Increased in vitro lipid peroxidation of gerbil cerebral cortex as compared with rat

The in vitro thiobarbituric acid test was used as a measure of lipid peroxidation in the gerbil and rat. Synaptosomal preparations were isolated from the cerebral cortex of each species and incubated with a free radical generating system. Varying concentrations of ADP-Fe3+, with ascorbate and oxygenated incubation medium were used to generate hydroxy-radicals. Peroxidation of the synaptosomal membrane lipids was determined using malondialdehyde (MDA) accumulation. Both the gerbil and rat demonstrated significant increases in MDA in the presence of the generating system, while the gerbil P2 fraction consistently showed an increased level of MDA accumulation as compared with rat at each of the concentrations of ADP-Fe3+. Across a range of concentrations, there was a 2-2.6-fold greater increase in MDA accumulation in gerbil as compared with rat. Free radical generation is currently thought to be involved in the associated damage following cerebral ischemia. An in vitro model capable of producing biochemically similar damage to membrane systems by means of a controlled free-radical generating system may prove useful in studying possible mechanisms of ischemic damage.