Systemic meloxicam reduces tactile allodynia development after L5 single spinal nerve injury in rats.
BACKGROUND
Although recent evidence suggests that cyclooxygenase-2 (COX-2) may contribute to the development and management of neuropathic pain, the efficacy of COX-2 inhibitor against neuropathic pain is still unclear. In this study, we investigated the effects of the systemic administration of the selective COX-2 inhibitor meloxicam at an early stage after nerve injury on the development of tactile allodynia in L5 single spinal-nerve injury in rats.


METHODS
Twenty-four young male Sprague-Dawley rats received L5 single spinal-nerve injury. Nerve-injured rats (6 per group) received repeated intraperitoneal administrations of meloxicam (1, 2, or 4 mg/kg) or vehicle 0, 12, 24, and 36 hours after nerve injury. Tactile allodynia was quantified for 4 weeks by use of von Frey filaments.


RESULTS
In animals given 2 mg/kg and 4 mg/kg, hind-paw withdrawal thresholds 4 weeks after nerve injury were significantly higher compared with those of the vehicle-treated animals. The area under the time-effect curve from preinjury to 4 weeks after nerve injury values were significantly higher in animals treated with 4 mg/kg of meloxicam compared with animals treated with vehicle.


CONCLUSIONS
Systemic administration of 2 mg/kg and 4 mg/kg of meloxicam at an early stage after nerve injury attenuated the development of tactile allodynia. These results suggest that COX-2 may be at least in part involved in the development of tactile allodynia in an L5 single spinal-nerve injury model.
Takahashi
Masahiro
M
Department of Anesthesiology, Nara Medical University, Japan. masakun@nmu-gw.naramed-u.ac.jp
Kawaguchi
Masahiko
M
Shimada
Keiji
K
Nakashima
Toshikatsu
T
Furuya
Hitoshi
H
D018712:Analgesics, Non-Narcotic / Q000494:pharmacology*; D000818:Animals; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D008297:Male; D000077239:Meloxicam; D010146:Pain / Q000517:prevention & control*; D011451:Prostaglandin-Endoperoxide Synthases / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013127:Spinal Nerves / Q000293:injuries*; D013843:Thiazines / Q000494:pharmacology*; D013844:Thiazoles / Q000494:pharmacology*
D018712:Analgesics, Non-Narcotic; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D013843:Thiazines; D013844:Thiazoles; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D000077239:Meloxicam