Background: The role of oxidative stress in the formation of aneurysms is not fully understood. We used the complementary DNA (cDNA) microarray technique to determine the transcription profile in the development of elastase-induced abdominal aortic aneurysm in rat models, with an emphasis on the oxidative stress-related genes.
Materials and methods: In the experimental group, rat abdominal aortas were perfused with elastase to induce AAA. In the control group, a sham operation was performed with perfusion of the aortas with saline solution. Four or five animals were used for each time point for each of the elastase-treated or saline-treated groups. At day 2, day 7, and day 10 after surgery, the external aortic diameter was measured and AAA formation was estimated. Total RNA was isolated from aortas and subjected to cDNA microarray analysis with the use of the rat genome U34A high-density oligonucleotide DNA chip (Affymetrix, Santa Clara, Calif), which contains a total number of 8799 genes of which 2017 are expressed sequence tag (EST) genes. The data were analyzed with the GENECHIP Data Mining Tool software (Affymetrix). For genes of interest, reverse-transcription polymerase chain reaction was performed to confirm their expression level.
Results: Comparison ranking analysis revealed that during AAA development, the expression of 212 genes, including 46 of EST genes, increased by more than two-fold and 229 genes, including 95 of EST genes, decreased by more than two-fold in at least one of the three time points. The regulated genes included those encoding heme oxygenase, inducible nitric oxide synthase, some extracellular matrix proteins, members of the matrix metalloproteinase family, and those associated with prooxidant/antioxidant and inflammatory responses. Reverse-transcription polymerase chain reaction analysis confirmed the upregulation of genes involved in oxidative stress, such as heme oxygenase, inducible nitric oxide synthase, 12-lipoxygenase, and heart cytochrome c oxydase subunit VIa, and the downregulation of antioxidant genes, such as superoxide dismutase, reduced nicotinamide adenine dinucleotide-cytochrome b-5 reductase, and glutathion S-transferase.
Conclusion: The cDNA microarray technique was useful for investigation of the transcription profiles during the development of AAA. Our results indicate that oxidative stress may play a pivotal role in the pathologic progression of AAA.