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 c holesterol 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 con trol rabbits (65.6 +/- 6.8 OD versus 16.5 +/- 2.5 OD, P < 0.01). An in crease in MDA protein was also found in rabbits intravenously injected with 2 mg of MDA-modifred low density lipoproteins or MDA-modified ra bbit serum albumin (RSA) at 0, 2, and 4 weeks of observation. The MDA proteins were not increased in cerebral tissue of cholesterol-fed rabb its. It is concluded that a high cholesterol diet is associated with i ncreased MDA modification of proteins in cerebral microvessels. The me chanism could be related to increased circulatory MDA proteins since e xogenously administered MDA-LDL or MDA-RSA resulted in similar increas es in MDA proteins in cerebral microvessels.