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PubMed2001

Osteoblastic differentiation of periosteum-derived cells is promoted by the physical contact with the bone matrix in vivo.

The periosteum contains osteoprogenitors that differentiate to osteoblasts in bone growth or repair. Our previous studies suggested the hypothesis that the physical contact of the periosteum with the bone matrix is requisite for the differentiation of osteoblasts. To test the hypothesis, the present study was designed to investigate how the contact between the periosteum and the bone matrix influences the osteoblastic differentiation of periosteal cells with establishing a new experimental model in vivo. Differentiation of osteoblasts was assessed by gene expression of type I collagen, osteocalcin and bone sialoprotein using in situ hybridization. A barrier was designed to prevent periosteal cells from contacting the bone matrix using the membrane filter. The membrane filter was inserted surgically between the surface of rat parietal bone and the periosteum after being punched out with pin holes. Periosteal cells were allowed to contact with the bone surface only through the pin holes. The pin hole was filled with cells derived from the periosteum 1 week after inserting the filter. Differentiation of osteoblasts in week 2 and noticeable bone formation in week 3 were identified on the bone surface only under the pin hole but not under the filter. The present study demonstrated that the physical contact with the bone matrix promotes osteoblastic differentiation of periosteum-derived cells in vivo.

Animals↗
PubMed1985

Induction of deer antlers by transplanted periosteum. I. Graft size and shape.

When discs of frontal periosteum from presumptive antler sites of 6-8 month old male fawns of the fallow deer are grafted beneath the foreleg skin, they will differentiate into pedicle bones and induce small antlers in the overlying integument. These antlers shed their velvet in the fall, and in succeeding years are replaced by larger outgrowths not exceeding 7 cm in length. Periosteal transplants 1.5 cm in diameter gave rise to ectopic antlers in 100% of the grafts, while discs measuring 1.05 cm, 0.75 cm and 0.4 cm did so in only 20% of the cases. Conversely, the donor sites produced antlers in 20-23% of the cases following removal of 1.05 cm or 1.5 cm of periosteum, while 80% and 100% grew antlers after deletions of 0.75 cm and 0.4 cm discs of periosteum, respectively. Semicircular grafts of periosteum induced antler development in most cases, especially when derived from the lateral halves of the antlerogenic region on the frontal bone. These findings confirm that the histogenesis of a deer's first pedicle and antler resides in the frontal periosteum over an area about 1.5 cm wide. They also show that leg skin is capable of antlerogenic development under the inductive influence of frontal periosteum, and that integumental wounding may enhance inductive interactions.

Animals↗
PubMed2004

Magnetic resonance imaging of periosteum with ultrashort TE pulse sequences.

PURPOSE: To assess the values of pulse sequences with ultrashort echo times (0.08 msec) for detecting and characterizing periosteum. MATERIALS AND METHODS: Two normal volunteers aged 33 and 58 years and 12 patients aged seven to 55 years were studied. A total of 10 of the patients had contrast enhancement with intravenous Gadodiamide. Two ovine tibias were examined before and after the periosteum was stripped from the bone. RESULTS: High signal regions were observed adjacent to cortical bone in all parts of the skeleton imaged. They were generally more conspicuous after fat suppression and contrast administration. In the ovine tibia there was a reduction in the high signal normally seen at the surface of the bone after periosteal stripping. The detached periosteum produced a high signal. Mean T(2)* values for adult human periosteum ranged from 5.3 to 11.4 msec. After enhancement the signal intensity increased. In two patients with tibial fractures, increased periosteal signal was seen and this showed marked enhancement. Signals from periosteum could be simulated by fat, contrast-enhanced blood and artifacts. CONCLUSION: The periosteum can be visualized with ultrashort echo time pulse sequences in health and disease.

Adult↗
PubMed2005

Molecular characterization of spontaneous and growth-factor-augmented chondrogenesis in periosteum-bone tissue transferred into a joint.

Multilineage potential of progenitor cells from periosteum is well established, but conditions for differentiation within their native niche are unclear. We evaluated at cellular and molecular levels whether chondrogenesis of periosteal progenitor cells is promoted spontaneously or by growth-factor mixture (GFM) application when transferring periosteum-bone cylinders into cartilage defects. Osteochondral defects in the patellar groove of minipigs were filled with periosteum-bone cylinders and randomly supplemented with GFM. Neochondrogenesis was characterized by histology, immunohistology, and quantitative gene expression analysis. According to morphology and glycosaminoglycan accumulation, spontaneous neocartilage formation occurred in the cambium layer already at 6 weeks, increased after 12 weeks, but declined until 52 weeks, independent of GFM. Multiple cartilage differentiation markers were induced after transfer. Expression of aggrecan, COMP, decorin, and Col10a1 increased significantly within 52 weeks. Sox 9 and Col2a1 mRNA levels were elevated at 6 versus 52 weeks in the GFM group and resulted in higher collagen type II protein accumulation. Neochondrogenesis was promoted in lower periosteum layers by transfer of periosteum-bone plugs into a joint, and collagen type II protein deposition was enhanced by GFM. The final tissue subsumed typical features of periosteum and fibrocartilage but lacked an intact tide mark and features of hyaline cartilage desired for cartilage repair.

Animals↗
PubMed2001

Biomechanical evaluation of two halo pin designs, with, and without, intact periosteum.

The presence of periosteum has been hypothesized to adversely affect halo pin penetration and performance (Voor, 1992. Ph.D. Dissertation, Tulane University, New Orleans, LA). However, biomechanical testing of halo pins has historically been conducted on bone specimens with periosteum removed. This may have lead to an unrealistic measure of biomechanical pin performance. Our study compares the biomechanical performance of two halo pin designs on bovine bone specimens with, and without, intact periosteum. The two pin designs included in this study were the conventional pin (Bremer Medical) with conical tip, and a newly released trochar-style pin (DePuy AcroMed). Results showed the mean peak load before failure of the trochar-style pin (mean +/- 95% confidence interval: 656+/-29 N) to be significantly higher than the conventional pin (517+/-53 N) on bone with intact periosteum (p = 0.001). With the periosteum removed, the mean peak load of the trochar-style pin (655+/-99 N) remained statistically the same (p = 0.987), while the mean peak load of the conventional pin (634+/-65 N) increased significantly (p = 0.026). Variation of the data of the conventional pin significantly decreased from 32 to 19% on removal of periosteum (sigma = 165-103 N, respectively, p = 0.0967), while variation of the trochar-style remained statistically the same at 30-29% (sigma = 193-188 N, respectively, p = 0.954). These results show that the trochar-style pin may be biomechanically superior to the conventional pin for vertical forces experienced during immobilization. The performance of this new pin style may also not be significantly affected by overlying soft tissue. Use of this new pin style may, therefore, improve overall stability and fixation of the halo apparatus.

Animals↗
PubMedDate not supplied

Enveloping of periosteum on the hamstring tendon graft in anterior cruciate ligament reconstruction.

Tendon-bone incorporation of a tendon graft within the bone tunnel is a major concern when using tendon graft for ligament reconstruction. Periosteum consists of multipotent mesodermal cells to form all varieties of connective tissue, including osteogenic and chondrogenic tissues. From our histologic and biomechanical studies in animals, a superior healing process and stronger healing strength can be achieved when periosteum is sutured onto the tendon inserted within a bone tunnel. We applied this idea to anterior cruciate ligament reconstruction to enhance tendon-bone healing. A quadruple-stranded hamstring tendon graft is used. A piece of periosteum, 3 x 3 cm, harvested from the anterior cortex of proximal tibia, is split into 2 rectangle flaps (1.5 x 3 cm each). The periosteum flaps are wrapped and sutured around the tendon graft at the portions near the femoral and tibial tunnel openings. The cambium layer is faced outside to the bone tunnel. Periosteum is easy to harvest from proximal tibia, where is a routine incision for harvesting hamstring tendons. Besides the potential for enhancement of tendon-bone healing, periosteum may be able to seal off the intra-articular opening in a very early period to avoid synovial fluid reflux into the tunnel.

Animals↗
PubMed2001

Localization of chondrocyte precursors in periosteum.

OBJECTIVE: Periosteal chondrogenesis is relevant to cartilage repair and fracture healing. Periosteum contains two distinct layers: a thick, outer fibrous layer and a thin, inner cambium layer which is adjacent to the bone. Specific chondrocyte precursors are known to exist in periosteum but have not yet been identified. In this study, the location of the chondrocyte precursors in periosteum was determined. METHOD: One hundred and twenty periosteal explants from 30 2-month-old NZ rabbits were cultured for up to 42 days. Histomorphological changes and spatio-temporal localization of Col. II mRNA and protein were analysed. RESULTS: On day 7, chondrocyte differentiation appeared in the most juxtaosseous region in the cambium layer. Col. II mRNA and protein were also evident in the same region. By day 14, chondrocyte differentiation progressed further into the juxtaosseous cambium layer, as did Col. II mRNA and protein. With growth of the neocartilage, the cambium layer gradually diminished to the extent that by 21-28 days it was no longer evident. Cartilage growth was significant and followed an appositional pattern, growing away from the fibrous layer. The fibrous layer remained essentially unchanged from 0-42 days, without evidence of hypertrophy or atrophy. Col. II mRNA expression was never seen in the fibrous layer. CONCLUSION: From these data, three conclusions can be drawn concerning chondrogenesis from periosteum: (1) the chondrocyte precursors are located in the cambium layer of periosteum; (2) chondrogenesis commences in the juxtaosseous area in the cambium layer and progresses from the juxtaosseous region to the juxtafibrous region of the cambium layer; (3) neocartilage growth is appositional, which displaces the fibrous layer away from the cartilage already formed, as new cartilage is formed between these two layers. These findings suggest that the least differentiated (stem or reserve) cells are located in the cambium layer furthest from the bone. CLINICAL RELEVANCE: These findings show that the chondrocyte precursors are located in the cambium layer of periosteum. Preservation of this layer is essential for chondrogenesis. As neocartilage growth is appositional, away from the fibrous layer, it can be expected that the new cartilage deposited in and adjacent to a periosteal graft would be expected to be located on the side of the cambium layer, rather than on the side of the fibrous layer of the graft.

Animals↗
PubMedDate not supplied

Hydraulic elevation of the periosteum: a novel technique for periosteal harvest.

Periosteum has been promoted as a potential substrate for tissue engineering. Its principal virtues are that it has a source of pluripotential mesenchymal cells and chondrogenic growth factors located in the cambium layer, and it can serve as a template for directional evolution of neo-tissue. The clinical use and in vitro study of periosteum-derived neo-tissue has been limited by the level of surgical skill required for harvest. Precise surgical technique, task-specific experience, adequate volume of procedures, and general surgical expertise are required for optimal harvest using the traditional periosteal elevator method. This report describes an easily mastered technique that preserves viability while providing the harvest of relatively large amounts of periosteum. Skeletally mature New Zealand white rabbits (11 males/20 tibias; 4 females/8 tibias; approximate weight 3.5 kg) and one Yucatan miniature pig were used for harvest of periosteum from the tibia using the traditional periosteal elevator and the developed hydraulic elevation approach. Histologic examination of the periosteal explants obtained by the developed method showed preservation of the cambium layer containing the progenitor cells necessary for the generation of neo-cartilage. This technique provides a simple method of harvesting large segments (>5 cm x 1 cm) of periosteum in a single procedure and may facilitate better exploitation of periosteum in tissue engineering.

Animals↗
PubMed2005

The use of free-periosteum for secondary bone grafting to the maxillary alveolar clefts.

Some modification on the surgical technique for bone grafting to the alveolar clefts has been required. Secondary bone grafting was performed with and without free-periosteum on 34 (mean age, 9.8 +/- 1.1 years) and 44 (mean age, 10.7 +/- 1.2 years) alveolar clefts, respectively. Vertical bone formation which scored 3 or 4 was obtained in 97.1% of free-periosteum grafted clefts, while it was obtained in 79.5% of the control group. The rate of postoperative wound dehiscence in free-periosteum grafted clefts (20.6%) was not significantly different from the control group (11.4%). In the wound dehiscence cases, however, the grafted periosteum covered the grafted bone and prevented bone exposure. The score of bone formation in the free-periosteum grafted clefts (3.57 +/- 0.79) was significantly higher than that of the control group (2.60 +/- 1.34). Thus, free-periosteum grafting in secondary bone grafting is useful for bone formation in alveolar clefts.

Alveolar Process↗
PubMed2001

Effects of cartilage-derived morphogenetic proteins and osteogenic protein-1 on osteochondrogenic differentiation of periosteum-derived cells.

Localization studies and genetic evidence have implicated cartilage-derived morphogenetic proteins-1, -2 (CDMP-1 and CDMP-2), and osteogenic protein-1 (OP-1) in the osteochondrogenic differentiation of mesenchymal progenitor cells during embryonic development and in postnatal life. Based on their expression pattern and the evidence that periosteum contains mesenchymal cells in the cambium layer that can undergo bone and cartilage formation, we hypothesized that CDMPs and OP-1 may be involved in long bone development and fracture healing. To test this hypothesis, periosteum-derived cells from young calves were cultured as monolayers under serum-free conditions with and without the addition of recombinant CDMP-1, CDMP-2 and OP-1. Phenotypic analysis indicate that periosteum-derived cell populations prepared, expanded, and cultured under the conditions described below, constitutively express messenger RNAs for the bone markers osteocalcin, osteopontin and collagen type I, and the chondrogenic markers collagen type II and aggrecan as determined by RT-PCR. Moreover, histologic examinations showed positive staining for alcian blue and alkaline phosphatase (AP). Treatment of periosteum-derived cells with CDMPs and OP-1 resulted in a dose-dependent increase of cell proliferation; CDMP-2 was less active in this regard. Furthermore, all growth factors enhanced osteogenic differentiation as assessed by a time- and dose-dependent stimulation of AP activity and OP-1 increased messenger RNA expression for osteocalcin and collagen type I. We further examined the effects of CDMPs and OP-1 on chondrogenic differentiation of periosteum-derived cells. Both CDMPs and OP-1 stimulated (35)S-sulfate incorporation into newly synthesized macromolecules with OP-1 having a more pronounced stimulatory effect when compared with CDMP-1 and CDMP-2. Our results indicate that distinct members of the BMP-family increase the mitotic and metabolic activity of periosteum-derived cells. The enhancement of both the chondrogenic and osteogenic differentiation suggests that these growth factors might contribute to the local regulation of bone formation and fracture repair.

Animals↗
PubMed1992

[Meniscal repair with autogenous periosteum and fibrin adhesive system].

It is well recognized that meniscal tear in the avascular portion is difficult to heal. The purpose of this study is to evaluate the ability of periosteum and fibrin adhesive system (FAS) in promoting the meniscal repair in the avascular zone. Full-thickness defects of 1 x 3 mm were created in the avascular portion of lateral menisci in adult mongrels. The control menisci were left without any treatment. The experimental defects were either repaired with autogenous periosteum or the combination of periosteum and FAS. Histologic and ultrastructural evaluation of the reparative tissue were compared at 4, 8, and 16 weeks postoperatively. The reparative tissue in the control group remained fibrous even at week 16, whereas that in the grafted and graft/FAS groups resembled normal adjacent fibrocartilage. Moreover, the regenerated chondrocytes in the graft/FAS group appeared more mature than those in the grafted group. Our results suggest that periosteum is a potential source of primitive cells from which chondrocytes could be differentiated and developed during the reparative process of meniscal fibrocartilage. As to FAS, it not only acted as a hemostatic agent and a fixant, but also could indirectly accelerate the chondrogenesis of periosteum in the meniscal defects. It is sufficient to conclude that the combination of periosteum and FAS in promoting meniscal defects or severe tears in the avascular portion bears its potential in future clinical application.

Animals↗
PubMed1987

Autoradiographic investigation of circadian rhythms in alveolar bone periosteum and cementum in young mice.

This report presents circadian rhythms in cell proliferation of alveolar bone periosteum and cementum of the maxillary first molars of male 5-week-old BNL, Swiss albino mice which were maintained on a 12 hr light/dark cycle. Mice were injected with 3H-TDR (luCi/gm. body wt.) 1 hr prior to sacrifice and killed every 3 hrs for 24 hrs starting at 9 a.m. Maxillae were decalcified, routinely processed histologically and autoradiographs prepared. Cell labeling indices of alveolar bone and cementum mesial to the first molar were determined. Alveolar bone periosteal and cemental cells show circadian rhythm in their DNA synthetic processes. Peaks in percent labeling exhibit higher values than previously reported for nontraumatized, normal dental periosteum and cementum. While the outer periosteum reveals a single 24 hr peak (6 p.m.), inner periosteum and cementum reveal two ultradian peaks 9 to 12 hrs apart involving both light and dark periods. Rodents are nocturnal, but high peaks are also evident in the light periods, consequently, not all peaks are synonymous with the period of animal activity and feeding. Although the single daylight peak of the outer periosteum may indicate growth of that surface at night to about noon, the double peaks exhibited by inner periosteum and cementum indicate light/dark, continuously active surfaces in terms of DNA synthesis and growth.

Animals↗
PubMed1985

Migration of craniofacial periosteum in growing guinea-pigs.

The use of a carbon particle tattoo provided stable periosteal markers and a means of recording periosteal movement both anteroposteriorly and transversely during growth in guinea-pigs. In general, the periosteum migrated toward the cranial sutures. The radial pattern, demonstrated on the frontal bones and indicated on the nasal and parietal bones, showed that a periosteal envelope is identifiable with each bone. The area of origin of this centrifugal pattern of migration coincided with the ossification centre of that bone. Trabeculae and vascular canals tended to point in the direction of periosteal migration. The anteroposterior periosteal migration was proportional to but less than the anteroposterior growth of the craniofacial bones studied. The absolute medial periosteal marker migration, similar on the frontal and parietal bones, was directed in the opposite direction from the slight transverse bone growth. This may indicate a biophysical response to tension on the fibrous periosteum from the principally anteroposterior craniofacial growth. The amount of growth at the frontonasal, coronal and midline sutures diminished from anterior to posterior. The observed histological and morphological sutural characteristics concurred with these growth changes which correlate with the decreased cranial and increased facial growth during the age period studied. Although the fibrous periosteum is continuous over the separate membranous bones its behaviour appears to be intimately related to the growth of the craniofacial bones which it covers. The blending of the fibrous periosteum within the transverse sutures may prevent significant migration across craniofacial bones. It seems that the observed migratory patterns result from a close association of the fibrous periosteum with each growing craniofacial bone. The relationship of the fibrous periosteum to the growth of the craniofacial bones is a question requiring further investigation.

Animals↗
PubMed1994

The role of the periosteum in the healing of the dog's Müller-plate treated femur fracture.

There are contradictory opinions of the role of the periosteum in the conditions of stable osteosynthesis. One group of authors (Küntscher, 1970; Zucman et al., 1968) and others believe that the periosteum, especially its cambian layer, has one of the most important roles in the healing of fractures. However, other group of authors (McEven, 1912; Antony et al., 1980) and others deny the crucial role of the periosteum in the healing of fractures. The authors of the present study performed osteosynthesis by the Müller plate in both femoral bones of 20 dogs. In the left femoral bone, the periosteum was removed 4 cm in the proximal and distal direction from the fracture site, while in the right femoral bone the periosteum remained intact. The healing of the fracture was controlled by X-ray every 15 days up to 2.5 months when the animals were subjected to euthanasia. After 2.5 months from the introduction of the fracture, the healing of the fracture line was recorded in both femoral bones. It is concluded that in the conditions of stable osteosynthesis the periosteum does not play a crucial role in the healing of bones.

Animals↗
PubMed2005

Split-thickness skin graft attachment to bone lacking periosteum.

OBJECTIVES: To develop an animal model to investigate the survival of split-thickness skin grafts (STSGs) on bone without periosteum, to compare STSG attachment to bone with and without periosteum, and to determine the effect of fibrin glue on STSG attachment to bone. DESIGN: Prospective laboratory study. SETTING: University laboratory. SUBJECTS: Sprague-Dawley rats. MAIN OUTCOME MEASURE: Percentage of survival of the STSGs at 2 weeks determined independently by the authors and a third, blinded head and neck surgeon. RESULTS: In experiment 1, which included 40 rats, the sutured STSGs showed an average survival rate of 38% when attached to bone with periosteum, 6% when attached to bare bone, and 10% when attached to bare bone using fibrin glue. The poor survival rate was thought to be attributable to the animals scratching at their bolster dressings. In experiment 2, 18 animals underwent a posteriorly based U-shaped flap of skin and subcutaneous tissue. The grafts were placed and isolated from the overlying flap with a biosynthetic wound dressing. The sutured STSG survival rates were as follows: 87% when attached to bone with periosteum, 94% when attached to bare bone, and 74% when attached to bare bone using fibrin glue. CONCLUSIONS: The survival of STSGs attached to bare bone was comparable to that of STSGs attached to bone with periosteum when grafts were protected with the skin-subcutaneous flap. The STSGs that were fixed with 0.1 cc of fibrin glue demonstrated poorer survival rates than those attached with sutures and were associated with more seromas.

Animals↗
PubMed2000

Osteoinductivity and biomechanics of a porous ceramic with autogenic periosteum.

Twenty-one dogs were used to study the osteoinductivity and biomechanical properties of a biphasic porous ceramic with autogenic periosteum implanted in muscle. The ceramic implants were swathed in fresh periosteum derived from the same animals and implanted in the femur muscles. The other two groups of animals served as controls using the same material implanted in the femur bones and muscles without periosteum. Biomechanical measurements showed that, in the muscles, the experimental group had a higher bending strength than the unswathed group by the time the samples were harvested. Six months postoperatively, the strength of the samples in the experimental group had almost reached that of normal bones. The results of X-ray diffraction and infrared spectrometric analysis suggested that the degradation rate and speed of tricalcium phosphate (TCP) of the ceramic in the experimental group were faster than in the unswathed samples, but slower than in samples implanted in bones. The bone replacement and bone-inducing activity were excellent in the periosteum-swathed samples. Histologically, satisfactory bone repair was seen in the experimental samples. All results indicate that autogenic periosteum could increase bioactivity of ceramics in heterosites and improve bone formation in the surroundings of porous calcium phosphate ceramics. The data also infer that the complicated procedure of culturing bone growth factors with biomaterials in vitro to obtain bioactive grafts could be replaced by this relatively simple method.

Animals↗
PubMed2001

Cellular origin of endochondral ossification from grafted periosteum.

Grafted periosteum is known to have potential for heterotopic bone formation by endochondral ossification. Although osteochondrogenic cells have been thought to originate from the osteogenic layer in grafted periosteum, no histological report has yet demonstrated this. The present study was designed to elucidate the origin of chondrogenesis preceding bone formation in grafted periosteum. Periostea harvested from young Japanese white rabbits' tibiae were grafted into suprahyoid muscles and examined radiographically and histologically at postoperative days 1, 7, 9, 14, 21, and 35. Normal periostea and tibial graft site were also examined. Surgical harvesting of the periosteum split and damaged its osteogenic layer but retained the fibrous layer intact. Most of the osteoblasts remained on the tibial bone surface, and only few cells of the osteogenic layer were present in grafted tissue. By the seventh day after grafting, the fibrous layer had thickened. The fibroblastic cells in the fibrous layer had significantly increased in number (P < 0.01) and were positively stained for proliferating cell nuclear antigen. These cells exhibited alkaline phosphatase activity at day 9. The differentiated chondrocytes had formed cartilage at postoperative day 14. Cells in the osteogenic layer appeared necrotic and subsequently disappeared. Following postoperative day 21, cartilage was replaced by trabecular bone. Bone formation was completed by 35 days. An X-ray analysis at this time also revealed new bone formation. These findings indicate that grafted periosteum forms bone by endochondral ossification and that the cells of the fibrous layer play essential roles in chondrogenesis that precedes such bone formation.

Alkaline Phosphatase↗
PubMed1996

Expression of syndecan-3 and tenascin-C: possible involvement in periosteum development.

The development of cartilaginous elements of long bone during embryogenesis and postnatal bone repair processes is a complex process that involves skeletal cells and surrounding mesenchymal periosteal cells. Relatively little is known of the mechanisms underlying these processes. Previous studies from this and other laboratories have suggested that the extracellular matrix protein tenascin-C is involved in skeletogenesis. Using in situ hybridization and immunofluorescence, we extended those studies by comparing the expression of tenascin-C with that of syndecan-3, which belongs to a family of cell surface receptors with which tenascins are known to interact. We found that syndecan-3 transcripts at first were very abundant in the presumptive periosteum surrounding the diaphysis of early chondrocytic skeletal elements in chick limb. As the elements developed further, syndecan-3 gene expression decreased in the diaphyseal periosteum, whereas it became stronger around the early epiphysis and within the forming articular cells. However, as the diaphyseal periosteum initiated osteogenesis and gave rise to the intramembranous bone collar, syndecan-3 gene expression increased again. At early stages of skeletogenesis: the tenascin-C gene exhibited patterns of expression that were similar to and temporally followed, those of the syndecan-3 gene. At later stages, however, tenascin-C gene expression was markedly reduced during intramembranous osteogenesis around the diaphysis. In addition, although syndecan-3 gene expression was low in osteoblasts and osteocytes located deep into trabecular bone, tenascin-C gene expression remained strong. Thus, tenascin-C and syndecan-3 display distinct temporal and spatial patterns of expression in periosteum and during the development of long bone. Given their multidomain structure and specific patterns of expression, these macromolecules may regulate site-specific skeletal processes, including interactions between developing periosteum and chondrocytes and delineation of the early cartilaginous skeletal elements.

Animals↗