Anti-inflammatory effects of memantine in carrageenan-induced paw edema model in rats

Background: The anti-inflammatory effect of memantine (MEM) was investigated using carrageenan-induced hind paw edema model in rats. Materials and Methods: Thirty male Wistar rats were randomly assigned to five groups (n = 6). Group 1 received 0.1mL of 1% carrageenan at the right hind paw. Group 2 received dexamethasone (10mg/kg) and Groups 3, 4, and 5 received 5, 10, and 20mg/kg MEM intraperitoneally (ip), 20min after injection of carrageenan into the right hind paw, respectively. Animals' paw thickness was measured at 0, 1, 2, 3, 4, and 5h after carrageenan injection. Then, animals were euthanized and myeloperoxidase (MPO) and malondialdehyde (MDA) levels were measured in the paw tissues. The tissue samples were further examined histopathologically using light microscopy. One-way ANOVA and Tukey post hoc test was used to compare the mean values between the groups. Results: Treating with MEM at all doses significantly decreased hind paw thickness at 2 (P < 0.05 and P < 0.01 at MEM 10mg/kg and MEM 5 and 20mg/kg, respectively), 3 (P < 0.001), and 4 (P < 0.001 at 5mg/kg and P < 0.01 at MEM 10 and 20mg/kg) hours after carrageenan injection in comparison to the carrageenan group. There was a significant (P < 0.05 and P < 0.001, respectively) reduction in MPO activity and MDA levels in MEM-treated groups when compared with the carrageenan group. Conclusion: This study showed that MEM decreased paw edema, leukocyte infiltration, MPO activity, and MDA levels, and MEM can be considered as an effective anti-inflammatory agent.