺癌细胞的凋亡、自噬反应。     

腰椎椎间隙高度与上位椎体高度的比值与椎间盘退行性变Pfirrmann分级的相关性

目的 探讨腰椎椎间隙高度与上位椎体高度的比值与椎间盘退行性变程度之间的关系,为腰椎椎间盘退行性疾病的诊断和治疗提供客观准确的依据。方法 回顾性分析2019年1月—2019年6月来本院就诊的61例腰椎椎间盘退行性变患者临床资料。在腰椎侧位X线片上测量腰椎椎间隙及相应上位椎体的高度,并计算椎间隙高度与上位椎体高度的比值;在腰椎矢状位MRI上评估腰椎椎间盘退行性变Pfirrmann分级;比较不同Pfirrmann分级椎间盘的椎间隙高度与上位椎体高度比值的差异,并采用Spearman相关分析研究椎间隙高度与上位椎体高度比值与相应节段椎间盘Pfirrmann分级之间的相关性。结果 除L₁/L₂节段,其余各节段椎间隙高度与上位椎体高度比值均随着Pfirrmann分级增加而逐渐减小,差异均有统计学意义（P < 0.05）。相同Pfirrmann分级的不同节段椎间盘之间椎间隙高度与上位椎体高度比值差异无统计学意义（P > 0.05）。Spearman相关分析结果显示,L₂/L₃、L₃/L₄、L₄/L₅、L₅/S₁节段Pfirrmann分级与椎间隙高度与上位椎体高度比值呈负相关（r =-0.568,P < 0.05）。结论 临床上测量L₂/L₃、L₃/L₄、L₄/L₅、L₅/S₁节段椎间隙高度与上位椎体高度比值对腰椎椎间盘退行性疾病的诊断可能具有重要意义。     

Therapeutic effect of co-culture of rat bone marrow mesenchymal stem cells and degenerated nucleus pulposus cells on intervertebral disc degeneration

BackgroundAfter non-contact co-culture of bone marrow mesenchymal stem cells (BMSCs) with nucleus pulposus cells (NPCs), exosomes secreted by BMSCs were able to ameliorate the degree of disc degeneration. The reason for this is, at least in part, that exosomes from BMSCs achieve by affecting the level of autophagy in NPCs, while the components in exosomes are diverse and their specific mechanism of action is still unclear.PurposeHere, we aimed to explore the therapeutic effect of co-culture of BMSCs and NPCs on NPCs and explore its specific mechanism of action.Study design/SettingIn vitro study.MethodsRat NPCs and BMSCs were isolated and cultured in vitro. The serum deprivation experiment (using oxygen, glucose, and serum deprivation [OGD]) simulates the pathological state of low blood supply of the intervertebral disc in vivo. We used apoptotic cell staining and flow cytometry to study the effect of BMSCs on the apoptosis rate of rat NPCs, and the apoptotic proteins active-caspase-3, active-caspase-9, autophagy marker proteins LC3 and Beclin 1 were further detected using Western blot analysis. The expression levels of the pro-apoptotic protein Bax and the apoptosis-inhibiting protein Bcl2 were measured. The differentially expressed miRNAs were screened in a gene expression profiling chip. Then qRT-PCR was used to detect the effect of different treatment methods on miR-155 expression. The effect of anti-miR-155 antibodies on autophagy was studied by flow cytometry and transmission electron microscopy. A luciferase reporter assay was used to study the direct interaction between miR-155 and BACH1 mRNA, which was analyzed by TargetScan software, and the results were verified by Western blotting.ResultsCompared with the OGD group, the expression level of miR-155 and the NPC autophagy level significantly increased; the HO-1 protein expression increased; and the Bach1 protein expression, degeneration index, and apoptosis index all significantly decreased in the co-culture group. After BMSCs transfected with anti-miR-155 were co-cultured with NPCs, the miR-155 expression in the cells was significantly reduced, the HO-1 protein expression and the level of cell autophagy was reduced. However, Bach1 protein expression, NPC degeneration index, and apoptosis index increased. After being inhibited by the autophagy inhibitor wortmannin, the cell degeneration index and apoptosis rate significantly improved.ConclusionIn the OGD model, BMSCs can significantly increase the viability, the level of autophagy, and reduce the level of apoptosis in rat NPCs. BMSC exosomes increase miR-155 expression in NPCs, which targets Bach1 and in turn upregulates HO-1 expression, activates autophagy in NPCs, inhibits the apoptosis level, and improves intervertebral disc degeneration.Clinical SignificanceOur experiment shows that it is maybe feasible to treat disc degeneration with drugs. At the same time, compared with BMSC injection method of treatment, side effects of drug therapy are smaller, and can be controlled, it also provides a new way for intervertebral disc degeneration drug treatment.     

Bone morphogenic protein-2 signaling in human disc degeneration and correlation to the Pfirrmann MRI grading system

BACKGROUND CONTEXTBack and neck pain secondary to disc degeneration is a major public health burden. There is a need for therapeutic treatments to restore intervertebral disc (IVD) composition and function.PURPOSETo quantify ALK3, BMP-2, pSMAD1/5/8 and MMP-13 expression in IVD specimens collected from patients undergoing surgery for disc degeneration, to correlate ALK3, BMP-2, pSMAD1/5/8 and MMP-13 expression in IVD specimens to the 5-level Pfirrmann MRI grading system, and to compare ALK3, BMP-2, pSMAD1/5/8 and MMP-13 expression between cervical and lumbar degenerative disc specimens.STUDY DESIGNAn immunohistochemical study assessing ALK3, BMP-2, pSMAD1/5/8, and MMP-13 expression levels in human control and degenerative IVD specimens.METHODSHuman IVD specimens were collected from surgical patients who underwent discectomy and interbody fusion at our institution between 1/2015 and 8/2017. Each patient underwent MRI prior to surgery. The degree of disc degeneration was measured according to the 5-level Pfirrmann MRI grading system. Patients were categorized into either the 1) control group (Pfirrmann grades I-II) or 2) degenerative group (Pfirrmann grades III-V). Histology slides of the collected IVD specimens were prepared and immunohistochemical staining was performed to assess ALK3, BMP-2, pSMAD1/5/8, and MMP-13 expression levels in the control and degenerative specimens. Expression levels were also correlated to the Pfirrmann criteria. Lastly, the degenerative specimens were stratified according to their vertebral level and expression levels between the degenerative lumbar and cervical discs were compared.RESULTSFifty-two patients were enrolled; however, 2 control and 2 degenerative patients were excluded due to incomplete data sets. Of the remaining 48 patients, there were 12 control and 36 degenerative specimens. Degenerative specimens had increased expression levels of BMP-2 (p=.0006) and pSMAD1/5/8 (p<.0001). Pfirrmann grade 3 (p=.0365) and grade 4 (p=.0008) discs had significantly higher BMP-2 expression as compared to grade 2 discs. Pfirrmann grade 4 discs had higher pSMAD1/5/8 expression as compared to grade 2 discs (p<.0001). There were no differences in ALK3 or MMP-13 expression between the control and degenerative discs (p>.05). Stratifying the degenerative specimens according to their vertebral level showed no significant differences in expression levels between the lumbar and cervical discs (p>.05).CONCLUSIONSBMP-2 and pSMAD1/5/8 signaling activity was significantly upregulated in the human degenerative specimens, while ALK3 and MMP-13 expression were not significantly changed. The expression levels of BMP-2 and pSMAD1/5/8 correlate positively with the degree of disc degeneration measured according to the Pfirrmann MRI grading system.CLINICAL SIGNIFICANCEBMP-SMAD signaling represents a promising therapeutic target to restore IVD composition and function in the setting of disc degeneration.     

Assessment of apparent diffusion coefficient in lumbar intervertebral disc degeneration

Objective

The aim of this study was to determine the relationship between the apparent diffusion coefficient (ADC) and lumbar intervertebral disc degeneration using diffusion-weighted magnetic resonance imaging (DWI).

Materials and methods

Using a 3 T magnetic resonance scanner, DWI of the lumbar spine was assessed in 109 patients, with a total of 545 lumbar discs analyzed. Apparent diffusion coefficient values were recorded for each disc, and all discs were visually graded by two independent observers using Pfirrmann’s grading system. Apparent diffusion coefficient values of disc were tested by correlation with qualitative clinical grading of degeneration severity, patient age, and sex. Correlations were investigated using Pearson’s and Spearman’s rank correlation analysis, and multiple regression analysis.

Results

Intervertebral disc degeneration was negatively correlated with ADC values of all levels (Spearman’s correlation coefficient ranged from ?0.381 to ?0.604, p < 0.001). There was a significant negative association between age and ADC values at all spinal levels (Pearson’s correlation coefficient ranged from ?0.353 to ?0.650, p < 0.001). When stepwise regression models were analyzed, both disc degeneration and age remained negatively associated with ADC values at each lumbar level (standardized coefficients ranged from ?0.231 to ?0.505, p < 0.01 and standardized coefficients ranged from ?0.179 to ?0.523, p < 0.05 respectively).

Conclusion

Apparent diffusion coefficient values obtained using DWI can assess lumbar intervertebral disc degeneration, and the ADC values were negatively correlated with the degree of disc degeneration.     

Disc degeneration contributes to the denser bone in the subendplate but not in the vertebral body in patients with lumbar spinal stenosis or disc herniation

BACKGROUND CONTEXTIt is commonly believed that decreased bone quality would lead to endplate degeneration and arthritic changes in the facet joints, and thus accelerated disc degeneration (DD). However, some more detailed studies of vertebral bone structure have found that bone mineral density (BMD) in the vertebral body is increased rather than decreased in moderate or greater disc degeneration. The relationship between BMD and DD still needs further study. MRI-based vertebral bone quality scores have been shown to be effective in reflecting BMD, rendering a new way to evaluate the changes of vertebral body bone with DD using MRI alone.PURPOSETo evaluate MRI-based vertebral bone quality and Pfirrmann grades in patients with lumbar spinal stenosis or disc herniation, and to identify if DD is associated with denser bone around the endplate.STUDY DESIGN/SETTINGA single-center, retrospective cohort study.PATIENT SAMPLEA total of 130 patients with lumbar disc herniation and lumbar spinal stenosis from January 2019 to November 2020 who had a complete dual-energy X-ray absorptiometry scan and noncontrast lumbosacral spine MRI data.OUTCOME MEASURESThe vertebral bone quality score (VBQ) and sub-endplate bone quality score (EBQ) was calculated as a ratio of the signal intensity of the vertebral bodies and sub-endplate regions to the signal intensity of the cerebrospinal fluid at L3 on the mid-sagittal T1-weighted MRI images, respectively. The Pfirrmann grades of the lumbar discs were assessed as well.METHODSThe age, gender, body mass index, and T-score of the lumbar spine of the patients were collected. The degeneration grades of the lumbar discs were evaluated according to the Pfirrmann classification. VBQ and EBQ were measured through T1-weighted lumbar MRI. The VBQ and EBQ scores were compared between cranial and caudal sides. The correlation between MRI-based bone quality and DD was calculated. A linear regression model was used to examine the association between DD and adjacent EBQ and VBQ.RESULTSThis study included 569 lumbar segments from 130 inpatients. Cranial and caudal EBQ decreased with the increase of the Pfirrmann grade. The discs with Pfirrmann grade 5 had significantly lower caudal EBQ than the discs with Pfirrmann grades 2, 3, and 4. In the osteoporosis patients, the Pfirrmann grades negatively correlated both with the cranial EBQ and caudal EBQ. Pfirrmann grade greater than 4 was an independent contributor to the cranial EBQ, whereas greater than 3 was an independent contributor to the caudal EBQ.CONCLUSIONSDisc degeneration grades correlated with the EBQ but not with the VBQ. In patients with lumbar spinal stenosis or disc herniation, DD contributes to the denser bone in the sub-endplate, but not in the whole vertebral body.     

Analysis of the influence of species,intervertebral disc height and Pfirrmann classification on failure load of an injured disc using a novel disc herniation model

Background ContextAnnular repair devices offer a solution to recurrent disc herniations by closing an annular defect and lowering the risk of reherniation. Given the significant risk of neurologic injury from device failure it is imperative that a reliable preclinical model exists to demonstrate a high load to failure for the disc repair devices.PurposeTo establish a preclinical model for disc herniation and demonstrate how changes in species, intervertebral disc height and Pfirrmann classification impacts failure load on an injured disc. We hypothesized that: (1) The force required for disc herniation would be variable across disc morphologies and species, and (2) for human discs the force to herniation would inversely correlate with the degree of disc degeneration.Study designAnimal and human cadaveric biomechanical model of disc herniation.MethodsWe tested calf lumbar spines, bovine tail segments and human lumbar spines. We first divided individual lumbar or tail segments to include the vertebral bodies and disc. We then hydrated the specimens by placing them in a saline bath overnight. A magnetic resonance images were acquired from human specimens and a Pfirrmann classification was made. A stab incision measuring 25% of the diameter of the disc was then done to each specimen along the posterior intervertebral disc space. Each specimen was placed in custom test fixtures on a servo-hydraulic test frame (MTS, Eden Prarie, MN) such that the superior body was attached to a 10,000 lb load cell and the inferior body was supported on the piston. A compressive ramping load was placed on the specimen in load control at 4 MPa/sec stopping at 75% of the disc height. Load was recorded throughout the test and failure load calculated. Once the test was completed each specimen was sliced through the center of the disc and photos were taken of the cut surface.ResultsFifteen each of calf, human, and bovine tail segments were tested. The failure load varied significantly between specimens (p<.001) with human specimens having the highest average failure load (8154±2049 N). Disc height was higher for lumbar/bovine tail segments as compared to calf specimens (p<.001) with bovine tails having the highest disc height (7.1±1.7 mm). Similarly, human lumbar discs had a cross sectional area that was greater than both bovine tail/calf lumbar spines (p<.001). There was no correlation between disc height and failure load within each individual species (p>.05). Cross sectional area and failure load did not correlate with failure load for human lumbar spine and bovine tails (p>.05) but did correlate with calf spine (r=0.53, p=.04). There was a statistically significant inverse correlation between disc height and Pfirrmann classification for human lumbar spines (r=?0.84, p<.001). There was also a statistically significant inverse relationship between Pfirrmann classification and failure load (r=?0.58, p=.02).ConclusionsWe have established a model for disc herniation and have shown how results of this model vary between species, disc morphology, and Pfirrmann classification. Both hypotheses were accepted: The force required for disc herniation was variable across species, and the force to herniation for human spines was inversely correlated with the degree of disc degeneration. We recommend that models using human intervertebral discs should include data on Pfirrmann classification, while biomechanical models using calf spines should report cross sectional area. Failure loads do not vary based on dimensions for bovine tails.Clinical SignificanceOur analysis of models for disc herniation will allow for quicker, reliable comparisons of failure forces required to induce a disc herniation. Future work with these models may facilitate rapid testing of devices to repair a torn/ruptured annulus.     

Quantitative MRI analysis of the surface area, signal intensity and MRI index of the central bright area for the evaluation of early adjacent disc degeneration after lumbar fusion

Purpose

The aim of this study was to evaluate early ASD at short-term follow-up in fused and unoperated patients with degenerative disc disease, using quantitative magnetic resonance imaging (MRI) analysis of the area, signal intensity and their product, i.e., MRI index of the central bright area of the disc as well as measures of intervertebral disc height and Pfirrmann grading scale. The further purpose was to determine whether fusion accelerates ASD compared with non-surgical treatment in short-term follow-up.

Methods

One hundred and eight chronic low back patients diagnosed as L4/L5 degeneration undertook either one-level instrumented posterior lumbar interbody fusion or conservative treatment. They were followed up for about 1?year. Finally 46 fused and 45 conservatively treated patients with MRI follow-up were included. Pre- and post-treatment MRIs were compared to determine the progression of disc degeneration at the two cranial adjacent segments.

Results

The area, signal intensity and MRI index of the central bright area of the adjacent discs decreased in the operated and unoperated groups from pre-treatment to follow-up, except for an insignificant decrease of signal intensity at the second adjacent segment in the unoperated group. The changes in these parameters were statistically greater at the first than the second adjacent segment in the fused group, but not in the unoperated group. And the changes in the fused group were more pronounced than those at both neighbouring levels in the unoperated group. However, the Pfirrmann grading scale and intervertebral disc height did not detect any changes at adjacent discs in either group.

Conclusions

Decrease in the parameters of quantitative MRI analysis indicated early degeneration at discs adjacent to lumbar spinal fusion. Fusion had an independent effect on the natural history of ASD during short-term follow-up. Continued longitudinal follow-up is required to determine whether these MRI changes lead to pathologic changes.     

Even mild intervertebral disc degeneration reduces the flexibility of the thoracic spine: an experimental study on 95 human specimens

BACKGROUND CONTEXTIntervertebral disc degeneration represents one of multiple potential trigger factors for reduced passive spinal mobility and back pain. The effects of age-related degenerative intervertebral disc changes on spinal flexibility were however mainly investigated for the lumbar spine in the past, while intervertebral disc degeneration is also highly prevalent in the thoracic spine.PURPOSETo evaluate the effect of the degeneration grade on the range of motion and neutral zone of the thoracic spine.STUDY DESIGNExperimental study including combined radiological grading of intervertebral disc degeneration and biomechanical testing of 95 human thoracic functional spinal units (min. n=4 per level from T1–T2 to T11–T12) from 33 donors (15 female / 18 male, mean age 56 years, age range 37–80 years).METHODSDegeneration grades of the intervertebral discs were assessed using the validated x-ray grading scheme of Liebsch et al. (0=no, 1=mild, 2=moderate, 3=severe degeneration). Motion segments were loaded with pure moments in flexion/extension, lateral bending, and axial rotation to determine range of motion and neutral zone at 5 Nm.RESULTSAll tested specimens exhibited degeneration grades between zero and two. Range of motion significantly decreased for grades one and two compared with grade zero in any motion direction (p<.05), showing the strongest decrease in extension comparing grade two with grade zero (-42%), while no significant differences were detected between grades one and two. Similar trends were found for the neutral zone with the strongest decrease in extension also comparing grade two with grade zero (-47%). Donor age did not significantly affect the range of motion, whereas the range of motion was significantly reduced in specimens from male donors due to the significantly higher degeneration grade in this study.CONCLUSIONSEven mild intervertebral disc degeneration reduces the range of motion and neutral zone of the thoracic spine in any motion plane, whereas progressing degeneration does not further affect its flexibility. This is in contrast to the lumbar spine, where a more gradual decrease of flexibility was found in prior studies, which might be explained by differences between thoracic and lumbar intervertebral disc morphologies.CLINICAL SIGNIFICANCEThoracic intervertebral disc degeneration should be considered as one of multiple potential causal factors in patients showing reduced passive mobility and middle back pain.     

Intervertebral disc viability after burst fractures of the thoracic and lumbar spine treated with pedicle screw fixation and direct end-plate restoration

Background contextControversies persist for the best treatment of burst fractures of the thoracolumbar spine. Anterior corpectomy and discectomy followed by reconstruction with intervertebral cage and posterior fixation, for example, are based mainly on the widespread assumption that intervertebral discs involved in burst-type fractures, typically, do not survive the traumatic event and will degenerate irrevocably.PurposeTo evaluate whether intervertebral discs, located adjacent to traumatic burst fractures and treated with pedicle screw fixation and direct end-plate restoration, survive the traumatic event or irrevocably progress to severe disc degeneration.Study designProspective trial.Patient sampleTwenty adult patients with traumatic burst fractures of the thoracolumbar spine and treated with pedicle screw fixation and direct end-plate reduction were included.Outcome measuresDisc degeneration according to the Pfirrmann classification.MethodsMagnetic resonance imaging scans were obtained preoperatively, 1 month after surgery and 1 month after pedicle screw removal 12 to 18 months after index surgery. Degeneration of the intervertebral discs adjacent to the fracture was assessed using the Pfirrmann classification. Grade 1/2/3 was defined as mild-to-moderate degeneration of the intervertebral disc (MDID), whereas Grade 4/5 was defined as severe-to-endstage degeneration of the intervertebral disc (SDID). Repeated measure analysis was performed to detect significant differences between MDID and SDID scores.ResultsA total of 19 patients (38 discs) were fully documented and available for study. All discs showed MDID preoperatively, and while five discs (13%) progressed to SDID at 12 to 18 months posttrauma, the other discs did not show progression of degeneration.ConclusionsIntervertebral discs adjacent to traumatic burst fractures treated with pedicle screw instrumentation and direct end-plate restoration do not routinely seem to progress to severe degeneration at 12 to 18 months postinjury.     

棘突间动态稳定系统治疗腰椎退行性疾病的中期疗效分析

目的:探讨Wallis和Coflex棘突间系统治疗腰椎退行性疾病的中期临床疗效以及对邻近节段退变的影响。方法:对2011年1月至2013年1月应用棘突间固定系统治疗的L_(4,5)节段腰椎退行性疾病55例患者进行回顾性分析,其中男31例,女24例;年龄25～67岁,平均43.3岁;腰椎管狭窄症21例,腰椎间盘突出症34例。根据所采用的棘突间固定系统不同将患者分为Wallis组(33例)和Coflex组(22例)。采用视觉模拟评分(visual analogue scale,VAS)对腰痛和下肢痛进行评分;根据腰椎日本骨科协会(Japanese Orthopaedic Association,JOA)评分和Oswestry功能障碍指数(Oswestry Disability Index,ODI)评价腰椎功能;通过影像学资料测量手术前后手术节段和邻近节段活动度、椎间盘高度以及上位邻近节段Pfirrmann等级的变化情况。结果:55例患者均获得随访,随访时间48～72个月,平均60.4个月。术后48个月时,两组患者腰痛VAS评分、下肢痛VAS评分、腰椎JOA评分和ODI评分较术前有明显改善(P0.01),组间比较差异无统计学意义(P0.05);两组手术节段的活动度和椎间盘高度较术前均明显减小(P0.05),而上下邻近节段的活动度和椎间盘高度无明显变化(P0.05),两组间椎间隙高度和活动度比较无统计学意义(P0.05);两组患者上位邻近节段Pfirrmann分级较术前差异不明显(P0.05)。4例腰椎间盘突出症患者手术节段在术后1～3年复发,其中Wallis组3例,Coflex组1例,平均年龄35.2岁。结论:Wallis和Coflex系统治疗腰椎退变性疾病具有相同中期疗效,可延缓邻近节段退变,但不能阻止椎间盘突出的复发。