Cholesterol enriched diet enhances malondialdehyde modification of proteins in cerebral microvessels of rabbits.
To determine the role of dietary cholesterol on malondialdehyde (MDA) modification of proteins, the cerebral microvessels of rabbits fed a cholesterol enriched diet for 8 weeks were compared to control rabbits. The MDA proteins were estimated with immunoblotting using a specific polyclonal antiserum against MDA proteins. Cholesterol-fed rabbits had a significantly increased MDA protein band at 175 kDa compared to control rabbits (65.6 +/- 6.8 OD versus 16.5 +/- 2.5 OD, P < 0.01). An increase in MDA protein was also found in rabbits intravenously injected with 2 mg of MDA-modified low density lipoproteins or MDA-modified rabbit serum albumin (RSA) at 0, 2, and 4 weeks of observation. The MDA proteins were not increased in cerebral tissue of cholesterol-fed rabbits. It is concluded that a high cholesterol diet is associated with increased MDA modification of proteins in cerebral microvessels. The mechanism could be related to increased circulatory MDA proteins since exogenously administered MDA-LDL or MDA-RSA resulted in similar increases in MDA proteins in cerebral microvessels.