Establishment and Evaluation of a T9-T10 Spinal Cord Hemisection-Induced Neurogenic Bladder Rat Model with Sacral Neuromodulation

Zikai L1, Yanping Z1, Wen Z1, Lei L1, Yan Z1, Chuanyu W1, Yongkun Z1, Shuo X1, JianGuo W1, Qingwei W1

Research Type

Pure and Applied Science / Translational

Abstract Category

Neurourology

Abstract 330
Science 4 - Neurourology
Scientific Podium Short Oral Session 28
Saturday 20th September 2025
16:37 - 16:45
Parallel Hall 2
Spinal Cord Injury Animal Study Detrusor Overactivity Neuromodulation Urodynamics Equipment
1. Department of Urology and Henan Joint International Paediatric Urodynamic Laboratory
Presenter
Links

Abstract

Hypothesis / aims of study
To establish a rat model of neurogenic bladder (NB) induced by T9-T10 spinal cord hemisection and evaluate the efficacy of S2 sacral neuromodulation(SNM) in treating NB
Study design, materials and methods
Thirty 8-week-old female Sprague-Dawley (SD) rats weighing 200-220g were randomly divided into three groups: Control(n = 10), NB(n = 10), and NB+SNM (n = 10). In the Control group, the T9-T10 vertebral lamina was removed to expose the spinal cord without further injury. In the NB group, the right T9-T10 spinal cord was hemisected. In the NB+SNM group, after hemisection of the right T9-T10 spinal cord, a specialized stimulation electrode was implanted through the S2 foramen(Figure 1). On the second postoperative day, the NB+SNM group received daily electrical stimulation for 1 hour, which continued for 3 weeks. Bladder function was assessed using ultrasound, cystography, and urodynamic measurements. Bladder tissue samples were collected for HE and Masson staining.
Results
Bladder ultrasound revealed significantly higher bladder volume in the NB group compared to the Control and NB+SNM groups[(4.02±0.16)ml vs(0.37±0.09)ml, (1.00±0.16)ml, P<0.0001], which was confirmed by cystography (Figure 2A). The bladder weight in the NB group were also significantly greater than that in the Control and NB+SNM groups[(0.66±0.26)g vs(0.11±0.01)g, (0.28±0.07)g,P<0.01]. Urodynamic analysis showed that the voiding contraction interval in the NB+SNM group was shorter than that in the Control group but longer than that in the NB group[(2.47±1.27)min vs(5.92±0.46)min, (1.01±0.45)min, P<0.001]. During bladder filling, the NB group exhibited multiple non-voiding contraction waves(4.33±3.20) with a maximum pressure of (18.61±4.46)cmH2O, whereas no significant non-voiding contractions were observed in the NB+SNM group 0(0,1.25), with a maximum pressure of 0.00(0.00,12.89)cmH2O (Figure 2B).These differences were statistically significant (P<0.05). Compared to the Control and NB+SNM groups, the NB group displayed disorganized bladder mucosal epithelial cells, loose and disrupted lamina propria, tissue edema, and increased fibrosis (Figure 3).
Interpretation of results
In this study, the NB group showed increased bladder capacity in ultrasound compared to the Control and NB+SNM groups. The number of non-voiding contraction waves during the filling phase was significantly higher in the NB group than in the NB+SNM and Control groups, and the voiding contraction interval was shorter than in the NB+SNM and Control groups. However, both the NB and NB+SNM groups exhibited significantly higher maximum bladder capacity and bladder compliance than the Control group. The NB group also had a lower leak point pressure compared to the Control and NB+SNM groups, which may be attributed to the relatively short experimental duration, preventing bladder contracture and severe fibrosis in the NB group. The NB group had significantly greater bladder weight than the Control and NB+SNM groups, along with abnormal gross morphology and imaging findings. HE staining revealed disorganized muscle bundles, loss of muscle fibers, and residual cytoplasmic vacuolization in the NB group. Masson staining indicated subserosal fibrosis in the NB group, whereas these pathological changes were alleviated in the NB+SNM group. These findings suggest that the NB group exhibited overactive bladder during the storage phase, along with structural remodeling and fibrosis, all of which were suppressed by SNM.
Concluding message
T9-T10 spinal cord hemisection induces neurogenic bladder overactivity and morphological changes. Early S2 sacral nerve electrical stimulation can effectively suppress bladder overactivity and ameliorate morphological alterations and fibrosis.
Figure 1 Surgical Procedures and Spinal Tissue Outcomes of rat models A:Operative procedure for T9-T10 spinal cord hemisection and S2 stimulating electrode implantation, localized and exposed the T9-T10 spinal cord. B:Gross morphology and HE staining results of th
Figure 2 Ultrasound, cystography, and urodynamic results in rat models A:Ultrasound and cystography revealed increased bladder volume in the NB group compared to the NB+SNM and control groups. B:Urodynamic results showed that the NB group had shorter voiding cont
Figure 3 Figure 3. Weight of bladders, HE staining, and Masson staining results in the rat models A: NB group showed abnormal bladder morphology and increased bladder weight compared to the NB+SNM and control groups. B: NB group exhibited abnormal bladder morpholo
Disclosures
Funding National Natural Science Foundation of China(82470806, 82470807) Clinical Trial No Subjects Animal Species Rat Ethics Committee Ethics Committee of the First Affiliated Hospital of Zhengzhou University
07/07/2025 09:26:18