RESUMO
BACKGROUND/AIMS: Arteries and veins modulate cardiovascular homeostasis and contribute to hypertension pathogenesis. Functional differences between arteries and veins are based upon differences in gene expression. To better characterize these expression patterns, and to identify candidate genes that could be manipulated selectively in the venous system, we performed whole genome expression profiling of arteries and veins. METHODS: We used the CodeLink platform and the major artery (thoracic aorta) and vein (caudal vena cava) of the rat. RESULTS: The most prominent difference was pancreatitis-associated protein (PAP1), expressed 64-fold higher in vena cava versus aorta. Expression of mRNA for thrombospondins (TSP-1, TSP-4) was greater than 5-fold higher in veins versus arteries. Higher mRNA expression of TSP-1, TSP-2, TSP-4 and PAP1 in vena cava versus aorta was confirmed by PCR. Immunohistochemical analysis of tissue sections qualitatively confirmed a higher expression of these proteins in vena cava versus aorta. CONCLUSION: This is the first gene array study of adult rat arterial and venous tissues, and also the first study to report differences in inflammatory genes between arteries and veins. Data from these studies may provide novel insights into the genetic basis for functional differences between arteries and veins in health and disease.
Assuntos
Antígenos de Neoplasias/genética , Aorta Torácica/química , Biomarcadores Tumorais/genética , Perfilação da Expressão Gênica , Lectinas Tipo C/genética , RNA Mensageiro/análise , Trombospondinas/genética , Veias Cavas/química , Animais , Antígenos de Neoplasias/análise , Biomarcadores Tumorais/análise , Perfilação da Expressão Gênica/métodos , Imuno-Histoquímica , Lectinas Tipo C/análise , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , Proteínas Associadas a Pancreatite , Ratos , Ratos Sprague-Dawley , Reprodutibilidade dos Testes , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Trombospondina 1/genética , Trombospondinas/análiseRESUMO
Described herein is a detailed analysis of the impact of three fixatives (10% neutral buffered formalin, modified methacarn and 70% ethanol) on RNA quality and utility using microarray analysis compared to OCT-embedded and flash frozen tissue. From rat livers fixed and stored in paraffin blocks for 1 month or 1 year, RNA was isolated and applied to rat whole genome microarrays. At both time points, RNA isolated from OCT-embedded tissue lost up to 5% of the information contained in snap frozen control liver. Of the fixatives used, modified methacarn was associated with the smallest loss of RNA information content (approximately 10%), while liver fixed in 70% ethanol and 10% neutral buffered formalin lost roughly 25% and 80%, respectively. We conclude that when optimum morphology is required for techniques such as laser microdissection, modified methacarn is the fixative least harmful to nucleic acids of the three tested in this study. In contrast, using traditional isolation techniques, RNA derived from tissue fixed in 10% NBF will not give reliable results on microarray studies, and should be reserved for techniques less affected by the fragmentation and modification of the template RNA, such as quantitative RT-PCR.