An autoradiographic study of smooth muscle hyperplasia in the swine ureter

Autoradiographs of healing ureteral defects demonstrated significant uptake of tritiated thymidine in pigs sacrificed during the first 2 weeks after ureterotomy. The earliest and most heavily labeled tissue was epithelium followed by proliferation of subepithelial connective tissues and smooth muscle of the muscularis. The labeling of significant numbers of myocytes within the muscularis was indicative of smooth muscle replacement by hyperplastic means. The fact that most mitotically active smooth muscle cells were seen in the muscle remnant adjacent to wound margins suggests this as the primary source for new muscle.