Studies of nephrotoxic agents in an improved renal proximal tubule system.
Renal proximal tubule fragments (RPT) were prepared from young-adult, male F-344 rats by deferoxamine/collagenase perfusion and evaluated as a potential model for mechanistic studies and screening, using known nephrotoxins. Chloroform and S-(1,2- dichlorovinyl )- l - cysteine (DCVC) produced depressed O(2) consumption rates (basal and/or nystatin-stimulated) and lactate dehydrogenase (LDH) release during 8-hr incubations at 0.5 mg RPT protein/ml. Cytochrome P-450 inhibitors piperonyl butoxide and metyrapone were either without effect or potentiated chloroform-induced toxicity. DCVC was more cytotoxic to RPT than to rat hepatocytes. The cytotoxic potency for cephalothin relative to cefazolin decreased as RPT content in the medium was increased to 3.0 mg protein/ml, giving a rank order more in accord with results reported in vivo. Cephalosporins markedly depressed brush border alkaline phosphatase (ALP) activity, without affecting gamma-glutamyltranspeptidase activity; the effect on ALP was less sensitive to the RPT level. Acetaminophen (25 mm) and p-aminophenol (1.0 mm) induced LDH release without ALP depression and inhibited mitochondrial respiration. These results in general corresponded well with in vivo responses and indicate that this RPT system may be valuable for studies of chemical-induced nephrotoxicity.
Tyson
C A
CA
SRI International, Menlo Park, CA 94025, USA.
Dabbs
J E
JE
Cohen
P M
PM
Green
C E
CE
Melnick
R L
RL