High-Fat, High-Cholesterol Diet Influence on Matrix Metalloproteinases and Transcription of c-Jun and TGF-βin Cardiac Muscle of ApoE (-/-) Mice

A high-fat, high-cholesterol diet (HFHCD) has a lipotoxic effect on the heart. It not only leads to the development of atherosclerosis but also influences the extracellular matrix within the heart. The aim of the study was to investigate the effect of HFHCD on matrix metalloproteinases MMP-2, MMP-9, MMP-13, and MMP-14 expression in both the cardiac tissue and plasma of ApoE (-/-) mice and on mRNA expression of c-Jun and TGF-β in the cardiac tissue of both ApoE (-/-) mice and wild-type C57BL/6J mice. The study was carried out on two groups of ApoE (-/-) mice: (1) mice from 10 weeks of age that were kept on a HFHCD (n = 10) for the following 14 weeks; (2) control mice (NFD, n = 10) that were kept on a standard, normal-fat diet for the same time as the HFHCD. Additionally, 10 wild-type (WT) mice on a standard, normal-fat diet were also included in the study for mRNA analysis of c-Jun and TGF-β. Atherosclerotic plaque, intima, and media dimensions were assessed in the aortas of the ApoE (-/-) mice by histopathology. Concentrations of MMP-2, MMP-9, MMP-13, and MMP-14 were assessed by ELISA both in cardiac tissue and in the plasma of the ApoE (-/-) HFHCD and ApoE (-/-) NFD mice, while the mRNA expression of c-Jun and TGF-β was assessed by RT-PCR in both the ApoE (-/-) and WT groups. The results demonstrate a significantly increased MMP-9 concentration in the cardiac tissue of the HFHCD mice compared to the NFD mice (2.83 ng/mL vs. 1.91 ng/mL, p = 0.006), and a moderate correlation between the cardiac and plasmatic MMP-9 in ApoE (-/-) mice (r = 0.492, p = 0.0398). Moreover, although the mRNA expression of c-Jun and TGF-β did not differ between NFD and HFHCD ApoE (-/-) mice, the c-Jun expression was significantly elevated in the WT group compared with both ApoE (-/-) groups. The study demonstrated that a high-fat, high-cholesterol diet increases MMP-9 concentration in cardiac tissue, which might reflect its influence on the extracellular matrix within the heart.