Mechanisms of the bacterial endotoxin-cephaloridine toxic synergy and the protective effects of saline infusion in the rabbit kidney.

To examine the mechanisms of the nephrotoxic synergy of bacterial cell wall lipopolysaccharide (LPS) (or endotoxin) and the cephalosporin antibiotics, we have studied: 1) the effects on mean arterial blood pressure and the clearances of inulin, p-aminohippurate and cephaloridine (Cld) of a 12%-lethal dose of Escherichia coli 0111-B4 LPS (0.05 mg/kg b.wt.i.v.), with both low and high rates of saline infusion (0.1 ml/min vs. a 7.5-ml/kg load followed by 0.4 ml/min, respectively, in approximately 2-kg rabbits); 2) the separate and combined effects of LPS and saline infusion on the concentrations of Cld in renal cortex and serum; and 3) the separate and combined effects of LPS and saline infusion on the nephrotoxicity of Cld, quantified by acute tubular necrosis scoring and serum creatinine concentrations 48 hr after treatment with 90 mg/kg of Cld i.v. and by mitochondrial respiratory toxicity, depletion of reduced glutathione and production of lipid peroxidation products in renal cortex 1 hr after treatment with 90 to 360 mg/kg of Cld i.v. The following was found: 1) the increased saline infusion (saline) largely prevented an LPS-induced fall of inulin clearance and partially prevented a fall of blood pressure and p-aminohippurate and Cld clearance; 2) as a result, saline prevented slightly elevated late serum and cortical Cld concentrations in LPS-treated animals; 3) the tubular necrosis and elevation of serum creatinine caused by Cld alone was reduced slightly and that produced by the combination of LPS plus Cld was reduced greatly by saline; 4) the comparable mitochondrial respiratory toxicity found after Cld and LPS-plus-Cld was prevented by saline infusion.(ABSTRACT TRUNCATED AT 250 WORDS)