Diagnostic frequency continuous ultrasonography directly mitigates venular ischemia reperfusion damage.
BACKGROUND
Our objective was to determine the effects of ischemia reperfusion (IR) treatment with continuous-mode diagnostic frequency ultrasonography exposure by assessing leukocyte-endothelial cell interactions, in terms of frequency and relative proportions of rolling and firmly attached leukocytes.


METHODS
Studies were carried out in the awake hamster chamber window preparation. Tourniquet ischemia was implemented by compressing a circular ring on the chamber window tissue for 4 hours, followed by reperfusion. Animals were randomly assigned into one of four groups as follows: IR; IR + ultrasonography; IR + N(omega)-nitro-L-arginine methyl ester (L-NAME); and IR + L-NAME + ultrasonography. Venules were exposed to epi-illumination, videorecorded, and leukocytes were categorized as "rolling"; flowing with endothelial contact; or "immobilized" cells, and counted during digital video-playback in 100-microm length segments.


RESULTS
Leukocyte interaction with venular endothelium substantially decreased, during longterm reperfusion (p < 0.05) with ultrasonography exposure. Nitric oxide production inhibition, after L-NAME treatment, and ultrasonography exposure resulted in additional earlier substantially decreased leukocyte-endothelial cell interactions (p < 0.05).


CONCLUSIONS
Venular function improvement, after IR damage, is a primary benefit derived from continuous-mode diagnostic frequency ultrasonography exposure. Although decreased interaction of adherent leukocytes can also be attributed to enhanced arteriolar flow, reduced interaction of rolling leukocytes is an immediate consequence of ultrasonography exposure.
Hightower
C Makena
CM
Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093-0412, USA.
Intaglietta
Marcos
M
D000818:Animals; D002450:Cell Communication / Q000502:physiology; D006224:Cricetinae; D042783:Endothelial Cells / Q000502:physiology; D004791:Enzyme Inhibitors / Q000627:therapeutic use; D036904:Leukocyte Rolling / Q000502:physiology; D007962:Leukocytes / Q000502:physiology; D008297:Male; D008647:Mesocricetus; D019331:NG-Nitroarginine Methyl Ester / Q000627:therapeutic use; D015427:Reperfusion Injury / Q000473:pathology / Q000517:prevention & control*; D014464:Ultrasonic Therapy / Q000379:methods*; D014699:Venules
D004791:Enzyme Inhibitors; D019331:NG-Nitroarginine Methyl Ester