[Effects of oxidatively modified low density lipoprotein and very low density lipoprotein on the expression of MCP-1 in macrophages].

OBJECTIVE

To examine whether oxidatively modified low density lipoprotein (OX-VLDL) and very low density lipoprotein (OX-VLDL) induce the expression of MCP-1 mRNA and protein by rabbit peritoneal exudate macrophages, and to clarify what a role of both lipoproteins play in atherogenesis.

METHODS

After exposure of the macrophages to 25 micrograms/ml of LDL, VLDL, OX-LDL and OX-VLDL respectively, and a 24 hour incubation at 37 degrees C, the total RNA was extracted from the cells by guanidinium isothiocyanate method, and the media conditioned by the cultured macrophages were collected. Meanwhile, MCP-1 protein in the conditioned media was determined by using sandwich ELISA. Monocyte migration induced by the media was assayed by micropore filter method using modified Boyden chamber.

RESULTS

After a 24 hour exposure to OX-LDL and OX-VLDL, the MCP-1 mRNA expression in macrophages was markedly increased (3.2-fold and 3.4-fold, respectively), and the level of MCP-1 protein was also increased (2.2-fold and 2.5-fold, separately), and furthermore, the monocyte migration distance was significantly increased. However, the expression of MCP-1 mRNA and protein was only slightly increased when exposed to LDL or VLDL.

CONCLUSIONS

Rabbit peritoneal exudate macrophages can express MCP-1 mRNA and protein, and OX-LDL and OX-VLDL induce stronger MCP-1 mRNA and protein expression in the cells.