Mechanism of anodic block electrical stimulation of sacral nerve root to reconstruct bladder function

doi:10.12307/2021.040

Abstract

Abstract: BACKGROUND: Our previous findings have shown that anodic block electrical stimulation of sacral nerve root can adjust urine storage and urination, but the specific molecular mechanism is unknown.
OBJECTIVE: To analyze the expression of neurotransmitter receptors and nerve growth factor in the bladder detrusor using immunohistochemistry from the perspective of protein function and to explore the mechanism of anodic block electrical stimulation of sacral nerve root on bladder function reconstruction. METHODS: Thirty New Zealand rabbits were randomly divided into control group (n=10), spinal cord injury group (n=10) and electrical stimulation group (n=10). In the latter two groups, animal models of post-spinal cord injury neurogenic bladder were made using spinal cord clippings. In the electrical stimulation group, the sacral nerve root was subjected to an intermittent electrical stimulation (300 μs, 1.05 mA, 20 Hz), 5 seconds on and 10 seconds off for 120 hours. Then, the bladder detrusor was harvested. The expression of nerve growth factor and neurotransmitter receptor in neurogenic bladder detrusor was analyzed qualitatively and quantitatively by immunohistochemistry from the perspective of protein function
RESULTS AND CONCLUSION: In the spinal cord injury group, there was a significantly smaller, dark-brown bladder, with reduced number of vessel plexuses on the tissue surface. The bladder boundary was blurred, with some adhesion to the surrounding tissue, and partial fibrosis and tissue necrosis on the section surface were observed. The morphology of the control group and the electrical stimulation group was relatively consistent, both with enlarged bladder volume and light red in color. Abundant arteriovenous networks were visible on the surface of the tissue. The boundary was clear. Residual urine amount was increased in the tissue. The color was yellowish and transparent. There was no abnormality in the section compared with the surrounding tissues. Immunohistochemical findings shown that the expression of M2 receptor, P2X3 receptor and nerve growth factor receptor in bladder detrusor muscle in the spinal cord injury group was significantly higher than that in the electric stimulation group and control group (P < 0.05), while the expression of M3 receptor and β2-AR receptor in bladder detrusor muscle in spinal cord injury group was significantly lower than that in the electric stimulation group and control group (P < 0.05). To conclude, electrical stimulation of the sacral nerve root by anodic block can adjust the expression of nerve growth factor and neurotransmitters in neurogenic bladder, thereby influencing the systolic and diastolic function of bladder detrusor, improving bladder compliance and remodeling the function of neurogenic bladder after spinal cord injury.

Key words: spinal cord injury, anodic block, electrical stimulation, sacral nerve root, immunohistochemistry, bladder function, remodeling

CLC Number:

Yan Peng, Ma Yufei, Cui Jingfu, Hao Shaofei, Liu Jinhui, Guan Chunlei, Wang Xiaoran, Yang Xiaoyu. Mechanism of anodic block electrical stimulation of sacral nerve root to reconstruct bladder function[J]. Chinese Journal of Tissue Engineering Research, 2021, 25(23): 3684-3689.

Figures/Tables 2

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