Objective:To study the interventional effect of polygonum cuspidatum sieb.et Zucc.on NOS system in vivo.Methods:Thirty-six Japanese rabbits were randomized into 6 groups:NC Group (fed normal control diet)

HC group (fed atherogenic diet)

SHZ group

MHZ group

LHZ group(fed atherogenic diet and three different doses of polygonum cuspidatum sieb.et Zucc.separately)and L-Arg group (fed atherogenic diet and L-arginine). At the different feeding time

the following contents were surveyed:1.serum NO

NOS

plasma ET;2.EDD and NEDD of external iliac artery in vivo;3.the area of AS plaque in thoracic aorta;4.NOS activity and the expression of iNOS mRNA and eNOS mRNA on the wall of the abdominal artery.Results:In group HC

EDD and NEDD of external iliac arteries were damaged at 1 week and 6 weeks

separately;the levels of serum NO

plasma ET and activity of NOS were elevated significantly;AS lesion was serious;the activity of NOS and expression of iNOS mRNA on the medial layer of the artery wall were much higher

the activity of NOS and expression of eNOS mRNA on endothelial cells were much lower.Except NEDD

polygonum cuspidatum sieb.et Zucc.could not only adjust the activities and expressions of disordered NOS systems on AS vessels

but also improve AS lesion in a dose-effect manner.Large dose of polygonum cuspidatum sieb.et Zucc.had the strongest effect.Conclusion:Polygonum cuspidatum sieb.et Zucc.can improve the function of the disordered NOS and lessen AS lesion on AS vessels in a dose-dependent manner.