GENE ANALYSIS IN AN ANIMAL MODEL OF SPONTANEOUS AORTIC DISSECTING ANEURYSM

Jaswant Basraon, D.O., Ya Xu, M.D. Ph.D., J. Russ Carmical, Ph.D., Paul Boor, M.D.

Departments of Internal Medicine, Pathology, and Biochemistry & Molecular Biology, UTMB

Objective: These experiments aim to identify genes of potential interest for therapeutic intervention in an animal model of spontaneous aortic dissection established by our laboratory. Methods: Sprague-Dawley rat dams were given semicarbazide (6.125 mg/kg/day) by intraperitoneal injection on gestation days 14-21, a period of rapid aortic development; previous published work from this lab has established this unique experimental model in which newborn rat pups are born with dissecting aortic aneurysms with > 90% incidence (Birth Defects Journal 76:29-38 (2006). Dams were killed on day 21, and fetal aortas dissected. Smooth muscle cells from media of the aorta were captured using LCM microscopy. Total RNA was extracted from the LCM samples, amplified and labeled according to the manufacture's (NuGen, Inc.) protocol. Gene expression analysis was preformed using Affymetrix Rat Genome 230 2.0 arrays. An ANOVA was applied to the extracted gene expression measures to test for differentially expressed genes. Values were then filtered for p-values of ≥ 0.5 and a log2 ratio between -1 and 1. Results: The resulting list included more than 15 aortic development related genes in the treated group with either up-regulation or down-regulation, including TGFβ2 up-regulation (3.375 folds), TGFβ2R (-1.2376 folds), Tnfrsf6 down-regulation (-1.27083 folds). Ingenuity based analysis showed the interactions of the genes of interest in the signal pathways of vascular related genes via a variety of gene expression levels, such as protein-protein, protein phosphorylation, and RNA-protein. Conclusion: Multiple genes are demonstrated showing significantly higher or lower expression in our model. Our genes can serve as potential therapeutic targets for future therapy. This work is supported by NIHealth grant, HL65416 (PJB), and grant ES006676 from NIEHS.