Study On The Treatment Of Abdominal Aortic Aneurysm With Smad3 Gene Sustained-release Paeticles

Research Background:Abdominal aortic aneurysm(AAA)is a dilated and life-threatening disease of the aorta in the lower segment of the kidney aorta.Once ruptured,the mortality rate is as high as 90%.For the treatment of large AAA(diameter? 5.5cm),endoaortic repair or classic AAA resection and vascular replacement is still the only recommended method in clinical practice.The operation is complex and relatively expensive,and there are complications such as aneurysm continuous growth,internal leakage and displacement of aneurysm after operation.The development of small diameter AAA is slow,and it will take a long time to reach the indication of surgical intervention,and there is a high risk in the period.Therefore,it is our unremitting pursuit that the effective treatment can inhibit the expansion of AAA,even make the aneurysm shrink and reduce the rate of AAA rupture.Smad3 is TGF-?/NF-?B key molecule in the signal pathway,and participate in the production of extracellular matrix,and participate in the regulation of matrix metalloproteinases,collagen,and a series of the expression of inflammatory cytokines.And our new study has found that patients with AAA in the peripheral blood Smad3 mRNA level obviously down,which may prompt Smad3 gene involved in the development of AAA.In this paper,we want to test our hypothesis that overexpression of Smad3 Gene can inhibit the progression of AAA.Objective:To explore the therapeutic effect of Smad3 Gene sustained-release particles on abdominal aortic aneurysm.Methods:The male ApoE-/-mice,16 to 18 weeks,high-fat feeding,randomly divided into 3 groups:treatment group(Treat group),AAA model group(AAA group)and sham operation group(Sham group);C57BL/6 male mice of the same week old were selected as the blank control group(Blank group),20 in each group.Blank control group:no treatment;AAA model group(Ang-? subcutaneous pump);sham operation group:(Ang-? subcutaneous pump+equal volume alginate gel+empty carrier plasmids);treatment group(Ang-?subcutaneous pump+alginate gel+Smad3 gene overexpression qualitative particle aortic para aortic infiltration).Collecting the aortic tissues after 28th operation.Then record the happening of AAA and the diameter of the aortic.Test the T cells of peripheral blood and spleen by flow cytometry test.The techniques of Western blot,HE staining,Reverse transcriptase-polymerase chain reaction,EVG/Masson staining,and immunofluorescence are used to test the aortic tissues.Results:1.Compared with the Blank group and Sham group,the rate of expansion of aortic diameter increased sharply in AAA group on the 28th operation(PI<0.001).2.Compared with AAA model group and sham operation group,the aneurysm rate and aortic diameter of the treatment group decreased significantly(P2<0.001,P3<0.001).3.The Smad3 Gene Plasmid treatment could significantly increase the Smad3,p-Smad3 and TGF-? in the mouse aorta.The expression of MMP-2,TIMP1/2,apoptosis of aortic smooth muscle cells,infiltration of T lymphocytes and Inflammatory cells were significantly decreased.Conclusions:The Smad3 gene carried by the plasmid can stably release the Smad3 gene and express the Smad3 protein through the alginate gel system,and at the same time promote the phosphorylation of the Smad3 protein,and reduce inflammation by regulating the TGF?1/Smads/NF-?B signaling pathway that Tregs may participate,thereby reducing the secretion of matrix metalloproteinase MMPs,reducing the inflammatory response,and reduces the degradation of elastin and collagen and significantly reduces the apoptosis of aortic smooth muscle cells to protect the vascular wall structure,thereby achieving treatment or slowing Ang-?-induced ApoE-/-mouse abdominal aortic aneurysm-like expansion,reducing the formation of AAA.This provides a possibility for AAA's gene therapy.