Lipid peroxidation by Pseudomonas aeruginosa in the pathogenesis of nosocomial sepsis.

Background: To study whether Pseudomonas aeruginosa may directly trigger peroxidation of polyunsaturated fatty acids, since lipid peroxidation is a mechanism involved in the pathogenesis of sepsis.

Methods: Gamma-linolenic acid (GLA) was administered intravenously at a dose of 25mg/kg in an infusion time of 10 minutes to seven male rabbits. Blood samples were collected from the hepatic veins and from the carotid artery at regular time intervals.

Rapid alterations of serum oxidant and antioxidant status with the intravenous administration of n-6 polyunsaturated fatty acids.

In an attempt to achieve the safe intravenous administration of two n-6 polyunsaturated fatty acids (PUFAs), gamma-linolenic acid (GLA) and arachidonic acid (AA), and to study the subsequent changes on the total oxidant and antioxidant status, various steadily increasing doses of each acid were injected intravenously at different infusion times in 28 male rabbits. Blood samples were collected at 15-min time intervals by the hepatic veins and from the carotid artery; oxidant status was determined by the thiobarbiturate assay and total antioxidant status (TAS) was assessed by a colorimetric assay. Both n-6 PUFAs were administered with safety at a dose of 25 mg/kg within 10 min accompanied by an increase of malonodialdehyde concentrations in the hepatic veins and in the carotid artery 30-45 min, respectively, after the end of the infusion of GLA and/or AA.