Rats Exposed to Excess Sucrose During a Critical Period Develop Inflammation and Express a Secretory Phenotype of Vascular Smooth Muscle Cells

Abstract

Background: Neonatal rats that receive sucrose during a critical postnatal period (CP, days 12 to 28) develop hypertension by the time they reach adulthood. Inflammation might contribute to changes during this period and could be associated with variations in the vascular smooth muscle (VSMC) phenotype. Objective: We studied changes in inflammatory pathways that could underlie the expression of the secretory phenotype in the VSMC in the thoracic aorta of rats that received sucrose during CP. Methods: We analyzed histological changes in the aorta and the expression of the COX-2, TLR4, iNOS, eNOS, MMP-2 and -9, and β- and α-actin, the quantities of TNF-α, IL-6, and IL-1β using ELISA, and the levels of fatty acids using gas chromatography. Results: The aortic wall presented disorganization, decellularization, and wavy elastic fibers and an increase in the lumen area. The α- and β-actin expressions were decreased, while COX-2, TLR4, TNF-α, and the activity of IL-6 were increased. Oleic acid was increased in CP in comparison to the control group. Conclusions: There is transient hypertension at the end of the CP that is accompanied by inflammation and a change in the phenotype of VSMC to the secretory phenotype. The inflammatory changes could act as epigenetic signals to determine the development of hypertension when animals reach adulthood.

Keywords

• hypertension
• sucrose ingestion
• critical window
• synthetic phenotype
• vascular smooth muscle cells
• inflammation