Comparative Cytotoxicity Rankings of Four Aminoglycoside Antibiotics in the Chang,SIRC and LLC-PK1 Cell Lines

Abstract

A series of structurally related aminoglycosides — neomycin, gentamicin, amikacin, and streptomycin — were screened for cytotoxicity in three cell lines, Chang (liver), SIRC (corneal epithelial), and LLC-PK1 (kidney). The main objectives of this study were: firstly, to determine whether the proximal tubule origin of the LLC-PK1 cell line conferred increased sensitivity to this class of xenobiotic when compared to cell lines derived from organs other than the kidney; and secondly, to determine whether any of the cell lines would rank the in vitro cytotoxic potential of the compounds in an order consistent with their in vivo toxicities. LDH leakage and cell proliferative effects (CP) were the endpoints used to measure cytotoxicity.

The proximal tubule derivation of the LLC-PK1 cell line did not appear to confer significantly increased sensitivity to any of the aminoglycosides tested using LDH release and cell proliferation as endpoints of cytotoxicity. The relative cytotoxicity rankings were as follows: Chang — gentamicin>neomycin>amikacin>streptomycin (LDH), neomycin∼gentamicin∼streptomycin >amikacin (CP); SIRC — neomycin∼gentamicin∼streptomycin>amikacin (LDH and CP); and LLC-PK1 — gentamicin∼streptomycin>neomycin>amikacin (LDH), and streptomycin >neomycin>gentamicin∼amikacin (CP). The results suggest that the Chang line provides a cytotoxicity ranking consistent with in vivo nephrotoxicity data. The SIRC line ranks amikacin the least cytotoxic, but fails to discriminate between the cytotoxicities of gentamicin, neomycin and streptomycin. The LLC-PK1 cell line ranks the compounds in an order which is inconsistent with in vivo results. The LLC-PK1 cell line appears to be the most sensitive to streptomycin, which is the only agent tested that is not accumulated in the kidney in vivo. The results may reflect basal cytotoxicity, since relatively non-specific endpoints were used. Perhaps the LLC-PK1 cell line would rank the cytotoxic potential of this class of compounds more accurately if parameters which are more renal-specific were measured as endpoints.