Comparison of the effects of captopril, tamoxifen and L-carnitine on renal structure and fibrosis after total unilateral ureteral obstruction in the rat.

OBJECTIVE: To compare the effects of captopril, tamoxifen and L-carnitine on renal structure and the collagen content of the unilateral obstructed kidney in the rat using unbiased stereological methods.
MATERIAL AND METHODS: Rats (n=25) were assigned equally to one of five groups after ligation of the ureter: (i) normal controls (no hydronephrosis); (ii) positive controls (hydronephrotic rats without drug treatment); (iii) hydronephrotic rat with captopril treatment (CAP); (iv) hydronephrotic rats with L-carnitine treatment (L-CAR); and (v) hydronephrotic rats with tamoxifen treatment (TAM). Two weeks after unilateral ureteral obstruction the kidney was removed and histological sections were prepared. The kidney volume and the fractional volumes and absolute amounts of the cortex, medulla, tubules, renal corpuscles, vessels and fibrous tissue were determined using modern stereological techniques.
RESULTS: Kidney volume increased in the CAP group in comparison with the other groups. The absolute volume of the tubules was the same in the CAP group compared to the normal control group. However, in the other experimental groups, the amount of tubules decreased. The absolute volumes of the renal corpuscles and vessels did not show any significant differences between groups. The absolute volume of fibrous tissue showed significant increases in all groups in comparison with the normal controls. There were no differences in the absolute amounts of fibrous tissue between the positive control, CAP and L-CAR groups, but in the TAM group the collagen content was decreased.
CONCLUSIONS: Captopril preserved the amount of renal tubules and tamoxifen decreased fibrous tissue formation in unilateral obstructed kidneys but there were no differences in other hydronephrotic kidneys.