Anodic oxidation and hydrothermal treatment of commercially pure titanium surfaces increases expression of bone morphogenetic protein-2 in the adherent macrophage cell line J774A.1.
The surface property of commercially pure titanium (cpTi) was improved by forming a thin hydroxyapatite (HA) layer by anodic oxidation and hydrothermal treatment (HA/cpTi). We hypothesize that the adhesion of macrophages to HA/cpTi surfaces is important to the process of osseointegration. This study investigates the effect of adhesion of macrophages to HA/cpTi surfaces on the expression of bone morphogenetic protein-2 (BMP-2). The murine macrophage cell line J774A.1 was cultured on HA/cpTi and polished cpTi (S/cpTi). Macrophage cell adhesion was examined by SEM, 0-72 h following plating onto HA/cpTi and S/cpTi. BMP-2 gene expression was examined by RT-PCR analysis. The level of BMP-2 secreted into the supernatant was measured using an ELISA assay. The extent of macrophage adhesion increased with time on both the HA/cpTi and S/cpTi surfaces, with a" higher degree of spreading observed on HA/cpTi than onS/cpTi surfaces after 24 or 72 h. The ratio of BMP-2 mRNA was higher on HA/cpTi than on S/cpTi after 24 h (0.348 vs. 0, p < 0.05) and 72 h (0.584 vs. 0.189, p < 0.05). After 24 h, secretion of BMP-2 was detected in cultures grown on HA/cpTi, but not on S/cpTi. After 72 h, secretion of BMP-2 was detected in cultures grown on S/cpTi, but the levels were higher in cultures grown on HA/cpTi. These findings show that macrophages have the capacity to adhere to HA/cpTi endosseous implants and provide a source of osteoinductive cytokines that may play a key role in the process of osseointegration.
Takebe
J
J
Department of Fixed Prosthodontics, School of Dentistry, Iwate Medical University, 1-3-27 Chuodori, Morioka, Iwate 020-8505, Japan. takebej@iwate-med.ac.jp
Ito
S
S
Champagne
C M
CM
Cooper
L F
LF
Ishibashi
K
K
D000818:Animals; D001672:Biocompatible Materials / Q000494:pharmacology*; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000235:genetics*; D002448:Cell Adhesion; D002460:Cell Line; D004566:Electrodes; D005786:Gene Expression Regulation / Q000187:drug effects*; D006358:Hot Temperature; D008264:Macrophages / Q000166:cytology* / Q000187:drug effects; D051379:Mice; D016348:Osseointegration / Q000187:drug effects; D010084:Oxidation-Reduction; D013499:Surface Properties; D014025:Titanium / Q000494:pharmacology*; D016212:Transforming Growth Factor beta / Q000235:genetics*
D001672:Biocompatible Materials; C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D016212:Transforming Growth Factor beta; D014025:Titanium