Milnacipran attenuated carrageenan-induced hyperalgesia and inflammation in male rats

Background and Aim : Many injuries caused pain and inflammation, which are one of the major challenges for physicians. Existing anti-inflammatory and analgesic drugs such as NSAIDs and opioids have many side effects. In this study, the analgesic and the anti-inflammatory effects of milnacipran were investigated on carrageenan-induced nociception and inflammation in male rats.Methods : Pain and inflammation were induced by intraplantar injection of λ-carrageenan (1% v/v) in the right hind paw. Indomethacin (10 mg/kg) or milnacipran (20 mg/kg) were administered half an hour before carrageenan injection. Analgesia was measured by Hotplate test, and inflammation was assessed by paleothermometer. Finally, the effect of milnacipran on lipid peroxidation and myeloperoxidase (MPO) activity evaluated spectrophotometrically.Results : The results showed that carrageenan caused hyperalgesia and inflammation in the hind paw tissue. Milnacipran (20 mg/kg: i.p) significantly attenuated (P<0/01) inflammation percentage and significantly increased (P<0.001) nociception threshold. Also, milnacipran significantly suppressed malondialdehyde (MDA) levels (P<0.05) and MPO activity (P<0.001) following intraplantar injection of carrageenan in the hind paw tissue.Conclusion : In the present study, milnacipran showed anti-nociceptive and anti-inflammatory effects on carrageenan-induced nociception and inflammation. Milnacipran reduced inflammatory edema and increased the paw withdrawal threshold probably through suppression of MDA level and MPO activity in the hind paw tissue. Therefore, milnacipran holds important potential as an anti-inflammatory and anti-nociceptive drug. Although, there is need more clinical trial studies to prove this issue.

Keywords:

Carrageenan , Milnacipran , Plethysmometer , Pain and Inflammation , Myeloperoxidase , Malondialdehyde