Behaviour of bone marrow osteoblast-like cells on mineral trioxide aggregate: morphology and expression of type I collagen and bone-related protein mRNAs.
OBJECTIVE
To investigate the in vitro behaviour of rat bone marrow cells (RBM) on mineral trioxide aggregate (MTA) (ProRoot, MTA Root Canal Repair Material; Dentsply Tulsa, Tulsa, OK, USA) compared with intermediate restorative materials (IRM) (Dentsply Caulk, Milford, DE, USA).


METHODS
RBM were obtained from rat femur and were primary cultured and then subcultured. Cells were then seeded on three dishes of each material, and cultured for 3 days, after which they were evaluated morphologically using scanning (SEM) and transmission (TEM) electron microscopy. Furthermore, the calcium released from hydrated material, the cell proliferation ratio and alkaline phosphatase (ALP) activity were analysed, and the expression of type I collagen and bone-related protein mRNAs were evaluated. The data were averaged and analysed via one-way analysis of variance (anova) and were then compared by the Scheffe's test.


RESULTS
SEM showed that RBM attached to MTA and had a flattened appearance without nuclear protrusions and microspikes. TEM showed that the cells attached in the same manner as the control group, but gaps larger than 2 microm were frequently seen. The calcium released from hydrated MTA was about 130 ppm after 3 days of immersion in saline. The ALP activity was similar to the control group. Cell proliferation and expression of type I collagen mRNA was significantly lower, while the expression of osteopontin mRNA was significantly higher than the control group at the third day of culture. In IRM groups, a few rounded cells were observed on the material but no living cells were seen.


CONCLUSIONS
MTA is a material of low toxicity which does not inhibit cell growth, but does suppress the differentiation of osteoblast-like cells.
Nakayama
A
A
Department of Endodontics, Nihon University School of Dentistry, Tokyo, Japan.
Ogiso
B
B
Tanabe
N
N
Takeichi
O
O
Matsuzaka
K
K
Inoue
T
T
D000469:Alkaline Phosphatase / Q000096:biosynthesis; D017607:Aluminum Compounds / Q000633:toxicity*; D000818:Animals; D001854:Bone Marrow Cells / Q000187:drug effects / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D017610:Calcium Compounds / Q000633:toxicity*; D002448:Cell Adhesion / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D048429:Cell Size / Q000187:drug effects; D002478:Cells, Cultured; D024042:Collagen Type I / Q000096:biosynthesis; D004338:Drug Combinations; D006863:Hydrogen-Ion Concentration; D008297:Male; D008768:Methylmethacrylates / Q000633:toxicity*; D008854:Microscopy, Electron; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism; D053495:Osteopontin; D010087:Oxides / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012387:Root Canal Filling Materials / Q000633:toxicity*; D012795:Sialoglycoproteins / Q000096:biosynthesis; D017640:Silicates / Q000633:toxicity*; D015035:Zinc Oxide-Eugenol Cement / Q000633:toxicity*
D017607:Aluminum Compounds; D017610:Calcium Compounds; D024042:Collagen Type I; D004338:Drug Combinations; D008768:Methylmethacrylates; D010087:Oxides; D012387:Root Canal Filling Materials; D012795:Sialoglycoproteins; D017640:Silicates; C506897:Spp1 protein, rat; D015035:Zinc Oxide-Eugenol Cement; C086631:mineral trioxide aggregate; D053495:Osteopontin; C031667:IRM cement; D000469:Alkaline Phosphatase; D002118:Calcium