Effects of gemcitabine on cisplatin-induced nephrotoxicity in rats: schedule-dependent study.

The effects of gemcitabine (dFdC) on the lipid peroxidation and kidney histopathology in the nephrotoxicity of an antitumour drug cisplatin (CDDP) were studied in rats. dFdC was administered intraperitoneally (i.p.) at single doses of 90 mgkg(-1) while CDDP was administered i.p. at single doses of 6 mgkg(-1). Both drugs were injected either alone or sequentially in combination. In one case, CDDP preceded dFdC by 4 h and 24 h and in the other case, dFdC preceded CDDP by 4 h and 24 h. Seven days after CDDP administration, the nephrotoxicity was manifested biochemically by elevation of serum creatinine, blood urea nitrogen and an increase in the kidney weight as a percentage of total body weight. In addition, marked decreases in serum albumin and calcium levels were observed. Lipid peroxidation in the kidney was monitored by measuring the malondialdehyde (MDA) production level and kidney glutathione (GSH) content, which were increased and depleted, respectively. Administration of dFdC 4 h and 24 h after CDDP administration did not significantly change the indices of CDDP-induced nephrotoxicity or the kidney platinum concentration levels in comparison with those animals treated with CDDP alone. On the contrary, administration of dFdC 4 h and 24 h prior to CDDP administration significantly aggravated CDDP-induced nephrotoxicity which was manifested by severe increases in the serum creatinine and blood urea nitrogen levels as well as kidney weight as a percentage of total body weight. In addition, kidney tissue showed severe GSH depletion and increases in the MDA production and platinum concentration levels. Moreover, treatment of rats with dFdC 24 h prior to CDDP resulted in much more aggravation of CDDP-induced nephrotoxicity in comparison with those animals treated with dFdC 4 h prior to CDDP. Histopathological examination demonstrated tubular atrophy, tubular necrosis and drug-induced nuclear changes in the CDDP-treated group. However, pretreatment of rats with dFdC 4 h and 24 h prior to CDDP revealed extensive interstitial nephritis, renal tubular atrophy and tubular necrosis with 'sloughing off' of the lining cells, especially with those rats treated with dFdC 24 h prior to CDDP. These results might suggest that administration of dFdC prior to CDDP enhanced the lipid peroxidation in kidney tissue and aggravated CDDP-induced nephrotoxicity.