| Research Abstract |
Selenium in an essential trace element and some epidemiological studies have shown that selenium levels in serum have an inverse relationship with the development of occlusive vascular disease. There sre at least three selenium-containing proteins in serum, i.e., albumin, extracellular glutathione peroxidase and selenoprotein P. Anew method (HPLC-ICP-MS) for separating selenium in serum samples was developed by Koyama. The method allows a rapid and direct chromatographic determination of serum selenium among GPx, albumin and selenoprotein P. The objective of the present study was to assess which of these three selenium-containing proteins was the most responsible for the development of vascular diseases, especially atherosclerosis in hyperlipidemic mice. All animals were housed in a room with alternating 12-hour light and dark periods. Tap water was provided ad libitum. A selenium-deficient diet similar to that reported by Yoshida et al. was prepared. The diet consisted of torula yeast
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(KR yeast ; Oriental Yeast, Tokyo, Japan) (40.0%), sucrose (47.3%), soybean oil (8.0%), selenium-free mineral mixture AIN 93M (3.5%), vitamin mixture AIN 93VX (1.0%) and choline bitartrate (0.2%). A fluorometric analysis indicated that the diet contained 0.004 mg selenium/kg. The remaining mice were fed with the torula yeast diet with 0.4 mg selenium/kg diet as sodium selenite. After 4 weeks of these selenium deficient and sufficient diets, the mice were fasted for 4 hours, anesthetized with diethyl ether, and exsanguinated by drawing blood from the vena cava inferior using a plastic syringe containing Na2EDTA as an anticoagulant. Plasma was separated by centrifugation. The entire brain, liver, kidney, muscle were removed from the animals. All tissue samples were frozen immediately after dissection and stored at - 70 oC until assayed. We, now, are measuring the contents of selenium and the activities of GPx in these mouse samples and analyzing the statistical relationship between selenium nutritional status and the development of vascular diseases, especially atherosclerosis. Less
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