Bladder Acellular Matrix Grafting Regenerates Urinary Bladder in the Spinal Cord Injury Rat

Objectives: To assess the feasibility of bladder acellular matrix (BAM) grafting onto the bladder of rats with spinal cord injury (SCI).

Methods: Female Wistar rats, weighing 100 to 150 g, were divided into four groups: neurologically intact groups with sham operation or BAM grafting and SCI rats with or without BAM grafting (grafted groups, n = 15 each; nongrafted groups, n = 5 each). The BAM was prepared from other normal rat bladder tissue. During BAM surgery, the rats underwent partial cystectomy, followed by BAM grafting as a bladder augmentation. The SCI was created by compressing the spinal cord at the 10th thoracic level. BAM grafting in SCI rats was performed 2 to 3 weeks after SCI. At 2, 4, and 12 weeks after grafting, cystometry was performed with the rats under pentobarbital anesthesia, and the bladders were subsequently harvested and immunostained with anti-PGP9.5, uroplakin III, and alpha-smooth muscle actin antibodies (n = 5 each time). For comparison, similar examinations were performed in the nongrafted groups (n = 5 each).

Results: Regenerated urothelium, smooth muscles, and nerve fibers in the grafted BAM appeared at 2, 4, and 12 weeks, respectively, in both intact and SCI rats. Immunohistologic examination showed that these regenerated tissues inherited each characteristic of the host bladder tissue. The grafted BAM itself also showed the proper storage function of distensibility in the intact and SCI groups receiving BAM.

Conclusions: Our data have indicated that BAM grafting is feasible, even in animals with spinal injury, suggesting that BAM may be one of the alternatives for patients with a neurogenic bladder who require augmentation enterocystoplasty in clinical situations.