Comparative toxicities of cephalosporin antibiotics in a rabbit kidney cell line (LLC-RK1).

The rabbit kidney cell line LLC-RK1 was tested for its ability to discriminate the toxicities of six cephalosporin antibiotics according to their in vivo nephrotoxic potentials in rabbits. With the exception of cephalothin, which was markedly toxic to kidney cells in vitro, a good correlation between in vitro toxicity and in vivo nephrotoxicity was obtained, yielding the following toxicity rank order: ceftazidime less than cefazolin approximately cefoperazone less than cephaloglycin approximately cephaloridine. The addition of a kidney microsomal S9 fraction to the cell cultures desacetylated cephalothin as occurs in vivo and detoxified this antibiotic, providing it with the proper toxicity relative to the other cephalosporins. When compared with parent structures, desacetylated derivatives of other cephalosporins such as cephapirin were similarly found to be less toxic to LLC-RK1 cells. The acetylated cephalosporin cephaloglycin was not detoxified by the kidney S9 fraction and was desacetylated three to four times slower than cephalothin by renal esterases. Thus, the rate and extent of desacetylation of cephalosporins may play a role in their in vivo nephrotoxic potential. Our results further suggest that LLC-RK1 cells will provide a useful model for evaluating the potential nephrotoxicity of new cephalosporin antibiotics before in vivo studies.