Effects of low-intensity ultrasound on gramicidin D-induced erythrocyte edema.

Abstract

OBJECTIVES:

To determine whether low-intensity ultrasound (US) can reduce red blood cell (RBC) edema and, if so, whether the US activity is associated with aquaporin 1 (AQP-1), a water channel in the cell membrane.

METHODS:

Red blood cell edema was induced by gramicidin D treatment at 40 ng/mL for 20 minutes and evaluated by a hematocrit assay. Low-intensity continuous wave US at 1 MHz was applied to RBCs for the last 10 minutes of gramicidin D treatment. To determine whether US activity was associated with AQP-1, RBCs were treated with 40 μM mercuric chloride (HgCl(2)), an AQP-1 inhibitor, for 20 minutes at the time of gramicidin D treatment. Posttreatment morphologic changes in RBCs were observed by actin staining with phalloidin.

RESULTS:

Red blood cell edema increased significantly with gramicidin D at 20 (1.8%), 40 (6.7%), 60 (16.7%), and 80 (11.3%) ng/mL, reaching a peak at 60 ng/mL, compared to the control group (20 ng/mL, P = .019; 40, 60, and 80 ng/mL, P < .001). No significant RBC hemolysis was observed in any group. Edema induced by gramicidin D at 40 ng/mL was significantly reduced by US at 30 (3.4%; P = .003), 70 (4.4%; P = .001), and 100 (2.9%; P = .001) mW/cm(2). Subsequent experiments showed that edema reduction by US ranged from 7% to 10%. Cotreatment with HgCl(2) partially reversed the US effect and showed a significantly different level of edema compared to gramicidin D-alone and US-cotreated groups (P = .001). These results were confirmed by microscopic observation of RBC morphologic changes.

CONCLUSIONS:

Low-intensity US could reduce gramicidin D-induced RBC edema, and its effect appeared to at least partly involve regulation of AQP-1 activity. These results suggest that low-intensity US can be used as an alternative treatment to control edema and related disorders.

• Authors: Mi Hyun Lim, A Rum Seo, Jiyoung Kim, Byoung-Hyun Min, Eun Joo Baik, So Ra Park, Byung Hyune Choi
• Journal: Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine (J Ultrasound Med) Vol. 33 Issue 6 Pg. 949-57 (Jun 2014) ISSN: 1550-9613 [Electronic] England
• PMID: 24866602 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2014 by the American Institute of Ultrasound in Medicine.

Chemical References

• Aqp1 protein, rat
• Gramicidin
• Aquaporin 1

Topics

• Animals
• Aquaporin 1 (metabolism, radiation effects)
• Body Water (metabolism)
• Cell Size (drug effects, radiation effects)
• Cells, Cultured
• Erythrocytes (cytology, drug effects, physiology, radiation effects)
• Gramicidin (pharmacology)
• High-Energy Shock Waves
• Ion Channel Gating (drug effects, radiation effects)
• Male
• Osmoregulation (drug effects, radiation effects)
• Radiation Dosage
• Rats
• Rats, Sprague-Dawley
• Ultrasonic Therapy (methods)