Cyclooxygenase-2 inhibitor delays fracture healing in rats.
BACKGROUND
Cyclooxigenase-2 (COX-2) inhibitors have been reported to delay fracture healing. To investigate the major inhibitory period of COX-2 inhibitors in fracture healing, we administrated etodolac, a COX-2-specific inhibitor, to a rat fracture model by altering the period of administration from early to late.


METHODS
After closed fractures had been created at the middle of the femoral shafts in 12-week-old Wister rats, a standardized dose of etodolac was administrated in three ways: group I received it for 3 weeks, group II for just the first week after operation, and group III for just the third (final) week. Group IV was the vehicle control group. Bone maturation was estimated by radiographic scoring system, and mechanically by a three-point bending test.


CONCLUSIONS
In both the radiographic and mechanical studies, groups I and II showed lower scores than group IV, indicating that even a short period of administration of a COX-2-specific inhibitor in the early phase of fracture healing creates a risk of delayed healing. blacksquare, square, filled.
Endo
Kenji
K
Department of Orthopedics, The University of Tokushima, Japan. endoken@clin.tokushima-u.ac.jp
Sairyo
Koichi
K
Komatsubara
Shinji
S
Sasa
Takahiro
T
Egawa
Hiroshi
H
Ogawa
Takayuki
T
Yonekura
Daisuke
D
Murakami
Ri-Ichi
R
Yasui
Natsuo
N
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage* / Q000009:adverse effects; D016861:Cyclooxygenase Inhibitors / Q000008:administration & dosage* / Q000009:adverse effects; D017308:Etodolac / Q000008:administration & dosage / Q000009:adverse effects*; D005264:Femoral Fractures / Q000000981:diagnostic imaging / Q000503:physiopathology; D005269:Femur / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology; D017102:Fracture Healing / Q000187:drug effects*; D007274:Injections, Intraperitoneal; D010012:Osteogenesis / Q000187:drug effects; D011859:Radiography; D051381:Rats; D017208:Rats, Wistar
D000894:Anti-Inflammatory Agents, Non-Steroidal; D016861:Cyclooxygenase Inhibitors; D017308:Etodolac