Morphometric analysis of arteriolar diameters in experimental nephropathies: application of microvascular casts.

Renal arteriolar diameters were measured, using microvascular resin casts, in two hyperfiltration models of rats: the remnants kidney of subtotal nephrectomy (NX) and streptozotocin-induced diabetic kidney (DM). In the NX, the blood pressure was elevated, urinary protein excretion was markedly increased and glomeruli were severely damaged. In the DM, although the blood pressure remained normal, urinary protein excretion was significantly increased and glomeruli were damaged but to a lesser extent than in the NX group. In the NX group, the afferent arteriole was dilated and the efferent arteriole was constricted. In the DM group, the afferent arteriole was dilated, while the efferent arteriole remained unchanged. The results showed that afferent arteriolar dilatation was seen in both the NX and DM groups, possibly leading to the glomerular damage. In the NX group, the systemic high blood pressure and efferent arteriolar constriction augmented glomerular damage significantly.