A New Experimental Model In Ratst

= A bs t r ac t = 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 t o 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 23G group (n=6) and in 57% in the 21G group (n=7) in a week. Complete obstruction occurred in 33% in the 23G group and in 29% in the 21G group. The control group (n=6) in which an 18G 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.