Postburn blood flow, edema, and survival of the hairy mouse ear after scald injury at different temperatures

In one group (a) one ear of NMRI hairy mice was scalded in water at 36 degrees C, 39 degrees C, 42 degrees C, 45 degrees C, 48 degrees C, 51 degrees C, 52 degrees C, 53 degrees C, 54 degrees C, 57 degrees C, and 60 degrees C for 20 s, using a new dip burn model, for evaluation of edema formation 2 h postburn. In another group of mice (b) one ear was scalded in the 45 degrees C-60 degrees C interval and the ear studied in a vital microscope repeatedly for 4 days. In a third group (c), one ear was scalded in the 36 degrees C-60 degrees C interval and the microcirculatory flow was recorded by a laser Doppler flowmeter (1Df) for a period of 2 h postburn. In a fourth group of animals (d) one ear was scalded at 53 degrees C or 54 degrees C. In some animals the ear was then cooled in 8 degrees C water or saline for 30 min. Others were treated preburn with cimetidine, Ketanserin, indomethacin or methylprednisolone. Edema was determined in group (a) by wet-dry weight measurements of punch biopsies from both the burned and the contralateral unburned ear and expressed as an increase in tissue water content. The long-term effect was determined by observing the survival of the ears (groups b and d); the area of necrosis was expressed as a percentage of the total area of the ear. Significant edema was formed in ears immersed in 48 degrees C to 60 degrees C water with a maximum after 53 degrees C burns.(ABSTRACT TRUNCATED AT 250 WORDS)