Immunohistochemical localization of apolipoprotein B-100 (ApoB-100) and expression of glutathione peroxidase (GSH-PO) in canine atherosclerotic lesions

We used immunohistochemistry to localize canine Apolipoprotein B-100 (CApoB -100) and glutathione peroxidase (GSH-PO) in canine atherosclerotic lesions . CApoB-100 was deposited in the tunica intima and cytoplasms of infiltrati ng macrophages in early atherosclerotic lesions. In advanced atheroscleroti c lesions, the cystic space of the lesions contained a large amount of CApo B-100 immunoreactive material. Expression of GSH-PO was recognized in the f oamy cytoplasm of macrophages and smooth muscle cells in the early and adva nced atherosclerotic lesions. These results indicate that expression of GSH -PO is closely associated with the deposition of CApoB-100. In addition, th ey suggest that, as in human atheromas, low-density lipoprotein (LDL) is pe roxidized and changed into modified LDL. Deposition of modified LDL (oxidiz ed or acetylated) may be a critical step in the formation of canine atheros clerotic lesions.