Cardiac reactive oxygen species after traumatic brain injury

Abstract

Background: Cardiovascular complications after traumatic brain injury (TBI) contribute to morbidity and mortality and may provide a target for therapy. We examined blood pressure and left ventricle contractility after TBI, and tested the hypothesis that β-adrenergic blockade would decrease oxidative stress after TBI.

Material and methods: Rodents received fluid-percussion injury or sham surgery, confirmed with magnetic resonance imaging (MRI) and histopathology. We followed recovery with sensorimotor coordination testing and blood pressure measurements. We assessed left ventricular ejection fraction using ECG-gated cardiac MRI and measured myocardial reactive oxygen species (ROS) with dihydroethidium. We randomized additional TBI and sham animals to postoperative treatment with propranolol or control, for measurement of ROS.

Results: Blood pressure and cardiac contractility were elevated 48 h after TBI. Myocardial tissue sections showed increased ROS. Treatment with propranolol diminished ROS levels following TBI.

Conclusions: TBI is associated with increased cardiac contractility and myocardial ROS; decreased myocardial ROS after β-blockade suggests that sympathetic stimulation is a mechanism of oxidative stress.