Limited inhibitory effects of non-steroidal antiinflammatory drugs on in vitro osteogenic differentiation in canine cells.
Cyclooxygenase (COX)-2 participates essentially in bone healing, demonstrated by COX-2 knockout mice that showed delayed fracture repair. Considerable controversy still exists on inhibitory effects of COX-2 inhibitors on bone healing in clinical cases. To assess stage-dependent effects of short-term treatment of COX-2 inhibitors on osteogenic differentiation, a canine POS osteosarcoma cell line which spontaneously differentiates into osteoblastic cell was exposed to COX-2 inhibitors such as carprofen and meloxicam for 72 hours during three different stages of osteoblast differentiation, including day 0 to 3 (pre-osteoblastic stage), day 4 to 7 (transitional stage) and day 8 to 11 (mature osteoblastic stage). As osteogenic markers, expression of alkaline phosphatase (ALP) was estimated by analysis of mRNA expression, enzymatic activity and ALP staining, and expression of osteocalcin was estimated by analysis of mRNA expression after the drug treatments. Calcified matrix formation was finally observed by von Kossa staining on day 14. Expressions of ALP showed no significant suppression by carprofen and meloxicam during all three stages. However, expressions of osteocalcin mRNA and non-calcified nodule formations were delayed by carprofen and meloxicam during transitional stage. Nevertheless, fully calcified nodule formation was observed in all experimental groups during post-medication period. These results indicate that short-term treatment of carprofen and meloxicam would reversibly suppress the differentiation of osteoblasts.
Laboratory of Veterinary Surgery, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan. ngism@hotmail.com
Namgil
N
Oh
Takafumi
T
Sunaga
Hiroki
H
Yamazaki
Kenji
K
Hosoya
Satoshi
S
Takagi
Masahiro
M
Okumura
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D002227:Carbazoles / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects*; D045744:Cell Line, Tumor; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004285:Dogs; D005786:Gene Expression Regulation / Q000187:drug effects; D000077239:Meloxicam; D051379:Mice; D018345:Mice, Knockout; D010006:Osteoblasts / Q000166:cytology / Q000502:physiology; D010012:Osteogenesis / Q000187:drug effects*; D013843:Thiazines / Q000494:pharmacology*; D013844:Thiazoles / Q000494:pharmacology*
D000894:Anti-Inflammatory Agents, Non-Steroidal; D002227:Carbazoles; D016861:Cyclooxygenase Inhibitors; D013843:Thiazines; D013844:Thiazoles; C077623:Ptgs2 protein, mouse; D051546:Cyclooxygenase 2; C007005:carprofen; D000077239:Meloxicam