Expression Of NF-κB And RANTES In Experimental Ascending Aortic Aneurysm Rat Model

ObjectiveIt is generally accepted that ascending aortic aneurysm is a degenerative disease of the tunica media,which is characterized by disruption and degradation of elastin,gross collegen deposition,apoptosis of smooth muscle cells(SMC),medial neovascularization, and extensive inflammatory cell infiltration.The main cells which infiltrate the ascending aortic wall are macrophages and lymphocytes.The chemokines play a key role in the activation and infiltration of inflammatory cells.RANTES may have chemotaxis towards monocyte-macrophages and certain T lymphocyte subsets,and it has been become the hot point that RANTES play the role in the pathogenesis of aortic aneurysm.The transcription starting point of NF-κB is located at the promoter region of lots of pro-inflammatory cytokines and immune-regulating factor,which may promote the formation and development of aortic aneurysm.Ours work is to study the role of NF-κ3 and RANTES at the formation of ascending aortic aneurysm.MethodTwenty young female Wistar rats(100-110g) were divided into two groups,the operated group(aneurismal group in 20 rats) and the sham operated group(control group in 20 rats).Opened the chest under sterile condition,segregated the thymus and isolated the asending aorta.According the diameter of the ascending aorta,banded a ring which was maded by a plastic soft tube(diameter 1mm,length 6-8mm) in the ascending aorta above the aortic valve 1cm.Than closed the chest.Sham operated group,didn't band the ring.After four months,the rat of operated group may formid an aneurysm over the ring.Using the all methods of HE stain,Masson'stain,Uana'orcein stain and Van Gieson'stain,we observed the network structure of collagen,elastin and vascular smooth muscle cells in the ascending aortic vascular wall of both group.Using Immunohistochemical stain method,we investigated the protein expression of NF-κB and RANTES in the aneurysms and control group,and protein located in the positive position.Using RT-PCR to investigate the expression of NF-κB and RANTES mRNA in the vascular wall of the both group.The semi-quantitative analysis between the two groups was done by Scion Image software.SPSS 13.0 statistical software was applied for data analysis.ResultHE staining showed that most of the aneurysm contained thrombosis,part of the tunica intima hyperplasysed prominently.A lot of inflammatory cells infiltrated in the adventitia and thrombosis.The structure of artery wall in control group was normal.Masson'stain and Van Gieson'stain showed that hyperplastic vascular smooth muscle cells arranged disorderly,some area even didn't have vascular smooth muscle cell.The structure of collagen fibers was disorder,and the space between the fibers was increased.Uana'orcein stain showed that elastic fibers in the aneurysm were partially degradated and some even broken dissolved.Immunohistochemisry staining results showed NF-κB and RANTES expression significantly increased in aneurysm,while there was a little positive staining in the control group.RT-PCR results indicated that the expression levels of NF-κB and RANTES in the aneurysm were stonger than the control group,P＜0.01.The expression of NF-κB and RANTES mRNA wre correlated.ConclusionExperimental ascending aortic aneurysm of rat have tunica intima hyperplasia,most of the aneurysm contained thrombosis,lots of the inflammatory cells infiltrate in the adventia and thrombosis.The structure of vascular smooth muscle cells was arranged disorderly.