Original Contribution| Volume 49, ISSUE 5, P1091-1101, May 2023

Low-Intensity Ultrasound Reduces Brain Infarct Size by Upregulating Phosphorylated Endothelial Nitric Oxide in Mouse Model of Middle Cerebral Artery Occlusion

  • Author Footnotes
    1 Catherine M. Davis and Azzdine Y. Ammi contributed equally to this work.
    Catherine M. Davis
    1 Catherine M. Davis and Azzdine Y. Ammi contributed equally to this work.
    Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA

    Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA
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  • Author Footnotes
    1 Catherine M. Davis and Azzdine Y. Ammi contributed equally to this work.
    Azzdine Y. Ammi
    1 Catherine M. Davis and Azzdine Y. Ammi contributed equally to this work.
    Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA
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  • Wenbin Zhu
    Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA
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  • Carmen Methner
    Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA
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  • Zhiping Cao
    Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA

    Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA
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  • David Giraud
    Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA
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  • Nabil J. Alkayed
    Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA

    Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA
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  • Randy L. Woltjer
    Department of Pathology, Oregon Health & Science University, Portland, OR, USA
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  • Sanjiv Kaul
    Corresponding author. Knight Cardiovascular Institute, Oregon Health & Science University, UHN 62, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA.
    Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA
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  • Author Footnotes
    1 Catherine M. Davis and Azzdine Y. Ammi contributed equally to this work.


      There have been attempts to use therapeutic ultrasound (US) for the treatment of both experimental and clinical stroke. We hypothesized that low-intensity US has direct beneficial effects on the brain independent of cerebral blood flow (CBF) during middle cerebral artery occlusion (MCAO).


      Three groups of mice were studied. Group I included 84 mice with MCAO undergoing US treatment/no treatment at two US frequencies (0.25 and 1.05 MHz) with three different acoustic pressures at each frequency in which infarct size (IS) was measured 24 h later. Group II included 11 mice undergoing treatment based on best US results from group I animals in which the IS/risk area (RA) ratio was measured 24 h later. Group III included 38 normal mice undergoing US treatment/no treatment for assessment of CBF, tissue metabolite and protein expression and histopathology.


      Ultrasound at both frequencies and most acoustic pressures resulted in reduction in IS in group I animals, with the best results obtained with 0.25 MHz at 2.0 MPa: IS was reduced 4-fold in the cerebral cortex, 1.5-fold in the caudate putamen and 3.5-fold in the cerebral hemisphere compared with control. US application in group III animals elicited only a marginal increase in CBF despite a 2.6-fold increase in phosphorylated endothelial nitric oxide synthase (p-eNOS)-S1177 and a corresponding decrease in p-eNOS-T494. Histopathology revealed no evidence of hemorrhage, inflammation or necrosis.


      Low-intensity US at specific frequencies and acoustic pressures results in marked neuroprotection in a mouse model of stroke by modulation of p-eNOS independent of its effect on CBF.



      US (ultrasound), MCAO (middle cerebral artery occlusion), OGD (oxygen glucose deprivation), p-eNOS (phosphorylated endothelial nitric oxide), EETs (epoxyeicosatrienoates), HETEs (hydroxyeicosatetraenoates), CBF (cerebral blood flow), PRAPAS (peak rarefactional acoustic pulse amplitudes), RA (risk area), IS (infarct size), TTC (tripheyl tetrazolium chroride), CH (cerebral hemisphere), CP (caudate putamen), CC (cerebral cortex), Ispta (Acoustic intensity, spatial peak temporal average), Isppa (Acoustic intensity, spatial peak pulse average), ELISA (enzyme-linked immunosorbent assay)
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