生长因子FGF在颅缝细胞培养中作用的研究

目的:研究生长因子FGF在颅缝闭合中的调控作用.方法:以颅缝早闭动物模型(SD鼠)的颅缝为研究模型,采用细胞生物学技术、组织化学技术,研究颅缝闭合期间,生长因子bFGF作用下,细胞胶原及骨钙素分泌情况;观察生长因子bFGF,对分离培养的颅缝细胞增殖与代谢影响.结果:在大鼠颅缝分离培养细胞中,bFGF促进颅缝分离培养细胞分泌胶原、骨钙素,加快细胞增殖生长曲线平台期出现,并有效促进大鼠颅缝分离培养细胞S期增殖(p＜0.05).结论:在体外器官培养中,bFGF能促进大鼠分离培养颅缝细胞的活性(p＜0.05).     

子宫内局部生物力学改变与胚胎兔颅缝早闭相关性的实验研究

目的研究兔子宫内作用于胚胎颅骨局部生物力在兔颅缝闭合过程中的调控作用。方法通过对妊娠25d大白兔宫内胚胎，硬脑膜外的颅骨矢状缝用5—0可吸收线缝合，改变其矢状缝局部生物作用力，建立子宫内胚胎颅骨局部生物力学改变的模型。采用胚胎外科技术、组织化学技术，研究局部生物动力学改变后，颅缝组织中的骨钙素（Osteocalcin，OCN）及骨桥蛋白（Osteopontin，OPN）的分泌情况。结果在胚胎兔出生后9d，其被缝合的矢状缝组织中OCN及OPN的含量明显增加。与对照组之间有明显差异（p〈0．05）。结论宫内局部生物力学改变，促进兔单条颅缝组织中OCN及OPN的分泌。     

生长因子在颅缝闭合中调节作用的实验研究

最近的研究表明硬脑膜和其分泌的生长因子(TGF)决定着颅缝的闭合，颅缝早闭的模型研究中发现许多生长因子的高表达，而在开放颅缝中生长因子表达微弱^[1]。我们拟进一步探讨生长因子对大鼠颅缝间质细胞的成骨诱导作用和IGF，体外对小鼠矢状缝闭合的直接作用。     

大鼠颅骨矢状缝牵引成骨的体外研究

目的：探讨建立幼年SD大鼠颅骨器官体外培养的方法，研究外源性张力对颅骨矢状缝成骨活动的影响。方法：取19日龄的ND大鼠颅顶骨矢状缝组织块，试验组加0．4g力，对照组不加力。经器官培养后进行组织学观察和免疫组织化学检查，并检查胰岛素样生长因子-1（insulin-1ike growth factor-1，IGF-1）等mRNA的变化情况。结果：试验组骨缝内成骨细胞活跃，IGF-1阳性染色位于颅缝内成骨细胞，实验组IGF-1 mRNA表达量高于对照组。结论：大鼠颅骨骨缝器官可在体外培养中成功存活并生长。外源机械张力可以扩宽骨缝，刺激成骨活动，可显著增加IGF-1的合成。     

补骨合剂调节大鼠骨髓间充质细胞分化机制的研究

目的：应用体外培养骨髓间充质细胞，在细胞和分子水平观察补骨合剂对细胞分化的影响，探讨补骨合剂治疗骨质疏松症的机制。方法：分离SD大鼠骨髓间充质细胞，通过形态学、碱性磷酸酶、细胞内骨钙素、转化生长因子β1基因表达等指标，对重组人骨形态发生蛋白2(rhBMP2)诱导下的骨髓间充质细胞向成骨细胞分化的程度进行探讨。结果：一定浓度的补骨合剂可促进分化中的骨髓间充质细胞分泌碱性磷酸酶和骨钙素，增强rhBMP2的活性，促进分化中的骨髓间充质细胞表达转化生长因子β1，补骨合剂的这种促进骨髓间充质细胞分化作用与密钙息基本相同。结论：补骨合剂不仅可以增强rhBMP2的活性，促进分化中的骨髓间充质细胞表达转化生长因子β1，大量分泌Ⅰ型胶原，以利于钙盐沉积；还可以促进rhBMP2诱导的骨髓间充质细胞分泌碱性磷酸酶和骨钙素，促进骨髓间充质细胞向成骨细胞表型分化．从而促进钙、磷在骨表面沉积。     

植块法在成骨细胞培养中的应用

目的：探讨植块法培养成骨细胞的可行性。方法：取10例先天性脊柱侧凸患者髂骨松质骨，应用植块法分离培养成骨细胞。培养过程中观察细胞形态学变化，并用碱性磷酸酶染色、RT-PCR检测Ⅰ型胶原和骨钙素表达、骨钙素免疫荧光检测、钙结节观察等方法对培养细胞进行鉴定。结果：应用植块法培养获得了较多的原代细胞，光镜下呈典型的成骨细胞形态，碱性磷酸酶染色、Ⅰ型胶原和骨钙素表达及钙结节形成等观察结果均证实所培养细胞表现成骨细胞特性。结论：植块法成骨细胞培养体系方法简单，在获得大量原代成骨细胞的同时，较好地保持了其生物学特征，是一种较理想的人成骨细胞培养方法。     

胰岛素样生长因子-1(IGF-1)对成骨细胞的成骨影响

目的：探讨不同浓度IGF－1对兔成骨细胞的成骨影响。方法：采用组织块细胞培养技术获得兔成骨细胞，第2代成骨细胞分别在含0.1ng/ml,1ng/ml,10ng/ml,20ng/mlIGF－1的DMEM中培养，24，36h后行MTT法检测细胞增殖情况，72，108h收集培养上清进行骨钙素放射免疫法（RI）测定。结果：IGF－1与成骨细胞培养24，36h，经MTT法检测，不同浓度IGF－1与对照组比较，有显著性差异（P＜0．001）；IGF－1浓度为0．1、1、10ng/ml，各组之间相比存在显著性差异（P＜0．05）；IGF－1与成骨细胞培养72．108h，经RI检测，不同浓度IGF－1对成骨细胞合成骨钙素与对照组比较无显著性差异（P＞0．05）：结论：IGF－1对成骨细胞有明显促进增殖作用，在0．1－10ng/ml范围，存在浓度依赖性，未发现IGF－1对成骨细胞合成骨钙素有影响。     

碱性成纤维生长因子对颅缝细胞成骨分化的影响

目的 探讨碱性成纤维生长因子（FGF-2）对颅缝细胞成骨方向分化的影响.方法 ①获取新生SD大鼠颅骨矢状缝及冠状缝处颅缝细胞.②添加不同浓度FGF-2,观察颅缝细胞ALP染色、ALP活性及成骨标志物（osteocalcin,OC）表达量,了解不同浓度FGF-2对颅缝细胞向成骨分化的影响.结果①各浓度FGF-2作用于颅缝细胞后,ALP染色、活性均较对照组减弱（P ＜0.05）.其中10ng/ml FGF-2诱导的细胞ALP受到的抑制最弱.②各浓度FGF-2作用于颅缝细胞后,OC表达量均较对照组增加（P ＜0.05）.其中10ng/mlFGF-2诱导的细胞其OC表达量最高.结论 ①FGF-2抑制颅缝细胞早期成骨标志物ALP的表达,而增强晚期成骨标志物OC的表达.②较低浓度的FGF-2（10ng/ml）对ALP抑制作用最弱,对OC促进作用最强,最利于促进颅缝细胞向成骨方向分化.     

胰岛素样生长因子-1对甲状旁腺激素介导成骨细胞增殖及成骨活性的影响

目的：通过构建乳鼠颅盖骨成骨细胞分离培养与鉴定方法,研究胰岛素样生长因子－1（Insulin－like growth factor－1,IGF－1）及IGF－1联合重组人甲状旁腺激素1－34（recombinant human parathyroid hormone 1－34,rhPTH1－34）对成骨细胞增殖及I型胶原蛋白mRNA表达的影响。方法培养乳鼠成骨细胞,并观察其形态及功能,以原代培养乳鼠成骨细胞为实验模型,分空白组、PTH组、IGF－1组及不同浓度IGF－1作用的PTH介导的成骨细胞组（0、10、50、100 ng／L）。通过不同剂量的胰岛素样生长因子－1（0、10、50、100 ng／L）联合10－9 mol／L重组人甲状旁腺素刺激体外培养的成骨细胞,用噻唑蓝（ MTT）法检测细胞的增殖能力,RT－PCR法检测成骨细胞I型胶原蛋白mRNA的表达。结果 PTH和IGF－1均可促进成骨细胞增殖;IGF－1联合PTH可以促进成骨细胞增殖,且具有剂量依赖性。 PTH联合IGF－1使成骨细胞增殖能力增强、I型胶原蛋白mRNA表达增强。 IGF－1可以促进成骨细胞I型胶原蛋白mRNA的表达,且具有剂量依赖性。 IGF－1可以促进成骨细胞I型胶原蛋白mRNA的表达,且具有剂量依赖性。结论 PTH与IGF－1均可刺激成骨细胞增殖和分化,IGF－1可促进PTH对成骨细胞的分化、增殖。两者合用其作用增强,有协同促进作用。     

人羊膜间充质细胞向成骨细胞诱导分化的实验研究

目的 观察人羊膜间充质细胞(human amnion mesenchymal cells,hAMCs)体外诱导向成骨细胞分化,为骨组织工程提供种子细胞。方法 从剖宫产后废弃的人羊膜组织分离培养hAMCs,经成骨细胞诱导条件培养基诱导后,对细胞形态特征、碱性磷酸酶、骨桥素、骨钙素表达以及I型胶原分泌进行观察和检测。结果 原代培养的hAMCs形态呈长梭形或不规则形,呈均匀分布生长,传代后细胞体积略变大,约5～7d传代1次。经成骨细胞诱导培养15d后,hAMCs碱性磷酸酶、骨钙素、骨桥素的表达呈阳性,并且检测有I型胶原分泌。结论 hAMCs易于体外分离培养及扩增,体外成骨细胞定向诱导的hAMCs具有典型的成骨细胞的形态和功能性特征,是良好的骨组织工程种子细胞。     

Regional differentiation of cranial suture-associated dura mater in vivo and in vitro: implications for suture fusion and patency.

Despite its prevalence, the etiopathogenesis of craniosynostosis is poorly understood. To better understand the biomolecular events that occur when normal craniofacial growth development goes awry, we must first investigate the mechanisms of normal suture fusion. Murine models in which the posterior frontal (PF) suture undergoes programmed sutural fusion shortly after birth provide an ideal model to study these mechanisms. In previous studies, our group and others have shown that sutural fate (i.e., fusion vs. patency) is regulated by the dura mater (DM) directly underlying a cranial suture. These studies have led to the hypothesis that calvarial DM is regionally differentiated and that this differentiation guides the development of the overlying suture. To test this hypothesis, we evaluated the messenger RNA (mRNA) expression of osteogenic cytokines (transforming growth factor beta1 [TGF-beta1] and TGF-beta3) and bone-associated extracellular matrix (ECM) molecules (collagen I, collagen III, osteocalcin, and alkaline phosphatase) in freshly isolated, rat dural tissues associated with the PF (programmed to fuse) or sagittal (SAG; remains patent) sutures before histological evidence of sutural fusion (postnatal day 6 [N6]). In addition, osteocalcin protein expression and cellular proliferation were localized using immunohistochemical staining and 5-bromo-2'deoxyuridine (BrdU) incorporation, respectively. We showed that the expression of osteogenic cytokines and bone-associated ECM molecules is potently up-regulated in the DM associated with the PF suture. In addition, we showed that cellular proliferation in the DM associated with the fusing PF suture is significantly less than that found in the patent SAG suture just before the initiation of sutural fusion N6. Interestingly, no differences in cellular proliferation rates were noted in younger animals (embryonic day 18 [E18] and N2). To further analyze regional differentiation of cranial suture-associated dural cells, we established dural cell cultures from fusing and patent rat cranial sutures in N6 rats and evaluated the expression of osteogenic cytokines (TGF-beta1 and fibroblast growth factor 2 [FGF-2]) and collagen I. In addition, we analyzed cellular production of proliferating cell nuclear antigen (PCNA). These studies confirmed our in vivo findings and showed that dural cell cultures derived from the fusing PF suture expressed significantly greater amounts of TGF-beta1, FGF-2, and collagen I. In addition, similar to our in vivo findings, we showed that PF suture-derived dural cells produced significantly less PCNA than SAG suture-derived dural cells. Finally, coculture of dural cells with fetal rat calvarial osteoblastic cells (FRCs) revealed a statistically significant increase in proliferation (*p < 0.001) in FRCs cocultured with SAG suture-derived dural cells as compared with FRCs cocultured alone or with PF suture-derived dural cells. Taken together, these data strongly support the hypothesis that the calvarial DM is regionally differentiated resulting in the up-regulation of osteogenic cytokines and bone ECM molecules in the dural tissues underlying fusing but not patent cranial sutures. Alterations in cytokine expression may govern osteoblastic differentiation and ECM molecule deposition, thus regulating sutural fate. Elucidation of the biomolecular events that occur before normal cranial suture fusion in the rat may increase our understanding of the events that lead to premature cranial suture fusion.     

Cranial deformation in craniosynostosis. A new explanation.

Skull growth after premature fusion of a single suture was described by Virchow in 1851. He observed that growth was restricted in a plane perpendicular to a fused suture. However, he failed to predict the compensatory growth patterns that produce many of the deformities recognized as features of individual craniosynostosis syndromes. The deformities resulting from premature closure of a coronal, sagittal, metopic, or lambdoid suture can be predicted by the following observations: (1) cranial vault bones that are prematurely fused act as a single bone plate with decreased growth potential; (2) asymmetrical bone deposition occurs mainly at perimeter sutures, with increased bone deposition directed away from the bone plate; (3) sutures adjacent to the stenotic suture compensate in growth more than those sutures not contiguous with the closed suture; and (4) enhanced bone deposition occurs along both sides of a nonperimeter suture that is a continuation of the prematurely closed suture. These four rules were derived by critically examining the clinical deformities observed with each form of craniosynostosis. These rules assume that cranial sutures have the capacity to compensate by depositing bone asymmetrically along their edges. Unequal growth patterns have been demonstrated in the frontonasal suture of rabbits by Selman and Sarnat. In addition, unequal bone deposition has also been demonstrated along the parieto-interparietal suture in albino rats by Baer. Human studies to determine if asymmetrical bone deposition actively occurs along cranial vault sutures in response to a stenotic suture have not been performed, however. It is also unclear whether these four guidelines apply to cranial base abnormalities observed with craniosynostosis. As new radiologic techniques develop to define the configuration of the skull in intricate detail, a skull pattern of growth explaining the pathogenesis of all deformities created by premature fusion of a cranial vault suture may become apparent.     

Expression of high-affinity receptors for TGF-beta during rat cranial suture fusion.

The etiology of craniosynostosis is unknown. The elucidation of the biological pathways responsible for this disorder has been hampered by an inability to evaluate cranial sutures before, during, and after cranial suture fusion. The programmed fusion of the rat posterofrontal (PF) suture postnatally provides an excellent model to study the molecular events that occur during cranial suture fusion. Previous experiments have implicated transforming growth factor beta (TGF-beta) growth factors in the regulation of PF suture fusion. The purpose of these experiments was to localize the expression of high-affinity receptors for these growth factors during cranial suture fusion. Four rats were sacrificed on postnatal days 8, 12, 17, and 40 (N = 16). The PF and sagittal sutures were harvested and prepared for immunohistochemical localization of TGF-beta receptor 1 and receptor 2 (Tbeta-RI, Tbeta-RII) protein. Results indicate that immunostaining for Tbeta-RI and Tbeta-RII is markedly increased in the dura mater and osteoblasts of the sutural margin of the PF suture during active suture fusion (on postnatal days 12, 17, and 40) compared with the osteoblasts and dura mater underlying the patent sagittal suture. These results, in combination with the authors' previous findings as well as studies supporting a role for TGF-beta molecules in the regulation of osteogenesis, implicate TGF-beta signaling in the regulation of suture fusion. The possible mechanisms of ligand-receptor interaction are discussed.     

Analysis of TGF-beta production by fusing and nonfusing mouse cranial sutures in vitro.

The role of transforming growth factor beta (TGF-beta) in the regulation of cranial suture fusion has been studied by various qualitative techniques such as in situ hybridization and immunohistochemistry. Although the relative expression of TGF-beta isoforms has been assessed in these studies, increased expression of TGF-beta has not been demonstrated in a quantitative fashion. Therefore, the purpose of this study was to quantify TGF-beta production by fusing (posterofrontal [PF]) and nonfusing (sagittal) mouse sutures using two different quantitative TGF-beta assays. The PF and sagittal sutures of 25-day-old mice were harvested and cultured separately in vitro. Culture media conditioned for 48 hours were collected after 3, 6, 9, 12, 15, 18, 21, 24, 27, and 30 days of culture, and total TGF-beta production was assessed using a TGF-beta bioassay. For a quantitative TGF-beta1 immunoassay, media conditioned for 48 hours were collected after 3, 5, 7, 9, 14, 22, and 28 days of culture. The TGF-beta bioassay revealed large amounts of total TGF-beta activity in both PF and sagittal sutures during the first week of culture, with decreasing amounts thereafter. Absolute TGF-beta activity in conditioned media collected from PF sutures at several early time points was higher than those obtained from sagittal sutures; however, these differences were not statistically significant. The results of the TGF-beta1 immunoassay (enzyme-linked immunosorbent assay) were similar to the bioassay in that the highest TGF-beta1 levels were noted during the first week of culture period and decreased thereafter. Analysis of variance of these samples, however, revealed significantly more TGF-beta1 protein in samples collected from the PF suture compared with the sagittal suture on days 3 and 5 of culture (p < 0.05). TGF-beta1 levels in the conditioned media obtained from PF sutures remained elevated compared with the sagittal suture on days 7 and 9; however, these differences were not statistically significant. Increased production of TGF-beta in the conditioned media of fusing PF sutures is the first such quantitative demonstration of growth factor upregulation during suture fusion and supports the hypothesis that TGF-beta expression may be important in cranial suture fusion.     

Microfocal CT: a method for evaluating murine cranial sutures in situ

INTRODUCTION: The murine model is a well-established surrogate for studying human cranial suture biology. In mice, all sutures with the exception of the posterior frontal (PF) suture remain patent throughout life. Histology is regarded as the gold standard for analyzing sutures. On this basis, PF suture fusion begins on day of life 25 and is complete by day 45. Cranial suture histology, however, requires sacrifice of the animal to obtain tissue for analysis. As a result, knowledge of the kinetics of cranial suture fusion is based on a patchwork analysis of many sutures from many different animals. The behavior of a single suture through time is unknown. Our goal is to develop a noninvasive means to repeatedly image mouse cranial sutures in vivo. As a first step, the present study was performed to evaluate microfocal computer tomography (micro-CT) technology for the use of capturing images of a mouse cranium in situ. METHODS: The micro-CT system consists of a microfocal X-ray source and a large format CCD camera optically coupled to a high-resolution X-ray image intensifier, digitally linked to a computer. The PF and sagittal sutures lie in continuity along the midline of the skull. Holes were drilled in the calvaria on both sides of the PF and sagittal sutures of a 45-day-old euthanized mouse. A micro-CT scan of this animal was performed and hundreds of cross-sectional images were generated for the cranium. These images were used to reconstruct three-dimensional volumetric images of the entire cranium. Comparisons were made between (1). the gross specimen and the three dimensional reconstructions; (2). two-dimensional coronal images obtained by micro-CT and those obtained by histology. RESULTS: Analysis of PF and sagittal sutures demonstrated the following: (1). The drilled holes were accurately rendered by micro-CT, when compared to both the gross specimen and the histology. (2). The sagittal suture was found to be patent by both micro-CT and histology. (3). The PF suture is fused by histology, but unexpectedly, the PF suture appears incompletely fused by micro-CT. By micro-CT, however, the anterior and endocranial regions appear more extensively fused than the remainder of the PF suture, a finding consistent with published histologic analysis. CONCLUSIONS: We successfully imaged 45-day-old mouse cranial sutures in situ using micro-CT technology. Precise correlation between histologic sections and radiologic images is difficult, but convincing similarities exist between the gross specimen and images from micro-CT and histology. PF suture fusion in a 45-day-old animal appears different by micro-CT than by histology. One possible explanation for this apparent discrepancy is that suture fusion in histology is determined based on the appearance of bone morphology and not tissue density, as the specimens are necessarily decalcified to section the bone. Micro-CT, on the other hand, distinguishes tissues on the basis of density. Newly forming bone may require bone matrix formation prior to complete calcification; PF suture in 45-day-old mice may be morphologically complete but incompletely ossified. Studies correlating histologic and micro-CT assessment of suture development are underway. Micro-CT appears to be a promising method for noninvasive imaging of mouse cranial suture.     

Cranial vault growth in craniosynostosis

Skull growth after single suture closure was described in 1851 by Virchow, who noted that growth in the plane perpendicular to a fused suture was restricted. However, this observation failed to predict compensatory growth patterns that produce many of the deformities recognized as features of individual syndromes. The deformities resulting from premature closure of a coronal, sagittal, metopic, or lambdoid suture can be predicted on the basis of the following observations: 1) cranial vault bones that are prematurely fused secondary to single suture closure act as a single bone plate with decreased growth potential; 2) asymmetrical bone deposition occurs mainly at perimeter sutures, with increased bone deposition directed away from the bone plate; 3) sutures adjacent to the prematurely fused suture compensate in growth more than those sutures not contiguous with the closed suture; and 4) enhanced symmetrical bone deposition occurs along both sides of a non-perimeter suture that is a continuation of the prematurely closed suture. These observations regarding growth in craniosynostosis are illustrated with clinical material in this report.     

Effects of bone associated growth factors on DNA, collagen and osteocalcin synthesis in cultured fetal rat calvariae

Studies in bone and bone cell cultures have shown that osteocalcin synthesis is dependent on the maturity of the osteoblast and the presence of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3. The bone matrix is a rich source of growth factors that play a role in bone formation, but their effects on osteocalcin synthesis and their interactions with 1,25(OH)2D3 have not been examined. Insulin-like growth factor I (IGF I), basic and acidic fibroblast growth factor (bFGF and aFGF), platelet-derived growth factor (PDGF) and transforming growth factor beta (TGF beta), are growth factors associated with the bone matrix. These factors were shown to stimulate [3H]thymidine incorporation into DNA in 24 h cultures of fetal rat calvariae, and their effect was not modified by 1,25(OH)2D3. IGF I and TGF beta stimulated [3H]proline incorporation into calvarial collagen while the other growth factors studied did not; 1,25(OH)2D3 inhibited collagen synthesis in control as well as in IGF I and TGF beta treated calvariae. IGF I, bFGF and aFGF stimulated osteocalcin synthesis 1.5 to 2.5 fold but only IGF I was synergistic with the stimulatory effect of 1,25(OH)2D3. PDGF and TGF beta had no effect on osteocalcin synthesis. In conclusion, bone matrix-associated factors have important mitogenic effects in bone cultures, but only IGF I and FGFs stimulate osteocalcin synthesis, an effect that is of small magnitude when compared to that of 1,25(OH)2D3.     

A Pro253Arg mutation in fibroblast growth factor receptor 2 (Fgfr2) causes skeleton malformation mimicking human Apert syndrome by affecting both chondrogenesis and osteogenesis

Apert syndrome is one of the most severe craniosynostosis that is mainly caused by either a Ser252Trp(S252W) or Pro253Arg(P253R) mutation in fibroblast growth factor receptor 2 (FGFR2). As an autosomal dominant disorder, Apert syndrome is mainly characterized by skull malformation resulting from premature fusion of craniofacial sutures, as well as syndactyly, etc. A P253R mutation of FGFR2 results in nearly one-thirds of the cases of Apert syndrome. The pathogenesis of Apert syndrome resulting from P253R mutation of FGFR2 is still not fully understood. Here we reported a knock-in mouse model carrying P253R mutation in Fgfr2. The mutant mice exhibit smaller body size and brachycephaly. Analysis of the mutant skulls and long bones revealed premature fusion of coronal suture, shortened cranial base and growth plates of long bones. In vitro organ culture studies further revealed that, compared with wild-type littermates, the mutant mice have prematurely fused coronal sutures and retarded long bone growth. Treatment of the cultured calvaria and femur with PD98059, an Erk1/2 inhibitor, resulted in partially alleviated coronal suture fusion and growth retardation of femur respectively. Our data indicated that the P253R mutation in Fgfr2 directly affect intramembranous and endochondral ossification, which resulted in the premature closure of coronal sutures and growth retardation of long bones and cranial base. And the Erk1/2 signaling pathway partially mediated the effects of P253R mutation of Fgfr2 on cranial sutures and long bones.     

Impaired posterior frontal sutural fusion in the biglycan/decorin double deficient mice

Biglycan (Bgn) and decorin (Dcn) are highly expressed in numerous tissues in the craniofacial complex. However, their expression and function in the cranial sutures are unknown. In order to study this, we first examined the expression of biglycan and decorin in the posterior frontal suture (PFS), which predictably fuses between 21 and 45 days post-natal and in the non-fusing sagittal (S) suture from wild-type (Wt) mice. Our data showed that Bgn and Dcn were expressed in both cranial sutures. We then characterized the cranial suture phenotype in Bgn deficient, Dcn deficient, Bgn/Dcn double deficient, and Wt mice. At embryonic day 18.5, alizarin red/alcian blue staining showed that the Bgn/Dcn double deficient mice had hypomineralization of the frontal and parietal craniofacial bones. Histological analysis of adult mice (45-60 days post-natal) showed that the Bgn or Dcn deficient mice had no cranial suture abnormalities and immunohistochemistry staining showed increased production of Dcn in the PFS from Bgn deficient mice. To test possible compensation of Dcn in the Bgn deficient sutures, we examined the Bgn/Dcn double deficient mice and found that they had impaired fusion of the PFS. Semi-quantitative RT-PCR analysis of RNA from 35 day-old mice revealed increased expression of Bmp-4 and Dlx-5 in the PFS compared to their non-fusing S suture in Wt tissues and decreased expression of Dlx-5 in both PF and S sutures in the Bgn/Dcn double deficient mice compared to the Wt mice. Failure of PFS fusion and hypomineralization of the calvaria in the Bgn/Dcn double deficient mice demonstrates that these extracellular matrix proteoglycans could have a role in controlling the formation and growth of the cranial vault.