Effects of maternal bilateral ureteral ligation on fetal development of kidney in rats: morphometrical changes in...

Development of the glomerulus in fetal kidney was studied morphometrically following ligation of both ureters of pregnant rats. The ligation was performed on days 17, 19, and 21 of gestation, and autopsy was done 24 hr after each operation. The percentage volumes of the five glomerular components (epithelial cells, capillary, mesangium, glomerular basement membrane, and Bowman's space) were determined by point counting, and the surface area of glomerular basement membrane per unit volume of glomerulus was calculated by intercept counting. On fetal days 18, 20, and 22, percentage volume of Bowman's space in the fetuses from the ligated mothers was significantly smaller than that in the fetuses from sham-ligated mothers. On fetal days 20 and 22, surface area of glomerular basement membrane and glomerular capillary length per unit volume of glomerulus and percentage of glomerular capillary volume in the fetuses from the ligated mothers were significantly larger than those in the fetuses from sham-ligated mothers. These results suggest that maternal bilateral ureteral ligation induces an increase in filtration area of glomerulus in fetal kidney when the fetal kidney is functional.