Effect Of Oxidized Low-density Lipoproteins On Human Umbiliacal Vein Endothelial Cells Prorenin Expression

Background:Atherosclerosis (AS) is a kind of arterial disease with dyslipidemiaand vascular wall composition change.There are many mechanisms about thepathogenesis of AS, such as lipid infiltration、thrombosis and vascular endothelial injury.So far, researches show that, endothelial dysfunction and inflammation plays anextremely important role in formation and development of AS. More and more scholarsagree with the mentioned view, which says the injury of endothelial cells is theinitiating agent in AS，while the atheromatous plaque formation is the result of injuryresponse to endarterium. Vascular endothelial cells have many important physiologicalfunctions: regulating blood vessel tone, vascular permeability, resistance of thrombosisand secretion of active substances, and so on.When vascular endothelial cells isstimulated by certain factors such as high blood pressure, increasing high cholesterol,angiotensin Ⅱ in blood、 adrenaline、 norepinephrine、epinephrine, decreasing oxygensaturation,the result is the vascular endothelial injuried. vascular endothelial cells induceand express a variety of adhesion molecules, promoting leukocyte chemotaxis andwander and adhersion to the subendothelial matrix, promoting the development of theAS. Many risk factors which cause AS can activate some signal pathway andinflammatory factors to cause endothelial dysfunction, including oxidation type lowdensity lipoprotein (ox-LDL) which is the most important factor of causingatherosclerosis and the the main factor of damaging endothelial cells and smoothmuscle cells.Conventional view is that, renin-angiotensin system (RAS) in adjustingcardiovascular system plays an important role in the regulation,and Angiotensin Ⅱ(Angiotensin Ⅱ, Ang Ⅱ) is the most important.In recent years, they have found some of the important new members in theRAS:angiotensin converting enzyme (ACE)2, angiotensin1-7(Ang1-7), Ang1-7 receptor Mas, renin、prorenin and prorenin receptor, etc. Prorenin is non-activatedzymogen form of the renin. Kidney is the body’s main source of prorenin, but is not theonly source.there may be other organization releasing prorenin.In recent years, someresearch has showed that renin and prorenin exert biological function independent ontraditional manner which renin angiotensin activates and generates Angiotensin Ⅱ. Thisfunction can be explained by renin and prorenin binding to (pro)renin receptor [(P)RR],which is activating the intracellular signalling pathways and up-regulating some geneexpression by independent angiotensinⅡ manner. Ox-LDL participates inatherosclerosis development,and prorenin through the receptor relying on mechanismplays an important role in cardiovascular and kidney disease. At present there are norelated researches,about effect of the ox-LDL on prorenin mRNA expression and theprorenin secretion amount.Objectives:To observe the effect of ox-LDL on Human Umbiliacal VeinEndothelial Cells (HUVECs)prorenin mRNA expression and secretion amount.Methods:1. HUVECs were cultured in vitro.2. HUVECs were exposed to100ug/ml ox-LDL for5min,15min,30min,60minand120min, respectively.Then collecting total RNA of HUVECs, with RT-PCRdetecting prorenin mRNA expression.3. HUVECs were exposed to different concentration of ox-LDLfor15min,respectively by25ug/ml,50ug/ml,100ug/ml,150ug/ml.Then collecting totalRNA of HUVECs,with RT-PCR detectiing prorenin mRNA expression.4. HUVECs were stimulated to100ug/ml ox-LDL for5min,15min,30min,60min and120min, respectively.Then collecting HUVECs supernatant, with ELISAobservating in HUVECs supernatant prorenin secretion amount.Results：1. Get growing well HUVECs.2. The prorenin mRNA expression may be able to increase when HUVECs werestimulated by100ug/ml ox-LDL.After the addition of ox-LDL5min the proreninmRNA expression first appeared,expressed the most at15min and decreased from30min to120min.3. HUVECs were exposed to different concentration of ox-LDL for15min,respectively by25ug/ml,50ug/ml,100ug/ml,150ug/ml. The prorenin mRNAexpression increased gradually from25ug/ml to50ug/ml, expressed the most at theconcentration of100ug/ml and reduced at150ug/ml.4．HUVECs were stimulated with100ug/ml ox-LDL for5min,15min,30min,60 min,120min, respectively. Secretion amount of prorenin started to increase at5min,themost at15min, gradually reduced from30minto60min.Conclusions:1. The prorenin mRNA expression can increase in HUVECsstimulated by Ox-LDL, and present a time-dependent manner.2. The prorenin mRNA expression can raise in HUVECs stimulated by differentconcentration of ox-LDL, and show a concentration-dependence manner.3.100ug/ml ox-LDL stimulating HUVECs at different time,the secretion amountof prorenin increased, and present a time-dependence manner.