雄激素对大鼠胎颅盖骨成骨细胞雌激素受体基因表达的影响

目的 通过研究雄激素（十一酸睾酮）对成骨细胞雌激素受体基因表达的影响，探讨雄激素对成骨细胞增殖和分化的调控机制。方法 通过对体外培养的胎鼠颅盖骨成骨细胞实施含10^-10mol／L、10^-9mol／L、10^-8mol／L三种浓度雄激素的培养液干预，采用RT-PCR的方法半定量观察成骨细胞中雌激素受体基因mRNA表达的变化，用以分析雄激素对成骨细胞中雌激素受体的影响，并进而探讨雄激素对成骨细胞的影响。结果 实验选用的各浓度组均未出现细胞毒性反应，雄激素干预使成骨细胞中雌激素受体alpha基因表达上调，而雌激素受体beta基因表达轻微下调。结论 雄激素可以特异性地在转录水平调节成骨细胞中雌激素受体基因的表达。     

骨碎补含药血清对成骨细胞增殖、成骨的影响

目的研究骨碎补含药血清对成骨细胞的增殖、成骨的影响。方法取乳鼠颅骨,利用二型胶原酶反复消化,离心,提取成骨细胞。利用骨碎补含药血清干预,分别测定细胞增殖率、ALP活性、钙盐沉积量、骨钙素分泌量等,研究骨碎补含药血清对成骨细胞的增殖、成骨分化及其抗氧化性的影响;结果用含药血清干预,测定增殖率、ALP活性、钙盐沉积量、骨钙素分泌量、钙化结节量均高于空白对照组。结论骨碎补含药血清可以促进成骨细胞的增殖、成骨分化及其增强其抗氧化性。     

WO-1对成骨细胞的生物学效应研究

目的 了解WO-1在体外环境中对人成骨细胞增殖、分化的影响，为骨组织工程学研究提供更多的方法。方法 采用培养人胚成骨细胞，以生长曲线和。HTdR法分析WO-1与成骨细胞生物学效应的量效关系，在最佳作用浓度下，以接种细胞克隆形成率，流式细胞技术分析细胞周期，透射电镜观察细胞形态学，了解WO-1对细胞活性和细胞增殖的影响；以ALP活性检测，^3H-Proline掺入实验，放射免疫法测骨钙素合成及I型胶原和骨钙素mRNA的表达等，从蛋白质和mRNA两个水平观察WO-1对细胞功能的影响。结果 WO—1在高浓度时对人胚成骨细胞增殖有抑制作用，低浓度时对人胚成骨细胞增殖有促进作用，最佳作用浓度8μg／ml，在0．25～8μg／ml浓度范围内存在量效关系。在8μg／ml WO-1作用下，实验组人胚成骨细胞接种克隆形成率增加，克隆体积增大；群体倍增时间明显缩短，电镜下见细胞器较对照组发达；而ALP活性、I型胶原合成、骨钙素合成等，在蛋白质及mRNA两个水平均有增加，且与对照组比较，差异有统计学意义（P〈0．05）。结论 低浓度WO-1，可促进体外培养的人胚成骨细胞活性及增殖，加强细胞合成I型胶原、骨钙素等基质的功能，可用作成骨细胞增殖及分化的促进剂。     

TGF-β和BMP对胎兔颅骨成骨样细胞增殖和分化相互作用的实验研究

目的研究转化生长因子β(TGF-β)和骨形态发生蛋白(BMP)对成骨细胞增殖和分化的影响及其相互作用。方法取胎兔颅骨成骨样细胞进行体外培养，使用不同方法，加入TGF-β与BMP，在不同时间点检测其成骨样细胞增殖和分化的相互作用。结果TGF-β增加成骨样细胞DNA含量，抑制ALP活性、骨钙素的产生和矿化骨基质的形成。而BMP的作用相反。联合应用时，TGF-β减弱了BMP对成骨样细胞骨钙素产生和ALP活性的增强作用，BMP降低了TGF-β对成骨样细胞DNA合成的促进作用。在序惯性给药时，早期(9d)用BMP治疗并不影响随后加入的TGF-β对成骨样细胞ALP活性和基质钙化的抑制作用。而早期(10d)用TGF-β治疗却诱导了随后加入的BMP对成骨样细胞分化的促进作用。结论TGF-β促进成骨细胞增殖，BMP促进成骨细胞分化，它们在各自的不同时期发挥对成骨样细胞增殖和分化的影响。     

低频振动对人成骨细胞生物学特性影响的研究

目的:研究低频振动对人成骨细胞增殖分化及基质分泌的影响.方法:取成人的髂骨松质骨,获得人成骨细胞.并在培养48h后,施加0.1、0.2、0.5、2和5Hz的低频微振动,通过流式细胞仪检测成骨细胞增殖状况:化学比色法和放射免疫法检测碱性磷酸酶(ALP)活性和骨钙素含量.结果:加载 0.2和0.5Hz可使成骨细胞的ALP活性明显增高(P＜0.01);0.1和2Hz振动后其ALP活性与对照组无明显差异;5Hz振动则明显降低ALP活性(P＜ 0.01).加载 0.2和0.5Hz振动的成骨细胞,S期细胞从10.4%增加至12.45%和16.12%,增殖指数从20.14%增加到26.21%和 28.75%.0.1和2Hz低频振动则显示出对细胞增殖指数无明显影响(P＞0.05).而5Hz使细胞增殖指数明显降低至13.22%(P＜0.05).同时,加载0.2和0.5Hz振动可明显增加成骨细胞骨钙素分泌量至1.87和 2.47ng/ml(P＜0.05),而加载0.1Hz对骨钙素分泌量无明显影响(P＞0.05),加载2和5Hz相应降低了骨钙素分泌量(P＜0.05).结论:0.2～0.5Hz的低频振动能促进成骨细胞增殖分化和成骨活性物质分泌,对低频振动应用于骨折治疗有指导作用.     

甲状旁腺激素联合辛伐他汀对成骨细胞分化及OPG和RANKL mRNA表达的影响

目的联合甲状旁腺激素(rhPTH1-34)和辛伐他汀(SIM)在体外对乳鼠颅盖骨成骨细胞分化及骨保护素(OPG)和核因子κB受体活化因子配体(RANKL)基因表达的影响。方法以乳鼠成骨细胞为体外试验模型,rhPTH1-34(10-9mol/L)联合不同浓度SIM(10-8、10-7、10-6mol/L)作用于体外培养的乳鼠成骨细胞,采用对硝基苯磷酸盐(PNPP)法测定碱性磷酸酶(ALP)活性;RT-PCR法测定OPG和RANKL基因的表达。结果 rhPTH1-34和SIM单独给药均可促进成骨细胞ALP活性及OPG基因、降低RANKL基因表达(P0.05);两者联合后与SIM单独作用组比较,ALP活性明显增加,并能协同促进OPG、降低RANKL基因表达(P0.05)。结论 rhPTH1-34和SIM联合应用对成骨细胞分化和代谢有协同作用。     

低频振动对人成骨细胞生物学特性影响的研究

目的研究低频振动对人成骨细胞增殖分化及基质分泌的影响.方法取成人的髂骨松质骨,获得人成骨细胞.并在培养48h后,施加0.1、0.2、0.5、2和5Hz的低频微振动,通过流式细胞仪检测成骨细胞增殖状况化学比色法和放射免疫法检测碱性磷酸酶(ALP)活性和骨钙素含量.结果加载 0.2和0.5Hz可使成骨细胞的ALP活性明显增高(P＜0.01);0.1和2Hz振动后其ALP活性与对照组无明显差异;5Hz振动则明显降低ALP活性(P＜ 0.01).加载 0.2和0.5Hz振动的成骨细胞,S期细胞从10.4%增加至12.45%和16.12%,增殖指数从20.14%增加到26.21%和 28.75%.0.1和2Hz低频振动则显示出对细胞增殖指数无明显影响(P＞0.05).而5Hz使细胞增殖指数明显降低至13.22%(P＜0.05).同时,加载0.2和0.5Hz振动可明显增加成骨细胞骨钙素分泌量至1.87和 2.47ng/ml(P＜0.05),而加载0.1Hz对骨钙素分泌量无明显影响(P＞0.05),加载2和5Hz相应降低了骨钙素分泌量(P＜0.05).结论0.2～0.5Hz的低频振动能促进成骨细胞增殖分化和成骨活性物质分泌,对低频振动应用于骨折治疗有指导作用.     

低频振动对人成骨细胞生物学特性影响的研究

目的:研究低频振动对人成骨细胞增殖分化及基质分泌的影响。方法:取成人的髂骨松质骨,获得人成骨细胞。并在培养48h后,施加0.1、0.2、0.5、2和5Hz的低频微振动,通过流式细胞仪检测成骨细胞增殖状况:化学比色法和放射免疫法检测碱性磷酸酶(ALP)活性和骨钙素含量。结果:加载0.2和0.5Hz可使成骨细胞的ALP活性明显增高(P<0.01);0.1和2Hz振动后其ALP活性与对照组无明显差异;5Hz振动则明显降低ALP活性(P<0.01)。加载0.2和0.5Hz振动的成骨细胞,S期细胞从10.4％增加至12.45％和16.12％,增殖指数从20.14％增加到26.21％和28.75％。0.1和2Hz低频振动则显示出对细胞增殖指数无明显影响(P>0.05)。而5Hz使细胞增殖指数明显降低至13.22％(P<0.05)。同时,加载0.2和0.5Hz振动可明显增加成骨细胞骨钙素分泌量至1.87和2.47ng/ml(P<0.05),而加载0.1Hz对骨钙素分泌量无明显影响(P>0.05),加载2和5Hz相应降低了骨钙素分泌量(P<0.05)。结论:0.2～0.5Hz的低频振动能促进成骨细胞增殖分化和成骨活性物质分泌,对低频振动应用于骨折治疗有指导作用。     

丹仙康骨胶囊对培养成骨细胞影响的观察

目的：为了解补肾活血中药丹仙康骨胶囊对体外培养成骨细胞的作用。方法：应用透射电镜、MTT、对硝基苯磷酸盐法(PNPP)及骨钙素(BGP)含量放免测定法，观察丹仙康骨胶囊对成骨细胞超微结构、增殖与分化作用的影响。结果：丹仙康骨胶囊刺激(20mg／ml)的成骨细胞，ALP活性提高及骨钙素含量增多；透射电镜观察其细胞线粒体致密、游离核糖体增多、内质网丰富扩大增粗呈中等电子密度，而糖原溶解与脂肪空泡均较少。结论：丹仙康骨胶囊具有促进成骨细胞的代谢、增殖和分化的作用。     

人骨膜细胞体外成骨分化的基因表达和功能检测

目的 探讨并鉴定骨膜细胞经骨形成蛋白7(BMP7)诱导分化为成骨细胞的基因表达和细胞功能.方法 成人胫骨骨膜常规体外细胞培养法,分实验组和对照组,分别加入BMP7加成骨辅助剂和单纯成骨辅助剂进行体外培养.CCK-8法检测细胞增殖活性,第5、10、15和20天分别采用Real Time-PCR检测骨钙素基因表达,ELISA法检测上清液碱性磷酸酶(alkaline phosphatase,ALP)、骨钙素(osteocalcin,OCN)及骨桥蛋白(osteopontin,OPN)的水平,甲苯胺蓝染色检测糖胺聚糖(GAG),Real Time-PCR检测Ⅱ型胶原基因,比色法检测细胞ALP活性,ALP染色法检测ALP,Yon Kossa染色法检测钙结节.结果 两组骨钙素基因表达及上清液ALP、骨钙素、骨桥蛋白的含量均增高,实验组与对照组差异有统计学意义(P＜0.05).两组细胞的ALP和钙结节染色阳性率增高,实验组与对照组差异有统计学意义(P＜0.05).甲苯胺蓝染色阳性率及Ⅱ型胶原基因表达表现为先高后低,实验组与对照组差异有统计学意义(P＜0.05).结论 骨膜细胞在BMP7诱导下体外大量增殖和分化成骨,表达出明显的成骨特异基因,并具有合成分泌成骨特异蛋白的功能;成骨化过程中,除直接分化成骨外,还存在部分细胞先经软骨形成再钙化成骨的现象;经骨膜细胞-BMP7途径在体外获取大量成骨细胞可用于组织工程的体外构骨及临床应用.     

Effect of surface roughness on proliferation and alkaline phosphatase expression of rat calvarial cells cultured on polystyrene.

Rough-surfaced substrates made by a variety of methods have been shown to influence osteoblast proliferation and differentiation. The purpose of this study is to confirm the role of surface roughness in promoting osteoblastic differentiation using tissue culture polystyrene as substrate, by excluding factors other than roughness. Immature osteogenic cells derived from fetal rat calvariae were cultured on the plastic cover strips having varied degrees of roughness created by treatment with four kinds of grinding paper of different particle sizes. The proliferation and gene expression of alkaline phosphatase (ALP) and osteocalcin of the calvarial cells increased on the rough-surfaced cover strips. These levels increased in response to the increase in the degree of surface roughness up to 0.8 microm of average roughness and then decreased to the level observed for the smooth surface. These results demonstrate that the surface roughness itself caused increases in osteoblastic proliferation and differentiation in cell cultures.     

Hormonal Regulation of the Osteoblastic Phenotype Expression in Neonatal Murine Calvarial Cells

Osteoblastic cell cultures from fetal rat calvariae have provided a popular model for studying the effects of dexamethasone (DEX) and 1,25 dihydroxyvitamin D₃ [1,25(OH)₂D₃] on gene expression but data from murine calvarial cells are scarce. Species-specific responses of rat and mouse osteoblastic cells to these hormones have been reported previously. In the present study, we investigated the effects of DEX and 1,25(OH)₂D₃ on expression of the osteoblastic phenotype by mouse calvarial cells. These murine osteoblast-like (MOB) cells expressed alkaline phosphatase (ALP) activity and osteocalcin and formed calcified nodules. Unlike the rat calvarial cells, ALP activities and nodule formation in MOB were inhibited by DEX. 1,25(OH)₂D₃ enhanced and DEX lowered the amount of osteocalcin synthesized by MOB. 1,25(OH)₂D₃ did not affect the number of nodules, but increased their sizes. Treating the cells for 2 days with only DEX at the beginning of the culture enhanced the effect of 1,25(OH)₂D₃ on ALP. We found that in murine calvarial cells, DEX inhibits and 1,25(OH)₂D₃ enhances ALP activity, osteocalcin synthesis, and calcified nodule formation. This is in contrast to previous reports of rat calvarial cells where DEX is a positive and 1,25(OH)₂D₃ can be a negative regulator of the osteoblastic phenotype. These results suggest that profound species-specific differences exist between mice and rats in the regulation of the osteoblastic phenotype. Received: 15 October 1997 / Accepted: 16 June 1998     

氟化钠及其拮抗剂硫酸锌对成骨细胞的影响

目的观察不同剂量氟化钠（ＮａＦ）对成骨细胞的影响及硫酸锌（ＺｎＳＯ４）的拮抗作用,为临床治疗提供实验依据。方法取新生２４ｈＳＤ鼠头盖骨分离成骨细胞,在不同浓度的ＮａＦ和／或ＺｎＳＯ４（１０＾－５ｍｏｌ／Ｌ）中培养。经ＭＴＴ法测定细胞增殖,细胞分化由碱性磷酸酶（ＡＬＰ）和骨钙素水平测定得到。结果ＮａＦ对成骨细胞增殖及分化呈双向调节,主要表现为大剂量抑制,小剂量促进。当ＮａＦ浓度为１０＾－６ｍｏｌ／Ｌ     

PKCα suppresses osteoblastic differentiation

Protein kinase C (PKC) plays an essential role in cellular signal transduction for mediating a variety of biological functions. There are 11 PKC isoforms and these isoforms are believed to play distinct roles in cells. Although the role of individual isoforms of PKC has been investigated in many fields, little is known about the role of PKC in osteoblastic differentiation. Here, we investigated which isoforms of PKC are involved in osteoblastic differentiation of the mouse preosteoblastic cell line MC3T3-E1. Treatment with G?6976, an inhibitor of PKCα and PKCβI, increased alkaline phosphatase (ALP) activity as well as gene expression of ALP and Osteocalcin (OCN), and enhanced calcification of the extracellular matrix. Concurrently, osteoblastic cell proliferation decreased at a concentration of 1.0 μM. In contrast, a PKCβ inhibitor, which inhibits PKCβI and PKCβII, did not significantly affect osteoblastic differentiation or cell proliferation. Knockdown of PKCα using MC3T3-E1 cells transfected with siRNA also induced an increase in ALP activity and in gene expression of ALP and OCN. In contrast, overexpression of wild-type PKCα decreased ALP activity and attenuated osteoblastic differentiation markers including ALP and OCN, but promoted cell proliferation. Taken together, our results indicate that PKCα suppresses osteoblastic differentiation, but promotes osteoblastic cell proliferation. These results imply that PKCα may have a pivotal role in cell signaling that modulates the differentiation and proliferation of osteoblasts.     

Expression of the parathyroid hormone receptor and correlation with other osteoblastic parameters in fetal rat osteoblasts

Primary fetal rat calvarial cell cultures were examined for the expression of different osteoblastic parameters at the single cell level and in the whole population. The presence of the parathyroid hormone (PTH) receptor was studied by employing receptor autoradiography. After 3 days of culture, 10% of the cells expressed the PTH receptor. Immunolocalization of osteocalcin in 3-day-old cell cultures was found to be strongly correlated with the presence of the PTH receptor. Alkaline phosphatase (APase) localization in 3-day-old cultures correlated with only 69% of the PTH receptor expressing cells. Our results show that in 3-day-old rat calvarial cell cultures, only about 10% of the cells show markers of osteoblastic differentiation. The presence of the PTH receptor is strongly correlated with the presence of osteocalcin, but less with the presence of APase, indicating that it is the mature osteoblast that expresses the PTH receptor. After 7 days of culture, most receptor labeling, APase, and osteocalcin expression was found in multilayered areas of cells (nodules). Received: 28 February 1995 / Accepted: 27 July 1995     

Cyclooxygenase-2 gene disruption promotes proliferation of murine calvarial osteoblasts in vitro

Cyclooxygenase-2 (COX-2) is highly expressed in osteoblasts, and COX-2 produced prostaglandins (PGs) can increase osteoblastic differentiation in vitro. The goal of this study was to examine effects of COX-2 expression on calvarial osteoblastic proliferation and apoptosis. Primary osteoblasts (POBs) were cultured from calvariae of COX-2 wild-type (WT) and knockout (KO) mice. POB proliferation was evaluated by (3)H-thymidine incorporation and analysis of cell replication and cell cycle distribution by flow cytometry. POB apoptosis was evaluated by annexin and PI staining on flow cytometry. As expected, PGE(2) production and alkaline phosphatase (ALP) activity were increased in WT cultures compared to KO cultures. In contrast, cell numbers were decreased in WT compared to KO cells by day 4 of culture. Proliferation, measured on days 3-7 of culture, was 2-fold greater in KO than in WT POBs and associated with decreased Go/G1 and increased S cell cycle distribution. There was no significant effect of COX-2 genotype on apoptosis under basal culture conditions on day 5 of culture. Cell growth was decreased in KO POBs by the addition of PGE(2) or a protein kinase A agonist and increased in WT POBs by the addition of NS398, a selective COX-2 inhibitor. In contrast, differentiation and cell growth in marrow stromal cell (MSC) cultures, evaluated by ALP and crystal violet staining respectively, were increased in MSCs from WT mice compared to MSCs from KO mice, and exogenous PGE(2) increased cell growth in KO MSC cultures. We conclude that PGs secondary to COX-2 expression decrease osteoblastic proliferation in cultured calvarial cells but increase growth of osteoblastic precursors in MSC cultures.     

Col1a1-driven transgenic markers of osteoblast lineage progression.

The modular organization of the type I collagen promoter allows creation of promoter-reporter constructs with preferential activity in different type I collagen-producing tissues that might be useful to mark cells at different stages of osteoblastic differentiation. Primary marrow stromal cell (MSC) and mouse calvarial osteoblast (mCOB) cultures were established from transgenic mice harboring different Col1a1 promoter fragments driving chloramphenicol acetyltransferase (CAT). In these models, Col1a1 messenger RNA (mRNA) and alkaline phosphatase (ALP) are the first markers of differentiation appearing soon after the colonies develop. Bone sialoprotein (BSP) is detected 2-3 days later, followed by osteocalcin (OC) expression and nodule mineralization. A 3.6 Col1a1 fragment (ColCAT3.6) initiated activity concomitant with ALP staining and type I collagen mRNA expression. In contrast, a 2.3 Col1a1 fragment (ColCAT2.3) became active coincident with BSP expression. The pattern of transgene expression assessed by immunostaining was distinctly different. ColCAT3.6 was expressed within and at the periphery of developing nodules whereas the ColCAT2.3 expression was restricted to the differentiated nodules. The feasibility of using green fluorescent protein (GFP) as a marker of osteoblast differentiation was evaluated in ROS17/2.8 cells. A 2.3-kilobase (kb) Col1a1 promoter driving GFP (pOB4Col2.3GLP) was stably transfected into the cell line and positive clones were selected. Subcultures lost and then regained GFP expression that was localized in small clusters of cells throughout the culture. This suggests that expression from the 2.3-kb Col1A1 fragment is determined by the state of differentiation of the ROS17/2.8 cells. Col1a1 transgenes should be useful in appreciating the heterogeneity of a primary or immortalized culture undergoing osteoblastic differentiation.     

Evidence for a role of p38 MAP kinase in expression of alkaline phosphatase during osteoblastic cell differentiation.

In the present study, we investigate the implication of the mitogen-activated protein kinases (MAPKs) Erk, p38, and JNK in mediating the effect of fetal calf serum (FCS) on the differentiation of MC3T3-E1 osteoblast-like cells. Erk is stimulated by FCS in proliferating, early-differentiating, as well as in mature cells. Activation of p38 by FCS is not detected in proliferating cells but is observed as the cells differentiate. JNK is activated in response to FCS throughout the entire differentiation process, but a maximal stimulation is observed in early differentiating cells. The roles of Erk and p38 pathways in mediating MC3T3-E1 cell differentiation was determined using specific inhibitors such as U0126 and SB203580, respectively. These experiments confirmed that the Erk pathway is essential for mediating cell proliferation in response to FCS, but indicated that this MAP kinase has little effect in regulating the differentiation of MC3T3-E1 cells. In contrast, p38 only marginally influenced proliferation, but appeared to be critical for the control of alkaline phosphatase (ALP) expression in differentiating cells. Finally, results obtained with high doses of SB203580, which also affected JNK activity, suggest that p38 and/or JNK are probably also involved in the control of type 1 collagen and osteocalcin expression in differentiating cells. The data indicate that MAPKs regulate different stages of MC3T3-E1 cell development in response to FCS. Distinct MAPK pathways seem to independently modulate osteoblastic cell proliferation and differentiation, with Erk playing an essential role in cell replication, whereas p38 is involved in the regulation of ALP expression during osteoblastic cell differentiation. JNK is also probably involved in the regulation of osteoblastic cell differentiation, but its precise role requires further investigation.