Microvasculature of hydronephrotic kidneys in KK-A(y) mice

Spontaneous hydronephrosis in KK-A(y) mice was studied using light and elec tron microscopy and scanning electron microscopy of resin casts to evaluate micro vascular changes in the kidney. The renal parenchyma was extremely t hin as a result of tubular atrophy. Histologically, varying degrees of glom erulosclerosis were observed. Ultrastracturally, marked thickenings of the glomerular basal lamina, an increase in mesangial cells and matrix, and mar ked effacement of foot processes were observed. In resin casts, a marked re duction in number of glomeruli was evident. The capillaries were thin, stra ngulated and torn-off to varying degrees in severely affected glomeruli. In the medulla, the three-dimensional capillary network running along the tub ules was lost and changed to a two-dimensional vascular bed. Despite severe hydronephrosis, the glomerular capillary network was relatively well prese rved, being either slightly or moderately injured in approximately 60% of s urviving glomeruli.