To determine if aging in rats is associated with increased susceptibility of cerebral microvessels to oxidative damage microvessels from the cerebrum of 4-, 12-, 18- and 26-month-old male Fischer 344 rats were studied. The malondialdehyde (MDA) (micrograms/mg protein) content of cerebral microvessels from 12-month-old rats (0.032 +/- 0.002) was significantly higher than that in 4-month-old rats (0.020 +/- 0.015) P < 0.01. The difference between 26-month-old (0.025 +/- 0.002) and 4-month-old rats did not reach statistical significance. The antioxidative potential was measured in the presence of a peroxy radical generator 2,2'-azobis(2-amidionopropane)hydrochloride (AAPH) with monitoring of the fluorescence of phycoerythrin at 37 degrees C. The free radical quenching activity of cerebral microvessels expressed as % inhibition of phycoerythrin oxidation by AAPH was significantly reduced in 12-month-old (33.6 +/- 4.6%) and 18-month-old rats (26.9 +/- 1.4%) compared with 4-month-old rats (54.3 +/- 4.9%) (P < 0.01). The 26-month-old rats (46.4 +/- 4.6%) were not significantly different from 4-month-old rats. It is concluded that aging is associated with increased lipid peroxidation byproducts in cerebral microvessels along with a transient decrease in their antioxidative capacity.
Aging Amidines