title: Tissue responses to nacreous implants in rat femur: an in situ hybridization and histochemical study.
abstract: The interface of bone and aragonite nacre (Margaritifera, fresh water pearl mussel) was studied by in situ hybridization and a tartrate-resistant acid phosphatase (TRAP) histochemical assay. Columnar implants were inserted into rat femora for 4, 7, 14, 28 and 56 days. In medullary region, a burst of transient bone formation was observed, which propagated from the periphery towards the nacre implant. A fused interface of bone and nacre was observed at 14 days. Later, the new medullary bone was resorbed and bone marrow was re-established while a thin layer of bone tissue remained covering the implant surface. Expressions of collagen alpha1(I), osteocalcin, osteopontin mRNAs and TRAP in the surrounding tissue were monitored. Correlated with the histology events, a strong transient induction of collagen alpha1(I) and osteocalcin mRNAs as well as TRAP expression, exhibiting a peak signal intensity on day 7 and subsequent down-regulation after day 14 was observed. Osteopontin mRNA, in contrast, was expressed continuously. The degrading nacre surface appeared in direct contact with macrophages and multinucleated giant cells at both days 14 and 28. These cells expressed osteopontin mRNA intensively and some TRAP enzyme activity occasionally.
authors.affiliation: Department of Clinical Research, Center for Oral Biology, Karolinska Institutet, Sweden. haihong.liao@cob.ki.se
authors.forename: Haihong
authors.initials: H
authors.lastname: Liao
authors.forename: Harry
authors.initials: H
authors.lastname: Mutvei
authors.forename: Lars
authors.initials: L
authors.lastname: Hammarström
authors.forename: Tilmann
authors.initials: T
authors.lastname: Wurtz
authors.forename: Jianguo
authors.initials: J
authors.lastname: Li
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D018786:Bone Substitutes / Q000737:chemistry*; D002119:Calcium Carbonate / Q000494:pharmacology*; D003094:Collagen / Q000096:biosynthesis; D005269:Femur / Q000378:metabolism*; D015726:Giant Cells / Q000378:metabolism; D017403:In Situ Hybridization; D007527:Isoenzymes / Q000378:metabolism; D008297:Male; D015675:Osteocalcin / Q000096:biosynthesis; D053495:Osteopontin; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012795:Sialoglycoproteins / Q000096:biosynthesis*; D000071681:Tartrate-Resistant Acid Phosphatase; D013997:Time Factors
chemical_list: D001672:Biocompatible Materials; D018786:Bone Substitutes; D007527:Isoenzymes; D012333:RNA, Messenger; D012795:Sialoglycoproteins; C506897:Spp1 protein, rat; D015675:Osteocalcin; D053495:Osteopontin; D003094:Collagen; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase; D002119:Calcium Carbonate