Effects of chloroform and dimethylnitrosamine on renal carcinogenesis in unilaterally nephrectomized rats fed formic acid 2-[4-(5-nitro-2-furyl)-2-thiazolyl]hydrazide

Abstract

Factors enhancing renal carcinogenesis induced by formic acid 2-[4-(5-nitro-2-furyl)-2-thiazolyl]hydrazide (FNT) were studied. Five groups of rats were used. Groups 1 and 2 were subjected to right nephrectomy and 2 days later they were injected with 20 mg/kg body weight of dimethylnitrosamine (DMN). From one week after nephrectomy, group 1 was fed on 0.2% FNT diet continuously to the end of the experiment, and group 2 was given normal diet. In week 2, they were given 400 mg/kg body weight of chloroform (CHCI ₃ ) orally. Groups 3 and 4 were given CHCI ₃ first and 2 days later injected with DMN. Group 3 was then fed FNT diet and group 4 was fed basal diet continuously. In week 2, groups 3 and 4 were subjected to unilateral nephrectomy. Group 5 was given FNT diet without other treatments. The incidences of tubular hyperplasia in groups 1, 3 and 5 were 53.3%, 52.9%, and 0%, respectively, at week 16 and 100%, 94.9% and 94.1%, respectively, at week 32. Moreover, the incidences of renal cell tumors in these groups were 85.0%, 88.9% and 17.6%, respectively, at week 32. Thus, the inductions of tubular hyperplasia and renal cell tumor were markedly enhanced by combined treatment with CHCI ₃ , DMN, unilateral nephrectomy and FNT in the initiating and promoting stages.