Increased Expression of Connexin43 on the Aortic Valve in the Hypercholesterolemic Rabbit Model

Abstract

Background: Aortic valve sclerosis is associated with increased risk of cardiovascular death and myocardial infarction. However, the relevance of connexin43 in aortic valve sclerosis remains unclear. We hypothesized that the mechanism regulating aortic valve sclerosis is associated with the alteration of cell-to-cell communication. Methods: Twenty male New Zealand rabbits were divided into two groups. Group 1 (n = 10) were fed a normal chow diet, while those in group 2 (n = 10) received a diet containing 1% cholesterol for 12 weeks. After utanizing the animals, the aortic valves were excised for analysis. Results: Myofibroblasts and macrophages were more highly expressed in the cholesterol diet group. Osteopontin and connexin43 were found to concentrate within the endothelial layer on the aortic side of the valve leaflets in the cholesterol diet group. A real-time polymerase chain reaction revealed increased connexin43 and osteopontin mRNA levels in the hypercholesterolemic aortic valves. Conclusions: The present study demonstrates that hypercholesterolemia increases the expression of connexin43 in the rabbit aortic valve. The results suggest that alterations in gap junctional intercellular communication via connexin43 gap junctions may play a role in the development of aortic valve sclerosis.