Effect of Neuromodulation with Deep Brain Stimulation on Bladder Function in Traumatic Brain Injury Rats

According to FDA statistics in 2012, accident injuries was the top ten causes of death, in which twenty percent of death were resulted from traumatic brain injury. With medical technology development which leads to the significant enhancement of survival rate. But it always leads to the motor, sensation, and urinary system disorders in most of patients in their life span due to the permanent damage of brain tissue. The chronic voiding dysfunction would likely cause urinary tract infections, incontinence, severe and even lead to kidney failure or death. Therefore, the patient with voiding dysfunctions can not be ignored. In clinical treatment, there is no convenience or effective approaches for improving urination. Previous literature shows that patients receiving long-term deep brain stimulation, not only enhance the motor function, but also improve the bladder functions. Therefore, deep brain stimulation could be a new solution for this disease. On the other hand, it is very important to detect the status of a bladder, and to give the deep brain stimulation at the right time. Clinical detection of the bladder status nowadays depends on urodynamic study, such as the volume of the bladder by external ultrasound, or the intravesical pressure by catheterization. However, external ultrasound can not give the electrical neural moderation immediate feedback, and long-term catheterization is also unsuitable for patients. The purpose of this study was to use neural engineering aspect for constructing a stable brain damage animal model and automatic stimulator which feedback signal is to use external urethral sphincter electromyography (EUS-EMG) as detector of the bladder status, then apply the deep brain stimulation at the suitable time in the rats which is suffering from traumatic brain injury. In result, a significant decrease in average cystometrogram (CMG) was detected in rats one week after traumatic brain injury. Abnormal urodynamic measurements including contraction amplitude, residual volume as well as contraction duration were decrease, and indicated inefficient voiding. To treat these symptom, using low frequency (50Hz with 1V to 2.5V) deep brain stimulation of the pontine reticular nucleus (PnO) is a potential method for underactive bladder. After deep brain stimulation, voiding efficiency increased from 28% to 70%. These results raise the possibility that using low frequency deep brain stimulation to excite detrusor contraction which may provide a new approach for improving voiding in traumatic brain injury patients.