Dexamethasone and basic-fibroblast growth factor regulate markers of mineralization in cementoblasts in vitro.
BACKGROUND
The aim of this study was to determine the effects of basic-fibroblast growth factor (b-FGF) and/or dexamethasone (Dex) on cementoblasts in vitro.


METHODS
Murine cementoblasts were treated as follows: 1) 5% FBS (fetal bovine serum) + ascorbic acid (AA, 50 microg/ml, control); 2) 5% FBS + Dex (10(7)M) + AA; 3) 5% FBS + b-FGF (50 ng/ml)+AA; or 4) 5% FBS + Dex (10(7) M) + b-FGF (50 ng/ml)+AA and then evaluated by Northern analysis for changes in specific genes and by von Kossa stain for changes in mineral nodule formation.


RESULTS
Mitotic activity: b-FGF stimulated DNA synthesis significantly versus negative control. Gene expression: osteocalcin (OCN): Dex or b-FGF or the combination resulted in a decrease in expression versus control. Bone sialoprotein (BSP): Dex increased expression of BSP mRNA levels, b-FGF decreased transcript for BSP at 6 and 24 hours. Long-term (8 days) Dex, b-FGF, or Dex plus b-FGF caused a decrease in BSP expression versus control; osteopontin (OPN): both Dex and b-FGF increased transcripts for OPN seen by 6 hours, with a greater increase noted with b-FGF versus Dex. No apparent additive effect of Dex with b-FGF was noted; matrix gamma-carboxyglutamic acid protein (MGP): b-FGF induced transcripts for MGP and addition of Dex increased this effect, while Dex alone had no effect on expression. Biomineralization: Dex increased cementoblast- mediated biomineralization, while b-FGF blocked this activity, and addition of Dex to b-FGF did not alter FGF associated inhibition.


CONCLUSIONS
Dex and FGF alone and in combination alter cementoblast behavior, but additional studies are required to determine whether these factors have beneficial effects at the clinical level.
Hakki
Sema S
SS
Selcuk University, Faculty of Dentistry, Department of Periodontology, Konya, Turkey. sshakki@selcuk.edu.tr
Nohutcu
Rahime M
RM
Hakki
Erdogan E
EE
Berry
Janice E
JE
Akkaya
Mahinur S
MS
Somerman
Martha J
MJ
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D002113:Calcification, Physiologic / Q000187:drug effects; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002417:Cattle; D002460:Cell Line; D003739:Dental Cementum / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology*; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology*; D058574:Integrin-Binding Sialoprotein; D051379:Mice; D015675:Osteocalcin / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012795:Sialoglycoproteins / Q000378:metabolism; D000097568:Matrix Gla Protein
D000893:Anti-Inflammatory Agents; D002135:Calcium-Binding Proteins; D003907:Dexamethasone; D016326:Extracellular Matrix Proteins; D016222:Fibroblast Growth Factor 2; D058574:Integrin-Binding Sialoprotein; D015675:Osteocalcin; D012333:RNA, Messenger; D012795:Sialoglycoproteins; D000097568:Matrix Gla Protein; C546872:Ibsp protein, mouse