Analgesic effects of lidocaine, morphine and diclofenac on movement-induced nociception, as assessed by the Knee-Bend and CatWalk tests in a rat model of osteoarthritis

• Published in: Pharmacology, biochemistry and behavior biochemistry and behavior, 2012-06, Vol.101 (4), p.617-624
• Main Authors: Ferreira-Gomes, Joana, Adães, Sara, Mendonça, Marcelo, Castro-Lopes, José Manuel
• Format: Article
• Language: English
• Subjects: Administration, Oral; Analgesics - administration & dosage; Analgesics - pharmacology; Animals; Arthralgia - drug therapy; Arthralgia - physiopathology; CatWalk; Diclofenac; Diclofenac - administration & dosage; Diclofenac - pharmacology; Disease Models, Animal; Injections, Intra-Articular; Injections, Subcutaneous; Knee-Bend; Lidocaine; Lidocaine - administration & dosage; Lidocaine - pharmacology; Male; Morphine; Morphine - administration & dosage; Morphine - pharmacology; Movement - physiology; Nociception - drug effects; Nociception - physiology; Osteoarthritis; Osteoarthritis - drug therapy; Osteoarthritis - pathology; Osteoarthritis - physiopathology; Pain; Pain Measurement - methods; Pharmacological modulation; Rats; Rats, Wistar
• ISSN: 0091-3057; 1873-5177
• DOI: 10.1016/j.pbb.2012.03.003

Pain is the major symptom of osteoarthritis (OA) and the main reason for patients seeking medical care, but its treatment is not optimal. Animal studies are necessary to elucidate mechanisms underlying OA-induced pain and assess analgesics' efficacy. Previously, we showed that the Knee-Bend test and dynamic weight bearing by the CatWalk test are clinically relevant methods for assessing movement-induced nociception in the mono-iodoacetate (MIA) OA model. Using the same tests, in the present study we investigate the effects of lidocaine (5mg, 10% solution, intra-articular), morphine (6mg/kg, subcutaneous) and diclofenac (30mg/kg per os) on nociceptive behavior in OA animals, on days 3 and 20 of OA evolution. Morphine reduced nociceptive behavior in both tests at both time-points. Lidocaine also decreased nociceptive behavior in both tests on day 3, but on day 20 only reduced the Knee-Bend score. Diclofenac was highly effective in both tests on day 3, while on day 20 it induced a less pronounced decrease in the Knee-Bend score and was ineffective in the CatWalk test. The results showed that the Knee-Bend and CatWalk tests are reliable alternative methods for evaluating movement-induced nociception in OA animals, and measure nociception in a clinically relevant way, since an analgesic profile similar to the one described in humans was observed. Therefore, these tests might be important as good predictors of drug efficacy. ► Evaluation of lidocaine, morphine and diclofenac effect on nociception in OA animals. ► Nociception induced by movement was evaluated by the Knee-Bend and CatWalk tests. ► Morphine, Lidocaine and Diclofenac were highly effective in both tests on day 3. ► On day 20, only morphine reduced nociceptive behavior in both tests. ► Knee-Bend and CatWalk assess movement-induced nociception in a clinical relevant way.