Background: Foam cells as a crucial atherosclerotic plaque cell-based could give rise to atherosclerosis and coronary artery diseases (CAD). These cells may have induced by ox-LDL accumulation in macrophages via platelets activity. The goal of the current study was to investigate the simultaneous effect of ox-LDL and platelets on foam cell formation and cell markers modification.
Material and methods: The human monocytic cell line (U937) was cultured in RPMI-1640. To determine the effect of ox-LDL in the formation of foam cells, ox-LDL (80 µg/ml) and isolated platelets were added to the culture medium. Oil red O (ORO) staining was used to evaluate the foam cell formation and the expression of foam cell's surface markers was determined by flow cytometry. The genes expression of CD36, ABCA1, SR-B1, ACAT1 and LXRα which involving in ox-LDL uptake and metabolism in macrophages, were assessed by real-time PCR method.
Results: Our data demonstrated that platelets induced more foam cell formation (ORO-positive cells), which accompanied with a higher level of CD163+ cells (M2 macrophages). Furthermore, the expression of CD36, ABCA1, SR-B1, ACAT1 and LXRα genes involved in cholesterol accumulation in macrophages, was significantly increased in the ox-LDL+ platelets group in comparison with the control group (P < 0.05). Moreover, up-regulation of CD36, ABCA1, and SR-B1 genes in the ox-LDL+ platelets group was more observed, in comparison with the ox-LDL group alone (P < 0.05).
Conclusion: Owing to the platelet-inducer effects on foam cells and CD163+ cells formation, platelet dual-activity could be supposed.