A METHOD OF PRODUCING OPEN HYDRONEPHROSIS IN THE RAT

Abstract

A method of producing open hydronephrosis in the rat was studied. Three groups of rats were employed. In the first group (Group A), consisting of 20 rats, partial ureteral obstruction was induced by placing a drop of α·cyanoacrylate monomer on the left ureter. The second group (Group B), comprised of 5 rats, underwent complete obstruction of the left ureter by ligature. The third group (Group C), similarly consisting of 5 rats, was subjected to a sham-operation to serve as a control. The degree of hydronephrosis was classified into grade 0 to III at week 1, 4 and 8 after treatment based on the findings obtained by intravenous pyelography and, after sacrifice, macroscopic examination of the kidney.
In group A, grade I hydronephrosis was observed in 14 of the 20 rats (70%) at week 1 and 8 of 16 rats (50%) at week 4. Grade II hydronephrosis was seen in 4 of the 20 rats (20%) at week 1, 7 of 16 rats (46%) at week 4 and 1 of 4 rats (25%) at week 8. Grade III hydrouephrosis was detected in 3 of 4 rats at week 8. Transverse sections of the treated ureter revealed partial mechanical obstruction with periureteral fibrosis. Group B displayed grade II-III hydronephrosis and a rapid decrease in renal function from week 1 onwards. However, long-term odservations indicated that the thinning of the parenchyma was milder than in group A. Group C did not exhibit any morphological or functional changes of the kidney.
The present method of producing open hydronephrosis wes found to be superior to previously reported techniques in terms of reproducibility and ease of preparation.