Autofluorescence of skin burns detected by fiber-optic confocal imaging: Evidence that cool water treatment limits progressive thermal damage in anesthetized hairless mice

Background: Although full-thickness burns present no difficulty to clinical judgment, accurate assessment of burn depth immediately after injury in pa rtial thickness burns has always been difficult. Methods: Thermal burns (applied by a 3-mm-diameter brass rod heated to 50 d egrees -80 degreesC for 20 seconds) were induced on the skin of anesthetize d hairless mice. Anesthesia was maintained throughout all experiments. Both burns and normal skin were investigated noninvasively in vivo using fiber- optic confocal imaging (FOCI) microscopy (excitation, 488 mm; detection, 50 5 mm), Results: Autofluorescence was detected in burned skin, and the depth of the autofluorescent region was found to correlate with the intensity of heat a pplied. Cool water treatment (for 20 minutes immediately after burn inducti on) significantly reduced the progressive increase in autofluorescence in d eeper layers of the skin over the 4-hour postburn observation period. Histo logy showed burn-associated changes at a lower temperature than that at whi ch autofluorescence was first detected in vivo by FOCI, However, there was a good correlation (r = 0.78) between depth of damage revealed by FOCI comp ared with that by histology, Conclusion: These results suggest that FOCI may be used to provide an index of burn depth.