A study of vascular response to thermal injury on hairless mice by fibre optic confocal imaging, laser doppler flowmetry and conventional histology.

Burn injury causes vascular thrombosis and occlusion by thermal damage to the vascular network in the dermis. In this study, fibre optic confocal imaging (FOCI) and laser doppler flowmetry were used to detect changes in vascular morphology and local dermal blood flux over 4 h, in three defined zones after a thermal burn (50 degrees C, 20 s duration, 3 mm in diameter) was induced on fully anaesthetised hairless mice. FITC-dextran (i.v.) was used to enable FOCI of vascular morphology including three-dimensional imaging of the burn site and its surrounding areas. Samples of the affected areas were collected for conventional histology, including Masson's trichrome. There was vascular damage in the zone of coagulation which showed no change during the 4 h period. The zone of stasis showed an initial reduction in blood flux and confocal imaging of the area indicated significant vessel leakage during the first 2 h which later improved. The zone of hyperaemia showed an initial increase in total blood flux and confocal imaging of the area showed initial blood vessel dilatation. This study demonstrates that FOCI is a useful non-invasive tool in the assessment of vascular changes in thermal burns in vivo, and compares the findings of FOCI with those from laser doppler flowmetry and histology.