基质金属蛋白酶13和转化生长因子β1在瘢痕疙瘩和增生性瘢痕中的表达

背景：与瘢痕疙瘩和增生性瘢痕发生机制相关的基质金属蛋白酶13和转化生长因子β1信号传递通路研究多集中在体外成纤维细胞的培养上,而在组织中的相关研究少见报道。 目的：观察瘢痕疙瘩和增生性瘢痕中基质金属蛋白酶13和转化生长因子β1蛋白的表达。 方法：取自2004/2008唐山市工人医院烧伤整形科手术患者,瘢痕疙瘩54例,增生性瘢痕42例。选取同期45例因非感染手术切除的正常瘢痕组织作为对照组,选取同期45例正常皮肤组织作为正常对照组。应用流式细胞仪检测4组中基质金属蛋白酶13和转化生长因子β1的表达,分析两者的相关性。 结果与结论：瘢痕疙瘩和增生性瘢痕中转化生长因子β1的表达明显高于正常瘢痕组织和正常皮肤组织;正常瘢痕组织中转化生长因子β1的表达明显则高于正常皮肤组织,而基质金属蛋白酶13的表达与之相反。瘢痕疙瘩、增生性瘢痕和正常瘢痕组织中基质金属蛋白酶13和转化生长因子β1表达呈负相关。由此推测基质金属蛋白酶13和转化生长因子β1在瘢痕组织中异常表达,二者可能具有协同负向作用,共同参与病理性瘢痕的发生发展。     

原代成纤维细胞和纤维肉瘤细胞自分泌转化生长因子β1浓度检测及对转化生长因子β1增殖的调节

背景：体外实验常采用外源性转化生长因子β1刺激来观察细胞增殖变化,易忽略细胞本身自分泌转化生长因子β1的影响。 目的：检测原代成纤维细胞和纤维肉瘤细胞(L929)自分泌转化生长因子β1的浓度和细胞增殖的变化。 方法：Elisa试剂盒检测原代成纤维细胞和纤维肉瘤细胞各时相点细胞内和培养上清中生长转化因子β1水平。 结果与结论：纤维肉瘤细胞内转化生长因子β1浓度随培养时间延长而升高,原代成纤维细胞内转化生长因子β1浓度随培养时间延长而降低;两种细胞培养上清转化生长因子β1浓度均随时间而上升,但纤维肉瘤细胞显著高于原代成纤维细胞  (P < 0.01),峰值时达到原代成纤维细胞的20倍;两种细胞增殖曲线在72 h内均随时间而显著增高(P < 0.01),同一时间点比较,纤维肉瘤细胞明显高于原代成纤维细胞。提示自分泌转化生长因子β1具有促进细胞增殖的作用,不同的自分泌水平可能是影响原代成纤维细胞这种正常细胞和纤维肉瘤细胞肿瘤细胞对于外源转化生长因子β1反应不同的重要原因。     

转化生长因子β1与体外血管外膜成纤维细胞的增殖和迁移

背景：近年来的研究表明,血管外膜成纤维细胞在血管损伤后新生内膜的增生中起重要作用。当血管损伤后,转化生长因子β1在局部水平上调激活下游多种信号途径,其对血管外膜成纤维细胞参与新生内膜增生过程中所起的作用尚不十分清楚。 目的：观察转化生长因子β1对体外血管外膜成纤维细胞增殖和迁移的影响 方法：体外培养大鼠胸主动脉成纤维细胞,分别以0,3,5,10,15 μg/L的转化生长因子β1刺激成纤维细胞0,2,12,24,48,72 h。以MTT法检测细胞增殖活性,Transwell Chamber测试细胞迁移。 结果与结论：转化生长因子β1能诱导血管外膜成纤维细胞增殖,随着转化生长因子β1质量浓度、作用时间的增加,诱导血管外膜成纤维细胞增殖能力增强(P< 0.05),其中10 μg/L转化生长因子β1作用48 h增殖较对照组增强最为明显(P < 0.01)。不同剂量转化生长因子β1刺激后迁移的细胞数目随转化生长因子β1质量浓度增加而增加,促进作用逐渐增强,呈剂量依赖关系。     

大鼠皮肤创伤修复过程中转化生长因子β1和β3的表达

背景：转化生长因子β在组织创伤修复中发挥核心和关键作用。 目的：观察转化生长因子β1和转化生长因子β3在大鼠皮肤瘢痕性创伤愈合过程中表达量及表达部位的变化。 方法：制备大鼠皮肤全层切伤模型,长度1.5-2.0 cm,深及筋膜层。于伤后0 h,12 h,1 d,2 d,3 d,4 d,5 d,6 d,7 d处死大鼠,取损伤部位皮肤,采用免疫组织化学染色检测各时间点转化生长因子β1和转化生长因子β3的表达,并进行定量分析。 结果与结论：免疫组织化学染色显示,在创伤愈合的早期阶段(伤后1-5 d),转化生长因子β1和转化生长因子β3免疫阳性颗粒主要出现在上皮细胞、上皮基底层细胞胞浆、巨噬细胞等免疫细胞胞浆及肉芽组织中;随着创伤修复时间的持续,免疫阳性颗粒主要出现在真皮层的成纤维细胞及细胞外基质中。其中转化生长因子β1的表达在创伤后1-5 d最强,而转化生长因子β3在创伤后六七天时开始明显表达。可见在大鼠皮肤瘢痕性创伤愈合过程中,转化生长因子β1的表达先于转化生长因子β3,提示转化生长因子β1与胶原形成及创伤修复关系密切,而转化生长因子β3在愈合后期表达量有升高趋势,其可能与创伤后期的组织改建密切相关。     

A型肉毒毒素可抑制人增生性瘢痕成纤维细胞增殖和胶原蛋白的合成

背景：A型肉毒毒素伤口周围局部注射可以减少瘢痕的形成,而且对瘢痕的增生挛缩有抑制作用,可以促进瘢痕的萎缩变平。 目的：观察A型肉毒毒素对人增生性瘢痕成纤维细胞的增殖和胶原蛋白合成的影响。 方法：体外分离、培养人增生性瘢痕成纤维细胞,取对数生长期的细胞接种培养,使用稀释浓度为0.1 U/L A型肉毒素DMEM细胞培养基对细胞的生长过程进行干扰,对照组以含胎牛血清的DMEM培养基培养。 结果与结论：细胞接种第1~15天,对照组可见梭形的增生性瘢痕成纤维细胞分裂增殖,局部融合成细胞单层,细胞生长旺盛,细胞排列呈现高度一致性。A型肉毒毒素组细胞增殖速度慢,细胞数量少,细胞排列方向散乱,A型肉毒毒素组细胞数为对照组细胞数的79.3%,A型肉毒毒素实验组胶原蛋白合成量为正常对照组的48.4%,差异有显著性意义(P < 0.05)。提示A型肉毒毒素可以抑制人增生性瘢痕成纤维细胞的增殖以及胶原蛋白的合成。      

损伤家兔动脉后外膜成纤维细胞增殖、表型变化与TGF-β1表达的关系

目的:观察损伤家兔动脉后外膜成纤维细胞增殖、表型变化与TGF-β1表达的关系。方法:采用免疫组化、透射电镜和原位杂交技术,观察兔腹主动脉损伤后外膜细胞增殖、细胞表型、超微结构和TGF-β1 mRNA表达水平的变化。结果: 损伤后3 d和7 d血管外膜PCNA 阳性细胞显著增多, 14 d接近正常。外膜细胞在损伤后逐渐获得α-actin表达 ,3 d呈弱阳性,7 d和14 d呈强阳性改变。损伤后7 d和14 d外膜细胞发生了显著的超微结构改变:大量的微丝出现和粗面内质网明显扩张,呈现出肌成纤维细胞的特征。损伤后3 d,外膜开始出现TGF-β1 mRNA表达,7 d和14 d表达持续上调,至28 d表达开始下调。 结论: 提示动脉损伤后外膜成纤维细胞增殖水平和表型变化与TGF-β1表达水平具有相关性。     

灯盏花素对腹膜透析液诱导人腹膜间皮细胞转化生长因子β1的影响

背景：从不同层面了解灯盏花素阻止/延缓腹膜功能衰竭的作用及其机制,从而在临床上推广使用灯盏花素来阻止/延缓腹膜功能衰竭从而延长终末期肾脏病患者腹膜透析时间、提高透析质量、减少透析失败率,提高腹膜透析远期疗效具有广泛的应用前景。 目的：观察灯盏花素对腹膜透析液诱导的人腹膜间皮细胞转化生长因子β1分泌及其增殖活性的影响。 方法：体外培养人腹膜间皮细胞,分为5组：分别为对照组、腹膜透析液组、灯盏花素终浓度为5,10,20 µmol/L组。检测各组上清液中转化生长因子β1的水平以及间皮细胞的增殖活性。 结果与结论：腹膜间皮细胞在腹膜透析液诱导下,转化生长因子β1分泌显著增加、细胞增殖活性显著降低。灯盏花素5 µmol/L组转化生长因子β1分泌低于腹膜透析液组(P < 0.05),细胞增殖活性高于腹膜透析液组(P < 0.05);灯盏花素10,20 µmol/L组转化生长因子β1分泌显著低于腹膜透析液组(P < 0.01),细胞增殖活性显著高于腹膜透析液组(P < 0.01)。结果显示灯盏花素可以抑制腹膜间皮细胞转化生长因子β1分泌,拮抗腹膜透析液对腹膜间皮细胞增殖活性的抑制作用。     

环孢素干预小肠移植物中转化生长因子β1的表达

背景：小肠移植慢性排斥反应的发生是影响其长远预后的重要因素。 目的：观察环孢素对于小肠移植物中转化生长因子β1表达的影响。 方法：近交系F344(RT11vr)大鼠和Lewis(RT11)大鼠作为小肠移植的供体和受体,利用显微外科技术构建异系大鼠小肠移植模型,分别在建模后7,28,60 d进行移植物活检,常规病理学检测,应用Real time-PCR技术检测移植物内转化生长因子β1因子mRNA转录水平,并采用免疫组织化学方法对转化生长因子β1的表达进行定位。 结果与结论：在建模后7-28 d应用环孢素的过程中转化生长因子β1 mRNA转录水平呈现明显减低趋势;在28-60 d,停用环孢素后该因子表达则明显升高。说明环孢素对于异系小肠移植中转化生长因子β1的表达有一定的抑制作用。     

转化生长因子β1对瘢痕成纤维细胞合成细胞外基质的调节作用

目的：研究转化生长因子β1(TGF-β1)对瘢痕成纤维细胞胶原蛋白和粘连蛋白(FN)合成的影响,探讨TGF-β1与瘢痕细胞外基质(ECM)的关系。方法：采用细胞培养、VG化学染色、免疫组化、图像分析扫描和氯胺T法观察不同浓度TGF-β1对瘢痕成纤维细胞胶原蛋白及FN合成的影响。结果：TGF-β1在浓度为10-50ng／ml下能刺激胶原蛋白和FN的合成,并呈剂量效应关系;当TGF-β1浓度为100ng／ml时,作用达饱和。结论：TGF-β1可能与瘢痕形成过程中ECM的过度沉积有关。     

全反式维甲酸对人胚肺成纤维细胞增殖及α-SMA表达的影响

目的: 研究全反式维甲酸(ATRA)对人胚肺成纤维细胞(HFL-I)增殖与分化的影响。方法: 体外培养HFL-I, MTT法检测不同浓度ATRA(0.1 μmol/L、1 μmol/L、10 μmol/L)作用3 d对HFL-I增殖能力的影响。5 μg/L 转化生长因子β₁(TGF-β₁)刺激0 h、6 h、12 h、24 h、48 h、72 h后,RT-PCR法检测α-平滑肌肌动蛋白(α-SMA) mRNA表达,刺激0 d、1 d、3 d、5 d后,Western blotting法检测α-SMA蛋白表达。不同浓度ATRA干预,24 h后RT-PCR方法检测α-SMA mRNA表达,3 d后用Western blotting方法检测α-SMA蛋白表达。结果: (1) MTT法检测显示不同浓度ATRA以浓度依赖性方式抑制HFL-I细胞的增殖(P<0.05)。(2)5 μg/L TGF-β₁诱导后,HFL-I细胞中α-SMA mRNA和蛋白表达均上调(P<0.05)。(3) ATRA以浓度依赖性方式下调TGF-β₁诱导的α-SMA mRNA和蛋白的表达(P<0.05)。结论: ATRA能够抑制HFL-I细胞的增殖和TGF-β₁诱导的分化,该作用可能是通过下调α-SMA mRNA和蛋白的表达实现的。     

Endothelial cells synthesize basic fibroblast growth factor and transforming growth factor beta

Endothelial cells, including human umbilical vein endothelial cells (HUVEC), bovine aortic endothelial cells (BAEC), and bovine capillary endothelial cells (BCEC) in culture synthesize basic fibroblast growth factor (bFGF) and transforming growth factor type beta (TGF-beta). Basic FGF was cell-associated and synthesis was demonstrated by (i) the presence of bFGF mRNA species, (ii) binding to heparin-Sepharose and elution at 1.5 M NaCl, (iii) cross-reactivity with anti-bFGF antibodies when analyzed by electrophoretic blotting, and (iv) biological activity. Basic FGF was found in cell lysates at 2.3 ng/10(6) cells in HUVEC, 2.0 ng/10(6) cells in BCEC, and 13 ng/10(6) cells in BAEC. TGF-beta was secreted into media, and synthesis was demonstrated by (i) presence of TGF-beta mRNA species, (ii) cross-reactivity with anti-TGF-beta antibodies when analyzed by immunoprecipitation, (iii) competitive binding with authentic human platelet-derived TGF-beta that was blocked by TGF-beta specific blocking antibodies, and (iv) inhibition of [3H]TdR incorporation in CCl-64 cells. TGF-beta was secreted in an inactive form and required acid activation for detection. HUVEC synthesized 2.0 ng TGF-beta/10(6) cells per 12 hr; BCEC, 3.5 ng; and BAEC, 3.5 ng. HUVEC proliferation was not affected by treatment with exogenous TGF-beta, while BCEC proliferation was decreased by treatment with TGF-beta. Vascular endothelium is thus a source for these two potent multifunctional regulatory molecules, both of which may affect the growth of endothelium and neighboring fibroblasts, smooth muscle cells and white blood cells. The activation or release of these factors by endothelium may be a precipitating event in important cellular processes such as wound healing, organogenesis, and angiogenesis.     

肠道缺血再灌流对肾内源性碱性成纤维细胞生长因子和 …

目的和方法：研究肠道缺血再灌流过程对肾脏内源性碱性成纤维细胞生长因子和转化生长因子β基因表达的影响，采用肠系膜上动脉夹闭４５ｍｉｎ与再灌流６ｈ和２４ｈ动物模型，用原位杂交与逆转录ＰＣＲ（ＲＴ－ＰＣＲ）技术研究两种生长因子基因在正常，缺血以及再灌流肾组织中的表达。     

Fibroblast growth factor 2 and transforming growth factor beta1 synergism in human bronchial smooth muscle cell proliferation

Bronchial smooth muscle cell (BSMC) hyperplasia is a typical feature of airway remodeling and contributes to airway obstruction and hyperresponsiveness in asthma. Fibroblast growth factor 2 (FGF-2) and transforming growth factor beta1 (TGF-beta1) are sequentially upregulated in asthmatic airways after allergic challenge. Whereas FGF-2 induces BSMC proliferation, the mitogenic effect of TGF-beta1 remains controversial, and the effect of sequential FGF-2 and TGF-beta1 co-stimulation on BSMC proliferation is unknown. This study aimed to assess the individual and sequential cooperative effects of FGF-2 and TGF-beta1 on human BSMC proliferation and define the underlying mechanisms. Mitogenic response was measured using crystal violet staining and [3H]-thymidine incorporation. Steady-state mRNA and protein levels were measured by semiquantitative RT-PCR, Western blot, and ELISA, respectively. TGF-beta1 (0.1-20 ng/ml) alone had no effect on BSMC proliferation, but increased the proliferative effect of FGF-2 (2 ng/ml) in a concentration-dependent manner (up to 6-fold). Two distinct platelet-derived growth factor receptor (PDGFR) inhibitors, AG1296 and Inhibitor III, as well as a neutralizing Ab against PDGFRalpha, partially blocked the synergism between these two growth factors. In this regard, TGF-beta1 increased PDGF-A and PDGF-C mRNA expression as well as PDGF-AA protein expression. Moreover, FGF-2 pretreatment increased the mRNA and protein expression of PDGFRalpha and the proliferative effect of exogenous PDGF-AA (140%). Our data suggest that FGF-2 and TGF-beta1 synergize in BSMC proliferation and that this synergism is partially mediated by a PDGF loop, where FGF-2 and TGF-beta1 upregulate the receptor (PDGFRalpha) and the ligands (PDGF-AA and PDGF-CC), respectively. This powerful synergistic effect may thus contribute to the hyperplastic phenotype of BSMC in remodeled asthmatic airways.     

Effect of transforming growth factor beta 1 on neonatal rat latent transforming growth factor beta binding protein 2 in cardiomyocytes

目的 探讨转化生长因子β1 (TGF-β1)在诱导心肌细胞表达转化生长因子结合蛋白2(LTBP2)中的作用及信号传导通路.方法 培养乳鼠心肌细胞;实时定量聚合酶链式反应、蛋白质印迹和免疫细胞化学方法检测不同时间和不同浓度的TGF-β1对大鼠乳鼠心肌细胞LTBP2基因及蛋白表达的影响;用TGF-β1相关信号通路阻断剂探讨TGF-β1调节LTBP2表达改变的信号传导机制.结果 LTBP2基因表达随着TGF-β1浓度增加(0、2、5及10 μg/L)而明显升高,在5μg/L时刺激最强(P＜0.05);5μg/L的TGF-β1刺激下心肌细胞内LTBP2基因和蛋白表达的升高呈时间依赖性,均在12 h最高,24 h开始呈下降趋势(P＜0.05或P＜0.01);免疫细胞化学结果显示TGF-β1明显升高LTBP2的表达.信号传导通路研究显示TGF-β1在心肌细胞内主要通过ERK信号通路和PI3K信号通路诱导LTBP2的表达.结论TGF-β1在乳鼠心肌细胞内通过ERK信号通路和PI3K信号通路上调LTBP2的表达.     

Enhanced expression of transforming growth factor-beta type I and type II receptors in wound granulation tissue and hypertrophic scar.

In the present study we have analyzed and compared, by immunohistochemistry and in situ hybridization, the expression pattern of the R4/ALK5 transforming growth factor (TGF)-beta type I receptor (RI) and the TGF-beta type II receptor (RII) in normal human skin, in wounded skin at various stages during the transition of wound granulation tissue to scar, and in long-persisting post-burn hypertrophic scars. In normal human skin, expression of RI and RII was clearly visible in the epidermis, in epidermal appendages, and in vascular cells, although only a small number of dermal fibroblasts revealed detectable levels of TGF-beta receptor expression. In contrast, granulation tissue fibroblasts showed strong expression of both TGF-beta receptor types, although in normal-healing excisional wounds their density decreased during granulation tissue remodeling. However, in post-burn hypertrophic scars, RI- and RII-overexpressing fibroblasts were found in high densities up to 20 months after injury. From these findings we suggest that the repair process of deep wounds involves the transformation of a subset of fibroblastic cells toward an increased TGF-beta responsiveness and a transient accumulation of these cells at the wound site. In addition, our study provides evidence that excessive scarring is associated with a failure to eliminate TGF-beta receptor-overexpressing fibroblasts during granulation tissue remodeling, which leads to a persistent autocrine, positive feedback loop that results in over-production of matrix proteins and subsequent fibrosis.     

转化生长因子β1对乳鼠心肌细胞转化生长因子结合蛋白2表达的影响

 目的：探讨转化生长因子β1（TGF-β1）在诱导心肌细胞表达转化生长因子结合蛋白2（LTBP2）中的作用及信号传导通路。 方法：培养乳鼠心肌细胞;实时定量聚合酶链式反应（Real-time PCR）、蛋白质印迹和免疫细胞化学方法检测不同时间和不同浓度的TGF-β1对大鼠乳鼠心肌细胞LTBP2基因及蛋白表达的影响;用TGF-β1相关信号通路阻断剂探讨TGF-β1调节LTBP2表达改变的信号传导机制。 结果：LTBP2基因表达随着TGF-β1浓度增加（0、2、5、10 ng/mL）而明显升高,在5 ng/mL时刺激最强（P < 0.05）;5 ng/mL的TGF-β1刺激下心肌细胞内LTBP2基因和蛋白表达的升高呈时间依赖性,均在12 h最高,24 h开始呈下降趋势（P < 0.05或P<0.01）;免疫细胞化学结果显示TGF-β1明显升高LTBP2的表达。信号传导通路研究显示TGF-β1在心肌细胞内主要通过ERK信号通路和PI3K信号通路诱导LTBP2的表达。 结论：TGF-β1在乳鼠心肌细胞内通过ERK信号通路和PI3K信号通路上调LTBP2的表达。     

下颌骨牵引成骨过程中基因干预对牵引区转化生长因子β1表达的影响?****

 背景：局部基因治疗能促进牵引区新骨的生成,但关于基因治疗后对局部生长因子表达的影响目前尚不清楚。 目的：观察电穿孔介导的基因治疗对兔下颌骨牵引成骨过程中转化生长因子β1表达的影响。 方法：新西兰大白兔双侧下颌骨截骨后3 d开始下颌骨牵引,0.8 mm/d,连续牵引7 d后,随机分为5组,分别在牵引区注射2 μg(0.1 g/L)重组质粒pIRES-hVEGF165-hBMP2、pIRES-hBMP2、pIRES-hVEGF165、空质粒pIRES及相同剂量的生理盐水。之后施加电穿孔刺激。 结果与结论：免疫组织化学染色发现转化生长因子β1主要在细胞胞浆中表达,给药7 d时骨端骨细胞、编织骨痂骨细胞、骨痂表面成骨细胞呈转化生长因子β1染色阳性;14 d时新生成的编织骨痂骨细胞、骨痂表面成骨细胞、肉芽组织中的间质细胞、单核巨细胞、多核巨细胞转化生长因子β1染色阳性;28 d时转化生长因子β1阳性细胞明显减少。其中注射重组质粒pIRES-hVEGF165-hBMP2、pIRES-hBMP2、pIRES-hVEGF165后转化生长因子β1的表达明显多于注射空质粒pIRES及生理盐水(P < 0.05或P < 0.01)。说明基因治疗能促进转化生长因子β1的表达,促进牵引区细胞基质的形成和新骨生成。       

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。     

Effects of transforming growth factor beta1 on bonelike tissue formation in three-dimensional cell culture. I. Culture conditions and tissue formation

Bone tissue engineering based on growing bone marrow stromal cells on poly(L-lactic-co-glycolic acid) fiber meshes suffers from limited matrix production and mineralization when the cells are cultured with the standard differentiation supplements (dexamethasone, beta-glycerophosphate, and ascorbic acid). To overcome this problem we included transforming growth factor beta1 (TGF-beta1), which is described as playing a key role in collagen type I formation, although its effect on mineralization is controversially discussed. The investigations focused on establishing culture conditions for the application of TGF-beta1 in three-dimensional cell culture and on the effects of different doses of TGF-beta1 (1-20 ng/mL) on bonelike extracellular matrix formation. Immunohistochemical staining showed that TGF-beta1 enhanced the formation of procollagen type I, collagen type I, and collagen type V, especially under dynamic culture conditions (orbital shaker). A long-term study confirmed positive effects on the formation of extracellular matrix, which penetrated the scaffold to a depth of 250 to 300 microm. Mineralization, qualified by scanning electron microscopy in combination with energy-dispersive X-ray analysis and evaluated by determination of the Ca2+ content per scaffold, was up to 1.7-fold increased by TGF-beta1 compared with the control. In conclusion, the growth factor TGF-beta1 seems to be effective in improving extracellular bonelike matrix formation in vitro.