Partial Ureteral Obstruction: A New Experimental Model In Rats

Abstract

Partial ureteral obstruction in rats has been usually created by implanting the mid ureter into the psoas muscle. However, this method does not allow us to choose the obstruction site or the degree of obstruction. On the other hand, the extrinsic stent insertion method needs highly sophisticated operation skill. Hence, we tried to make a new experimental model using a bisected segment of 8 F feeding tube. We made various sizes of central holes with needles in that piece and then placed the left ureter into the hole through a J-shaped incised route. The occurrence of partial ureteral obstruction was checked by excretory urogram, direct injection of indigocarmine into the upper dilated ureter and histopathological examination. Actually, partial ureteral obstruction occurred in 67% of rats in the 236 group (n=6) and in 57% in the 216 group (n=7) in a week. Complete obstruction occurred in 33% in the 236 group and in 29% in the 216 group. The control group (n=6) in which an 186 needle (greater than ureter diameter) was used showed 33% of partial obstruction but there was no case of complete obstruction.These data show that our new experimental model inducing partial ureter obstruction in rats has reliability, variability and simplicity.