Early and late morphological changes (including carcinoma of the urothelium) induced by irradiation of the rat urinary bladder

Abstract

Summary.-Effects of X-irradiating the urinary bladder of female F344 rats with a single dose of 20 Gy were studied by light and electron microscopy. The animals were killed 1 week-20 months post-irradiation, and all tissues of the bladder wall were found to be affected by the irradiation.In the urothelium, damage was initially restricted to the basal cells but slowly extended to intermediate cells, and by 6 months post-irradiation the urothelium was focally hyperplastic. Twenty months post-irradiation, transitional-cell carcinomas were found in 10 of the surviving 17 animals (59%). The blood vessels in the bladder wall showed damage to both the endothelial cells and the smooth muscle. The fibroblasts in the connective tissue of the bladder wall appeared to show increased secretion after irradiation, and there was abundant collagen deposition, resulting in severe fibrosis of the bladder wall. After a latent period of a few months, focal degeneration and extensive necrosis of the smooth muscle cells were seen, leading to severe destruction and disorganization of the muscular coats of the bladder wall.Thus, a single dose of irradiation of 20 Gy was sufficient to produce severe fibrosis of the bladder wall with smooth muscle degeneration and to induce carcinoma of the urothelium in most of the treated animals within 20 months.

Effects of Ageing and X-lrradiation on the Diurnal Rhythm of Mouse Urinary Bladder Capacity

“…Chronic progressive changes in bladder compliance resulted in a reduction in absolute capacity data at all the different times of day as well as in a decrease in the amplitude of diurnal variations, indicating a higher absolute reduction in bladder capacity at times with normally high capacity. During this late response phase, which is associated with pronounced histological and cell kinetic changes [20], increased deposition of col lagen and ensuing fibrosis of the bladder wall [21] are like ly causes of decreased elasticity of the bladder wall. The organ may then be unable to respond to the factors nor mally regulating diurnal variations in capacity.…”

Exogenous Modulation of TGF-β1 Influences TGF-βR-III-Associated Vascularization during Wound Healing in Irradiated Tissue

“…The animal model used in this experimental study showed significant activation and de novo synthesis of TGF-1 following irradiation and surgery [32]. It has been shown that total reference doses between 30 and 50 Gy caused lesions in tissues that are comparable to those found in humans after radiotherapy [3]. Preresearch with a total reference dose of 30 Gy, 40 Gy, 50 Gy and fractionation of 3 ϫ 10 Gy, 4 ϫ 10 Gy, 5 ϫ 10 Gy, 10 ϫ 3 Gy, 10 ϫ 4 Gy was carried out to identify the fractionation model corresponding to the clinical situation [30].…”

Transurethral resection of the prostate after radiotherapy for prostate cancer: Impact on quality of life

“…The response of urothelial tissue to radiation is characterized by early edamatous changes, followed by proliferation and loss of differentiation . Edematous tissue changes explain the improvement of urinary incontinence for patients after prior TURP.…”

“…The response of urothelial tissue to radiation is characterized by early edamatous changes, followed by proliferation and loss of differentiation. 24 Edematous tissue changes explain the Impact of TURP on RT for prostate cancer improvement of urinary incontinence for patients after prior TURP. However, this improvement has not been observed in the patient group without prior TURP, with normal vascular function and compensation capacity.…”