Changes in Urinary Bladder Structure and Systemic Inflammation Response Following Incomplete Transection versus Contusion Spinal Cord Injury in Rat Model

Objective- The current study was conducted to evaluate changes in the urinary bladder structure and leukocyte profile as an important index of the systemic inflammation response for two different types of spinal cord injury (SCI) in a rat model. Design- Experimental Study.Animals- Forty adult healthy female Sprague-Dawley rats.Procedure- Animals were assigned into two equal model groups: the incomplete transection group (ITG) and the contusion group (CG). In both groups, SCI was created at the T9-10 level of the column. Alterations in the urinary bladder construction and changes in the leukocytes were examined in both groups post-surgically. Results- Degenerative changes and a reduction in the cellular volume in the mucous layer, hyperemia, and the presence of inflammatory cells in the submucosa were the most important findings in both SCI groups. The extent of the destructive lesions was more prominent in the CG 14 days after operation. At 28 days after surgery, pathological lesions including leukocyte infiltration in the submucosa, denudation of the urothelial mucosa, severe edema, atrophy of the muscle layer, and necrosis of muscle fibers in some areas were recorded in both groups; the extent and severity of the lesions were more evident in the CG. There was no significant difference between the white blood cells and N/L ratio at the different times in the CG and ITG groups. Conclusion and Clinical Relevance- Despite the similar leukocyte response in the IGT and CG, more severe degenerative histological alternations in the urinary bladder structure were observed in the CG. Therefore, attention should be paid to the extent of cystitis in these patients in clinical trials and interventions.