Poly-L-aspartic acid does but triiodothyronine does not protect against gentamicin-induced cytotoxicity in the porcine kidney cell line LLC-PK1.
This study investigated the protective effect of thyroid hormone and poly-L-aspartic acid (PAA) in an in vitro model of gentamicin nephrotoxicity. LLC-PK1 porcine renal cells were grown in Medium 199 supplemented with either fetal bovine serum or thyroid hormone-depleted fetal bovine serum. After a preincubation with or without 30 nM L-triiodothyronine for 3 days, or 0.1 mM PAA for 1 hr, cells were coincubated with 1 mM gentamicin for an additional 3 days. Determinations were made of the following indicators of cell damage and/or viability: the numbers of detached dead cells, the total lactate dehydrogenase activity and its percentage release and gamma-glutamyl transpeptidase activity. Preincubation with L-triiodothyronine did not protect from gentamicin-induced cell death but did reduce cellular accumulation of gentamicin (3.2 +/- 0.8 micrograms/mg of protein vs. 5.2 +/- 1.8 micrograms/mg of protein in controls; P less than .05). In contrast, preincubation with 0.1 mM PAA decreased gentamicin-induced cell death (gentamicin: 685 +/- 416% of control dead cells and 487 +/- 48% of control lactate dehydrogenase release; PAA + gentamicin: 164 +/- 63% of control dead cells and 257 +/- 85% of control lactate dehydrogenase release; P less than .05) but failed to attenuate inhibition by gentamicin of gamma-glutamyl transpeptidase activity (gentamicin: 69 +/- 7% of control; PAA+gentamicin: 76 +/- 3% of control) and failed to alter cellular gentamicin levels. Protection against gentamicin nephrotoxicity by L-triiodothyronine was not demonstrated in LLC-PK1 cells, indicating that its protective effect in vivo is likely due to a systemic effect of the hormone.(ABSTRACT TRUNCATED AT 250 WORDS)
Whittem
T
T
Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens.
Schnellmann
R G
RG
Ferguson
D C
DC
D000818:Animals; D002460:Cell Line; D005839:Gentamicins / Q000493:pharmacokinetics / Q000633:toxicity*; D007668:Kidney / Q000187:drug effects*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008871:Microvilli / Q000187:drug effects / Q000201:enzymology; D010455:Peptides / Q000494:pharmacology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000032:analysis; D013552:Swine; D014284:Triiodothyronine / Q000494:pharmacology*; D005723:gamma-Glutamyltransferase / Q000032:analysis
D005839:Gentamicins; D010455:Peptides; D014284:Triiodothyronine; C017645:polyaspartate; D007770:L-Lactate Dehydrogenase; D005723:gamma-Glutamyltransferase; D000254:Sodium-Potassium-Exchanging ATPase