Lipoperoxidation in human and rat brain tissue: developmental and regional studies

Lipoperoxidation in human and rat brain was studied on the basis of formation in vitro of thiobarbituric acid positive (TBA) materials. In rats aged 1--540 days, the endogenous pools of reactive material were unchanged but on subsequent incubation of their homogenates the level of TBA-positive materials fell by 3 fold (fresh weight basis) and 5.4 fold (protein basis). In human brain, there was a distinct regional distribution of reactive materials in the endogenous pools with highest levels in the cerebellar vermis, and lower levels in thalamus, cortical regions, substantia nigra, caudate nucleus, pallidum, putamen, and hypothalamus. Only trace levels were detected in the pineal gland. On incubation all values rose 13--25 fold within 3 h at 37 degrees C except for cerebellar vermis which was increased 6 fold, and pineal gland 9 fold. Four TBA-positive materials were separated from rat brain by TLC, three of which were identical to malonyldialdehyde and its polymers. Lipoperoxidation in rat homogenates was inhibited 75--90% by sera from several different sources. The inhibitory properties were unaffected by dialysis and were not reproduced by addition of a large number of low and high mol. wt. components including vitamin E when added in concentrations equal to or exceeding that of native serum.