Antioxidant Properties of Whole Body Periodic Acceleration (pGz)

Abstract

The recognition that oxidative stress is a major component of several chronic diseases has engendered numerous trials of antioxidant therapies with minimal or no direct benefits. Nanomolar quantities of nitric oxide released into the circulation by pharmacologic stimulation of eNOS have antioxidant properties but physiologic stimulation as through increased pulsatile shear stress of the endothelium has not been assessed. The present study utilized a non-invasive technology, periodic acceleration (pGz) that increases pulsatile shear stress such that upregulation of cardiac eNOS occurs, We assessed its efficacy in normal mice and mouse models with high levels of oxidative stress, e.g. Diabetes type 1 and mdx (Duchene Muscular Dystrophy). pGz increased protein expression and upregulated eNOS in hearts. Application of pGz was associated with significantly increased expression of endogenous antioxidants (Glutathioneperoxidase-1(GPX-1), Catalase (CAT), Superoxide, Superoxide Dismutase 1(SOD1). This led to an increase of total cardiac antioxidant capacity along with an increase in the antioxidant response element transcription factor Nrf2 translocation to the nucleus. pGz decreased reactive oxygen species in both mice models of oxidative stress. Thus, pGz is a novel non-pharmacologic method to harness endogenous antioxidant capacity.

Conflict of interest statement

Competing Interests: The authors have read the journal's policy and have the following competing interests: The authors AU, JB, PK, FA, and JRL have declared that no competing interests exist. JAA owns minimal number of stocks in Noninvasive Monitoring Systems (NIMS), a company which manufactures a platform similar to the one described in this study. This does not alter the authors' adherence to PLOS ONE policies on sharing data and materials.

Figures

Fig 1. Antioxidant Protein Expression is Induced by pGz.

This figure depicts the effects of 1, 2, and 4 wk. of daily pGz in normal mice on the expressions of (A). Glutathioneperoxidase-1 (GPX1), (B). Catalase (CAT), and (C). Superoxide Dismutase 1 (SOD1). The relative protein expressions of GPX1, CAT and SOD1 over time compared to time of CONT values showed that pGz significantly increased GPX1, CAT, and SOD1 expression at 1, 2 and 4 wk compared to time CONT (‡p < 0.01 1, 2, and 4 wk. pGz vs. CONT). One, 2, and 4 wk. of pGz significantly increased expression of GPX1, CAT, and SOD1 compared to baseline (BL) values for both CONT and pGz groups (* p< 0.01 1,2, and 4 wk. vs. BL values). Representative Immunoblots of protein expression of GPX1, CAT, SOD1 and protein quantity loading Glyceraldehyde 3-phosphate dehydrogenase (GADPH) after 4 wk. of pGz, for CONT and pGz groups showing significant expression of these compared to time CONT.

Fig 2. pGz Increases Total Antioxidant Capacity.

Total antioxidant capacity (Trolox Equivalent Capacity) was expressed as % Inhibition of control values, measured at baseline (BL) for CONT and pGz groups, and after 1, 2 and 4 wk. of pGz or time CONT. One, 2 and 4 wk. of daily pGz significantly increased antioxidant capacity compared to time CONT (‡p < 0.01 1, 2 and 4 wk. vs. time CONT). One, 2, and 4 weeks of pGz also significantly increased total antioxidant capacity compared to baseline (BL)values for both CONT and pGz (* p< 0.01 1,2 and 4 wk. vs. BL values for CONT and pGz groups). Optical Units = O.U.

Fig 3. The Expression and Translocation of Nrf2 Transcription Factor after pGz Treatment.

This figure depicts the expression and translocation of Nrf2 transcription factor after 4 wk of daily pGz or no pGz (CONT) (A). pGz significantly increased upregulation of the Antioxidant Response Element transcription factor Nrf2 compared to CONT (*p< 0.01) (B). Translocation of Nrf2 is expressed as the ratio of Nrf2 in nucleus and cytosol. pGz also significantly increased Nrf2 translocation to nucleus compared to CONT (*p< 0.01). Representative Immunoblots of Nrf2 in nucleus and cytosol with respective protein loading controls Anti-Laminin B1 (nucleus) and Anti-α Tubulin (cytosol) in CONT and pGz groups showed increased protein expression of Nrf2 in nucleus of pGz treated mice. Optical Units = O.U.

Fig 4. The Effects of pGz treatment on Diabetes Induced Oxidative Stress in Cardiomyocytes.

The effects of pGz treatment for 14 days on ROS in cardiomyocytes in Control (CONT-pGz) and Diabetic mice (Diab-pGz) and their respective controls without pGz treatment in non diabetic (CONT) and diabetic (Diab). ROS was measured using the method of DCF fluorescence. Diabetes significantly increased ROS in cardiomyocytes (*p

Fig 5. The Effects of pGz treatment on Duchene Muscular Dystrophy Induced Oxidative Stress in Cardiomyocytes.

Twelve month of age mdx mice had a significant increase in oxidative stress in cardiomyocytes compared to age matched wild type (Wt) controls (*p < 0.001). Treatment with pGz (mdx-pGz) for 14 days significantly reduced the levels of ROS measured by DCF fluorescence (*p<0.001) Optical Units = O.U.