[Aortic expression of monocyte chemotactic protein-1 (MCP-1) gene in rabbits with experimental atherosclerosis]

The theory of Ross describes atherosclerosis as a process induced by inflammatory reactions involving cytokines, cell adhesion molecules, and chemokines. The latter have been identified as the principal mediator of cell recruitment into the vascular wall when accumulating monocytes become a source of foam cells. The most potent monocyte attractant among known chemokines is the monocyte chemotactic protein-1 (MCP-1). This protein is synthesized in vivo by cells of the vascular wall and its expression is largely controlled by NF-kB nuclear transcription factor. The importance of inflammation for the induction and progression of atherosclerosis suggests that anti-inflammatory drugs could be a useful modality in this condition. The present work was undertaken to: 1) adapt the RT-PCR technique to measurements of MCP-1 gene expression in rabbit aorta, 2) assess MCP-1 gene expression in rabbit aorta during atherosclerosis induced with a cholesterol-rich diet, 3) evaluate the effect of ibuprofen on MCP-1 gene expression in rabbit aorta during atherosclerosis induced with a cholesterol-rich diet. The study was done in 72 rabbits assigned to eight even groups on the basis of body weight and starting cholesterol and triglyceride concentrations in serum. All rabbits were fed a standard chow. In some groups, the diet was supplemented with cholesterol and/or ibuprofen. Two months later rabbits in four groups, i.e. control (K2), control with ibuprofen (IK2), cholesterol-rich (M2) and cholesterol-rich with ibuprofen (IM2) were weighed and blood was sampled for measurements of cholesterol and triglyceride concentrations in serum. The liver, heart, kidneys and adrenals were collected at autopsy and weighed. Additionally, a fragment of the ascending aorta was obtained for RT-PCR. The extent of atherosclerosis in aorta was determined using planimetry. Another month later this procedure was repeated for the remaining groups K3, IK3, M3 and IM3. RT-PCR was applied to measure MCP-1 gene expression in relation to constitutive expression of the GAPDH gene. Significantly lower expression was found in rabbits given ibuprofen (groups IK2, IK3, IM3) as compared with groups K2, K3 and M2 (Tab. 1, Fig. 1). Significantly higher concentrations of cholesterol and triglycerides, as well as liver and adrenal mass indices were revealed in rabbits fed a cholesterol-rich diet with or without ibuprofen, in comparison to groups K2, K3, IK2 and IK3. No atherosclerotic lesions were disclosed in control groups. Atheromatous lesions were demonstrated in rabbits fed a cholesterol-rich diet with or without ibuprofen, occupying more than 60% of the intimal surface. The following conclusions were made: 1) RT-PCR corrected for contamination of RNA samples with genomic DNA is a reliable technique for studying MCP-1 gene expression in rabbit aorta, 2) Three months of cholesterol-rich diet is without effect on MCP-1 gene expression in rabbit aorta, 3) Ibuprofen suppresses MCP-1 gene expression in the aorta without affecting the progression of atherosclerosis induced with the cholesterol-rich diet.