[EXPERIMENTAL ASSESSMENT OF BLADDER REGENERATION BY COLLAGEN MEMBRANE SCAFFOLDS].

OBJECTIVE: To observe the bladder regeneration by collagen membrane scaffolds for bladder construction to find a new alternative scaffold material.

METHODS: Twelve healthy adult male Sprague Dawley rats, weighing 300-350 g, were randomly divided into collagen membrane scaffold group (experimental group, n = 6), and sham operated group (control group, n = 6). Upper hemicystectomy was performed and collagen scaffold was used for reconstruction in experimental group, while the bladder was turned over without bladder resection in control group. At 30 days after operation, the animals were sacrificed and grafts were harvested; HE staining and Masson staining were used to evaluate the bladder regeneration, immunohistochemical staining was performed with α-smooth muscleactin (α-SMA) and von Willebrand factor (vWF) markers to evaluate the percentage of α-SMA positive area and capillary number.

RESULTS: The rats of 2 groups survived to the end of the experiment, and no urine leakage or infection was observed in experimental group. Histologically, control group presented a pattern of normal bladder structure, experimental group presented a pattern of almost normal urothelium with a small amount of smooth muscle cells and a thin layer of undegraded collagen fibers. Immunohistochemically, experimental group showed ingrowth of smooth muscle fibers and new capillary formation along the collagen membrane scaffolds. The percentage of α-SMA positive area and capillary number in experimental group were significantly lower than those in control group (6.49% ± 2.14% vs. 52.42% ± 1.78% and 4.83 ± 0.75 vs. 14.83 ± 1.17, respectively) (t = 40.40, P = 0.00; t = 17.62, P = 0.00).

CONCLUSION: The collagen membrane scaffolds could be an effective scaffold material for bladder reconstruction.