An Experimental Study on Bladder Regeneration

Kwak, Dae Hee

Abstract

One hundred and ten rats weighing 100 gm. or more were used. These animals were divided into two study groups. The first consisted of 80 rats and this groupwas used to follow up the process of bladder regeneration. The second consisted of 30 rats and in this group polyethylene tube (I.D. .023" X O.D. .038") was placed in the space after subtotal cystectomy through the urethra, and the tube was sutured to the urethra with 4-0 silk to investigate whether the urinary retention is necessary for the bladder regeneration. Anesthesia was accomplished by intraperitoneal and through a subumbilical median incision the bladder was exposed transperitoneally and subtotal cystectomy was done saving the trigone andureteral orifices. To prevent the urinary leakage the edge of remnant bladder wasclosed with 4-0 chromic catgut. In the first group, 10 rats each were sacrificed at intervals of one week after initial operation for 8 weeks. There was complete restoration of what appeared to be normal bladder capacity at the end of 8 weeks. The regenerated bladder was a definite thick-walled pouch lined with normal epithelium and many capillaries. In the second group, 30 rats were sacrificed after the initial operation: 6 each at the 4th, 5th, 6th, 7th and 8th week. At the end of 8 weeks regeneration of the bladder was markedly inhibited as compared with the first group. It is felt that the mechanical stretch of the bladder is the main factor by which the bladder grows. The urine pooling in the pouch serves not only to preserve and enlarge the pouch but also to develop the elements of new bladder wall by intermittent filling and emptying. The most inhibitory factorin bladder regeneration is the wound infection.