A non-reflexive method based on the variability of temperature and bioimpedance in measuring inflammatory hyperalgesia and analgesia in mice.

Background: Preclinical studies measure withdrawal responses to evoking thermal and mechanical stimuli instead of the more clinically important spontaneous pain.

New Method: Therefore, we studied the effect of peripheral inflammation induced by intraplantar administration of complete Freund's adjuvant (CFA) in mice on the variability of temperature and bioimpedance as an index of pain produced by inflammation. To this end, we initially determined mathematical scores based on changes in temperature and bioimpedance (STB) for animals with an inflamed paw and compared these scores with commonly used measures of inflammatory pain.