Differential expression of apolipoprotein D and apolipoprotein E in the kainic acid-lesioned rat hippocampus.
Expression of apolipoprotein D, a member of the lipocalin superfamily of transporter proteins, was investigated in the kainic acid-lesioned rat hippocampus. Using an anti-rat apolipoprotein D antibody and biotin avidin-enhanced immunocytochemistry, in the normal rat hippocampus there was little apolipoprotein D expression, that was restricted mainly to scattered astrocytes. By contrast, kainic acid-injected rats showed apolipoprotein D immunoreactivity in the pyramidal neurons of the affected CA fields 24-48 h after injection of the excitotoxin, at a time when there was no histological evidence of cell death. Apolipoprotein D immunoreactivity peaked by day 3, coincident with neuronal cell death, and declined thereafter, reaching very low levels by day 7. Besides pyramidal neurons, apolipoprotein D immunoreactivity was also observed in a small number of reactive glial cells in the affected CA fields, but not in the vascular compartments at any time-point. In contrast to the neuronal expression of apolipoprotein D, apolipoprotein E immunoreactivity was observed predominantly in degenerating astrocytes. In conclusion, following excitotoxic injury with kainic acid, apolipoprotein D is expressed in hippocampal pyramidal neurons destined for subsequent cell death.
Ong
W Y
WY
Department of Anatomy, National University of Singapore.
He
Y
Y
Suresh
S
S
Patel
S C
SC
D000818:Animals; D001053:Apolipoproteins / Q000378:metabolism*; D053399:Apolipoproteins D; D001057:Apolipoproteins E / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism* / Q000648:ultrastructure; D007608:Kainic Acid / Q000494:pharmacology; D008297:Male; D008854:Microscopy, Electron; D051381:Rats; D017208:Rats, Wistar
D001053:Apolipoproteins; D053399:Apolipoproteins D; D001057:Apolipoproteins E; D007608:Kainic Acid