The optimal dose of Adriamycin to create a viable rat model potentially applicable to congenital obstructive uropathy

The Adriamycin rat model is an established model for different organ anomalies including congenital obstructive uropathy. In the current study, we carried out a dose-response analysis to find out the optimal dose of Adriamycin to create a viable rat model of obstructive uropathy.

Thirty time-mated Sprague-Dawley rats were divided into 5 groups including 1 control group and 4 different treatment groups. The 4 Adriamycin dosage regimens investigated in this study were 1.25, 1.5, 1.75, and 2 mg/(kg d). Experimental rats (n = 24) were injected intraperitoneally with different doses of Adriamycin on gestational days 7 to 9 (6 rats in each group). Control rats (n = 6) were injected with an equivalent volume of saline on the same days. Viable term fetuses were harvested on gestational day 21 by cesarean delivery and dissected under a dissecting microscope. Serial transverse sections from urinary tract system were obtained for histological examination.

One hundred thirty-three viable fetuses were recovered from Adriamycin-treated rats, and 50 were from rats in the control group. There were no resorptions in the control group; however, 52 resorptions were recorded in Adriamycin groups. The rates of hydronephrosis and resorptions were 60% and 0%, 80.5% and 5.8%, 100% and 17.3%, and 100% and 76.9% at doses of 1.25, 1.50, 1.75, and 2 mg/(kg d), respectively. Histologic examination of the kidneys in the treated groups showed a significant decrease in renal parenchyma compared with the control group.

The dosage of 1.5 mg/(kg d) of Adriamycin yielded the highest number of viable hydronephrotic fetuses. At this dose, urinary abnormalities are milder; but the highest number of viable fetuses is provided, which is necessary to create a reproducible and viable animal model.