The chronic complex stress combined atherogenic diet accelerates the process of atherosclerosis in mice

Abstract

The effects of stress on the atherosclerosis are complex. Here we discuss how the chronic complex stress (CCS), when combined with an atherogenic diet (AD), leads to the development of atherosclerosis in mice. The CCS mouse model consisted of physical and psychosocial stressors of different types and intensities presented in a random order. Eighty-seven mice were divided into a standard chow diet (n=44) and AD (n=43) groups and bred for 4 months. Both groups were subdivided into groups without and with CCS treatment. The CCS was performed during the last month of the study. Ultrasound bio microscopy, histopathological and fluorescence immunohistochemical examinations, ELISA, PCR, and flow cytometry were used. We showed that CCS, when combined with atherogenic diet, resulted in accelerated process of the atherosclerosis, as measured by the maximum intima media thickness and hypoechoic plaque formation in the ultrasound bio microscopy, mean aortic well area in the hematoxylin and eosin staining, max Oil-Red-O content in the Oil Red O staining, and the aortic triglyceride level. These changes were accompanied by endothelial dysfunction and excessive inflammation based on down-regulation of aortic Nos3 mRNA expression, up-regulation of aortic syndecan-1 (Sdc1) and thrombomodulin (Thbd) mRNA expressions, and an increased percentage of CD45-positive cells in the aorta. Stressed mice had upregulation of aortic tumor necrosis factor-alpha (Tnf-α) gene expression, co-up-regulation of aortic nuclear receptor subfamily 3, group C, member 1 (Nr3c1) and Nfkb1 mRNA expressions, and hyperactivity of adrenal gland function based on increased phenyl ethanolamine-N-methyltransferase (PNMT) and NR3C1-positive cells, up-regulation of Nr3c1 and Pnmt mRNA expressions in the adrenal gland. These observations may demonstrate that CCS, via hyperactivity of the adrenal gland and aortic proinflammatory cytokine (Tnf-α)-related co-up-regulation of aortic Nr3c1 and Nfkb1 gene expressions, accelerated the atherosclerosis development in mice, especially when combined with atherogenic diet.