转移生长因子β1对体外培养破骨细胞功能影响的实验研究

目的探讨转移生长因子β1(TGF-β1)对体外培养破骨细胞功能影响的机制.方法酶动力学法测定培养基中酸性磷酸酶和抗酒石酸酸性磷酸酶活性;共聚焦激光扫描显微镜观察体外培养破骨细胞内氢离子随TGF-β1浓度的变化情况;Leica Quantimet 500图像分析系统对骨吸收陷窝进行图像分析;扫描电镜观察骨吸收陷窝变化.结果随着TGF-β1浓度的升高,处理组与对照组ACP和TRAP的活性分别从(1.71±0.33U)/L和(1.41±0.29)U/L降低到(1.32±0.21)U/L和(1.01±0.11)U/L(均为P＜0.01),骨吸收陷窝的数目与面积从(16.67±1.35)个/片和(582.24±178.68)μm2减少到(13.29±1.47)个/片与(442.38±148.27)μm2,处理组与对照组比较差异具有显著性(P＜0.01).破骨细胞相对荧光值无显著性差异,表明TGF-β1对体外培养破骨细胞分泌H+无明显影响.结论TGF-β1虽然不能抑制氢离子释放,但能通过改变酸性磷酸酶和抗酒石酸酸性磷酸酶活性,进而直接抑制体外培养破骨细胞的骨吸收功能.     

体外培养破骨细胞的功能观察

观察破骨细胞在离体状态下的骨吸收功能。新鲜牛皮质骨经锯式切片机横切成５０μｍ厚０．５×０．５ｃｍ大小骨片。参照已建立的破骨细胞分离培养方法，从新生Ｗｉｓｔａｒ大鼠四肢长骨分离破骨细胞，培养于２．５ｃｍ细胞培养皿内或上述骨片上，相差倒置显微镜或扫描电镜观察，可见培养的细胞具有典型破骨细胞的形态特点，接种子骨片上的破骨细胞分别培养１、３、５、７天，扫描电镜观察，可见破骨细胞能在骨片表面形成吸收陷窝，其形态多样，深浅不一，边界清晰，底面粗糙，而且随培养时间延长，陷窝扩大，数量增多。结论，破骨细胞在体外培养条件下具有良好的骨吸收功能，可进行药物干预的研究。     

破骨细胞体外培养研究进展

破骨细胞是骨吸收的主要功能细胞,体外培养破骨细胞是骨吸收研究和抑制骨吸收药物开发研究的基础.该文综述破骨细胞体外培养常用的5种方法及近年研究进展,并对各种方法进行比较.成熟破骨细胞分离培养法仍是目前获得成熟破骨细胞的最佳途径;骨髓诱导破骨细胞培养法是目前最常用的破骨细胞培养法;脾干细胞诱导培养法和外周血单核细胞诱导培养法是近年新发展起来的培养方法,能排除骨髓基质细胞及其他造血干细胞干扰,更具有应用价值;骨巨细胞瘤破骨细胞样细胞分离培养法是其他破骨细胞培养方法的一个重要补充.     

源于脾细胞的破骨细胞样细胞体外培养及其对成骨细胞的影响

目的探讨破骨细胞及其亚细胞结构对成骨细胞生长的影响。方法C57雌性小鼠,经尾静脉注射5-FU后,取其脾脏细胞,在白介素(IL)-3,6和粒细胞-巨噬细胞集落刺激因子(GM-CSF)、1α,25-(OH)2D3的诱导下获得大量的破骨样细胞(OLC)。将破骨样细胞、NaF、离心去除OLC的培养基及其亚细胞结构——细胞核、线粒体与成骨细胞共培养5d后,检测成骨细胞增殖率和碱性磷酸酶含量以及成骨细胞Cbfα1的表达活性。结果OLC及离心去除OLC的50%培养基均可使成骨细胞增殖率显著增加(P<0.05)。NaF、OLC、OLC细胞核和离心去除OLC的25%培养基均可使成骨细胞的碱性磷酸酶活性增高(P<0.05);离心去除OLC的培养基对成骨细胞的碱性磷酸酶比活性具有显著的促进作用(P<0.05)。NaF、OLC细胞质和离心去除OLC的50%培养基均可使成骨细胞的Cbfα1的表达明显加强(P<0.05)。结论OLC对成骨细胞的生长和功能均有促进作用。     

破骨细胞体外培养技术

由于破骨细胞在骨质疏松及相关疾病中的关键作用,对它的研究成为攻克这些疾病的必由之路。选择便捷高效的体外培养方法,是开展体外破骨细胞研究的前提。破骨细胞是终末分化细胞,不能增殖传代,因此破骨细胞的体外培养一直是一个具有挑战性的难题。本文就常见的破骨细胞体外培养技术和鉴定方法做简要概述。     

体外培养破骨细胞的标志酶染色

破骨细胞体外培养是从细胞与分子水平研究骨吸收机理与骨质疏松症防治药物的基础［１］。由于破骨细胞数量少,很难分离到纯的破骨细胞,体外培养所获破骨细胞常与其他细胞混合存在,因此从这些混杂细胞内辨别出破骨细胞尤为重要。鉴别破骨细胞的方法有多种,其中最方便而具特异性的指标为标志酶ＴＲＡＰ与ＴｒＡＴＰａｓｅ染色,作者应用细胞化学方法成功地对体外培养破骨细胞的标志酶进行了染色,报道如下。１　材料和方法１１　动物　出生２４小时内的Ｗｉｓｔａｒ大鼠,本所实验动物房提供,沪医实验动物准字：３４。１２　试剂　Ｍ…     

成年大鼠破骨细胞体外培养及细胞凋亡的观察

目的　为研究骨重建过程中破骨细胞的关键作用,建立成年大鼠（１２ ～５０ 周龄） 破骨细胞的体外培养方法并进行细胞凋亡观察。方法　大鼠处死后,在无菌条件下取出股骨,剪去两骺端,以αＭＥＭ 将骨髓细胞冲洗出, 并离心洗细胞２ 次,置于αＭＥＭ 培养液,内含αＭＥＭ,体积分数为１０％ 的胎牛血清（ＦＣＳ） 和１α,２５（ＯＨ）２ Ｖｉｔ Ｄ３ １０ －８ ｍｏｌ／Ｌ,在２４ 孔板内,以体积分数为５ ％ 的ＣＯ２ ,３７ ℃,培养８ 天。按原位ＤＮＡ 末端标记（ＴＵＮＥＬ）检测试剂盒方法染色细胞,以荧光显微镜观察细胞凋亡。结果　经活体观察、ＨＥ染色、抗酒石酸酸性磷酸酶（ＴＲＡＰ） 染色,光学显微镜、扫描电镜观察骨片之陷窝的形成,证实培养的细胞为破骨细胞;ＴＵＮＥＬ 检测,荧光显微镜下可见破骨细胞核染色质浓缩、裂解等凋亡细胞的典型变化与未凋亡的破骨细胞。结论　本实验建立了成年大鼠破骨细胞的体外培养方法并进行细胞凋亡观察。     

破骨细胞体外培养生存数的观察与鳗鱼降钙素的影响

应用改良的Ｆｅｎｔｏｎ方法由出生２４小时内的新生Ｗｉｓｔａｒ大鼠分离破骨细胞（ＯＣ）培养于盖玻片与骨片上，并应用改良的ＶａｎＤｅＷｉｊｎｇａｅｒｔ和Ｍｏｓｔａｆａ方法对培养在骨片上的ＯＣ进行ＴＲＡＰ染色，观察体外培养ＯＣ的形态与生存时间。培养于骨片上的ＯＣ生存时间可长达２４０小时。１×１０（－９）ｍｏｌ／Ｌ鳗鱼降钙素能明显减少体外培养的多核ＯＣ生存数，但对单核前ＯＣ数没有明显影响     

长期低剂量镉暴露对大鼠破骨细胞形成的影响

目的探讨低剂量镉暴露对大鼠破骨细胞形成的影响。方法 24只Sprague-Dawley雄性大鼠随机分成3组,通过饮水进行镉染毒,染毒剂量为2 mg/L和10 mg/L;对照组饮水中加入相同体积的生理盐水。染毒后第24周,收集血液、腰椎及两侧胫骨,分别用于血抗酒酸酸性磷酸酶5b测定、骨密度测定及组织形态分析。通过酶组织化学染色,观察大鼠胫骨破骨细胞形成情况。结果染毒组大鼠骨密度较对照组有不同程度下降,其中高剂量组大鼠骨密度和对照组相比有显著差异(P0.05)。骨组织形态分析显示镉作用后大鼠胫骨骨髓腔增宽,骨小梁数量及骨小梁连接明显减少。组织化学染色显示镉染毒可以增加大鼠胫骨破骨数量及面积,和对照组相比有显著差异(P0.05)。染毒组大鼠血抗酒石酸酸性磷酸酶5b水平显著高于对照组(P0.05)。结论低剂量镉染毒能增加大鼠骨组织内破骨细胞数量,骨吸收的过度活跃可能是低剂量镉骨损害的重要途径。     

正常和双侧卵巢切除大鼠体外骨髓培养破骨细胞凋亡变化的研究

目的观察正常和双侧卵巢切除(Ovariectomized,OVX)大鼠体外骨髓破骨细胞样细胞(Osteoclastic like cell,OLC)凋亡变化。方法24只Wistar大鼠,分别在术后2 w、1、2、3、5和6个月取大鼠骨髓,24孔培养板上培养7 d后观察OLC凋亡变化。结果 OVX大鼠体外OLC凋亡百分数明显低于正常对照组(P<0.05)。结论 OVX大鼠因雌激素明显降低,破骨细胞凋亡减少,骨吸收增加,导致骨质疏松发生。     

鸡破骨细胞分离培养方法的建立

为了寻找一种获得大量、纯化、有活力的破骨细胞的方法，我们对已经建立的兔破骨细胞体外分离培养方法的基础上加以改进。利用冲洗的方法，从２８天的鸡的长骨中得到细胞团１破骨细胞后，又对鸡的长骨相继进行胶原酶和胰蛋白酶的消化，得到细胞团２和细胞团３破骨细胞。将这些分离的细胞与盖玻片或骨磨片共同培养，通过相差显微镜观察到：这些分离的多核巨细胞能够运动，并能在骨磨片上形成吸收陷窝。另外，这些细胞对酸性磷酸酶染色呈阳性反应，而酸性磷酸酶是鉴别破骨细胞的标志。表明此分离培养鸡破骨细胞的实验技术是成功的。通过此方法获得的鸡破骨细胞比用以往方法获得的兔破骨细胞量多，且活力强。本方法的建立，为进一步研究骨吸收机理奠定了基础。     

两种方法培养大鼠破骨细胞的比较研究

目的比较分析直接分离培养的Wistar大鼠破骨细胞（osteoclast，OC）和诱导培养的Wistar大鼠破骨样细胞（osteoclast-like cell，OLC）的形态和功能的差异，为体外药物干预试验奠定基础。方法采用两种培养法，即从新生（24h内）的Wistar大鼠的四肢长骨骨髓腔内壁机械分离成熟OC直接培养和10^-8mol／L的1，25（OH）2D3诱导4周龄Wistar大鼠骨髓单核细胞形成OLC的方法，对获得的OC／OLC进行形态和破骨功能观察。结果两种方法都培养出了抗酒石酸酸性磷酸酶（tartrate resistant acid phosphatase，TRAP）染色阳性的多核细胞，诱导法获得的破骨细胞数量较多（P〈0．05）。成熟OC与诱导获得的OLC形态特征相似，但后者在骨片上形成的陷窝较小而浅。结论直接分离培养法可获得骨吸收功能较活跃的OC，但数目较少，适合骨吸收功能分析、破骨迁移黏附、凋亡研究及单细胞分子生物学研究。1，25（OH）2D3诱导鼠骨髓单核细胞形成的OLC数量较多，但骨吸收功能较差，适合用于破骨细胞分化发育过程的研究。     

福莫特罗和ICI118551对大鼠成熟破骨细胞骨吸收功能的影响

目的研究选择性β2肾上腺素能激动剂福莫特罗(Formoterol)和阻滞剂ICI118551对体外培养大鼠成熟破骨细胞(osteoclast,OC)功能的影响,探讨β2肾上腺素能受体信号对骨代谢的影响。方法取清洁级出生24h内的SD乳大鼠,长骨干骨髓腔内壁机械分离成熟OC后分别加入不同浓度(10-5mol/L～10-9mol/L)的Formoterol和ICI118551,以抗酒石酸酸性磷酸酶(TRAP)染色观察破骨细胞形态,甲苯胺蓝染色计数骨片上的骨吸收陷窝数目,Image-ProPlus6.0图像软件分析骨片上骨吸收陷窝面积。结果破骨细胞与骨片共培养6天,不同浓度的Formoterol与对照组相比均可增加骨片上OC的骨吸收陷窝数目和面积;随着ICI118551浓度的提高骨片上骨吸收陷窝的数目和面积逐渐减少。结论β2肾上腺素能受体激动剂可促进体外培养OC的骨吸收功能,阻滞剂对OC的骨吸收功能有抑制作用,且呈剂量依赖性。     

Electron microscopy of developing calvaria reveals images that suggest that osteoclasts engulf and destroy osteocytes during bone resorption

Summary It is generally accepted that osteoclasts are responsible for the breakdown and removal of bone matrix constituents. However, very little is known about the fate of osteocytes during bone resorption. In the present study we have examined sites of bone destruction in calvaria of young rats aged 4–9 days in the hope of obtaining information on the fate of osteocytes. Decalcified glutaraldehyde-formaldehyde-fixed specimens were prepared for ultrathin section electron microscopy. When sequentially arranged, the images obtained suggest that osteoclasts engulf and destroy osteocytes during bone degradation. We propose that the following sequence of events takes place when a lacuna is opened up by an osteoclast: (1) When the osteoclast comes in contact with an osteocyte, the villi of the ruffled border become flat and broad. (2) Long osteoclastic extensions surround the osteocyte. (3) The osteocyte is subsequently internalized with apparent degradation.     

Visualizing mineral binding and uptake of bisphosphonate by osteoclasts and non-resorbing cells

Bisphosphonates (BPs) target bone due to their high affinity for calcium ions. During osteoclastic resorption, these drugs are released from the acidified bone surface and taken up by osteoclasts, where they act by inhibiting the prenylation of small GTPases essential for osteoclast function. However, it remains unclear exactly how osteoclasts internalise BPs from bone and whether other cells in the bone microenvironment can also take up BPs from the bone surface. We have investigated this using a novel fluorescently-labelled alendronate analogue (FL-ALN), and by examining changes in protein prenylation following treatment of cells with risedronate (RIS). Confocal microscopic analysis showed that FL-ALN was efficiently internalised from solution or from the surface of dentine by resorbing osteoclasts into intracellular vesicles. Accordingly, unprenylated Rap1A accumulated to the same extent whether osteoclasts were cultured on RIS-coated dentine or with RIS in solution. By contrast, J774 macrophages internalised FL-ALN and RIS from solution, but took up comparatively little from dentine, due to their inability to resorb the mineral. Calvarial osteoblasts and MCF-7 tumour cells internalised even less FL-ALN and RIS, both from solution and from the surface of dentine. Accordingly, the viability of J774 and MCF-7 cells was drastically reduced when cultured with RIS in solution, but not when cultured on dentine pre-coated with RIS. However, when J774 macrophages were co-cultured with rabbit osteoclasts, J774 cells that were adjacent to resorbing osteoclasts frequently internalised more FL-ALN than J774 cells more distant from osteoclasts. This was possibly a result of increased availability of BP to these J774 cells due to transcytosis through osteoclasts, since FL-ALN partially co-localised with trancytosed, resorbed matrix protein within osteoclasts. In addition, J774 cells occupying resorption pits internalised more FL-ALN than those on unresorbed surfaces. These data demonstrate that osteoclasts are able to take up large amounts of BP, due to their ability to release the BP from the dentine surface during resorption. By contrast, non-resorbing cells take up only small amounts of BP that becomes available due to natural desorption from the dentine surface. However, BP uptake by non-resorbing cells can be increased when cultured in the presence of resorbing osteoclasts.     

Inhibition of bone resorption by bisphosphonates: Interactions between bisphosphonates,osteoclasts, and bone

Summary Bisphosphonates are nonbiodegradable pyrophosphate analogues that are being used increasingly to inhibit bone resorption in disorders characterized by excessive bone loss. We have previously found that dichloromethylene bisphosphonate (Cl₂MBP) inhibits bone resorption through injury to the cells that resorb Cl₂MBP-contaminated surfaces. 3-amino-1-hydroxypropylidene-1,1-bisphosphonate (AHPrBP) is a more potent inhibitor of bone resorptionin vivo, and we have attempted to identify a step in the resorptive pathway that accounts for this increased potency. We found that when osteoclasts, isolated from neonatal rat long bones, were incubated on bone slices in the presence of bisphosphonates, AHPrBP was less, rather than more potent as a resorption-inhibitor than Cl₂MBP. The greater sensitivity of resorption to AHPrBPin vivo could neither be attributed to an effect of AHPrBP on the ability of osteoblastic cells to stimulate resorption in response to calcium-regulating hormonesin vitro nor to an effect on osteoclast generation: osteoclast formation was unaffected by concentrations of AHPrBP 10-fold higher than those of Cl₂MBP which inhibit bone resorption in the bone slice assay. We also found no evidence for impaired osteoclast generationin vivo in AHPrBP-treated rats. These results suggest that the comparisons of potencyin vitro do not include all the factors responsible for determining bisphosphonate potencyin vivo. Because bisphosphonates owe the specificity of their actions to their ability to bind to bone surfaces, we performed experiments using bone slices that had been immersed in bisphosphonates before use. Bone resorption was virtually abolished on bone slices preincubated in 10⁻³ M AHPrBP. Inhibition was associated with degenerative changes in osteoclasts and a more rapid decrease in the number remaining on the bone surface than occurred with Cl₂MBP. The effect was specific for osteoclasts, could be prevented if bone resorption was suppressed by calcitonin, and was not seen in osteoclasts incubated in AHPrBP on plastic coverslips. These observations suggest that AHPrBP inhibits bone resorption through injury to osteoclasts when they solubilize bisphosphonate-contaminated bone. We found that the concentration of AHPrBP used in the preincubation phase could be reduced by an order of magnitude if the volume of the AHPrBP solution was correspondingly increased. This implies that the concentration of bisphosphonate is less relevant to potency comparisons than the density of bisphosphonate on the bone surface. The latter will be strongly influencedin vivo not only by affinity for bone but by the pharmacokinetic and other properties of the compound.     

Differential response in alveolar bone osteoclasts residing at two different bone sites

Summary Using a histochemical method for demonstrating acid phosphatase activity, we have studied osteoclasts residing at two different bone sites in rat incisor alveolar bone, one at the endosteum and the other at the tooth socket, and compared the response of these osteoclasts to systemic changes. After 12 days of calcium (0%) or phosphorus (0.2%) deprivation, the number of osteoclasts/cross section at the endosteum increased 463% (P<0.001) and 103% (P<0.002), respectively. After 10 days of calcium or phosphorus replenishment, the number of osteoclasts at this bone site decreased to levels not significantly different from those in the control. In contrast, the number of osteoclasts at the incisor socket remained insignificantly changed throughout the experimental period. A similar osteoclast differential response was also observed in the alveolar bone surrounding the first molar tooth. After 12 days of calcium deprivation, the number of osteoclasts/mm bone surface increased 371% (P<0.001) at the endosteum but remained insignificantly changed at the first molar socket. These results suggest that an osteoclast differential response exists in alveolar bone and that the response may be of significance inasmuch as the major function of alveolar bone is to support the teeth. The work described here supports the concept of local as well as systemic regulation of bone metabolism to simultaneously perform the dual functions of mineral homeostasis and mechanical support.     

The effects of bisphosphonates on the resorption cycle of isolated osteoclasts

Binding sites for wheat germ agglutinin (WGA)-lectin have been shown to become revealed in the demineralized resorption lacunae that osteoclasts excavate on bone substrate. Peroxidase-conjugated WGA-lectin, which binds to bone matrix glycoconjugates and proteoglycans, was used in pit formation assays to assess the activity of isolated osteoclasts cultured on either 3-amino-1,1-hydroxy-propylidene-bisphosphonate (APD)-or dichloromethylene bisphosphonate (Cl₂MBP)-covered bone slices. Immunofluorescence and histochemical techniques were also used to study the effects of bone-bound bisphosphonates on isolated rat osteoclasts. Neither APD nor Cl₂MBP interfered with the special organization of actin or vinculin in osteoclasts when the cells were initializing their resorption cycle. After 24 hours of culture, the number of resorbing osteoclasts increased strongly on control slices, but remained low on either APD- or Cl₂MBP-treated slices. At this time, the actin and vinculin rings in osteoclasts also started to exhibit abnormal, more diffuse staining. Both bisphosphonates studied resulted in signs of cytotoxicity: the number of osteoclasts decreased on APD- or Cl₂MBP-covered bone during the course of the study and those remaining attached exhibited severe cytoplasmic retractions. The total areas of resorption remained at significantly lower levels in both experimental groups studied, and this was due to decreases in both the number and sizes of individual resorption pits. The size of the most extensive lacunae detected on the Cl₂MBP slices did not exceed 5x10³ m², whereas on the control slices, resorption pits bigger than 15x10^{3 2} were frequently discovered.     

The lifespan of osteoclasts: Experimental studies using the giant granule cytoplasmic marker characteristic of beige mice

Osteoclasts are large multlnucleated skeletal cells that form by fusion of bloodborne mononuclear precursors. Fusion with mononuclear precursors occurs throughout life, and survival of Osteoclasts is believed to be dependent upon continued replenishment by fusion. This study examined osteoclast lifespan, defined as maximal survival without fusion, in normal mice irradiated to eliminate host stem cells and rescued with stem cells from beige (bg) mice whose osteoclasts have a distinctive phenotype. Osteoclasts of donor phenotype appeared during the second week and progressively increased so that by the sixth week no osteoclasts of host phenotype were present. Radiation alone did not produce any change in osteoclast phenotype. These data are interpreted to indicate that the maximal survival of osteoclasts without fusion of precursors is less than 6 weeks.