The role of hyperlipidemic serum on the proliferation and necrosis of aortic medial cells in vitro

Abstract

The effects of hyperlipidemic rabbit serum on the proliferation and death of subcultured rabbit aortic medial cells were evaluated. The cultured cells were grown from the aortic media of normal adult male rabbits, prelabeled with [ 3H]thymidine, and then trypsinized, pooled, and subcultured. Either normal or hyperlipidemic rabbit serum was added to the culture media. Proliferative activity was measured by cell count and by the isotopic dilution of the prelabeled DNA, with corrections made for cell loss. Cell loss, presumed to represent mainly cell death, was assessed from the total loss of [ 3H]thymidine from the cultured cell population. The cells grown in basal medium of Eagle containing 10% normal serum showed a 25% loss in the first 3 days after trypsinization. The loss rate stabilized at 1.5% per day 5 days after the subculture. When these cells were exposed to hyperlipidemic serum, the rate of cell loss showed a 5.5-fold increase in the initial 3 days, and thereafter returned to the levels seen in the presence of normal serum. Cells exposed to hyperlipidemic serum also showed a 25–50% increase in proliferative activity. These alterations have been demonstrated in both the early proliferative phase and later stationary phase. Cells grown in hyperlipidemic serum were larger on the average and showed a 50% increase in protein content per cell.