Diagnostic ultrasound induces change within numbers of cryptal mitotic andapoptotic cells in small intestine

Recent work on gas filled organs, including the lung and small intestine, h as concentrated on the hemorrhaging effects of ultrasound, with little atte ntion paid to cell cycle perturbations and apoptosis-two very sensitive ind icators of environmental insult. This study addresses this by exploring the effects of ultrasound on these two features. The anterior abdominal surfac e of anaesthetised male, adult CD1 mice was shaved and exposed to ultrasoun d. An 8 MHz linear array transducer was manually swept from the midline to the left mouse flank on a continuous basis. Each mouse was scanned for 15 m inutes with B mode and color flow modes selected. The Thermal Index registe red 1.0. Groups of mice were killed at various times after treatment, the s mall intestine was excised and histologically examined. Analysis of the dat a demonstrates a statistically significant 22% reduction in numbers of mito tic figures at 4.5 hours after the ultrasonic insult (p=0.011). Numbers of apoptotic bodies increased by 153% (p=0.003), 166% (p=0.014) and 160% (0.00 1) at 1, 3 and 4.5 hours post-treatment respectively. These preliminary res ults suggest that bioeffects of ultrasound maybe more diverse than previous ly described. Further work will establish thresholds and explore mechanisms for these deterministic effects. (C) 2001 Elsevier Science Inc. All rights reserved.