Experimental Study On The Reendothelialization And Inflammation Of Vascular Neointima After PTA With SIS Covered Stent

Objective: To explore the role of small intestinal submucosa(SIS) inreendothelialization on the internal stent surface and inflammatory reactionafter percutaneous transluminal angioplasty (PTA).Materials and Methods: 13 healthy swines were used in the experiment. Inthe same swine, bilateral common iliac arteries(CIR) were extended excessivelyby 60mm×40mm balloon catheters via internal carotid artery. A 60mm×30mmSIS-covered stent was grafted into one of CIR randomly as experiment group whilea 60mm×30mm bare stent in the opposite side as control group. Histomorphologywas observed by means of microsope,immunohistochemistry and scanningelectron microscope.Result: The result showed: Neointima formed on the internal surface inall stents.;Experimental group: neointima were yellow-white, have smoothsurface, and the metal fibra of the stent can be seen through the neointima.Control group: neointima were thicker, smooth surface, and the metal librawere absent. HE result demonstrated: Experimental group: outer layer ofneointima was EC. Under the EC, multilayer of vascular smooth muscle cell (VSMC)arranged tightly and in form of fusiform/oval and had a regular morphous. Pinkextracellular matrix existed in the neointima and distributed unevenly. Theneointima were infiltrated by inflammatory cells. Control group: VSMC layerwas loose and irregular. Inflammatory cells Infiltrated in neointima intensively.Immunohistochemistry result showed: The expression of CD3 (+),CD68(+) cellswere lower in experimental group than that Of control group and t test wasstatistically significant(P＜0.05). The Actin staining displayed thatproliferation of smooth muscle cell in the same diretion experimental group wasnot obvious compared to control group. There was a better regularity and lessinterspace of EC under Scanning electron microscope examination. In experimentalgroup, EC arranged in direction of blood flow. Nucleus of EC were satiation.Control group: EC arranged disorder relatively and its interspace was loose.Nucleus of EC were engorge insufficiently.Conclusion: (1) SIS promotes the endothelialization on the internal stentsurface after PTA. (2)SIS reduces the proliferation of neointima by reducinginflammation after PTA.