Attenuation of LDL receptor gene expression by selenium deficiency during hypercholesterolemia

Abstract

Selenium deficiency has been associated with hypercholesterolemia. Present study was aimed to determine the effect of selenium (Se) deficiency on LDL receptor (LDL-R) activity as well as mRNA expression during experimental hypercholesterolemia in SD male rats. Animals were fed Se adequate (0.2 ppm) and deficient (0.02 ppm) control diet as well as high cholesterol (2%) diet (HCD) for 1 and 2 months. LDL-R activity was measured in vivo by injecting radiolabeled LDL to rats and percent decrease in cpm with time was taken as a measure of LDL clearance and in turn LDL-R activity. LDL-R mRNA expression was studied by RT-PCR. LDL-R activity and mRNA expression decreased significantly on HCD feeding in both Se deficient and adequate diet fed rats after 2 months. In Se deficiency receptor activity and mRNA expression decreased significantly. After 2 months LDL-R activity and expression decreased in both the Se deficient groups and in Se adequate HCD fed group in comparison to 1 month data. But after 4 month there was no significant difference observed in LDL-R activity and mRNA expression in selenium deficiency as well as on HCD feeding. So the present results demonstrate that Se deficiency act synergistically with hypercholesterolemia to downregulate LDL-R activity as well as mRNA expression.