The Effect Of Extract From Tipterygium Hypoglaucum Hutch(TH-1)Eluting Stent On Preventing Porcine Coronary Restenosis In Miniwine

Objectives:Percutaneous Coronary Intervention(PCI)has become a main means of treatment of coronary heart disease,but in-stent restenosis is the main bottleneck of the development of this therapy.Now sirolimus-eluting stent and paclitaxel-eluting stent have not only showed people a good prospect to prevent restenosis,but also pointed out the research direction about how to develop new more effective anti-restenosis drugs.So the research of new types of drug-eluting stents is one of the key roads to resolve the hard nut of in-stent restenosis.In order to observe the efficiency and safety of TH-1 eluting stent on inhibiting the neointimal proliferation in a porcine model of coronary stent lesion and restenosis,we set another sirolimus-eluting stent group as positive group and bare metal stent group as negative group.Methods:20 healthy pigs(weight 25-35kg,aged 4-6months)were divided at random into five groups:negative group(4,implanting stainless steel bare metal stent),low dose group(4,implanting TH-1 eluting stent with 0.14?g/mm2),middle dose group(4,implanting TH-1 eluting stent with 0.7?g/mm2),high dose group(4,implanting TH-1 eluting stent with 2.8?g/mm2),positive group(4,implanting sirolimus-eluting stent with 1.4?g/mm2 sirolimus).Each pig was implanted 2 equal stents.Animals underwent angiographic study and were then sacrificed afer 28 days.The samples of artery with stent were fixed and proceeded to resin embedding,sectioning and staining.The sections were analyzed by professional image analysis software to measure and analyze parameters of restenosis.After that,the sections were analyzed under microscope to evaluate the injury,inflammation and endothelialization score.All data were conducted difference analysis and correlation between groups to assess efficiency and safety of anti-restenosis effect.'Results:17 pigs were survived after 28 days,and 34 stents were implanted into pigs' coronary.One of them died from respiratory failure,maybe caused by over dose of anesthetic.One of them died from bleeding.Another one died from pericardial effusion after 3 days.Neointimal thickness shows that low dose group is the highest,negative group takes second place,high dose group takes third place,positive group takes fourth place,and middle dose group is the least.The middle dose group,high dose group and positive group compare respectively with low dose group and negative group showing statistical significance(P<0.05).There is no statistical significance in other groups'comparison.Lumen area shows that middle dose group occupies first,positive group comes second,followed by high dose group,low dose group ranks last.The middle dose group,high dose group and positive group compare respectively with low dose group and negative group showing statistical significance(P<0.05).There is no statistical significance in other groups' comparison.Neointimal area shows that low dose group is the highest,negative group takes second place,high dose group takes third place,positive group takes fourth place,and middle dose group is the least.The middle dose group,high dose group and positive group compare respectively with low dose group and negative group showing statistical significance(P<0.05).There is no statistical significance in other groups' comparison.The degree of area restenosis shows that low dose group is the highest,negative group takes second place,high dose group takes third place,positive group takes fourth place,and middle dose group is the least.The middle dose group,high dose group and positive group compare respectively with low dose group and negative group showing statistical significance(P<0.05).There is no statistical significance in other groups' comparison.Inflammation score shows that low dose group occupies first,negative group comes second,followed by high dose group,middle dose group ranks last.The middle dose group,high dose group and positive group compare respectively with low dose group and negative group showing statistical significance(P<0.05).There is no statistical significance in other groups' comparison.There is no statistical significance in parameters of internal elastic lamina area,injury score and endothelialization score amomg every group.There are statistically positive correlation between inflammation score and parameters of restenosis,including neointimal thickness(r= 0.746,P<0.01),neointimal area(r= 0.499,P<0.01)and degree of area restenosis(r= 0.625,P<0.01).Conclusions:Middle dose group and high dose group can obviously inhibit the neointimal proliferation.Middle dose group and high dose group have a good biocompatibility and safety.There are statistically positive correlation between inflammation score and parameters of restenosis,including neointimal thickness,neointimal area.and degree of area restenosis.This shows that inflammation maybe becoming an essential factor of promoting neointimal proliferation after coronary stent implantation.