Tissue responses to nacreous implants in XXXX femur: an in situ hybridization and histochemical study.

@entity35 @entity9356 @entity62674
The interface of bone and aragonite nacre (Margaritifera, fresh water pearl mussel) was studied by in situ hybridization and a @entity62674 ( @entity62674 ) histochemical assay. Columnar implants were inserted into @entity35 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), @entity9356 , osteopontin mRNAs and @entity62674 in the surrounding tissue were monitored. Correlated with the histology events, a strong transient induction of collagen alpha1(I) and @entity9356 mRNAs as well as @entity62674 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 @entity62674 enzyme activity occasionally.
