| To investigate the effect of local cotransfection of hepatocyte growth factor ( HGF) gene and heme oxygenase - 1 ( HO - 1) gene on the remodeling of auto-grafting veins in rat. Autografting veins are widely used in bypass grafting in treating coronary artery obstructions and peripheral arterial diseases, though the occurrence ratios of restenosis in five years and in ten years are high to 30% and 50%. After transplantation, the venous segments are exposed into a new arterial environment of high pressure circulation. To fit for the changes, their smooth muscle cells proliferate and form a neointima, thus causing the thickening of the vascular wall. These proliferating vascular smooth muscle cells and the contemporary dysfunction of endothelial cells increase the sensitivity of the implants, accelerate the process of sclerosis. It has been reported that, on the vein transplanting animal models and humans, the dysfunction of endothelial cells includes the decrease of NO synthetase activity, fall of vascular reactivity, increase of the inflammatory adhesive factors' expression.Hepatocyte growth factor is composed of a heterodimer, which is connected by disulfide bond. The a. heavy chain contains kringle framework and the molecular weight is 69 - kDa. The molecular weight of B light chain is 34 - kDa. It is a new potential therapeutic growth factor ( enhance the vascular growth, healing of injuries and the living of cells). A certain research showed that administrating human recombination HGF could regulate the healing of liver, kidney and pulmonary diseases. The recent research showed that HGF is a special endothelial growth factor, which can protect vessels or improve vascular repair. When the hepatocyte growth factors work, they first combine with the c - Met receptors which are on the surface of endothelial cells, then through Grb2 Grb1 PI3 signal passway to have effect. Now, we suppose local gene transfer can increase the HGF level of this part, which may enhance the proliferation and repair of grafting veins, decrease the over hyperplasia of intima.Heme oxygenase is a kind of rate - limiting enzymes and it can catalyze he-machrome to degrade to CO, free iron, and biliverdin. Heme oxygenase -1 is the induced isoenzyme of heme oxygenase, can protect cells in vivo and in vitro. The culture of rat fibroblasts of HO -1 gene knocking shows, it has a high sensitivity to hemachrome and hydrogen peroxide mediated cytotoxin. Several evidences strongly suggested that heme oxygenase played an important part in vessels. Transfecting HO -1 gene to coronary endothelial cells which are cultured in vitro, can reduce the damage of free hemachrome. Recent research showed that pharmaceutical regulating of HO -. 1 over expression has an important effect on the remodeling of arterial sacculus injured rats. Namely, systemically upreg-ulation of vascular HO -1 can significantly reduce the development of neointi-ma. HO -1 catalyzes hemachrome to release CO, which is the important transmitter for HO - 1 to protect vessels. The recent research of Henricus J etc showed that HO -1 could limit the smooth muscle cells in G0/G1 phase through CO -cGMP- P21cipl.Our research is to enhance the expression of HGF and HO -1 through local cotransfection of HGF gene and HO -1 gene in autografting veins with adenovirus as vector to promote the proliferation of vascular endothelial cells, to inhibit the proliferation of intimal and medial vascular smooth muscle cells, so as to reach the final destination of the inhibition of neointima thickeningMethods1. Constructed the recombinant of adenovirus and purpose gene through the method of homologous recombination: using lipofectamine as vector, transfected the recombinant of adenovirus and purpose gene into human embryonic cells and packaged to reactivate the infection of the virus.2. Autografting model was established through transplanting the right common jugular vein into abdominal aorta of Wistar rat. All were divided into 5 groups randomly, named Ad - HGF and Ad - HO - 1 co - tran...
|
PDF Full Text Request