Effect of severity of intervertebral disc injury on mesenchymal stem cell-based regeneration

Mesenchymal stem cell (MSC) implantation has been shown previously to arrest disc degeneration. This study aims to assess the effect of severity of disc degeneration on the ability of MSCs to arrest the degeneration. Disc degeneration was induced in New Zealand white rabbits at lumbar levels by annular puncture. The degeneration was allowed to progress for 1 month (early group) or 7 months (late group), followed by intradiscal injection of autologous MSCs. For disc levels that received MSCs treatment, 1 x 10(5) BrdU-labeled MSCs were injected per disc level. For the early group, MSC-injection had no significant effects on disc height or the progression of disc degeneration. For the late group, although the MSC-injected discs displayed lower disc heights than the control discs, they were significantly less degenerated together with near normal level of proteoglycan in localized areas. This is the first pilot study to demonstrate that severity of degeneration can influence the therapeutic effect of MSCs. Future studies of cell-based intervertebral disc regeneration should be carefully controlled in the context of stage of disc degeneration.     

Regenerative effects of transplanting mesenchymal stem cells embedded in atelocollagen to the degenerated intervertebral disc

Intervertebral disc (IVD) degeneration, a common cause of low back pain in humans, is a relentlessly progressive phenomenon with no currently available effective treatment. In an attempt to solve this dilemma, we transplanted autologous mesenchymal stem cells (MSCs) from bone marrow into a rabbit model of disc degeneration to determine if stem cells could repair degenerated IVDs. LacZ expressing MSCs were transplanted to rabbit L2-L3, L3-L4 and L4-L5 IVDs 2 weeks after induction of degeneration. Changes in disc height by plain radiograph, T2-weighted signal intensity in magnetic resonance imaging (MRI), histology, immunohistochemistry and matrix associated gene expressions were evaluated between normal controls (NC) without operations, sham operated with only disc degeneration being induced, and MSC-transplanted animals for a 24-week period. Results showed that after 24 weeks post-MSC transplantation, degenerated discs of MSC-transplanted group animals regained a disc height value of about 91%, MRI signal intensity of about 81%, compared to NC group discs. On the other hand, sham-operated group discs demonstrated the disc height value of about 67% and MRI signal intensity of about 60%. Macroscopic and histological evaluations confirmed relatively preserved nucleus with circular annulus structure in MSC-transplanted discs compared to indistinct structure seen in sham. Restoration of proteoglycan accumulation in MSC-transplanted discs was suggested from immunohistochemistry and gene expression analysis. These data indicate that transplantation of MSCs effectively led to regeneration of IVDs in a rabbit model of disc degeneration as suggested in our previous pilot study. MSCs may serve as a valuable resource in cell transplantation therapy for degenerative disc disease.     

Transplantation of mesenchymal stem cells embedded in Atelocollagen gel to the intervertebral disc: a potential therapeutic model for disc degeneration

Intervertebral disc degeneration is considered to be one of the major causes of low back pain. Despite this irreversible phenomenon, attempts to decelerate disc degeneration using various techniques have been reported. However, to date there has been no proven technique effective for broad clinical application. Based on previous studies, we hypothesize that maintenance of proteoglycan content in the disc is achieved by avoiding the depletion of nucleus pulposus and preserving the structure of the annulus is a primary factor in decelerating disc degeneration.One novel approach to solve the dilemma of intervertebral disc degeneration is found at the stem cell level. Mesenchymal stem cells (MSCs) are known to possess the ability to differentiate into various kinds of cells from mesenchymal origin. Although the majority of cells that contribute to disc formation are known to obtain chondrocyte-like phenotypes, no reported study has emphasized the correlation with mesenchymal stem cells.To evaluate the possible potential of MSCs in disc cell research and treatment of degenerative disc disease, autologous MSCs embedded in Atelocollagen gel were transplanted into the discs of rabbits which had undergone a procedure proven to induce degeneration. The results suggest that MSC transplantation is effective in decelerating disc degeneration in experimental models and provided new hopes for treatment of degenerative disc disease in humans. Atelocollagen gel served as an important carrier of MSCs in transplantation, permitting proliferation, matrix synthesis and differentiation of MSCs. This study strengthens the viable efficacy of practical application of MSCs in treatment of intervertebral disc disease.     

退行性变腰椎间盘中基质细胞衍生因子1的表达及意义

背景：目前腰椎间盘退行性变确切的发病机制并不十分清楚。炎症参与腰椎间盘退行性变的发病机制,基质细胞衍生因子1属于趋化因子家族成员,与炎症有关。 目的：检测腰椎间盘退行性变患者椎间盘中基质细胞衍生因子1的表达水平,分析其与病情严重程度的关系。 方法：选取84例腰椎间盘退行性变患者和28例椎体爆裂性骨折患者,收集2组患者术后的椎间盘组织,用酶联免疫吸附的方法测定椎间盘中基质细胞衍生因子1的表达水平。根据Schneiderman标准进行分级,分析椎间盘中的基质细胞衍生因子1水平与疾病分级的关系。 结果与结论：与椎体爆裂性骨折患者相比,腰椎间盘退行性变患者的腰椎间盘组织中基质细胞衍生因子1水平明显升高,差异有显著性意义(P < 0.01)。Schneiderman 4级的患者椎间盘组织中基质细胞衍生因子1水平明显高于Schneiderman 2级和3级的患者,而Schneiderman 3级的患者椎间盘组织中基质细胞衍生因子1水平明显高于2级患者。另外,Spearman相关分析也显示,基质细胞衍生因子1的蛋白水平与Schneiderman分级呈正相关(r=0.412, P < 0.01)。提示腰椎间盘退行性变患者椎间盘中基质细胞衍生因子1的表达增高,与疾病严重程度呈正相关,可能参与了腰椎间盘退行性变的发病机制。     

可注射型纤维蛋白凝胶转化生长因子β1复合骨髓间充质干细胞移植治疗椎间盘退变

背景：纤维蛋白凝胶主体胶与催化剂未混合前为液态,具有可注射的优点,注射混合后凝固成凝胶状,与髓核相似,并且凝固时间可控性强,作为间充质干细胞的载体植入到椎间盘内有诸多优点。 目的：观察可注射型纤维蛋白凝胶转化生长因子β1复合骨髓间充质干细胞移植抑制椎间盘退变的可行性。 方法：将新西兰大白兔随机分为退变模型组、纤维蛋白凝胶组,骨髓干细胞+纤维蛋白凝胶组。3组采用针刺法诱导建立退变模型后,纤维蛋白凝胶组及干细胞+纤维蛋白凝胶组分别移植入纤维蛋白凝胶转化生长因子β1复合物及骨髓间充质干细胞纤维蛋白凝胶转化生长因子β1复合物,于植入后2,6,10周行CR、MRI及病理检查。 结果与结论：退变模型组与纤维蛋白凝胶组椎间隙高度下降明显,并与时间呈正相关,干细胞+纤维蛋白凝胶组下降较缓慢(P < 0.01)。免疫组织化学及组织学检查显示,退变模型组髓核细胞的数量及Ⅱ型胶原含量进行性减少,细胞凋亡率明显增加,纤维蛋白凝胶组与退变模型组相似,干细胞+纤维蛋白凝胶组髓核细胞数量及Ⅱ型胶原含量较退变模型组及纤维蛋白凝胶组明显增多,细胞凋亡率下降。说明骨髓间充质干细胞联合纤维蛋白凝胶转化生长因子β1能很好抑制椎间盘退变,而单纯纤维蛋白凝胶转化生长因子β1移植不能抑制椎间盘退变。     

Localization of degradative enzymes and their inhibitors in the degenerate human intervertebral disc

The histological and biochemical changes that occur in the extracellular matrix of the intervertebral disc (IVD) during ageing and degeneration have been investigated extensively. However, the mechanisms behind these changes are not fully understood. A number of studies have suggested the involvement of matrix metalloproteinases (MMPs) and ADAMTS in IVD degeneration, but few have localized the site of production of these enzymes to the cells of the degenerate disc. This study uses immunohistochemical techniques to localize and quantify the production of degrading enzymes (MMPs 1, 3, and 13, and ADAMTS 4) and their inhibitors (TIMPS 1, 2, and 3) within non-degenerate and degenerate discs of varying severity of degeneration. In all discs investigated, the cells that produced the enzymes and their inhibitors were the chondrocyte-like cells of the nucleus pulposus and inner annulus fibrosus (AF), with little immunopositivity in the outer AF. Non-degenerate discs showed low numbers of cells expressing the degradative enzymes MMP 1 and ADAMTS 4, suggesting a role for these enzymes in normal homeostasis. No MMP 3 or MMP 13 immunopositivity was observed in non-degenerate discs. In degenerate discs, the number of cells immunopositive for MMPs 1, 3, 13 and ADAMTS 4 increased with the severity of degeneration. This increase in degrading enzymes was also accompanied by increases in the number of cells immunopositive for TIMPs 1 and 2 but not TIMP 3. This study highlights that although the expression of a number of MMPs increases with degeneration, this is accompanied by an increase in their inhibitors. However, the increase in the number of cells immunoreactive for ADAMTS 4 with increasing degeneration was not paralleled by a rise in its inhibitor TIMP 3. This finding indicates that the aggrecanases, rather then the MMPs, are a possible therapeutic target for the inhibition of disc degeneration.     

椎间注射转化生长因子β1对兔退变腰椎间盘蛋白多糖表达的影响

背景：体外研究证实转化生长因子β1可以促进蛋白多糖合成,延缓椎间盘退变,但体内实验鲜见报道。 目的：观察局部应用转化生长因子β1对兔退变腰椎间盘髓核蛋白多糖表达的影响。 方法：取30只新西兰大白兔建立兔腰椎间盘退变模型,造模12周,经X射线证实退变后,随机选择6只模型兔及6只未造模正常兔,处死取材。分别向剩余24只模型兔L_4~5椎间隙注射转化生子因子β1和生理盐水。末次给药2,4周取材,间苯三酚法测定兔椎间盘髓核内蛋白多糖的水平。 结果与结论：造模12周,兔退变椎间盘髓核中蛋白多糖水平明显降低(P < 0.01)。经局部注射转化生子因子β1后,兔退变椎间盘髓核中蛋白多糖表达明显增多(P < 0.01)。说明在兔椎间注射转化生子因子β1 可以促进髓核蛋白多糖的合成,延缓椎间盘退变。     

Association between bone mineral density and lumbar disc degeneration

Objectives

Higher vertebral bone mineral density (BMD) has been found to be related with lumbar disc degeneration (LDD), while relationship between femoral neck BMD and LDD remains controversial. The aim of our research was to study the relationship between LDD and BMD of the lumbar spine and femoral neck.

Study design

The study population consisted of 168 postmenopausal women (aged 63.3–75.0 years, mean 68.6 years) from the prospective OSTPRE and OSTPRE-FPS study cohorts. The severity of LDD was graded from T2-weighted MRI images using the five-grade Pfirrmann classification. Four vertebral levels (L1-L4) were studied (total 672 discs). The association between lumbar BMD and Z-score and the severity of LDD was studied separately for each vertebral level with AN(C)OVA analysis, using potential confounders as covariates.

Results

Higher lumbar BMD and Z-score were associated with more severe LDD at all studied levels (L1-L4): between L4-L5 disc and L4 BMD (p = 0.044) and L4 Z-score (p = 0.052), between L2-L3 disc and L3 BMD (p = 0.001) and at all other levels (p < 0.001). The mean degeneration grade of the studied discs was associated with the mean L1-L4 BMD and Z-score (p < 0.001). Statistical significance of any result did not alter after controlling for confounding factors. There was no significant association between femoral neck BMD and LDD.

Conclusions

Higher lumbar BMD/Z-score were associated with more severe LDD. There was no significant association between femoral neck BMD and disc degeneration. Femoral neck BMD may be a more reliable measurement for diagnosing osteoporosis in postmenopausal women with degenerative changes in the lumbar spine.     

Intervertebral disc degeneration induced by intradiscal poly(methyl methacrylate) leakage after spine augmentation in an in vivo rabbit model

Although intradiscal cement leakage is a common complication of spine augmentation, the effects of cement leakage into the intervertebral disc (IVD) have not been well investigated. This study aimed to determine the effects of cement leakage on IVD degeneration in rabbits. Poly(methyl methacrylate) (PMMA) particles were injected into lumbar discs of rabbits using 26G needles. Tissue effects were assessed using disc height, sagittal T2-weighted images, histology and immunohistochemistry. The results showed that stimulation with PMMA particles significantly reduced disc height compared with that in the sham-operation group at 3 weeks after injection. The mean signal intensity of the operated discs showed little to no changes among all groups at 3 weeks post-operation. After 6 weeks, the signal intensity of the PMMA-injected group decreased by 22% compared with that in the sham-operation group. Histological and quantitative immunohistochemical examination indicated phenotypic tissue changes from cartilaginous tissue into fibrotic tissue, with apparent degeneration in the PMMA group. Additionally, more collagen type II-containing tissues, but fewer matrix metalloproteinase-7-positive cells or apoptotic cells, were detected in the sham-operation group. The PMMA particle-induced degeneration rate was slower than that of the degeneration group, whereas the histologic data showed no difference in the progression of degeneration between the two groups. These data suggest that PMMA particles can moderately accelerate disc degeneration compared with the 18G needle puncture model. In conclusion, intradiscal injection of PMMA particles induced significant IVD degeneration in vivo. Therefore, further study of the adverse effects of PMMA leakage on IVD degeneration is required.     

Differentiation of Bone Marrow-derived Mesenchymal Stem Cells into Hepatocyte-like Cells on Nanofibers and Their Transplantation into a Carbon Tetrachloride-Induced Liver Fibrosis Model

There are limited data available on the effect of a physicochemical microenvironment on mesenchymal stem cell (MSC) differentiation and repopulation of the liver. Therefore, in this study nanofibers have been used to better differentiate and maintain the function and engraftment of differentiating MSCs both in vitro and in vivo. Mouse MSCs were differentiated into early (day 18) and late (day 36) hepatocyte-like cells (HLCs) in the presence or absence of ultraweb nanofibers (nano⁺ and nano⁻) and their transplantation for recovery in mice with CCl₄ induced hepatic fibrosis was investigated. In the nano⁺ group, hepatocyte markers-ALB and HNF4α- were elevated in a time-dependent manner; however, those were similar levels or slightly decreased in the nano⁻ group from day 18 to 36. Ultrastructural studies of the differentiated cells revealed some similarities to hepatocytes. Urea production, secretion of albumin and α-fetoprotein, and metabolic activity of the CYP450 enzymes were significantly increased within in vitro differentiated HLCs on nanofibers at day 36. MSCs, early and late HLCs in both nano⁻ and nano⁺ culture conditions that were transplanted by an intravenous route caused a decrease in liver fibrosis when engrafted in the recipient liver and were able to differentiate into functional hepatocytes (ALB⁺), except for late HLCs in the nano⁻ group. Late HLCs transplanted in the nano⁺ group were more effective in rescuing liver failure, enhancing serum ALB, homing transplanted cells and undergoing functional engraftment than the other groups. These results showed that topographic properties of nanofibers enhance differentiation of HLCs from MSCs and maintain their function in long-term culture, which has implications for cell therapies.     

透明质酸钠溶液复合可注射型骨髓间充质干细胞修复退变椎间盘

背景：透明质酸作为椎间盘组织工程支架的基质材料,可提供蛋白多糖附着点,增加蛋白多糖的沉积,以足够大的孔率允许种子细胞长入。 目的：观察透明质酸钠混合溶液复合骨髓间充质干细胞修复兔退变椎间盘的效果。 方法：以后外侧穿刺抽吸L1/2和L3/4髓核构建日本大耳白兔椎间盘退变模型,造模后2周应用微量注射器向L3/4椎间盘内注射同种异体骨髓间充质干细胞与透明质酸钠混合溶液作为实验组,L1/2椎间盘注射透明质酸钠作为对照组。注射后2,4,8,12 周时行兔椎间盘影像学及病理学检查。 结果与结论：对照组椎间盘高度呈降低趋势,实验组注射后2周椎间盘高度缓慢下降,之后缓慢升高,两组在4个时间点椎间盘高度指数改变差异有显著性意义(P < 0.05)。病理结果显示实验组髓核纤维环形态得到保留,髓核纤维环边界清晰,植入的骨髓间充质干细胞产生增殖分裂,并向周围迁徙规律排列,其病理学评分明显高于对照组。12周内实验组Ⅱ型胶原含量高于对照组(P < 0.05)。说明移植于退变椎间盘内的骨髓间充质干细胞能够存活,且有增殖能力,其与透明质酸钠混合溶液联合移植可以延缓退变椎间盘进一步退变,并促进退变椎间盘修复。     

The effect of hyaluronan-based delivery of stromal cell-derived factor-1 on the recruitment of MSCs in degenerating intervertebral discs

Intervertebral disc (IVD) degeneration is the leading cause of low back pain and disability in the active population. Transplantation of mesenchymal stem cells (MSCs) in a hydrogel carrier can induce regenerative effects in degenerated IVDs. Moreover, it was found that degenerative discs release chemoattractants effective in MSC recruitment. Based on these findings, we hypothesized that an injectable hydrogel that can enhance the number of migrated MSCs in the IVD and provide a suitable matrix for their survival and differentiation would be ideal. The purpose of this study was to evaluate the potential of a thermoreversible hyaluronan-poly(N-isopropylacrylamide) (HAP) hydrogel as chemoattractant delivery system to recruit human MSCs in degenerative IVDs. The results demonstrate that HAP hydrogels containing stromal cell derived factor-1 (SDF-1) significantly increased the number of MSCs migrating into nucleotomized discs compared with discs treated with only HAP or SDF-1 in solution. HAP hydrogels releasing SDF-1 enhanced both the number of recruited cells and their migration distance in the IVD tissue. Furthermore, this phenomenon was dependent on MSC donor age. In conclusion, HAP SDF-1 is effective for the recruitment of stem cells in the IVD, thus opening new possibilities for the development of regenerative therapies based on endogenous cell migration.     

Association between bone mineral density and lumbar disc degeneration

ObjectivesHigher vertebral bone mineral density (BMD) has been found to be related with lumbar disc degeneration (LDD), while relationship between femoral neck BMD and LDD remains controversial. The aim of our research was to study the relationship between LDD and BMD of the lumbar spine and femoral neck.Study designThe study population consisted of 168 postmenopausal women (aged 63.3–75.0 years, mean 68.6 years) from the prospective OSTPRE and OSTPRE-FPS study cohorts. The severity of LDD was graded from T2-weighted MRI images using the five-grade Pfirrmann classification. Four vertebral levels (L1-L4) were studied (total 672 discs). The association between lumbar BMD and Z-score and the severity of LDD was studied separately for each vertebral level with AN(C)OVA analysis, using potential confounders as covariates.ResultsHigher lumbar BMD and Z-score were associated with more severe LDD at all studied levels (L1-L4): between L4-L5 disc and L4 BMD (p = 0.044) and L4 Z-score (p = 0.052), between L2-L3 disc and L3 BMD (p = 0.001) and at all other levels (p < 0.001). The mean degeneration grade of the studied discs was associated with the mean L1-L4 BMD and Z-score (p < 0.001). Statistical significance of any result did not alter after controlling for confounding factors. There was no significant association between femoral neck BMD and LDD.ConclusionsHigher lumbar BMD/Z-score were associated with more severe LDD. There was no significant association between femoral neck BMD and disc degeneration. Femoral neck BMD may be a more reliable measurement for diagnosing osteoporosis in postmenopausal women with degenerative changes in the lumbar spine.     

Resveratrol Has Anabolic Effects on Disc Degeneration in a Rabbit Model

This study was done to evaluate whether injections of resveratrol, a natural compound found in the skin of grapes, had anabolic effects on degenerated intervertebral discs in a rabbit model. Two non-continuous lumbar discs were punctured in rabbits to induce disc degeneration. Four weeks and 6 weeks after puncture, the rabbits were treated by injections with dimethylsulfoxide (DMSO) or resveratrol. At 4, 8, and 16 weeks after initial injection, rabbits were sacrificed and the spine was extracted for magnetic resonance image (MRI), mRNA expression, and histological staining. Resveratrol treatment resulted in stronger signal intensity in T2-weighted images. MRI grade showed significantly lower in the resveratrol group than the DMSO group (P = 0.039). In the resveratrol group, aggrecan gene expression was significantly increased than that in the DMSO group at 16 weeks after injection (P = 0.027). MMP-13 mRNA levels in the resveratrol group were significantly decreased than those in the DMSO group at 8 and 16 weeks (P = 0.006 and P = 0.048, respectively). In hematoxylin and eosin stain, resveratrol-treated discs showed the features of regeneration. Histologic grade revealed improvement in resveratrol-treated discs, compared with DMSO-treated discs (P = 0.024). These anabolic effects on degenerated discs indicate that resveratrol is a promising candidate for treatment of degenerative disc disease.     

退变椎间盘中护骨素水平与Schneiderman分级的关系

背景：护骨素可抑制破骨细胞活性,调节软骨重塑过程,在维持椎间盘软骨组织完整性方面具有重要作用。 目的：观察腰椎间盘退行性变患者椎间盘中护骨素的表达及其与病情严重程度的关系。 方法：选取64例腰椎间盘退行性变患者及25例椎体爆裂性骨折患者作为研究对象,收集患者术后的椎间盘组织,检测椎间盘中护骨素mRNA和蛋白的水平。以腰椎间盘MRI检查结果为依据,根据Schneiderman分级方法进行分级,并分析椎间盘中的护骨素水平与疾病分级的关系。 结果与结论：实时荧光定量PCR及ELISA检测发现腰椎间盘退行性变患者的腰椎间盘组织中护骨素mRNA和蛋白水平均明显高于椎体爆裂性骨折患者(P < 0.01)。非条件logistic回归分析表明,升高的护骨素mRNA和蛋白是腰椎间盘退行性变发病的独立危险因子。且护骨素mRNA和蛋白水平均与Schneiderman分级显著正相关(r=0.367,0.412,P < 0.01),说明高表达的护骨素参与了腰椎间盘退行性变的发生,并可反映疾病的严重程度。     

腰椎间盘退变MRI：与Modic改变相关的影像学分析

背景：部分椎间盘源性下腰痛患者MRI可出现Modic改变,但Modic改变的相关因素及Modic改变与椎间盘退变之间因果关系目前尚不十分清楚。 目的：分析存在腰椎间盘Modic改变的下腰痛患者性别、年龄分布特点及腰椎间盘发生Modic改变的相关因素。 方法：回顾性分析634例(2 536个椎间盘)存在腰椎间盘Modic改变患者的性别、年龄分布特点,并分析腰椎间盘Modic改变与椎间盘突出或膨出、Schmorl结节、椎体滑脱、椎间盘解剖水平及椎间盘退行性改变程度的相关性。 结果与结论：634例患者中,女性患者ModicⅡ、Ⅲ型出现率均较男性高,而ModicⅠ型出现率小于男性患者(P < 0.001);40岁以上患者较40岁以下患者Modic各型改变的出现率均高(P < 0.001)。2 536个腰椎间盘中,有椎体滑脱、出现Schmorl结节、有椎间盘突出或膨出者Modic各型改变的出现率均比无此类表现者高(P < 0.001);L4/5、L5/S1水平(低位)Modic各型改变的出现率均比L2/3、L3/4水平(高位)高(P < 0.001);椎间盘退行性改变越严重,Modic各型改变的出现率越高(P < 0.001)。椎间盘退行性改变分级、Schmorl结节与Modic改变有显著相关性。结果说明,腰椎间盘Modic改变与患者性别、年龄、椎间盘有无突出或膨出、有无Schmorl结节、椎体有无滑脱、椎间盘解剖水平及椎间盘退行性改变分级均有相关性。其中,椎间盘退行性改变分级、Schmorl结节与腰椎间盘Modic改变间的相关性最高,且椎间盘退行性改变分级较Schmorl结节与之相关性更高。     

椎间盘退变过程中MMP/Timp基因表达变化的研究

目的:采用新西兰大白兔的纤维环损伤制作腰椎间盘退变模型,以证实和比较在人椎间盘退变中的基因变化情况.方法:损伤L4.5、L5.6纤维环,行核磁共振及计算机扫描摄影拍片证实椎间盘退变情况,同时取椎间盘行精确定量逆转录聚合酶链式反应观测MMP/Timp系列基因的变化.结果:证实了兔腰椎纤维环损伤后腰椎逐渐退变,且与人类退变结果相似,基因表达情况MMP-1、MMP-2、MMP-3、Timp-1、Timp-2早期均上调,MMP-3、Timp-1在退变的晚期出现下调.结论:人类腰椎间盘退变中明显上调的基因在此退变模型椎间盘中被发现同样上调,从而在分子水平证实了此动物退变模型与人类的相似性.     

腰椎间盘的扩散张量成像观测及临床应用

目的　为腰椎间盘退变导致的腰腿痛等病症的临床诊断提供影像学依据。 方法　选取脊柱腰段扩散张量成像（DTI）扫描检查正常者200例和腰椎间盘退变者100例,在工作站划分腰椎间盘和腰椎间盘退变的感兴趣区,测量感兴趣区的表观扩散系数（ADC）和各向异性分数（FA）,比较不同解剖部位、年龄组腰椎间盘和不同Pfirrmann分级腰椎间盘退变的FA、ADC值。 结果　不同解剖部位腰椎间盘的FA值和ADC值均有统计学差异（P<0.05）,L1~2、L2~3、L3~4椎间盘的FA值逐渐降低,L4~5、L5~S1椎间盘的FA值则逐渐增高;L1~2、L2~3、L3~4椎间盘的ADC值逐渐增高,L3~4、L4~5、L5~S1椎间盘的ADC值则无明显变化。不同年龄组腰椎间盘的FA值无统计学差异（P>0.05）,ADC值有统计学差异（P<0.05）,随着年龄增长ADC值逐渐降低。不同Pfirrmann分级腰椎间盘退变的FA值和ADC值均有统计学差异（P<0.05）,随着Pfirrmann分级增高,FA值逐渐增高,ADC值逐渐降低。 结论　解剖部位、年龄均影响腰椎间盘的ADC值,DTI的FA值和ADC值可以定量评估腰椎间盘及其退变程度,为早期腰椎间盘退变的临床诊断提供影像学依据。     

腰椎间盘的扩散张量成像观测及临床应用

目的　为腰椎间盘退变导致的腰腿痛等病症的临床诊断提供影像学依据。 方法　选取脊柱腰段扩散张量成像（DTI）扫描检查正常者200例和腰椎间盘退变者100例,在工作站划分腰椎间盘和腰椎间盘退变的感兴趣区,测量感兴趣区的表观扩散系数（ADC）和各向异性分数（FA）,比较不同解剖部位、年龄组腰椎间盘和不同Pfirrmann分级腰椎间盘退变的FA、ADC值。 结果　不同解剖部位腰椎间盘的FA值和ADC值均有统计学差异（P<0.05）,L1~2、L2~3、L3~4椎间盘的FA值逐渐降低,L4~5、L5~S1椎间盘的FA值则逐渐增高;L1~2、L2~3、L3~4椎间盘的ADC值逐渐增高,L3~4、L4~5、L5~S1椎间盘的ADC值则无明显变化。不同年龄组腰椎间盘的FA值无统计学差异（P>0.05）,ADC值有统计学差异（P<0.05）,随着年龄增长ADC值逐渐降低。不同Pfirrmann分级腰椎间盘退变的FA值和ADC值均有统计学差异（P<0.05）,随着Pfirrmann分级增高,FA值逐渐增高,ADC值逐渐降低。 结论　解剖部位、年龄均影响腰椎间盘的ADC值,DTI的FA值和ADC值可以定量评估腰椎间盘及其退变程度,为早期腰椎间盘退变的临床诊断提供影像学依据。     

The use of SA-β-Gal to assess cell senescence in intervertebral disc cells

Introduction The intervertebral disc is reported to age faster than other connective tissues with significant degenerative changes already seen in the second decade of life. In other tissues, senescent cells have an altered phenotype, often with a decreased synthetic ability and response to anabolic cytokines. They appear to contribute to age‐related pathologies such as the degeneration of articular cartilage in osteoarthritis. Little is known of cell senescence in the intervertebral disc. In this study, we have investigated the production of senescence‐associated‐ß‐galactosidase (SA‐ß‐Gal), a ‘biomarker’ of cell senescence, in intervertebral disc cells both in cultured populations in vitro, and in vivo, in pathological human discs. Material and methods Intervertebral disc cells were extracted from coccygeal bovine discs and cultured for 3 months. Confluent cell preparations were stained for SA‐β‐Gal ( Fenton et al. 2001 ) at passages 0, 1, 2, 3 and 4. Preparations were fixed in 3% paraformaldehyde in phosphate‐buffered saline (PBS) for 5 min at room temperature and incubated for 24 h at 37 °C in SA‐ß‐Gal solution containing 1 mg/ml 5‐bromo‐4‐chloro‐3‐indolyl ß‐d ‐galactopyranoside (X‐Gal, Sigma, Poole, UK), 5 mmol/l potassium ferrocyanide, 5 mmol/l potassium ferricyanide, 150 mmol/l NaCl, 2 mmol/l MgCl₂ and 40 mmol/l trisodium citrate, titrated with NaH₂PO₄ to pH 6.0. Lysosomal (nonsenescent) ß‐galactosidase activity was detected using the same solution but titrated to pH 4.0. After staining, preparations were rinsed in ice‐cold PBS, dehydrated and mounted. Pathological human disc from patients with disc herniations or discogenic back pain were also stained for SA‐β‐Gal (immersing the tissue in the stain solution overnight) then cryosectioning (10 µm thick) and fixing. Articular cartilage was studied for comparison ( Price et al. 2002 ). Results Cultured intervertebral discs demonstrated some staining for SA‐ß‐Gal at all passages investigated, but there was little change in staining with passage number. Cells in most pathological human discs demonstrated staining for SA‐ß‐Gal. Positive cells were seen more commonly in herniated discs [7/9 (78%); mean age: 46 ± 13] than in those removed from patients with discogenic back pain [2/6 (33%); mean age: 32 ± 5]. Discussion To our knowledge, this is the first study of cell senescence in intervertebral disc cells. The greatest level was seen in tissue from herniated discs where cell cluster formation and cell proliferation are common (but the mean age of the herniation group was slightly higher than the discogenic back pain group). However, for a tissue demonstrating such significant age‐related degenerative changes, there is surprisingly little expression of SA‐ß‐Gal in comparison with that found in other pathological cartilages. These preliminary data suggest that, unlike the situation in osteoarthritis, early cell senescence is not a major contributing factor in the pathogenesis of disc degeneration.