The effect of acoustically-induced cavitation on the permeance of a bullfrog urinary bladder.
It is well known that ultrasound enhances drug delivery to tissues, although there is not a general consensus about the responsible mechanisms. However, it is known that the most important factor associated with ultrasonically-enhanced drug permeance through tissues is cavitation. Here we report results from research conducted using a experimental approach adapted from single bubble sonoluminescence experiments which generates very well defined acoustic fields and allows controlled activation and location of cavitation. The experimental design requires that a biological tissue be immersed inside a highly degassed liquid media to avoid random bubble nucleation. Therefore, live frog bladders were used as the living tissue due to their high resistance to hypoxia. Tissue membrane permeance was measured using radiolabeled urea. The results show that an increase in tissue permeance only occurs when cavitation is present near the tissue membrane. Moreover, confocal microscopy shows a direct correlation between permeance increases and physical damage to the tissue.
Center for Multiphase Research, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, USA. silvina.cancelos@upr.edu
Silvina
S
Cancelos
Francisco J
FJ
Moraga
Richard T
RT
Lahey
William
W
Shain
Robert H
RH
Parsons
D000818:Animals; D002250:Carbon Radioisotopes; D002463:Cell Membrane Permeability / Q000502:physiology; D016503:Drug Delivery Systems / Q000295:instrumentation / Q000379:methods*; D000860:Hypoxia / Q000378:metabolism; D007552:Isotonic Solutions / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D011892:Rana catesbeiana; D000077325:Ringer's Lactate; D014465:Ultrasonics / Q000379:methods*; D014463:Ultrasonography; D014508:Urea / Q000493:pharmacokinetics; D001743:Urinary Bladder / Q000000981:diagnostic imaging* / Q000378:metabolism*
D002250:Carbon Radioisotopes; D007552:Isotonic Solutions; D000077325:Ringer's Lactate; D014508:Urea