Effect of habitual exercise on renal carcinogenesis by ferric nitrilotriacetate.

OBJECTIVES

We investigated whether habitual exercise (HE) (treadmill running) suppresses development of renal cell carcinoma (RCC) induced by ferric nitrilotriacetate (Fe-NTA).

METHODS

Male Fischer 344 rats were divided into six groups: group I, saline treatment (12 weeks = initiation period) and non-HE; group II, Fe-NTA treatment (12 weeks) and non-HE; group III, saline treatment and short-term (12 weeks) HE; group IV, Fe-NTA treatment and short-term HE; group V, saline treatment and long-term (40 weeks) HE; and group VI, Fe-NTA treatment and long-term HE. Saline treatment groups did not develop RCC, therefore we investigated the effects of HE among Fe-NTA treatment groups.

RESULTS

Gross nodules (diagnosed as RCC), RCC represented by microcarcinomas (Mcs), karyomegalic cells (KCs), and degenerative tubules (DTs) were seen in rats treated with Fe-NTA. The number of Mcs, KCs, and DTs were increased in the short-term HE group when compared with those in the non-HE group, but were decreased in the long-term HE group when compared with those in the short-term HE group.

CONCLUSIONS

Short-term (initiation period) HE promoted renal carcinogenesis induced by Fe-NTA; however, long-term HE after the initiation period suppressed the promoted carcinogenesis.