THE EFFECT OF POPULATION-DENSITY ON THE DEVELOPMENT OF EXPERIMENTAL ATHEROSCLEROSIS IN FEMALE MICE

The effect of cage population density on plasma lipids and the develop ment of atherosclerosis was examined in female C57BL/6 mice. Mice were housed at a density of one, two or five animals per cage and fed an a therogenic diet for 28 weeks. Subsequently, the animals were bled, sac rificed, the hearts removed and the extent of fatty lesion development in the aorta examined and quantified. As the population density incre ased, there was a statistically significant increase in total choleste rol levels, VLDL + LDL cholesterol levels, the VLDL + LDL/HDL ratio an d lesion severity. These differences are due to the psychosocial stres s associated with living within a confined space with high population density over an extended period of time.