Preliminary Research On The Expression Of Superoxide Dismutase In Human Thoracic Aortic Dissection And Thoracic Aortic Aneurysm

Objective:1. To measure all the three isoforms of the superoxide dismutase (SOD) expression in human thoracic aortic dissection (TAD) and thoracic aortic aneurysm (TAA).2. To detect the location of every SOD isoform in the morbid and normal aorta and the aorta's pathological changes.3. To discuss the SODs'possible roles in TAD and TAA.Methods:15 TAD and 15 TAA patients who were treated with surgery in Changhai Hospital from Jan 2006 to Dec 2008 were selected for study, as well as 12 transplant donor over the same period. The cases were divided into three groups:the TAD group, the TAA group and the NA group. The morbid and normal aorta were collected in corresponding parts. Western blotting (WB) was performed to detect the differential expression of every SOD isoform in every group with liquid nitrogen freezing samples. Immunohistochemistry (IHC) was used to validate their expression and localization and the aorta's pathological changes with paraffin-embedded specimens. The parameters were analyzed by SPSS 17.0 software.The F-test and t-test were used to compare the parameters in western blot. The data in immunohistochemistry were analyzed with Kruskal-Wallis H tset. P<0.05 means existence of significant difference in statistics.Results:1. Western blotting showed that SOD-1 and SOD-3 expression decreased significantly in TAD and TAA compared with normal controls (NA) (P<0.05), and there were no significant differences between the TAD and TAA groups (P>0.05). The SOD-2 expression in TAA group was distinctly lower than TAD and NA gorups (P<0.05), but there were no obvious differences between the TAD and NA groups (P>0.05).2. Immunohistochemistry displayed that every SOD isoform all expressed in the groups. The SOD-1 and SOD-2 mainly localized in the smooth muscle cells (SMCs) in the media and the nutritious vessels, while SOD-3 mainly in the extracellular matrix (ECM) of the vessel walls. The density and collocation of SMCs were normal in the NA group, there were no evident degeneration in the their media. Plenty of nutritious vessels and few inflammatory cells could be seen in the vessel walls. The intensity of staining went between positive to strongly positive. The density of SMCs decreased in TAD and TAA groups, the cells'arrangement were disorganized. In TAD group, the expression of SODs disappeared in the edges of the region where the media was divulsed, while the karyon in the region decrease obviously. It was able to see much inflammatory cells in the media and ectoblast. The expression of SODs also decreased in TAA group, but the inflammatory reaction in the ectoblast was not so evident as TAD group.Conclusions:1. The expression of SOD-1 which mainly localized in the smooth muscle cells (SMCs) in the media and the nutritious vessels, decreased significantly in TAD and TAA groups compared with normal controls (NA).2. The expression of SOD-2 which also mainly localized in the smooth muscle cells (SMCs) in the media and the nutritious vessels, decreased significantly in TAA group compared with TAD and normal controls (NA).3. The expression of SOD-3 which mainly localized in the extracellular matrix (ECM) of the vessel walls, has the same tendency among the three groups.4. TAD and TAA were both degeneration in the aortic media. In TAD group, the expression of SODs disappeared in the edges of the region where the media was divulsed, while the karyon in the region decrease obviously. It was able to see much inflammatory cells in the media and ectoblast. The expression of SODs decreased in TAA group, but the inflammatory reaction in the ectoblast was not so evident as TAD group.