Ultrasound at 27 kHz Increases Tissue Expression and Activity of Nitric Oxide Synthases in Acute Limb Ischemia in Rabbits

Shaul Atar, Robert J. Siegel, Rami Akel, Yumei Ye, Yu Lin, Shreyas A. Modi, Asif Sewani, Enrique Tuero, Yochai Birnbaum

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Transcutaneous low-frequency ultrasound (US) preserves myocardial and skeletal muscle viability by increasing tissue perfusion through an undefined nitric oxide (NO)-dependent mechanism. We have examined whether US increases tissue expression and activity of the three nitric oxide synthase (NOS) isoforms: endothelial (eNOS), neuronal (nNOS) and inducible (iNOS). The two femoral arteries of four New Zealand rabbits were ligated for a total of 120 min. After 60 min of ligation, transcutaneous low-frequency US (27 kHz, 0.13 W/cm2) was applied for 60 min to one thigh, while the contra-lateral artery served as a control (total ischemia time = 120 min). Calcium-dependent (cNOS) and -independent (ciNOS) NOS activity, and concentration of total eNOS, ser-1177 phosphorylated eNOS (P-eNOS), nNOS and iNOS were then determined in the gracilis muscle. Compared with the control, US application significantly increased cNOS activity [3.34 ± 0.28 versus 3.87 ± 0.10 × 1000 counts per minute (cpm), respectively, p = 0.031] and ciNOS activity (1.99 ± 0.09 versus 3.26 ± 0.68 cpm, respectively, p < 0.001). Western immunoblotting revealed a significant increase in protein content of both iNOS (184.5 ± 1.08%; p < 0.0001) and P-eNOS (381.5 ± 2.47%; p <0.001), with only a small increase in total eNOS and nNOS expression. In conclusion, application of transcutaneous low-frequency US to ischemic muscular tissue significantly increases both cNOS and ciNOS activity by increasing eNOS phosphorylation and iNOS expression, respectively. (E-mail: yobirnba@utmb.edu).

Original languageEnglish (US)
Pages (from-to)1483-1488
Number of pages6
JournalUltrasound in Medicine and Biology
Issue number9
StatePublished - Sep 2007


  • Ischemia
  • Nitric oxide synthase
  • Phosphorylation
  • Transcutaneous
  • Ultrasound

ASJC Scopus subject areas

  • Radiological and Ultrasound Technology
  • Biophysics
  • Acoustics and Ultrasonics


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