人颈椎间盘髓核细胞的体外培养和鉴定

目的：建立人颈椎间盘髓核细胞体外培养体系,并对其细胞表型进行鉴定。方法：采用酶消化法分离人颈椎间盘髓核细胞,进行单层培养,倒置相差显微镜观察细胞生长和形态,流式细胞仪测定细胞周期和凋亡率,并行甲苯胺蓝、Ⅱ型胶原及CK8免疫组化染色对其细胞表型进行鉴定。结果：原代髓核细胞凋亡率6.1±1.4%,S期细胞比例7.3±0.5%。贴壁后形态为多角形或短楔形,传代后生长加速。细胞呈甲苯胺蓝异染性;Ⅱ型胶原免疫组化染色阳性;只有少量椭圆形大细胞CK8免疫组化染色阳性。结论：成功建立人颈椎间盘髓核细胞体外培养模型,并证实成年后髓核内仍有少量细胞保持脊索细胞表型。     

改良胶原酶消化法分离培养人原代髓核细胞

目的:优化人原代髓核细胞的体外分离培养方法,为椎间盘退变的防治研究提供种子细胞。方法:无菌环境中摘取人椎间盘髓核组织,采用多次胶原酶消化法分离提取原代人髓核细胞,置于5%CO2培养箱中37℃恒温培养,倒置相差显微镜中观察细胞形态,采用MTT法绘制细胞生长曲线,甲苯胺蓝染色法检测髓核细胞内蛋白多糖的表达情况,细胞免疫荧光染色法检测Ⅱ型胶原蛋白表达情况。结果:本研究中获得的细胞形态不规则,呈梭形或多角形,原代细胞48 h内贴壁,培养第8天左右细胞融合度可达90%,第三代细胞12 h内即可贴壁,生长至融合90%约需5d。甲苯胺蓝染色及细胞免疫荧光染色均阳性,提示所得细胞具有分泌蛋白多糖及Ⅱ型胶原蛋白的功能。结论:改良胶原酶消化法可获得大量纯净的人髓核细胞,提高培养效率,原代及传代细胞具备类软骨细胞表型,且活性及功能均较为稳定,可作为椎间盘组织工程研究的种子细胞。     

低强度周期性静水压力对人膝关节软骨细胞的影响

目的:探讨低强度周期性静水压力对体外培养的人膝关节软骨细胞增殖、凋亡,以及细胞Ⅱ型胶原分泌表达的影响。方法:体外酶消化法分离培养成人膝关节正常软骨细胞,将培养的第3代软骨细胞分为两组:正常对照组、3.0MPa组压力实验组,应用多功能恒温体外细胞培养中高压静水压力加载装置加载低强度周期性压力,共5d,每天2h。Ⅱ型胶原免疫组织化学染色法和甲苯胺蓝染色法鉴定软骨细胞,流式细胞术检测细胞凋亡,四甲基偶氮唑蓝(MTT)法绘制细胞生长曲线,qRT-PCR、Western-Blot检测Ⅱ型胶原的分泌和表达。结果:软骨细胞Ⅱ型胶原免疫组织化学染色和甲苯胺蓝染色均显示为阳性。与正常对照组相比,3.0MPa组表现出促进软骨细胞增殖,抑制细胞凋亡,且Ⅱ型胶原的合成分泌明显升高(P0.05)。结论:通过体外模拟人生理情况下较低强度(3.0MPa)的周期性静水压力对人软骨细胞增殖、凋亡水平及周围基质分泌合成功能的影响,初步证实了较低强度压力有助于软骨自我修复和自身保护作用的发挥。     

葡萄糖对体外培养椎间盘髓核细胞的影响

目的:探讨葡萄糖对体外培养髓核细胞的生物学特性的影响。方法:酶消化法分离培养正常椎间盘髓核细胞。对照组:DF12+20%FBS培养液(葡萄糖浓度1000mg/L)、无糖组:无糖DMEM+20%FBS(葡萄糖浓度0mg/L)培养液培养髓核细胞。HE染色观察细胞形态变化,计数板计数细胞总数,台盼蓝染色计算髓核细胞活性比率,流式细胞仪检测细胞凋亡率,Hoechst33258染色观察凋亡细胞核的变化。结果:两组培养液培养细胞形态大体正常,并无明显变化。对照组细胞总数明显多于无糖组。细胞活性率对照组也高于无糖组。Hoechst33258染色凋亡细胞,凋亡细胞核内可见致密的颗粒状和块状荧光,细胞核形态不规则,少数细胞核碎裂,部分细胞核呈月牙形。结论:葡萄糖对椎间盘髓核细胞的增殖及凋亡有显著的影响。     

人骨形态蛋白-2对椎间盘细胞蛋白多糖和Ⅱ型胶原的影响

目的研究人骨形态蛋白(human bone morphogenetic protein-2,hBMP-2)对体外培养人腰椎间盘髓核细胞Ⅱ型胶原和aggrecan的影响。方法人退变髓核细胞体外分离培养,通过免疫组织化学鉴定椎间盘细胞。利用ELISA法检测对照组和不同剂量hBMP-2(10ng/ml和100ng/ml)组Ⅱ型胶原和aggrecan的表达水平。用RT-PCR检测细胞Ⅱ型胶原和aggrecan的mRNA表达水平。结果加入hBMP-2后Ⅱ型胶原和aggrecan表达增加,并存在剂量依赖关系(P<0.01)。在第6天RT-PCR结果显示hBMP-2组aggrecan和Ⅱ型胶原mRNA的表达高于对照组,并且随剂量增高aggrecan和Ⅱ型胶原mRNA的表达量逐渐增加。结论hBMP-2可促进体外培养人腰椎间盘细胞合成代谢,Ⅱ型胶原和aggrecan表达量增加,并存在剂量依赖关系,提示hBMP-2可能对退变椎间盘具有修复功能。     

大鼠髓核细胞原代培养及表型鉴定

目的:探讨Ⅱ型胶原酶联合透明质酸酶消化分离培养髓核细胞及免疫细胞化学表型鉴定的可行性。方法:无菌条件下分离SD大鼠凝胶状髓核,采用Ⅱ型胶原酶联合透明质酸酶消化分离髓核细胞并连续培养,倒置相差显微镜下观察,随后进行免疫细胞化学染色检测不同代次髓核细胞HIF-1、Ⅰ、Ⅱ型胶原、MMP2及蛋白聚糖的表达情况,并给予MTT法测定髓核细胞生长曲线。结果:Ⅱ型胶原酶联合透明质酸酶分离培养原代髓核细胞需要12 d左右贴壁,达95%融合需要34 d,而传代髓核细胞贴壁速率明显增快至10 h,且其倍增时间约为2.5 d;免疫细胞化学显示髓核细胞均表达HIF-1、Ⅰ、Ⅱ型胶原、MMP2和蛋白聚糖,且随着髓核细胞传代其HIF-1α、HIF-1β、Ⅰ型胶原及MMP2表达均增加,但Ⅱ型胶原表达降低,而蛋白聚糖表达无明显差异;MTT法显示随着髓核细胞传代其增殖有所减缓。结论:Ⅱ型胶原酶联合透明质酸酶可成功分离髓核细胞,提高培养效率,且HIF-1α、HIF-1β、Ⅰ、Ⅱ型胶原及MMP2可作为髓核细胞表型分子用于髓核细胞的鉴定。     

富血小板纤维蛋白对兔骨髓间充质干细胞成软骨分化的影响

目的：观察自体富血小板纤维蛋白（platelet-rich fibrin,PRF）对体外培养的兔骨髓间充质干细胞（Bonemarrowmesenchymalstemcells,BMSCs）成软骨分化的影响。方法：兔心脏采血制备PRF,电镜观察其超微结构;分离培养兔BMSCs,取第3代细胞用于实验．分为PIuF组、阳性对照组、空白对照组。诱导培养21d后,对三组细胞分别进行形态学观察,成软骨鉴定染色（甲苯胺蓝、Ⅱ型胶原免疫组化染色）,软骨相关基因表达检测（Ⅱ型胶原、Aggrecan、SOX9）。结果：PRF组和阳性对照组中BMSCs经诱导后,细胞由长梭形变为三角形、多角形、圆形;甲苯胺蓝、Ⅱ型胶原免疫组化染色均为阳性;Ⅱ型胶原、Aggrecan、SOX9基因表达水平均较高,两组比较无统计学差异,空白对照组未见相关分化现象。结论：PRF在体外可促进兔BMSCs成软骨分化,可作为自体生物材料,在构建组织工程软骨中发挥更好的作用。     

富血小板纤维蛋白对兔骨髓间充质干细胞成软骨分化的影响*

摘要目的：观察自体富血小板纤维蛋白（platelet-rich fibrin, PRF）对体外培养的兔骨髓间充质干细胞（Bone marrow mesenchymal stemcells, BMSCs）成软骨分化的影响。方法：兔心脏采血制备PRF,电镜观察其超微结构;分离培养兔BMSCs,取第3代细胞用于 实验,分为PRF组、阳性对照组、空白对照组。诱导培养21d 后,对三组细胞分别进行形态学观察,成软骨鉴定染色（甲苯胺蓝、II 型胶原免疫组化染色）,软骨相关基因表达检测（Ⅱ型胶原、Aggrecan、SOX9）。结果：PRF 组和阳性对照组中BMSCs经诱导后,细 胞由长梭形变为三角形、多角形、圆形;甲苯胺蓝、II 型胶原免疫组化染色均为阳性;Ⅱ型胶原、Aggrecan、SOX9基因表达水平均 较高,两组比较无统计学差异,空白对照组未见相关分化现象。结论：PRF在体外可促进兔BMSCs 成软骨分化,可作为自体生物 材料,在构建组织工程软骨中发挥更好的作用。     

人关节软骨细胞的体外分离、培养与鉴定

目的:研究人关节软骨细胞的体外分离、培养及鉴定方法,观察各代人关节软骨细胞的形态学特性。方法:取人创伤性截肢的无菌膝关节软骨,采用两步酶消化法分离培养人关节软骨细胞,并进行传代培养。通过倒置相差显微镜下观察细胞形态,绘制生长曲线,甲苯胺蓝染色及Ⅱ型胶原免疫组织化学染色对细胞进行鉴定。结果:两步酶消化法消化出的软骨细胞呈圆形,培养2-3天,细胞贴壁、变形,呈三角形或多角形,2周左右细胞融合成层,传代5次后出现去分化。软骨细胞增殖和生长缓慢。形态学、免疫组织化学染色显示细胞培养5代以内可以保持表型的稳定。结论:本研究采用胰蛋白酶及Ⅱ型胶原酶联合消化法获得大量高纯度、高活性的人关节软骨细胞。5代以内细胞生长良好,生物学特性明显,适合于实验研究,5代以后出现去分化现象。     

人正常及骨关节炎软骨细胞体外培养的对照研究

摘要目的：研究人正常软骨细胞及骨关节炎软骨细胞的体外分离、培养及鉴定方法,对其生物学特性进行对照并评价其生物学活性。方法：取人创伤性截肢与骨关节炎全膝置换的无菌膝关节软骨,采用两步酶消化法分离培养人关节软骨细胞,并进行传代培养。通过倒置相差显微镜下观察细胞形态,绘制生长曲线,测细胞增殖,甲苯胺蓝染色及Ⅱ型胶原免疫组织化学染色对细胞进行对照研究。结果：骨关节炎软骨细胞形态似成纤维细胞,生长速度明显较正常软骨细胞慢。MTT测细胞增殖显示,第2．4、6代骨关节炎软骨细胞在相同时间点大都比同代正常软骨细胞增殖速度慢（P〈0．05）。甲苯胺蓝及Ⅱ型胶原免疫组化染色显示,骨关节炎软骨细胞染色较正常软骨细胞浅,经多次传代后基本无着色。结论：正常软骨细胞5代以内细胞生长良好,生物学特性明显,5代以后出现去分化现象。骨关节炎软骨细胞增殖慢,生物学特征退变旱,符合软骨细胞退变的表现。这为骨关节炎在软骨细胞水平的研究提供了实验基础。     

周期性机械应力对髓核细胞增殖和细胞外基质表达的影响

目的：探讨周期性机械应力对髓核细胞增殖和细胞外基质表达的影响。方法：对兔髓核细胞进行体外细胞培养,对细胞施加周期性机械应力（0.25Mpa,0.1Hz）。实验分为2组,不加压组和加压组,不加压组置于单纯旋转式生物反应器内,加压组每天置于周期性机械应力场内2小时。分别于3天,7天检测细胞数目以及聚集蛋白聚糖（aggrecan）和Ⅱ型胶原的基因表达。结果：髓核细胞的增殖和聚集蛋白聚糖、Ⅱ型胶原基因的表达水平与周期性压力密切相关,在周期性机械应力刺激下髓核细胞增殖明显,细胞外基质的分泌增加,组织工程髓核细胞的活性显著提高。结论：周期性机械应力能够显著促进髓核细胞增殖,同时上调聚集蛋白聚糖、Ⅱ型胶原的基因的表达。     

Exploiting notochord cells for stem cell-based regeneration of the intervertebral disc

The nucleus pulposus is an avascular and aneural tissue that has significant influence on the homeostasis and overall function of the intervertebral disc. The nucleus pulposus is comprised of a heterogeneous population of cells including large notochord cells and smaller chondrocyte-like cells. Loss of notochord cells has been correlated with the pathogenesis of disc degeneration and consequently, it has been hypothesized that regeneration of the disc could be mediated by notochord cells. Attempts to grow and expand notochord cells in vitro have thus far been limited by cell availability and ineffective culturing methodologies. As a result, co-culturing techniques have been developed in order to exploit notochord-derived signals for the differentiation of proliferative mesenchymal stem cells. A recent study by Korecki et al. has demonstrated that notochord cell conditioned medium has the ability to differentiate mesenchymal stem cells toward a nucleus pulposus-like fate, producing high levels of glycosaminoglycans and type III collagen. These findings suggest that growth factors and other soluble proteins may be able to stimulate endogenous IVD tissue maintenance in vivo. While this study advances our understanding of intervertebral disc cell-cell interactions, limitations remain in our ability to determine the phenotype of terminally differentiated cells within the nucleus pulposus (ie mature notochord cells) and therefore assess the relevance of differentiated mesenchymal stem cells for disc regeneration. In order for the field to progress, elucidation of the notochord phenotype remains of utmost importance.     

Chondrocyte‐like nested cells in the aged intervertebral disc are late‐stage nucleus pulposus cells

Aging is a major risk factor of intervertebral disc degeneration and a leading cause of back pain. Pathological changes associated with disc degeneration include the absence of large, vacuolated and reticular‐shaped nucleus pulposus cells, and appearance of smaller cells nested in lacunae. These small nested cells are conventionally described as chondrocyte‐like cells; however, their origin in the intervertebral disc is unknown. Here, using a genetic mouse model and a fate mapping strategy, we have found that the chondrocyte‐like cells in degenerating intervertebral discs are, in fact, nucleus pulposus cells. With aging, the nucleus pulposus cells fuse their cell membranes to form the nested lacunae. Next, we characterized the expression of sonic hedgehog (SHH), crucial for the maintenance of nucleus pulposus cells, and found that as intervertebral discs age and degenerate, expression of SHH and its target Brachyury is gradually lost. The results indicate that the chondrocyte‐like phenotype represents a terminal stage of differentiation preceding loss of nucleus pulposus cells and disc collapse.     

Phenotypic characteristics of the nucleus pulposus: expression of hypoxia inducing factor-1, glucose transporter-1 and MMP-2

Attempts to study the biology of the nucleus pulposus have been limited in scope due to the low rates of cell proliferation, difficulties in maintaining viable disc cells in culture and the absence of a clearly defined phenotype. The major objective of this communication is to construct a phenotypic signature for cells of the nucleus pulposus that is based on the hypothesis that in response to restriction on oxygen and nutrient flux, there is expression of HIF-1, GLUT-1 and MMP-2. Nucleus pulposus, as well as annulus fibrosus and cartilage of the vertebral end plates, was collected from rat spinal units. Western blot analysis and immunohistochemistry clearly showed that there was a significant level of expression of the HIF-1 beta isoform in the nucleus pulposus; HIF-1 beta was present at lower levels in cells of the annulus and the end plate. In contrast to HIF-1 beta, HIF-1 alpha was expressed only in the nucleus pulposus. This isoform was absent from both the cartilage end plate and annulus. We detected HIF-1 alpha immunohistochemically in the nucleus pulposus; however, the staining was light and diffuse. Cells of the nucleus pulposus expressed GLUT-1; in contrast, when probed by Western blot analysis the annulus and cartilage were negative for this protein. Western blot analysis also showed that in the nucleus pulposus the level of MMP-2 was high when compared to the adjacent tissues. We suggest that the differential expression of the two HIF isoforms, and GLUT-1 and MMP-2, provides a phenotypic signature that permits cells of the nucleus pulposus to be distinguished from neighboring tissues. Moreover, the presence of these isoforms provides evidence that cells of the disc respond to hypoxia and nutrient stress by upregulating stress-responsive genes.     

miR-155对人椎间盘退变髓核细胞凋亡的作用及机制研究

目的:探讨mi R-155对人椎间盘退变髓核细胞凋亡的影响及其作用机制。方法:首先构建慢病毒表达载体,在293T细胞中获得重组慢病毒,然后感染椎间盘退变髓核细胞得到稳定过表达细胞系,同时设置空载体和空白细胞组对照。用荧光显微镜观察慢病毒载体的标签蛋白GFP的表达,分别提取三组细胞总RNA,采用RT-q PCR方法检测mi R-155的表达;通过流式细胞术检测细胞凋亡,Western-Blot检测细胞中凋亡相关蛋白FADD、Caspase-3、Bcl-2及Bax的表达,JC-1试剂盒检测细胞线粒体膜电位的变化情况。结果:在荧光显微镜下,经慢病毒感染的过表达细胞系和空载体细胞系均出现绿色荧光,而空白细胞组未见绿色荧光;RT-qPCR结果显示构建的稳定过表达细胞系(GV369-miR-155-NP)中mi R-155的表达水平较高,且与空载体细胞系及空白细胞对照组均呈显著性差异(P0.05);与空载体组(GV369-NP)及空白细胞对照组相比,过表达组(GV369-miR-155-NP)细胞凋亡率显著降低(P0.05),FADD、Caspase-3、Bax的表达水平均明显下降,而Bcl-2表达水平显著增加(P0.05)。结论:mi R-155可能通过靶向结合Caspase-3和FADD阻止FasL-Fas途径或通过线粒体途径抑制人椎间盘退变髓核细胞凋亡。     

过表达MicroRNA-21通过PTEN/PI3K/AKT信号通路调控人退变髓核细胞自噬的研究

目的:探讨过表达mi R-21通过PTEN/PI3K/AKT通路对人退变髓核细胞自噬的影响。方法:构建稳定过表达mi R-21 mimic人退变髓核细胞,转染无意义序列作为mi R-21 mimic control组,采用RT-qPCR检测转染效率;利用MDC荧光染色法观察细胞自噬泡;Western-Blot检测细胞自噬相关蛋白LC3和P62的表达以及PTEN/PI3K/AKT信号通路中关键蛋白PTEN、PI3K及AKT的表达水平。结果:RT-qPCR结果表明mi R-21 mimic转染成功且效率较高,与mi R-21 mimic control组及空白细胞对照组相比,差异显著(P0.05)。荧光显微镜观察MDC染色情况,mi R-21 mimic组的细胞中几乎没有发现自噬体,而mi R-21 mimic control组以及空白对照组细胞中自噬体均较多,与前者相比差异均明显,具有统计学意义(P0.05)。mi R-21 mimic组细胞中LC3-II/LC3-I表达量的比值均显著低于mi R-21 mimic control组及空白对照组细胞(P0.05);而P62在mi R-21 mimic组细胞中表达量显著高于mi R-21 mimic control组及空白细胞对照组,具有统计学意义(P0.05)。mi R-21 mimic组中PTEN蛋白的表达水平较低,与另外两组相比具有统计学意义(P0.05);磷酸化的PI3K(p-PI3K)和AKT(p-Akt)在mi R-21 mimic组中均明显高于mi R-21 mimic control组和空白细胞对照组,差异具有统计学意义(P0.05)。结论:mi R-21可以通过靶向沉默PTEN,促进PI3K和AKT发生磷酸化,进而使PTEN/PI3K/AKT信号通路被激活,最终抑制人椎间盘退变髓核细胞的自噬。