小鼠前成骨细胞MC3T3-E1在自组装多肽水凝胶支架中的成骨分化

目的研究MC3T3-E1细胞在自组装多肽水凝胶支架上的生长和成骨分化.方法在多肽水凝胶支架RADA16上接种MC3T3-E1细胞,荧光染色观察细胞形态和存活情况;组织化学染色检测MC3T3-E1细胞碱性磷酸酶活性以及细胞外钙质沉积;RT-PCR分析成骨特异性基因的表达.结果 MC3T3-E1细胞在水凝胶支架RADA16上粘附铺展良好,呈纺锤样形态.诱导培养后支架上的细胞有较高水平的碱性磷酸酶表达和矿化基质沉积.此外,骨分化特异性基因骨桥蛋白和骨涎蛋白也有表达,且表达量随培养时间的延长而增多.结论 在自组装水凝胶内MC3T3-E1细胞可向成骨方向分化,并能在凝胶内产生矿化的细胞外基质.     

改良组织块法培养小鼠成骨细胞的研究

目的 探讨简便、经济、高效的成骨细胞培养方法.方法 取新生乳小鼠的颅骨,用改良的组织块法分离培养成骨细胞;从细胞的形态学、增殖、碱性磷酸酶染色、矿化结节茜素红染色及骨钙素基因表达水平等方法鉴定、比较培养的成骨细胞.结果 分离培养的成骨细胞生长状态良好,纯度较高,具有典型的成骨细胞形态特征,碱性磷酸酶染色及矿化结节茜素红染色阳性,骨钙素基因表达水平明显高于阴性对照,差异有统计学意义(P＜0.05).比较1～4次分离培养的成骨细胞在形态、增殖及分化功能上差异均无统计学意义(P＞0.05).结论 改良的组织块法分离培养乳小鼠的颅骨可获得大量纯度较高的成骨细胞,节约经费、时间,操作简便.     

流体剪切力对成骨细胞LEF-1蛋白表达的影响

目的：探讨MC3T3-E1细胞在流体剪切力作用下LEF-1的表达。方法：通过流体剪切加载系统对MC3T3-E1爬片细胞施加12dyn/cm的流体剪切力,分别作用0h,2h,4h,8h,12h,用RT-PCR方法检测细胞受力前后LEF-1 mRNA表达的变化;应用免疫荧光双标记法检测不同时间点流体剪切力作用下MC3T3-E1细胞中的LEF-1 mRNA表达改变。结果：RT-PCR和免疫荧光双标记法的结果表明12dyn/cm 8h流体剪切力作用下的MC3T3-E1细胞LEF-1 mRNA的表达较其它各组明显增强。结论：通过流体剪切力力学刺激,激活了成骨细胞LEF-1/TCF1转录活动,LEF-1 mRNA的表达增强可能是成骨细胞经典Wnt信号通路对剪切应力的应答反应。     

模拟微重力通过调节AKT磷酸化抑制前成骨细胞的增殖

目的:研究模拟微重力对前成骨细胞的增殖作用及其分子机制。方法:利用2D回转器模拟失重条件培养前成骨细胞MC3T3-E1 24小时;将p-AKT激活剂SC79加入细胞培养基后模拟失重条件下培养前成骨细胞MC3T3-E1 24小时;利用Western blot技术分别检测细胞增殖相关蛋白PCNA以及AKT、p-AKT的表达变化情况。结果:(1)与对照组相比,模拟失重组前成骨细胞增殖受到抑制(P0.01),p-AKT/AKT比值减小(P0.01);(2)加入SC79组与对照组相比,p-AKT/AKT比值显著增加;(3)加入SC79的模拟失重组(MG+SC79)与模拟失重组相比(MG),p-AKT/AKT比值增加,PCNA蛋白表达增加(P0.01),成骨细胞增殖有所恢复。结论:模拟微重力可能通过抑制AKT的磷酸化形式抑制前成骨细胞的增殖,加入p-AKT激活剂可部分恢复前成骨细胞的增殖。     

不同温度下成骨细胞增殖及其OPG/RANKL mRNA表达的影响

目的:探讨不同温度下对小鼠成骨细胞MC3T3-E1的增殖以及OPG/RANKL表达水平的影响。方法:1.以小鼠成骨细胞MC3T3-E1为体外实验模型,MTT法检检测细胞的增殖情况。2.RT-PCR方法检测MC3T3-E1OPG/RANKL mRNA的表达水平。结果:设定对照组为37℃,高于对照组(38℃-39℃-40℃-41℃-42℃)分别作用于MC3T3-E1细胞1小时/天,连续1周,可刺激细胞增殖,OD值显著增加(P<0.05)。同时可增加OPG mRNA表达,降低RANKL mRNA表达,呈温度梯度依赖性。结论:热刺激促进MC3T3-E1细胞增殖,同时通过调节OPG/RANKL mRNA的表达,直接促进骨形成,抑制骨吸收。     

甲状旁腺激素对成骨细胞中ClC-3 氯通道表达及成骨分化影响的研究

目的:观察甲状旁腺激素(PTH)对成骨细胞中Cl C-3氯通道表达及成骨分化影响,初步探索Cl C-3介导PTH在细胞成骨分化中的作用。方法:采用10-8M、10-9M、10-10M PTH持续刺激和间断刺激MC3T3-E1细胞72 h后,通过CCK-8试剂盒法检测MC3T3-E1细胞的增殖情况,Real-Time PCR法检测MC3T3-E1细胞中Clcn3及成骨相关基因Alp、Runx2的表达情况,免疫荧光法检测10-9M PTH不同给药方式下对Cl C-3蛋白表达的影响。结果 :经不同浓度PTH连续和间断处理72 h后,结果显示10-9 M PTH间断刺激的MC3T3-E1细胞的增殖能力最强,且其Alp、Runx2 m RNA表达均高于10-8 M组和10-10 M组(P<0.05),而相同浓度间断刺激的MC3T3-E1细胞成骨相关基因的表达均高于持续刺激组,以10-9M间断刺激组差异最显著(P<0.05),而10-8 M和10-10M均无统计学差异(P>0.05),10-9 M PTH刺激的MC3T3-E1细胞中Cl C-3蛋白表达也显著增加(P<0.05)。结论 :成骨细胞的Cl C-3氯通道能够响应PTH的刺激发生变化,并伴随着成骨相关基因Alp、Runx2表达的增强。     

半乳糖凝集素‑3对骨关节炎成骨细胞矿化的作用研究

炎症反应以炎症因子为代表,是骨关节炎（osteoarthritis,OA）中软骨下骨发生病变的重要机制。炎症因子半乳糖凝集素?3（galectin?3,Gal?3）会引起软骨下骨OA样变,但机制尚不清楚。利用因膝关节OA行全膝关节置换患者的胫骨平台标本,培养成骨细胞。分别在正常氧和缺氧条件下用Gal?3处理成骨细胞后,检测骨钙素、ERRα和Sirtuin 1的表达情况。同时,给予矿化液培养的成骨细胞以Gal?3处理,28 d后使用茜素红染色检测成骨细胞矿化程度并进行定量分析。结果显示,Gal?3抑制成骨细胞骨钙素的表达,在缺氧条件下诱导ERRα和Sirtuin1的表达,在正常氧条件下Gal?3促进OA成骨细胞的矿化。正常氧条件下,Gal?3可以诱导OA成骨细胞的异常矿化,缺氧条件下Gal?3促进成骨,表明Gal?3在OA成骨细胞的矿化中扮演重要角色。     

原子力显微镜技术检测几种骨组织细胞力学性能

为了探究几种骨组织细胞系的力学性能及其与细胞功能的关系,该文采用原子力显微镜压陷法分别检测了前成骨细胞系（2T3和MC3T3-E1）、前骨细胞系（MLO-A5）和骨样细胞系（MLO-Y4）的杨氏模量,利用激光共聚焦显微镜观察了这几种细胞微丝和微管的排布。结果显示,2T3、MC3T3-E1、MLO-A5和MLO-Y4细胞的杨氏模量分别为（7000±2015）Pa、（6600±2024）Pa、（4700±644）Pa和（4500±1622）Pa,与原代骨组织细胞的杨氏模量及变化趋势保持一致,但两种前成骨细胞的杨氏模量要显著高于前骨细胞和骨细胞。细胞荧光染色结果表日月＇前成骨细胞细胞核周围的微丝和微管分布密度要高于前骨细胞和骨细胞,而前骨细胞MLO-A5,尤其是骨细胞MLO-Y4的骨架主要集中于细胞突触和边缘,这可能是导致几种细胞力学性能差异的原因。该研究从生物力学的角度为进一步深入理解骨组织细胞结构与功能的关系提供了实验依据。     

MC 3T3-E1细胞在纳米羟基磷灰石/壳聚糖复合支架上的增殖和分化

用原位合成纳米羟基磷灰石的方法制备多孔纳米羟基磷灰石/壳聚糖复合支架;在支架上接种MC 3T3-E1细胞,瑞氏染色检测细胞形态,MTT法检测其增殖情况;在诱导培养基中培养30d后,碱性磷酸酶染色比较其分化水平;定量检测细胞的碱性磷酸酶活性;RT-PCR检测成骨相关基因的表达情况。实验结果表明：MC 3T3-E1细胞在纳米级羟基磷灰石/壳聚糖复合支架上粘附铺展良好,其增殖率显著高于培养于纯壳聚糖支架上的细胞。碱性磷酸酶染色表明复合支架上的细胞有较高水平的碱性磷酸酶表达。进一步定量检测细胞的碱性磷酸酶活性,结果说明在复合支架上细胞比纯壳聚糖支架上培养的细胞碱性磷酸酶活性提高了约8倍。此外,骨分化相关特征基因骨桥蛋白OPN在复合支架上培养的细胞中的表达水平也明显高于纯壳聚糖上培养的细胞。分化成熟标志基因骨钙素OC在复合支架上培养的细胞中有表达,但是纯壳聚糖支架上培养的细胞中却未检测到。支架中纳米羟基磷灰石的加入不仅提高了前成骨细胞在复合支架上的增殖,而且还促进了它的分化。纳米羟基磷灰石/壳聚糖复合支架表现出良好的生物相容性和生物活性,是极具前景的骨组织工程支架材料。     

MC 3T3-E1细胞在纳米羟基磷灰石/壳聚糖复合支架上的增殖和分化

用原位合成纳米羟基磷灰石的方法制备多孔纳米羟基磷灰石/壳聚糖复合支架;在支架上接种MC3T3-E1细胞,瑞氏染色检测细胞形态,MTT法检测其增殖情况;在诱导培养基中培养30d后,碱性磷酸酶染色比较其分化水平;定量检测细胞的碱性磷酸酶活性;RT-PCR检测成骨相关基因的表达情况。实验结果表明:MC3T3-E1细胞在纳米级羟基磷灰石/壳聚糖复合支架上粘附铺展良好,其增殖率显著高于培养于纯壳聚糖支架上的细胞。碱性磷酸酶染色表明复合支架上的细胞有较高水平的碱性磷酸酶表达。进一步定量检测细胞的碱性磷酸酶活性,结果说明在复合支架上细胞比纯壳聚糖支架上培养的细胞碱性磷酸酶活性提高了约8倍。此外,骨分化相关特征基因骨桥蛋白OPN在复合支架上培养的细胞中的表达水平也明显高于纯壳聚糖上培养的细胞。分化成熟标志基因骨钙素OC在复合支架上培养的细胞中有表达,但是纯壳聚糖支架上培养的细胞中却未检测到。支架中纳米羟基磷灰石的加入不仅提高了前成骨细胞在复合支架上的增殖,而且还促进了它的分化。纳米羟基磷灰石/壳聚糖复合支架表现出良好的生物相容性和生物活性,是极具前景的骨组织工程支架材料。     

Effect of Azithromycin on Mineralized Nodule Formation in MC3T3-E1 Cells

Azithromycin displays immunomodulatory and anti-inflammatory effects in addition to broad-spectrum antimicrobial activity and is used to treat inflammatory diseases, including respiratory and odontogenic infections. Few studies have reported the effect of azithromycin therapy on bone remodeling processes. The aim of this study was to examine the effects of azithromycin on the osteogenic function of osteoblasts using osteoblast-like MC3T3-E1 cells. Cells were cultured in the presence of 0, 0.1, 1, and 10 µg/mL azithromycin, and cell proliferation and alkaline phosphatase (ALPase) activity were determined. In vitro mineralized nodule formation was detected with alizarin red staining. The expression of collagenous and non-collagenous bone matrix protein was determined using real-time PCR or enzyme-linked immunosorbent assays. In cells cultured with 10 µg/mL azithromycin, the ALPase activity and mineralized nodule formation decreased, while the type I collagen, bone sialoprotein, osteocalcin, and osteopontin mRNA expression as well as osteopontin and phosphorylated osteopontin levels increased. These results suggest that a high azithromycin concentration (10 µg/mL) suppresses mineralized nodule formation by decreasing ALPase activity and increasing osteopontin production, whereas low concentrations (≤l.0 µg/mL) have no effect on osteogenic function in osteoblastic MC3T3-E1 cells.     

Morphological and proteomic analysis of early stage of osteoblast differentiation in osteoblastic progenitor cells

Bone remodeling relies on a dynamic balance between bone formation and resorption, mediated by osteoblasts and osteoclasts, respectively. Under certain stimuli, osteoprogenitor cells may differentiate into premature osteoblasts and further into mature osteoblasts. This process is marked by increased alkaline phosphatase (ALP) activity and mineralized nodule formation. In this study, we induced osteoblast differentiation in mouse osteoprogenitor MC3T3-E1 cells and divided the process into three stages. In the first stage (day 3), the MC3T3-E1 cell under osteoblast differentiation did not express ALP or deposit a mineralized nodule. In the second stage, the MC3T3-E1 cell expressed ALP but did not form a mineralized nodule. In the third stage, the MC3T3-E1 cell had ALP activity and formed mineralized nodules. In the present study, we focused on morphological and proteomic changes of MC3T3-E1 cells in the early stage of osteoblast differentiation — a period when premature osteoblasts transform into mature osteoblasts. We found that mean cell area and mean stress fiber density were increased in this stage due to enhanced cell spreading and decreased cell proliferation. We further analyzed the proteins in the signaling pathway of regulation of the cytoskeleton using a proteomic approach and found upregulation of IQGAP1, gelsolin, moesin, radixin, and Cfl1. After analyzing the focal adhesion signaling pathway, we found the upregulation of FLNA, LAMA1, LAMA5, COL1A1, COL3A1, COL4A6, and COL5A2 as well as the downregulation of COL4A1, COL4A2, and COL4A4. In conclusion, the signaling pathway of regulation of the cytoskeleton and focal adhesion play critical roles in regulating cell spreading and actin skeleton formation in the early stage of osteoblast differentiation.     

牙源性间充质干细胞对成骨前体细胞成骨分化的影响

目的:探讨牙源性间充质干细胞对成骨前体细胞成骨分化的影响.方法:将小鼠成骨前体细胞MC3T3-El分为两组,观察组为牙源性间充质干细胞与MC3T3-E1细胞共培养,对照组为单一MC3T3-E1细胞培养.采用CCK-8法检测细胞增殖水平,采用酶联免疫法检测碱性磷酸酶(Alkaline phosphatase,ALP)活性...     

The Effect of Bovine Parathyroid Hormone Withdrawal on MC3T3-E1 Cell Proliferation and Phosphorus Metabolism

Hypocalcemia and hypophosphatemia are common complications after parathyroidectomy (PTX). Sudden removal of high circulating levels of parathyroid hormone (PTH) causes decreased osteoclastic resorption resulting in a decreased bone remodeling space. These phenomena are likely due to an increased influx of calcium and phosphorus into bone. However, there are currently no data to support this hypothesis. In this study, we found that PTX significantly reduced levels of PTH, calcium and phosphate. Compared with preoperative levels, after 1 year, postoperative PTH, calcium and phosphate levels were 295.6 ± 173.7 pg/mL (P < 0.05), 86.62 ± 15.98 mg/dL (P < 0.05) and 5.56 ± 2.03 mg/dL (P < 0.05), respectively. We investigated continuous bovine PTH administration as well as withdrawal of bovine PTH stimulation in the mouse osteoblast precursor cell line MC3T3-E1. MC3T3-E1 cells were cultured with continuous bovine PTH treatment for 20 days or with transient bovine PTH treatment for 10 days. High doses of continuous bovine PTH exposure strongly reduced cell proliferation, alkaline phosphatase activity and the number of mineralized calcium nodules. However, withdrawal of bovine PTH (100 ng/mL) significantly increased the number of mineralized calcium nodules and caused a rapid decline in calcium and phosphorus content of culture medium. In conclusion, continuous exposure to bovine PTH inhibited osteoblast differentiation and reduced the formation of mineralized nodules. However, this inhibition was removed and mineralized nodule formation resumed with withdrawal of bovine PTH. According to the results of our clinical examinations and in vitro experiments, we hypothesize that the sudden removal of high levels of PTH may cause an increased influx of calcium and phosphorus into bone after PTX.     

In vitro differentiation and calcification in a new clonal osteogenic cell line derived from newborn mouse calvaria

We investigated the capacity of a clonal osteogenic cell line MC3T3-E1, established from newborn mouse calvaria and selected on the basis of high alkaline phosphatase (ALP) activity in the confluent state, to differentiate into osteoblasts and mineralize in vitro. The cells in the growing state showed a fibroblastic morphology and grew to form multiple layers. On day 21, clusters of cells exhibiting typical osteoblastic morphology were found in osmiophilic nodular regions. Such nodules increased in number and size with incubation time and became easily identifiable with the naked eye by day 40-50. In the central part of well-developed nodules, osteocytes were embedded in heavily mineralized bone matrix. Osteoblasts were arranged at the periphery of the bone spicules and were surrounded by lysosome-rich cells and a fibroblastic cell layer. Numerous matrix vesicles were scattered around the osteoblasts and young osteocytes. Matrix vesicles and plasma membranes of osteoblasts, young osteocytes, and lysosome-rich cells showed strong reaction to cytochemical stainings for ALP activity and calcium ions. Minerals were initially localized in the matrix vesicles and then deposited on well-banded collagen fibrils. Deposited minerals consisted exclusively of calcium and phosphorus, and some of the crystals had matured into hydroxyapatite crystals. These results indicate that MC3T3-E1 cells have the capacity to differentiate into osteoblasts and osteocytes and to form calcified bone tissue in vitro.     

Constitutive expression of thrombospondin 1 in MC3T3-E1 osteoblastic cells inhibits mineralization

Thrombospondin 1 (TSP1) is a multifunctional extracellular glycoprotein present mainly in the fetal and adult skeleton. Although an inhibitory effect of TSP1 against pathological mineralization in cultured vascular pericytes has been shown, its involvement in physiological mineralization by osteoblasts is still unknown. To determine the role of TSP1 in biomineralization, mouse osteoblastic MC3T3-E1 cells were cultured in the presence of antisense phosphorothioate oligodeoxynucleotides complementary to the TSP1 sequence. The 18- and 24-mer antisense oligonucleotides caused concentration-dependent increases in the number of mineralized nodules, acid-soluble calcium deposition in the cell/matrix layer, and alkaline phosphatase activity within 9 days, without affecting cell proliferation. The corresponding sense or scrambled oligonucleotides did not affect these parameters. In the antisense oligonucleotide-treated MC3T3-E1 cells, thickened extracellular matrix, well-developed cell processes, increased intracellular organelles, and collagen fibril bundles were observed. On the other hand, the addition of TSP1 to the culture decreased the production of a mineralized matrix by MC3T3-E1 cells. Furthermore, MC3T3-E1 clones overexpressing mouse TSP1 were established and assayed for TSP1 protein and their capacity to mineralize. TSP1 dose-dependently inhibited mineralization by these cells both in vitro and in vivo. These results indicate that TSP1 functions as an inhibitory regulator of bone mineralization and matrix production by osteoblasts to sustain bone homeostasis.     

In vitro and in vivo evaluation of xenogeneic bone putty with the carrier of hydrogel derived from demineralized bone matrix

The demineralized bone matrix (DBM) putty is a traditional bone graft utilized to facilitate the repair and reconstruction of bone. Recent studies indicated the DBM putties with the various carriers were different in bone repairing ability. In order to prepare a kind of DBM putty with a good biocompatibility and bioactivity, the DBM gel was processed from the DBM and the feasibility as a carrier for the DBM putty was evaluated. After the bovine DBM gel was prepared, the BMPs content as well as the ability to promote osteogenic differentiation of MC3T3-E1 cells in vitro were investigated. Then the DBM putty was prepared and filled into the rat calvarial defect model to evaluate the bone repairing ability by micro-CT and histology. The result showed there was 2.953?±?0.054 ng BMP contained in per gram of the DBM gel. And the ALP production of MC3T3-E1 cells in the DBM gels group increased with prolonged culturing, the mineralized nodules formed in MC3T3-E1 cells on 14th day after co-culture. The putty prepared by DBM gel was easy to handle without loss of DBM particles at room temperature. In the rat calvarial bone defect experiment, histological observation showed more mature bone formed in the DBM putty group than that in the type I collagen group at 12 weeks, which indicated the bone putty prepared by DBM gel exhibited a better bone repair capability.     

Nicotine affects mineralized nodule formation by the human osteosarcoma cell line Saos-2

Several in vitro and in vivo studies have indicated that tobacco smoking may be an important risk factor for the development and severity of inflammatory periodontal disease. In the present study, we examined the effect of nicotine on cell proliferation, alkaline phosphatase (ALPase) activity, mineralized nodule formation, and the expression of extracellular matrix proteins in the human osteosarcoma cell line Saos-2. The cells were cultured with Dulbecco's modified Eagle medium containing 10% fetal bovine serum with 0, 10(-4) M, and 10(-3) M nicotine for up to 14 days. Mineralized nodule formation was examined by alizarin red staining, and the calcium content in mineralized nodules was determined using a calcium E-test kit. The expression of extracellular matrix proteins was estimated by determining the levels of their mRNAs using the real-time polymerase chain reaction. Mineralized nodule formation and calcium content in mineralized nodules were remarkably suppressed by nicotine on days 10 and 14 of culture, respectively. ALPase activity as well as type I collagen and osteopontin expression also decreased in the presence of nicotine after 5, 10, and 14 days of culture, respectively. By contrast, the amount of bone sialoprotein increased during 14 days of culture with nicotine. These results suggest that nicotine suppresses osteogenesis through a decrease in ALPase and type I collagen production by osteoblasts.