A Modified Inflammatory Pain Model to Study the Analgesic Effect in Mice

Pain has a negative impact on quality of life. The method for evaluating pain plays a key role in developing analgesic drugs. The present study tried to provide a reliable and superior method to evaluate analgesic effects.

The hot plate test is widely used to evaluate analgesic effects on inflammatory pain in mice. A commonly used method of inflammatory pain was induced with an intraplantar injection of carrageenin in one hind paw. We found that mice with a single hind paw carrageenin injection lifted their paws to avoid the during the hot plate test.

Because of this response, the injection method cannot accurately the mouse's pain threshold. Thus, we modified the previous method by injecting carrageenin into both hind paws to establish the model of inflammatory pain. The results demonstrated that both hind paw injection with carrageenin are sensitive, and the better method to induce inflammatory pain when used in the hot plate test than single hind paw injection.

In summary, we developed a superior method to induce a model inflammatory pain to evaluate analgesic effects. The present experiment used only ICR mice. To test the purposes in the future study, we will investigate whether this modified method accurately and consequently detects the pain associated in the other mouse's stress.