M. Neo et al., OSTEOBLAST REACTION AT THE INTERFACE BETWEEN SURFACE-ACTIVE MATERIALSAND BONE IN-VIVO - A STUDY USING IN-SITU HYBRIDIZATION, Journal of biomedical materials research, 39(1), 1998, pp. 1-8
Osteoblast activation after implantation of two kinds of surface-activ
e material in bone was investigated chronologically using in situ hybr
idization with digoxygenin-labeled procollagen alpha 1(I) complementar
y RNA probe. The bioactive materials used were hydroxyapatite (HA) and
apatite-and wollastonite-containing glass-ceramic (A-W GC). A hole wa
s drilled bilaterally in the distal epiphysis of rabbit femurs with su
bsequent implantation of HA or A-W GC cylinders in a press-fit manner.
Specimens were collected at 3, 7, 14, and 28 days after operation and
decalcified. Then the undecalcified implant cores were pushed out of
the hole without causing damage to the bony side of the interface. In
situ hybridization documented no qualitative differences in the expres
sion of procollagen alpha 1(I) RNA between KA and A-W GC. Few osteobla
sts at the bone-material interface showed a specific signal at day 3,
whereas many osteoblasts were positive around the materials at days 7
and 14, indicative of active new bone formation. The positive osteobla
sts seemed to originate from preexisting trabeculae and lined the trab
eculae, newly formed bone, and material surface. At day 28, many osteo
blasts lining material surrounding bone were negative, whereas those i
n remodeling canals were positive, suggesting that the bone was in the
remodeling stage after bone formation. These findings were comparable
to those with beta-tricalcium phosphate in a previous study, thus sug
gesting osteoconductive bone formation on HA and A-W GC. (C) 1998 John
Wiley & Sons, Inc.