Dose-related anti-inflammatory/analgesic effects of lornoxicam: A spinal c-Fos protein study in the rat

Objective: To evaluate the anti-inflammatory/analgesic effects of lornoxicam in the carrageenan model of inflammatory nociception. Material and Methods: Three hours after intraplantar carrageenan (6 mg/150 mu l of saline), we assessed the effects of pre-administered lornoxicam (0.1, 0.3, 1, 3 and 9 mg/kg i.v., n=10 rats for each group) on both the peripheral oedema and number of c-Fos-protein-like immunoreactive (c-Fos-LI) neurons in the lumbar L4-L5 segments. in the awake rat. Results: Lornoxcam dose-relatedly reduced both the carrageenan evoked oedema (r=0.63 and r=0.53 for paw and ankle diameter respectively: p<0.001 for both) and total number of spinal c-Fos-LI neurons (r=0.79, p<0.001), with the strongest effect corresponding to a 75 +/- 2% reduction of the number of f-Fos-LI neurons (p<0.001) for the highest dose (9 mg/kg), and a 45 +/- 3% reduction (p<0.001) for the low dose of 0.3 mg/kg. Reductions of both rile peripheral oedema and spinal c-Fos expression were correlated (r=0.74 and r=0.57 for the paw and ankle diameter respectively: p<0.001 for both). Conclusions: Our results demonstrate that lornoxicam reduces in parallel both the carrageenan-evoked oedema and spinal c-Fos expression, with clear evidence for a potent effect of low doses of lornoxicam. Correlated reductions in c-Fos expression and paw oedema suggest a predominantly peripheral site of action of lornoxicam.