Increasing bladder capacity by foot stimulation in rats with spinal cord injuries

Background: This study was to explore the possibility that foot stimulation increased bladder capacity(BC) in rats with neurogenic bladder secondary to T10 spinal cord injuries. Methods: In 20 awake rats (stimulation group) with T10 spinal cord injuries, 5 repeat cystometrograms (CMGs) were recorded. The 1st and 2nd CMGs were performed without stimulation. The 3rd, 4th, and 5th CMGs were done separately with 1 T, 2 T, and 4 T stimulation, respectively, through a pair of pad electrodes on the skin of the hind foot. In the control group of 20 rats, 5 repeat CMGs were recorded without foot stimulation. The threshold (T) was the minimal stimulation intensity to induce an observable toe twitch. Results: In the stimulation group, foot stimulation with 2 T significantly increased the BC an additional 68.9% +/- 20. 82% (p < 0.05). Foot stimulation with 4 T increased the BC an additional 120.9% +/- 24.82% (p < 0.05). Compared with the control group, BC in the 1st, 2nd, and 3rd (1 T) CMG had no significant difference in the stimulation group, but the 4th (2 T) and 5th (4 T) CMGs were significantly increased (p < 0.05). Conclusions: Electrical stimulation of the foot was effective in inhibiting reflex bladder activity and increasing bladder capacity in spinal cord injury rats.