Plantar test in carrageenan-induced inflammation

To induce acute inflammation, 100 μl of carrageenan Type IV (Sigma, USA) solution (1.5%, w/v in saline) was injected into the subcutaneous space of the right hind paw of the rats. Immediately following the injection of carrageenan, the test compounds were injected i.t. into the rats in distinct groups. An Ugo Basile 7371 plantar tester (Italy) was used to measure the withdrawal latency of the paw that received the carrageenan injection. The IR intensity was set at 45 and the cut-off time was 20 s. Basal latency was measured before the intraplantar injection of carrageenan (-1 h), and then paw-withdrawal latencies were measured after the injection at 0, 1, 2, 3, 4, 4.5, 5, 5.5, 6, 7, 24, and 31 h.