应用微创技术建立恒河猴腰椎间盘早期退变模型

目的 应用CT定位,经皮穿刺纤维环诱导恒河猴腰椎间盘退变,建立灵长类动物腰椎间盘早期退变模型.方法 恒河猴13只,随机分为三组:(1)造模组:在CT定位下,用20G穿刺针从左侧后方入路经皮穿刺L1,2:(n=12),L2,3、L3,4、L4,5、L5,6(n=13)椎间盘的纤维环全层至椎间盘髓核正中,共64个椎间盘.(2)穿刺对照组:15G穿刺针穿刺1只猴的L1,2椎间盘.(3)正常对照组:L6,7,L7-S1,共26个椎间盘.造模前及造模后4、8、12周对各组椎间盘行MRI检查,并行HE、Masson、番红O、免疫组织化学染色组织学观察.结果 (1)MRI:20G穿刺针穿刺的造模组椎间盘造模前及造模后4、8、12周,椎间盘信号强度按Pfirmann分级均为Ⅰ级.15G穿刺针穿刺椎间盘4周时信号降低(Pfirrmann Ⅲ级),8周时为黑色椎间盘(Pfirmann Ⅳ级).正常对照组椎间盘为Pfirmann Ⅰ级.(2)组织学:造模组椎间盘造模后4周未见改变,8周时HE染色示髓核内细胞数减少,12周时较为明显.Masson染色4周未见改变,8周时各层纤维间出现裂隙,12周时裂隙增宽.番红O染色见8、12周髓核内蛋白聚糖进行性减少.免疫组织化学结果显示4周和8周时同正常椎间盘比较差异无统计学意义(P＞0.05),12周时,Ⅱ型胶原合成减少(P＜0.05).15G穿刺对照组在8周时HE染色见髓核内细胞减少明显,Masson染色见纤维环各层间裂隙明显,呈波浪状.番红O染色示髓核内蛋白聚糖数量明显减少.免疫组织化学染色示Ⅱ型胶原合成减少.正常对照组在各时间点未见到形态学改变.结论 20G穿刺针可以诱发椎间盘缓慢进展的轻度退变.MRI平均信号强度观察椎间盘轻度退变时,不是敏感的指标,需要依靠组织学证实.     

可控轴向压力致兔腰椎间盘退变模型的建立及评价

[目的]建立可控轴向压力诱发的椎间盘退变动物模型并考察其特性.[方法]取4个月龄日本大白兔40只,将其随机分为5组(每组8只).采用基于横穿椎体的克氏针的自制加压装置,分别对2～4组动物腰椎间盘施加10 kg压力1、2、4周及8周,第1组作为假手术对照组.Thompson分级法及兔腰椎间盘磁共振(MRI)评价退变程度,HE染色及Ⅰ、Ⅱ型胶原免疫组化染色考察其组织学改变.另外构建纤维环损伤致兔腰椎间盘退变模型,并对标本行HE染色以供比较.[结果]①Thompson分级:第2组7只均为Ⅱ级,第3组6只Ⅲ级,第4组5只为Ⅳ级,第5组4只动物退变程度达到V级.②MRI评分显示,第2组椎间盘以轻度退变为主;第3组椎间盘主要为中度退变.第4组、第5组则以重度退变为主.③HE染色显示,该模型椎间盘各区域的退变情况较纤维环损伤模型更为均匀.④免疫组化染色显示,退变过程中椎间盘基质成分退化的趋势与人体相符.[结论]可控轴向压力致兔腰椎间盘退变模型可以高效诱发椎间盘退变,尤其在轻、中度椎间盘退变方面具有优势.该模型可供深入研究,并用于椎间盘退变的治疗研究.     

聚集蛋白聚糖酶-1在退变椎间盘中的表达及意义

[目的]探讨聚集蛋白聚糖酶-1(aggrecannase-1,Agase-1)在退变椎间盘组织中的表达、规律及其意义。[方法]实验组为手术切除的腰椎间盘突出患者的退变椎间盘组织,分为纤维环破裂组和未破裂组;对照组为取自腰椎骨折患者的正常腰椎间盘组织。应用HE染色检测各组椎间盘组织的病理形态学变化,RT-PCR检测Agase-1mRNA的表达;Western印迹法检测蛋白多糖(aggrecan)的含量。[结果]Agase-1mRNA在实验组中表达均明显高于对照组,纤维环破裂组明显高于纤维环未破裂组(P<0.01),Aggrecan在实验组中的含量低于对照组,纤维环破裂组中Aggrecan明显低于纤维环未破裂组(P<0.01),HE染色显示髓核细胞数量随着椎间盘退变程度的增加显著减少,纤维环破裂组髓核组织中有血管生成,伴有炎细胞浸润。[结论]Agase-1可能参与了人类椎间盘组织的退变过程,且在突出的椎间盘组织中有增高趋势。     

微创针刺旋切制备兔椎间盘退变模型

目的探讨微创针刺旋切制备兔椎间盘退变(intervertebral disc degeneration,IDD)模型的可行性。方法取40只新西兰大白兔,雌雄不限,体质量(2.9±0.3)kg;随机分为对照组和实验组(n=20)。对照组不予处理;实验组采用18G穿刺针在C臂X线机引导下经皮侧后方穿刺进入L4、5、L5、6椎间盘内,旋切髓核组织以促进椎间盘的退变。术后4、8、12、16周行大体观察、MRI观察并根据Pfirrmann分级法评价椎间盘退变情况,然后处死动物取材行Masson染色和番红O染色观察。结果实验组髓核组织颜色较对照组暗,弹性降低。对照组MRI T2加权像椎间盘信号强度早期未见明显改变,后期略减弱;实验组椎间盘信号强度随时间延长呈减弱趋势。根据Pfirrmann分级法评价椎间盘退变程度,两组随时间延长椎间盘退变程度均逐渐加重(P0.05);两组间比较除术后4周差异无统计学意义(P0.05)外,其余术后各时间点实验组椎间盘退变程度较对照组严重(P0.05)。Masson染色示随时间延长,对照组纤维环出现排列不规整,但结构仍完整;实验组纤维环排列紊乱,甚至出现断裂现象。番红O染色示对照组髓核细胞未见明显减少,实验组髓核细胞明显减少。结论微创针刺旋切法可成功制备兔IDD模型。     

纤维环穿刺抽吸法和纤维环切开法建立兔椎间盘退变模型的比较

[目的]通过纤维环穿刺抽吸法和纤维环切开法建立兔椎间盘退变模型,分析此两种方法的可行性及特点.[方法]取10个月龄健康日本大耳白兔24只,随机分为2组,其中A组为纤维环穿刺抽吸组,利用18G穿刺针分别在兔L3、4、L4、5、L5、6椎间盘刺入并抽吸髓核8～ 12 mg;B组为纤维环切开组,利用手术刀分别在兔L3、4、L4、5、L5、6椎间盘纤维环上做水平位切口;造模完毕,两组兔分别于术后4、8、12、16周进行MRI检查,病理组织学观察和免疫组化染色观察.[结果]A、B两组退变椎间盘MRI T2加权像信号随时间延长呈现持续减弱趋势,术后4、8周纤维环穿刺组T2加权像信号强度评分较纤维环切开组低(P＜0.05),组织学观察发现造模组髓核细胞逐渐减少;免疫组化染色观察Ⅱ型胶原和蛋白聚糖表达含量随时间延长逐渐降低,且B组含量明显低于A组.[结论]两种方法均能建立兔椎间盘退变模型,但纤维环切开法椎间盘的退变程度较纤维环穿刺法出现较早且较为剧烈.     

CT引导下经皮纤维环穿刺建立兔腰椎间盘退变模型

【摘要】 目的：在CT引导下经皮纤维环穿刺建立兔腰椎间盘退变模型,并通过影像学和病理学验证其退变过程及效果。方法：3月龄新西兰大白兔18只,体重2.7~3.3kg,雌雄不限,术前均行X线及MRI检查。每只兔在螺旋CT引导下,用18G穿刺针经侧方皮下穿刺兔L5/6椎间盘（穿刺组）,确认刺入椎间盘纤维环深度约为5mm,并对L4/5椎间盘进行假性穿刺（穿刺达椎间盘边缘,但不刺入纤维环内;假穿刺组）,L3/4椎间盘作为对照椎间盘（对照组）。术后4周、8周、12周随机选取6只兔行X线片及MRI检查,观察各组椎间隙高度、邻近骨质改变及椎间盘信号改变,以“术后椎间隙高度/术前椎间隙高度×100”计算椎间盘高度相对值(DHRV),并进行椎间盘改良Thompson分级法分级;X线片及MRI检查结束24h内处死动物,选取对照、假穿刺和穿刺组椎间盘进行组织形态学及免疫组织化学分析。结果：对照组及假穿刺组术后4、8、12周,X线片示椎间隙高度无降低,无终板骨质硬化与骨赘形成;MRI T2加权成像图像示各椎间盘均呈高信号;组织学检查见髓核细胞数量较多,分布均匀,纤维环排列呈同心圆层状;免疫组化分析髓核呈Ⅰ型胶原染色强阳性,Ⅱ型胶原染色阴性,在各时间点表现无明显差别。穿刺组椎间盘在术后4周X线片即可见椎间隙高度轻度降低（DHRV=70.78±4.55）,MRI示椎间盘信号强度轻度下降,组织学上见纤维环结构紊乱、髓核细胞轻度减少;术后8周椎间隙高度明显降低（DHRV=50.63±4.04）,开始出现终板骨质硬化,MRI示椎间盘信号强度明显下降,组织学上髓核被胶原组织分裂为含较多椭圆形细胞的细胞岛,出现纤维软骨细胞,纤维环层状结构变形、部分断裂;术后12周椎间隙高度继续下降（DHRV=44.78±2.61）,骨赘形成、终板骨质硬化明显,MRI示椎间盘信号强度继续减弱,组织学上见髓核被纤维软骨组织所代替,纤维环层状组织碎裂、解体;免疫组织化学分析示术后4、8、12周髓核Ⅰ型胶原染色逐渐增强,Ⅱ型胶原染色逐渐减弱。各时间点对照组椎间盘的DHRV及改良Thompson分级与假穿刺组比较均无统计学差异（P＞0.05）;穿刺组在术后不同时间点的DHRV降低、改良Thompson分级增高与对照组及假穿刺组比较均有统计学差异（P<0.05）;随着穿刺时间的延长,穿刺组DHRV呈进行性降低趋势,改良Thompson分级进行性升高,两者在术后4、8、12周间均有统计学差异（P<0.05）。结论：CT引导下经皮纤维环穿刺法诱导兔椎间盘退变模型构建成功,操作方法简单、创伤小,经影像学及病理学证实其退变过程为渐进性。     

纤维环穿刺法建立兔椎间盘退变模型

[目的]通过纤维环穿刺法建立兔椎间盘退变模型,分析其特点.[方法]将16只新西兰大白兔随机分为2组.经腹膜外入路暴露X2、3、L3、4椎间隙.A组为纤维环穿刺组,采用16号针头穿刺,B组为假手术对照组.术后2,4,6,8周通过MRI和组织病理学检查观察髓核变性及组织病理情况.[结果)纤维环穿刺组髓核信号强度在术后呈现逐渐降低趋势,髓核面积逐渐缩小,椎间隙高度也逐步下降,从术后4周开始两组差异有统计学意义(p＜0.O5 ).随着时间的进展,纤维环穿刺组髓核内细胞含量逐渐减少.[结论]纤维环穿刺法可成功建立椎间盘退变模型,比较真实地模拟了人类椎间盘损伤后的退变过程.     

自体富血小板血浆干预兔早期椎间盘退变的初步研究

目的富血小板血浆(platelet-rich plasma,PRP)具有刺激椎间盘细胞增殖、促进细胞外基质合成代谢及抑制纤维环细胞凋亡等作用。通过观察自体PRP干预兔早期椎间盘退变,明确其治疗效果,为临床应用提供理论依据。方法取健康成年新西兰大白兔45只,体重2.5～3.0 kg,雌雄不限;随机分为实验组、对照组、假手术组(n=15)。取实验组兔耳中央动脉血,采用Landesberg等方法制备PRP,同时对全血及PRP行血小板计数。实验组及对照组采用纤维环针刺法建立L4、5及L5、6椎间盘退变模型,造模2周后于L4、5及L5、6椎间隙分别注入100μL自体PRP及100μL PBS液;假手术组仅分离暴露椎间盘,不作处理。观察实验动物造模后一般情况;造模2周及干预1、2周时各组取5只实验动物行腰椎MRI、HE染色及Ⅱ型胶原免疫组织化学染色观察,腰椎MRI退变程度分级及Ⅱ型胶原阳性积分吸光度(IA)值检测。结果兔PRP中血小板计数约为外周血的4.92倍。实验动物均存活至实验完成。造模2周时,与假手术组相比,实验组和对照组椎间盘信号降低,髓核细胞减少,基质退变,Ⅱ型胶原表达降低。腰椎MRI退变程度分级及Ⅱ型胶原阳性IA值结果显示,各时间点实验组、对照组与假手术组相比差异均有统计学意义(P<0.05),干预1、2周时,实验组MRI退变程度分级显著低于对照组(P<0.05),但仍与假手术组有差异(P<0.05);干预1、2周时,实验组髓核细胞及软骨样基质较对照组增多,基质纤维化程度轻,Ⅱ型胶原表达明显强于对照组(P<0.05)。结论椎间盘内注射自体PRP可终止甚至一定程度逆转兔早期椎间盘退变,可能与PRP含有多种生长因子调控细胞功能、改善组织微环境、促进组织再生修复有关。     

髓核内注射过氧化还原酶Ⅱ对兔椎间盘退变过程的影响

目的探讨髓核内注射人重组过氧化还原酶（Peroxiredoxin,Prx）对兔椎间盘退变过程的影响。方法通过纤维环穿刺法建立新西兰大白兔椎间盘退变模型（L3～4～L5～6）,24只兔随机分为高浓度组、低浓度组和对照组,每组各8只。4周后MRI显示造模成功,然后行L3～4～L5～6椎间盘内注射,高浓度组和低浓度组分别注射1 mg/mL、10μg/mL Prx蛋白,对照组注射0.1%磷酸盐缓冲液,注射量均为25μL。在注射后2、4、12、16周每组分别随机取2只兔行脊柱MRI检查,采用硫酸咔唑法检测髓核蛋白多糖的含量,免疫组化检测型胶原含量,并做病理切片HE染色观察组织及细胞的改变情况。结果蛋白注射后三组椎间盘均发生不同程度退变,注射后16周,高浓度组髓核内水分的含量明显低于低浓度组和对照组（P〈0.05）;髓核内蛋白多糖含量高浓度组显著低于低浓度组和对照组（P〈0.05）;细胞外基质型胶原灰度值高浓度组显著低于低浓度组和对照组（P〈0.05）,而低浓度组和对照组比较差异没有统计学意义（P〉0.05）。结论高浓度（1 mg/mL）Prx在椎间盘退变过程中起促进退变作用。     

腺相关病毒介导的骨形态发生蛋白-2体内转染兔退变椎间盘的实验研究

目的 观察腺相关病毒介导的骨形态发生蛋白-2(AAV-BMP-2)基因对兔退变腰椎间盘的治疗作用.方法 将36只新西兰大白兔L2-3、L3-4、L4-5、L5-6椎间盘针刺制造退变模型后随机分为3组,其中12只注射AAV-BMP-2作为实验组,12只注射AAV作为实验对照组,12只注射生理盐水作为空白对照组.注射后的2、4、8周各组随机抽取4只兔行腰椎MRI扫描,扫描后将其处死,取L2-3、L3-4、L4-5、L5-6椎问盘髓核组织,用间苯三酚分光光度法检测髓核组织中的蛋白多糖含量.结果 在MRI影像学Thompson分级评估中,实验组各时间点椎间盘MRI信号比较,差异无统计学意义.实验对照组和空白对照组各时间点MRI信号比较,差异有统计学意义.实验组和实验对照组、实验组和空白对照组各时间点MRI髓核信号比较,差异有统计学意义;实验对照组和空白对照组比较,差异无统计学意义.在蛋白多糖含量测定中,实验组蛋白多糖含量在各时间点均高于实验对照组和空白对照组,实验对照组和空白对照组蛋白多糖均随时间的变化逐渐减少,各时间点两组比较无明显区别.结论 AAV-BMP-2对兔退变的腰椎间盘有治疗作用.     

Injection of AAV2-BMP2 and AAV2-TIMP1 into the nucleus pulposus slows the course of intervertebral disc degeneration in an in vivo rabbit model

Background contextIntervertebral disc degeneration (IDD) is a common cause of back pain. Patients who fail conservative management may face the morbidity of surgery. Alternative treatment modalities could have a significant impact on disease progression and patients’ quality of life.PurposeTo determine if the injection of a virus vector carrying a therapeutic gene directly into the nucleus pulposus improves the course of IDD.Study designProspective randomized controlled animal study.MethodsThirty-four skeletally mature New Zealand white rabbits were used. In the treatment group, L2–L3, L3–L4, and L4–L5 discs were punctured in accordance with a previously validated rabbit annulotomy model for IDD and then subsequently treated with adeno-associated virus serotype 2 (AAV2) vector carrying genes for either bone morphogenetic protein 2 (BMP2) or tissue inhibitor of metalloproteinase 1 (TIMP1). A nonoperative control group, nonpunctured sham surgical group, and punctured control group were also evaluated. Serial magnetic resonance imaging (MRI) studies at 0, 6, and 12 weeks were obtained, and a validated MRI analysis program was used to quantify degeneration. The rabbits were sacrificed at 12 weeks, and L4–L5 discs were analyzed histologically. Viscoelastic properties of the L3–L4 discs were analyzed using uniaxial load-normalized displacement testing. Creep curves were mathematically modeled according to a previously validated two-phase exponential model. Serum samples obtained at 0, 6, and 12 weeks were assayed for biochemical evidence of degeneration.ResultsThe punctured group demonstrated MRI and histologic evidence of degeneration as expected. The treatment groups demonstrated less MRI and histologic evidence of degeneration than the punctured group. The serum biochemical marker C-telopeptide of collagen type II increased rapidly in the punctured group, but the treated groups returned to control values by 12 weeks. The treatment groups demonstrated several viscoelastic properties that were distinct from control and punctured values.ConclusionsTreatment of punctured rabbit intervertebral discs with AAV2-BMP2 or AAV2-TIMP1 helps delay degenerative changes, as seen on MRI, histologic sampling, serum biochemical analysis, and biomechanical testing. Although data from animal models should be extrapolated to the human condition with caution, this study supports the potential use of gene therapy for the treatment of IDD.     

Disc degeneration reduces the delamination strength of the annulus fibrosus in the rabbit annular disc puncture model

Background contextDegenerative disc disease is a common pathologic disorder accompanied by both structural and biochemical changes. Changes in stress distribution across the disc can lead to annulus fibrosus (AF) damage that can affect the strength and integrity of the disc. Given that some present degeneration therapies incorporate biological regrowth of the nucleus pulposus (NP), it is crucial that the AF remains capable of containing this newly grown material.PurposeTo examine the resistance of AF to delamination using an adhesive peel test in experimentally degenerated rabbit discs.Study designExperimentally induced disc degeneration; excised AF tissue study.MethodsDisc degeneration was induced in eight New Zealand white rabbits by annular puncture; four additional rabbits served as controls. In experimental rabbits, an 18-gauge needle was inserted into the anterolateral AF region of levels L2–L3 and L4–L5, and disc height was monitored by X-ray. Animals were sacrificed at 4 and 12 weeks postsurgery and magnetic resonance images and X-rays were taken. Four discs were excised from the experimental animals; two punctured (L2–L3 and L4–L5) and two controls (L3–L4 and L6–L7). The same four discs were also excised from the age-matched control animals and served as nonpunctured control discs. To determine resistance to delamination, AF samples were dissected from each disc and subjected to a mechanical peel test at 0.5 mm/s.ResultsMagnetic resonance imaging and X-ray images confirmed dehydration of the NP and reduced disc height, similar to that found in clinical degeneration. Resistance to delamination was significantly lower in punctured/degenerated discs compared with both the nonpunctured discs from the same animal (27% lower) and the nonpunctured control discs (30% lower) (p=.024).ConclusionsThe findings of this study suggest that degeneration increases the potential for delamination between AF layers. Given this substantial change to the integrity of the AF after degeneration, clinical treatments should not only target rehydration or regrowth of the NP, but should also target repair and strengthening of the AF to confine the NP.     

Therapeutic effects of adenovirus-mediated growth and differentiation factor-5 in a mice disc degeneration model induced by annulus needle puncture

Background contextThe therapeutic strategies that have thus far been used for the treatment of intervertebral disc degeneration (IDD) have focused on relieving the symptoms, although reversal of the degeneration remains an important challenge for the effective treatment of IDD. Growth and differentiation factor-5 (GDF5), of which deficiency leads to early disc degeneration changes, has the potential to increase proliferation of disc cells and expression of extracellular matrix proteins.PurposeThe purpose of the study was to develop a lumbar disc degeneration model in mice and determine the effect of adenoviral GDF5 gene therapy.Study designThe study design was to compare the degeneration changes of discs punctured by different-size needles to develop a mice lumbar disc degeneration model and to evaluate the effects of in vivo gene therapy for the mice disc degeneration model by an adenoviral vector carrying GDF5 gene.MethodsA lumbar disc degeneration model was developed by needle punctures to the discs in Balb/c mice. Afterward, a gene therapy treatment to disc degeneration was evaluated. Two of the mice lumbar discs were randomly chosen to be punctured by a 30-gauge needle and then injected with adenovirus that had been engineered to express either the luciferase gene (Ad-Luc) or the GDF5 gene (Ad-GDF5). Animals were analyzed by bioluminescent imaging, radiographic, and magnetic resonance imaging (MRI) scanning, then sacrificed at 1, 2, 4, or 8 weeks after operation, and subjected to histological and biochemical assays.ResultsBy the detection of T2-weighted MRI scanning and histological study, the degeneration was found in all of the discs punctured by different-size needles. But the development of the degeneration in the discs injured by the 30-gauge needle was more reliable and moderate compared with that in other groups. The detection of luciferase activity by bioluminescent imaging revealed that adenovirus survived and the introduced genes were expressed over 6 weeks after injection. There were no T2-weighted MRI signals in the mice injected with either Ad-Luc or Ad-GDF5 up to 4 weeks after operation. At 6 and 8 weeks, T2-weighted signals were detected in the Ad-GDF5 group but none in the Ad-Luc control group. The percent disc height index (%DHI) was significantly decreased (～20%) by 1 week after injury in both groups, indicating the development of disc degeneration. At 2 weeks, the %DHI in the mice injected with Ad-GDF5 increased significantly compared with that of the mice injected with Ad-Luc; the increase was sustained for the rest of the experiment period. The disc histology treated with Ad-GDF5 was improved compared with that in the control group. Glycosaminoglycan (GAG) levels were significantly decreased in the Ad-Luc injection group since 2 weeks after injury, and the DNA content had diminished by 4 weeks after the operation. In contrast, in the discs injected with Ad-GDF5, there was no decrease in the GAG and DNA levels after injury throughout the 8-week treatment period.ConclusionsDisc degeneration animal model can be developed by using needle puncture to the discs in mice. The adenovirus is an effective vehicle for gene delivery with rapid and prolonged expression of target protein and resulting improvement in markers of disc degeneration. Ad-GDF5 gene therapy could restore the functions of injured discs and has the potential to be an effective treatment.     

Injection of human umbilical tissue–derived cells into the nucleus pulposus alters the course of intervertebral disc degeneration in vivo

Background contextPatients often present to spine clinic with evidence of intervertebral disc degeneration (IDD). If conservative management fails, a safe and effective injection directly into the disc might be preferable to the risks and morbidity of surgery.PurposeTo determine whether injecting human umbilical tissue–derived cells (hUTC) into the nucleus pulposus (NP) might improve the course of IDD.DesignProspective, randomized, blinded placebo–controlled in vivo study.Patient sampleSkeletally mature New Zealand white rabbits.Outcome measuresDegree of IDD based on magnetic resonance imaging (MRI), biomechanics, and histology.MethodsThirty skeletally mature New Zealand white rabbits were used in a previously validated rabbit annulotomy model for IDD. Discs L2–L3, L3–L4, and L4–L5 were surgically exposed and punctured to induce degeneration and then 3 weeks later the same discs were injected with hUTC with or without a hydrogel carrier. Serial MRIs obtained at 0, 3, 6, and 12 weeks were analyzed for evidence of degeneration qualitatively and quantitatively via NP area and MRI Index. The rabbits were sacrificed at 12 weeks and discs L4–L5 were analyzed histologically. The L3–L4 discs were fixed to a robotic arm and subjected to uniaxial compression, and viscoelastic displacement curves were generated.ResultsQualitatively, the MRIs demonstrated no evidence of degeneration in the control group over the course of 12 weeks. The punctured group yielded MRIs with the evidence of disc height loss and darkening, suggestive of degeneration. The three treatment groups (cells alone, carrier alone, or cells+carrier) generated MRIs with less qualitative evidence of degeneration than the punctured group. MRI Index and area for the cell and the cell+carrier groups were significantly distinct from the punctured group at 12 weeks. The carrier group generated MRI data that fell between control and punctured values but failed to reach a statistically significant difference from the punctured values. There were no statistically significant MRI differences among the three treatment groups. The treated groups also demonstrated viscoelastic properties that were distinct from the control and punctured values, with the cell curve more similar to the punctured curve and the carrier curve and carrier+cells curve more similar to the control curve (although no creep differences achieved statistical significance). There was some histological evidence of improved cellularity and disc architecture in the treated discs compared with the punctured discs.ConclusionsTreatment of degenerating rabbit intervertebral discs with hUTC in a hydrogel carrier solution might help restore the MRI, histological, and biomechanical properties toward those of nondegenerated controls. Treatment with cells in saline or a hydrogel carrier devoid of cells also might help restore some imaging, architectural, and physical properties to the degenerating disc. These data support the potential use of therapeutic cells in the treatment of disc degeneration.     

大鼠腰椎间盘针刺退变模型的建立

[目的]建立大鼠腰椎间盘针刺退变模型并进行MRI和组织学观察。[方法]Sprague-Dawley大鼠32只,20只进行腰椎间盘纤维环厚度测量,确定针刺深度;12只经腹膜手术,L3、4、L4、5、L5、6椎间盘使用21G针分别行纤维环部分针刺或全层针刺,L6S1椎间盘作为对照,术前及术后4、8周行MRI检查,然后处死,椎间盘行HE染色。[结果]测量大鼠腰椎间盘纤维环厚度后,确定适用于L3、4、L4、5、L5、6、L6S1椎间盘纤维环部分针刺深度为1.5mm,纤维环全层针刺深度为2.3mm。MRI检查在纤维环全层针刺4周,部分针刺8周后的椎间盘信号强度显著降低。组织学检查发现纤维环全层针刺和部分针刺椎间盘4周时都发生退变,而纤维环全层针刺退变较严重。[结果]纤维环部分针刺或全层针刺方法可以成功建立大鼠腰椎间盘退变模型,方法可靠、有效、重复性好。     

Optimization of puncture injury to rat caudal disc for mimicking early degeneration of intervertebral disc

The caudal discs of rats have been proposed as a puncture model in which intervertebral disc (IVD) degeneration can be induced and novel therapies can be tested. For biological repair, treatments for ongoing IVD degeneration are ideally administered during the earlier stages. The purpose of this study was to elucidate the optimal puncture needle size for creating a model that mimicked the earlier stages of IVD degeneration. According to the disc height index, histologic score, and MRI grading, a puncture needle sized 21G or larger induced rapid degenerative processes in rat caudal discs during the initial 2–4 weeks. The degenerative changes were severe and continued deteriorating after 4 weeks. Conversely, puncture injury induced by needles sized 25G or smaller also produced degenerative changes in rat caudal discs during initial 2–4 weeks; however, the changes were less severe. Furthermore, the degenerative process became stabilized and showed no further deterioration or spontaneous recovery after 4 weeks. In the discs punctured by 25G needles, the expression of collagen I was increased at 2–4 weeks with a gradually fibrotic transformation thereafter. The expressions of collagen II and SOX9 were enhanced initially but returned to pre‐injury levels at 4–8 weeks. The above‐mentioned findings were more compatible with earlier degeneration in discs punctured by needles sized 25G or smaller than by needles sized 21G or larger, and the appropriate timing for intradiscal administration of proposed therapeutic agents would be 4 weeks or longer after puncture. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:202–211, 2018.     

大鼠正常与退变性髓核突出导致神经根性疼痛的对比研究

目的探讨正常与退变髓核突出对大鼠疼痛阈值以及背根神经节中TNF-α表达的影响,研究椎间盘退变与神经根性疼痛之间的关系。方法72只大鼠随机分为4组:正常对照组(n=18)、假手术组(n=19)、正常髓核(N-NP)组(n=16)和退变髓核(P-NP)组(n=19)。对P-NP组大鼠利用尾椎椎间盘纤维环穿刺的方法建立椎间盘退变模型。分别取出N-NP组和P-NP组大鼠自体的正常髓核与退变髓核组织,置于手术显露后的腰5左侧神经根处,建立髓核突出致神经根性疼痛动物模型。采用行为学测试的方法分别观察各组大鼠术前1天,术后1、4、7、10、14、21天机械刺激阈值与热刺激阈值的变化;采用免疫组化方法分别检测术后第4、14天各组大鼠背根神经节中TNF-α的表达。结果行尾椎间盘纤维环穿刺后2周,组织学与MRI检查均证实椎间盘组织发生明显退变。对照组和假手术组动物未出现明显的痛觉过敏现象,N-NP组和P-NP组大鼠机械性刺激阈值均显著下降,该痛觉过敏现象持续至术后2周消失;与正常髓核组织相比,退变髓核所致机械性刺激阈值下降程度更为严重。各实验组均未发生热刺激阈值的规律性变化。术后第4、14天对照组和假手术组背根神经节中未见TNF-α明显表达,而正常及退变髓核组TNF-α表达量均显著升高。结论大鼠尾椎纤维环穿刺是建立大鼠椎间盘退变模型的一种有效方法。与正常髓核组织相比,发生退变的髓核组织可导致神经根性疼痛的加重,提示椎间盘退变过程中释放的炎症因子在疼痛的发生机制中可能起到了重要作用。