Figure 1.
Changes in peak systolic velocity (PSV) of blood flow in the renal arteries of rats during FUS exposure.
(A) The boxes extend from the 25th to the 75th percentile, with horizontal lines indicating the median. Bar lines indicate the 10th and 90th percentiles (* p<.05). (B) Normalized change in PSV (mean ± SEM) of blood flow in the renal arteries of rats in response to various acoustic power levels immediately before and after FUS exposure. The normalized change in PSV was significantly greater in the high-power group (12 or 18 W) than in the low-power group (3 or 6 W) (mean ± SEM; standard t-test; ***, ### p<.001).
Figure 2.
Changes in pulsatility index (PI) of blood flow in the renal arteries of rats immediately before and after FUS exposure.
Significant changes in PI were observed at every acoustic power level. The boxes extend from the 25th to the 75th percentile, with horizontal lines indicating the median. Bar lines indicate the 10th and 90th percentiles (* p<.05).
Figure 3.
Changes in resistance index (RI) of blood flow in the renal arteries of rats immediately before and after FUS exposure.
Significant changes in RI were observed at every acoustic power level. The boxes extend from the 25th to the 75th percentile, with horizontal lines indicating the median. Bar lines indicate the 10th and 90th percentiles (* p<.05).
Figure 4.
Protein-creatinine ratios before and after FUS treatment.
(A) At the highest acoustic power of 18 W, the highest protein-creatinine ratio after FUS treatment was significantly different from the pretreatment value. (B) Graph showing the normalized change in urinary protein-creatinine ratios as a function of acoustic power. The normalized change for rats with arteries sonicated at the lower power levels of 3 and 6 W was significantly different from that for rats with arteries sonicated at the highest power level of 18 W (mean ± SEM; standard t-test; *, # p<.05; ** p<.01; n = 7 rats for each group).
Figure 5.
Protein-creatinine ratios before and after FUS treatment with microbubbles.
(A) There are three acoustic powers at a dose of 450 μL/kg. (B) Graph showing the normalized change in urinary protein-creatinine ratios at different acoustic power levels with microbubbles at a dose of 450 μL/kg. No significant difference was found at various acoustic power levels (mean ± SEM; n = 3 rats for each group).
Figure 6.
Microphotographs of hematoxylin- and eosin-stained sections of a renal artery (top row, arrow) and glomerulus (bottom row, arrow) after renal artery FUS treatment at the highest acoustic power level with and without microbubbles.
No histological changes were found (original magnification ×200).
Figure 7.
Schematic diagram of the experimental setup.
The renal artery was exteriorized and sonicated with focused ultrasound (FUS). The diameter (D) of the renal artery was measured by ultrasound imaging.
Figure 8.
Measurement by ultrasound image.
(A) B-mode ultrasound images of the renal artery and kidney of a rat. The inner diameter of the renal artery is about 1.1 mm. (B) Doppler spectral waveforms of blood flow in the renal artery of a rat during pulsed FUS exposure; interference caused by sonication (bright column) and the waveforms of peak systolic velocity (PSV) immediately before and after sonication (indicated by arrows).