Low-magnitude high-frequency vibration ameliorates high glucose-induced endothelial injury by restoring mitochondrial function via AMPK/mTOR pathway

Abstract

ABSTRACT High glucose-induced dysfunction of endothelial cells is a critical and initiating factor in the genesis of diabetic vascular complications. Low-magnitude high-frequency vibration (LMHFV) is a non-invasive biophysical intervention. It has been reported that it exhibits protective effects on high glucose-induced osteoblast dysfunction, but little was known on diabetic vascular complications. In this work, we aim to clarify the role of LMHFV on high glucose-induced endothelial dysfunction and hypothesized that the protective effects functioned through adenosine monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway. We cultured primary murine aortic endothelial cells (MAECs) in normal or HG medium, respectively, before exposing to LMHFV. The tube formation, paracellular permeability assay, and aortic ring sprouting assay showed that the high glucose injured-function of MAECs was improved after LMHFV treatment. The intracellular ROS generation analysis, mitochondrial complex I activities measurement, ATP measurement and mitochondrial membrane potential (MMP), and mitochondrial ROS generation analysis of MAECs indicated that mitochondrial function was restored by LMHFV loading in a high glucose environment. Mechanically, western blot assays showed that AMPK phosphorylation was promoted and mTOR was inhibited in LMHFV-induced endothelial function restoration. After the administration of the AMPK inhibitor, Compound C, these protective effects resulting from LMHFV are reversed. These findings suggest that LMHFV plays a significant role in protecting endothelial cells’ function and mitochondrial function in high glucose-induced injured MAECs via AMPK/mTOR signalling.