膀胱再生に関する実験的研究

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Studies on bladder regeneration after total or subtotal cystectomy were made with fifty-two female dogs. The experiments were divided into two groups. The first consisted of forty-two dogs and this group was used to follow up the process of bladder regeneration. In this group, 5 cc Foley catheter was placed in the space after cystectomy through the urethra, and the ends of ureters were sutured to the peritoneum or perivesical tissue. Thirty out of the 42 died of peritonitis or other infections within the first two postoperative weeks and most of them were excluded from this study. The second group consisted of 10 dogs and was used for investigating whether the bladder rest or urethra is necessary for bladder regeneration. The methods employed were various. In 3 dogs, bladder neck or urethra after cystectony were closed with suture and covered with the adjacent perivesical tissue. The ends of ureters were anastomosed to the skin of the lateral abdominal wall. Then, a piece of mucosa from the extirpated bladder was implanted in the remaining perivesical tissue to examine whether new smooth muscle fibers are generated or induced under the cyst which will be formed from the implanted mucosa. Four dogs of this group died within a few postoperative weeks and were of no value in the study. The following results were obtained. The source and the process of bladder regeneration : The surface of the tissue surrounding the bag of retained catheter was lined with granulation tissue in about 7 days after operation and a pounch was formed. The transitional epithelium spread out over the granulation tissue continuously from the edge of the residual bladder neck or urethra. The smooth muscle fibers extended through the granulation tissue upward from the musculature of the bladder neck or urethra behind epithelial lining. There were no signs supporting the theory that new muscle cells develop from the totipotent mesenchymal fibroblastic cells in the perivesical tissue. The ends of ureters played only a small part in bladder regeneration. Bladder regeneration was not observed in the space after cystectomy shut off from the residual bladder neck or urethra. Structure and function of the regenerated bladder : They were almost the same as normal bladder when the regeneration progressed favourably. Such cases were observed in 5 dogs in the first group. Factors governing bladder regeneration: It is thought that the essential factor of bladder regeneration is the residual bladder neck or urethra opening into the space, from which new bladder wall develops. Bladder regeneration can not take place without this factor even if epithelial cells and totipotent mesenchymal fibroblastic cells are present in the retained perivesical tissue. In the course of formation of a hollow viscus, the preservation of the space after cystectomy seems to be an important promoting factor. This is accomplished by means of various molds or bag catheter but these forign bodies should be removed as soon as the abdominal wound has closed completely. After removal of mold or bag catheter, 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 mechanical stimulation from micturition. No chemical effect of urine on bladder regeneration was observed in this study. Infection of the wound is the most troublesome inhibiting factor in bladder regeneration. In the early stage of regeneration, it prevents the growth of granulation tissue, epithelium or muscle layers by inflammatory infiltration and formation of abscess or tissue necrosis and in the later stage, it arrests en largement of the capacity of new bladder through fibrosis.
社団法人日本泌尿器科学会の論文

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中山創生
信州大学医学部泌尿器科教室

膀胱再生に関する実験的研究

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