Karyomegaly of tubular cells as early stage marker of the nephrotoxicity induced by ochratoxin A in rats

Cases of karyomegaly were described by Sclare(30) and by Mihatch(31) in pat ients affected with tubular-interstitial nephropathy. The Karyomegalic cell s showed enlarged nuclei with accumulation of genetic material. No aetiolog y was suggested. Our study of rats experimentally intoxicated by ochratoxin A, a well-known nephrotoxic compound, indicates the presence,of karyomegaly with alteration of the tubular tissue. In control animals no karyomegalic cells were detec ted. These observations suggest that karyomegaly with megacytosis may be ca used by the nephrotoxic ochratoxin A in the kidney. In addition abnormal mitosis together with karyomegalic cells were observed at an earlier stage of the intoxication (30 days) suggesting possible rege neration if the OTA insults are stopped. After 90 days of treatment, the degeneration increased and only karyomegali c and apoptotic-like cells were observed indicating that the regeneration n o longer occurs and that the degeneration becomes irreversible.