Osteoblast reaction at the interface between surface-active materials and bonein vivo: A study usingin situ hybridization

Neo, Masashi; Voigt, Christian; Herbst, Hermann; Groß, Ulrich

doi:10.1002/(sici)1097-4636(199801)39:1<1::aid-jbm1>3.0.co;2-u

Cited by 22 publications

(8 citation statements)

References 26 publications

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“…Osteocytes are detectable a few micrometers in proximity of the coating [5][6][7][8][9] and produce new bone which is so tightly apposed to the coating that high magnification SEM and BSEM cannot resolve any discontinuity at the interface. This is not observed with uncoated materials, even with those which are known to promote a close apposition with bone.…”

Section: Discussionmentioning

confidence: 99%

A back-scattered electron microscopy (BSEM) study of the tight apposition between bone and hydroxyapatite coating

Merolli¹,

Leali²,

Santis³

2000

J Orthopaed Traumatol

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IntroductionHydroxyapatite coating of orthopedic metallic implants by plasma-spray technique is presently a well assessed process. Hydroxyapatite (HA) favors the fixation of an orthopedic implant, like a hip prosthesis, by enhancing bone growth in tight apposition with the coating [1, 2]. We performed an electron microscopic analysis at the interface between newly formed bone and hydroxyapatite coating, in an experimental model in the rabbit. Samples were analyzed by scanning electron microscopy (SEM) to evaluate morphologic characteristics such as alignment of lamellae, location of haversian systems, and porosity of the hydroxyapatite coating. Then, on the same field of observation, we followed with a back-scattered electron microscopy (BSEM) analysis to evaluate the actual material distribution on the sample. With this technique, electrons are directed with a certain angle towards the surface of the sample and interact with the material so that they are reflected with a different energy; the final energy is detected and rendered graphically in gray tones [3] on a photomicrograph. BSEM is particularly suited to study the interface between bone and biomaterials because it allows the creation of a map of material distribution in which metallic substrate, hydroxyapatite coating with different densities, bone tissue in different stages of maturation, embedding media and artifactual detachments are easily discerned. AbstractWe performed a backscattered electron microscopy analysis of the interface between newly formed bone and hydroxyapatite coating, in an experimental rabbit model. Twenty cylinders made of Ti6Al4V and coated with hydroxyapatite at different crystallinity were implanted in the distal femural canal and retrieved at 4, 8, 26 and 34 weeks. Crystallinity of the coating varied from 90% to 60% and thickness varied between 50 and 100 µm. Osteocytes were detectable a few micrometers in proximity of the coating. They produced new bone which was so tightly apposed to the coating that high magnification BSEM did not resolve any discontinuity at the interface. This was not observed in uncoated implants. Degradation of the hydroxyapatite coating is not a simple hydrolytic process because newly formed bone is remodelled in areas were a tight apposition with hydroxyapatite is present. The coating itself is likely to be attacked by the resorptive action of multinucleated giant cells and osteoclasts. In conclusion, response to coated samples is morphologically characterized by tight apposition with bone. The substitution of areas of the coating by newly formed bone is possible.

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Section: Discussionmentioning

confidence: 99%

A back-scattered electron microscopy (BSEM) study of the tight apposition between bone and hydroxyapatite coating

Merolli¹,

Leali²,

Santis³

2000

J Orthopaed Traumatol

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“…Osteopontin is produced by osteoblasts and facilitates the adhesion of osteoblasts to the extracellular matrix and accelerates the calcifi cation process. Neo et al (22,23) reported that collagen is found both on the β-TCP and between β-TCP granules, but that osteopontin is found mostly on β-TCP and is also found in the cytoplasm of macrophages. Ohsawa et al (28) demonstrated expression of osteopontin mRNA induced by β-TCP in rat tibia by in situ hybridization, suggesting that osteopontin may play a role in bone formation on the materials and helps to determine their biocompatibility.…”

Section: Bone Related Protein Mrna Expression Around β-Tcpmentioning

confidence: 99%

“…Resorbable tricalcium phosphate (TCP) ceramics (such as β-TCP) of identical initial structure undergo resorption and extensive substitution under the same experimental conditions (10). Some studies have examined the behavior of osteoblasts around implanted β-TCP granules using in situ hybridization in rats (9,20,(22)(23)(24)(25) and other studies have investigated mRNA expression in osteoblasts around the β-TCP (23,28). However, little is known about cell behavior around β-TCP.…”

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confidence: 99%

Bone formation in .BETA.-tricalcium phosphate-filled bone defects of the rat femur: Morphometric analysis and expression of bone related protein mRNA

et al. 2005

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The purpose of the current study was to evaluate the bone formation when β-tricalcium phosphate (TCP) was implanted in bone defects of rat femurs. β-TCP granules were applied to defects created in the femurs of 65 male rats who were sacrifi ced 3, 7, 10, 14 or 30 days later. Bone tissues were embedded in paraffi n, serial sections were cut and then stained with hematoxylin-eosin. Histomorphometric analyses were also conducted. Furthermore, total mRNAs were extracted, homogenized, and reverse transcribed, after which quantitative PCR assays were conducted with a LightCycler™ using the double-stranded DNA dye Syber Green I with primers for either rat osteopontin or osteocalcin. Tissues in defects without β-TCP were used as controls. The amount of newly formed bone tissue in the β-TCP implanted group was signifi cantly greater in both the side areas and the central area of defects than in the control group. Expressions of osteopontin and osteocalcin mRNAs of cells in the defects of the experimental group were up-regulated compared with the control group at all time periods. Taken together, these results prove that β-TCP is an appropriate material for osteoconduction and promotes bone formation in bone defects.

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“…To obtain further information, Neo et al [12][13][14] studied in vivo osteoblast activation around some bioactive materials using in situ hybridization with procollagen ␣1(I) (COL) probe. They concluded that bioactive materials showed no definite stimulative or suppressive effects on osteoblasts, consistent with osteoconductive bone formation.…”

Section: Introductionmentioning

confidence: 99%

The expression of bone matrix protein mRNAs around ?-TCP particles implanted into bone

Ohsawa

Neo

Matsuoka

et al. 2000

J. Biomed. Mater. Res.

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Tissue response around beta-tricalcium phosphate (beta-TCP) particles (150-300 microm in diameter) implanted into rat tibiae was analyzed by in situ hybridization with digoxigenin-labeled procollagen alpha1(I) (COL), osteonectin, osteocalcin, and osteopontin (OPN) RNA probes. Specimens were collected at 3, 5, 7, and 10 days after the operation. Holes without implantation were used as control. In both the beta-TCP implanted and control groups, new bone was formed centripetally and all four kinds of mRNA were expressed in activated osteoblasts. A COL signal was expressed most strongly and widely, and was detected at the peripheral region of the hole at day 3. The other three mRNAs were also expressed in bone forming osteoblasts by day 7. However, in the earlier cell reaction stage, OPN expression in the beta-TCP implanted group was different than that in the control group: OPN mRNA was seen exclusively in the cells on the particles, and an OPN signal was detected not only in COL-positive cells, but also in COL-negative cells. The former cells may be osteoblasts and reflect the early process of bone formation on biomaterials. The latter cells may be macrophages and reflect foreign body reactions. Expression of these OPN mRNAs induced by implantation of beta-TCP may play a role in bone formation on the materials and in determining their biocompatibility.

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Osteoblast reaction at the interface between surface-active materials and bonein vivo: A study usingin situ hybridization

Cited by 22 publications

References 26 publications

A back-scattered electron microscopy (BSEM) study of the tight apposition between bone and hydroxyapatite coating

A back-scattered electron microscopy (BSEM) study of the tight apposition between bone and hydroxyapatite coating

Bone formation in .BETA.-tricalcium phosphate-filled bone defects of the rat femur: Morphometric analysis and expression of bone related protein mRNA

The expression of bone matrix protein mRNAs around ?-TCP particles implanted into bone

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