A New Rat Model of Sacral Cord Injury Producing a Neurogenic Bladder and Its Functional and Mechanistic Studies

Sacral spinal cord injury (SSCI) can disrupt bladder neuromodulation and impair detrusor function. Current studies provide limited information on the histologic and genetic changes associated with SSCI-related neurogenic lower urinary tract dysfunction (NLUTD), resulting in few treatment options. This study aimed to establish a simple animal model of SSCI to better understand the disease progression. Ninety 8-week-old Sprague-Dawley (SD) rats were randomly separated into sham operation and SSCI groups. The SSCI group underwent sacral spinal cord injury, while the sham group did not. Urodynamic and histological assessments were conducted at various intervals (1, 2, 3, 4, and 6 weeks) post-injury to elucidate the disease process. Urodynamic examinations revealed significant bladder dysfunction in the SSCI group compared to the sham group, stabilizing around 3-4 weeks post-injury. Histological examination, including hematoxylin-eosin and Masson's trichrome staining, correlated these functional changes with bladder microstructural alterations. RNA-seq was performed on bladder tissues from the sham group and SSCI group at 6 weeks to identify differentially expressed genes and pathways. Selected genes were further analyzed using polymerase chain reaction (PCR). The findings indicated a pronounced inflammatory response in the first 2 weeks post-SSCI, progressing to bladder fibrosis at 3-4 weeks. In conclusion, this study presents a reliable, reproducible, and straightforward SSCI model, providing insights into bladder functional and morphological alterations post-SSCI and laying the groundwork for future therapeutic research.