Evaluation Of the Effectiveness of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) According to Their Cyclooxygenase Selectivity in Neuropathic Pain Model in Rats (Experimental Study)

Aim: Recent studies on neuropathic pain treatment and mechanisms reveal that NSAIDs, which are mostly used in types of pain related to inflammation, may also be effective in neuropathic pain. In this experimental study, we created a neuropathic pain model in rats with sciatic nerve ligation. We investigated the effectiveness of lornoxicam (nonselective COX enzyme inhibitor), meloxicam (selective COX-2 enzyme inhibitor), and dexketoprofen (nonselective COX enzyme inhibitor) on mechanical hyperalgesia, which is a clinical finding of neuropathic pain and can be measured objectively and numerically with electronic von Frey (evF) according to their cyclooxygenase enzyme (COX) selectivity. Thus, we aimed to contribute to the literature and clinical practice by demonstrating the effectiveness of COX selectivity in the treatment of neuropathic pain. Materials and Methods: 35 male Wistar-albino rats with normal motor activity were included in the study. The animals were randomly divided into 5 groups as control (Group I n=7), lornoxicam (Group II n=7), meloxicam (Group III n=7), dexketoprofen (Group IV), and sham surgery (Group V). The Chronic Constriction Injury (CCI) - induced neuropathy model described by Bennett and Xie was applied. As described in this model, after the sciatic nerve of the right hind legs of the rats was surgically exposed, three loose knots were tied with 4/0 catgut at 1 mm intervals from 4 different places. In the group that underwent sham surgery, the sciatic nerve was re-closed without any procedure after being exposed. In this way, lornoxicam 1.3 mg/kg, meloxicam 5.8 mg/kg, and dexketoprofen 15 mg/kg were administered intraperitoneally to the groups that developed neuropathic pain. Drug applications were performed in a single-blind manner. Mechanical hyperalgesia measurements were made with an EVF device and recorded. The study was completed without any problems with 35 subjects. Results: In rats with neuropathic pain, a significant difference was found between the control group that received physiological serum and the groups that received COX inhibitors at all measurement times (p<0.008). When the drug-administered groups were compared in pairs; Intraperitoneal dexketoprofen administration was found to be statistically more significant than intraperitoneal lornoxicam or meloxicam administration at 30th minute (p<0.008). Intraperitoneal lornoxicam administration was found to be statistically more significant than intraperitoneal meloxicam or dexketoprofen administration at 150th and 180th minute (p<0.008). Conclusion: COX inhibitors are effective in preventing mechanical hyperalgesia in neuropathic pain.