Use of infrared thermography in an animal model as a complementary tool for monitoring the inflammatory process: a preliminary study

Abstract PurposeTemperature changes on a surface can be measured by infrared thermographic cameras. Thus, the images obtained by these cameras can be useful for a wide range of biological in vivo studies, including animal models of inflammation. In this preliminary study, the use of thermography in rat paw inflammation was evaluated.MethodsCFA-induced paw edema on rats (n=5) was performed and discrepancies between animals treated or not with anti-inflammatory drugs as triamcinolone acetonide and diclofenac sodium were analyzed. Experimental times were: T0, before chemical induction of inflammatory process (control); and times after injection: T1 (30 min); T2 (24 hours); T3 (48 hours); T4 (72 hours); T5 (96 hours); T6 (7 days); T7 (14 days); T8 (21 days); T9 (28 days). The measured parameters were temperature, the edema (thickness and volume) of each animal paw (left and right), histological analysis, and blood leukocyte count.ResultsThe results demonstrated that the profile of local temperature changes was similar to the volume and thickness of the paws, with an increase at 24 hours. Such increase (the 24 hours peak) is expected for this specific type of inflammation model. From T7 onwards, the temperature values, in all groups, returned to baseline values (T0).ConclusionsThis preliminary study shows a possible use of quantitative high-resolution infrared as a complementary tool for monitoring the inflammatory process.