Vascular endothelial growth factor gene expression is up-regulated
in electrically stimulated rat skeletal muscle.
Hang, Jian, Lan Kong, Jian-Wei Gu, and Thomas H. Adair.
Department of Physiology and Biophysics, Department of
Microbiology, University of Mississippi Medical Center, 2500 North
State Street, Jackson, Mississippi 39216-4505
APStracts 2:0387H, 1995.
Vascular endothelial growth factor (VEGF; also called vascular
permeability factor) is a secreted mitogen with distinct target cell
specificity for vascular endothelial cells. Hypoxia up-regulates VEGF
expression making it a likely mediator of the angiogenesis that
occurs in poorly perfused tissues. The purpose of this study was to
determine if VEGF gene expression is up-regulated in chronically
stimulated skeletal muscles, where hypoxia is thought to trigger the
growth of blood vessels. The right anterior tibialis and extensor
digitorum longus muscles of 12 rats were stimulated electrically (10
Hz, 300 (s pulses) for up to 21 days by way of the peroneal motor
nerve. The contralateral muscles served as control. Northern analysis
showed that VEGF mRNA levels increased by 6 fold after 4 days of
stimulation and then decreased gradually over the next several days.
VEGF mRNA levels were still elevated by 2-3 fold after 21 days of
stimulation. Higher VEGF mRNA levels in the early stages of muscle
stimulation and gradually decreasing levels in later stages is
consistent with a metabolic hypothesis in which tissue oxygenation
controls VEGF expression. These studies support the hypothesis that
VEGF has a physiological role in promoting angiogenesis in stimulated
skeletal muscle.
Received 20 July 1995; accepted in final form 22 August 1995.
APS Manuscript Number H686-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 September 1995.