Effects of Rosiglitazone on the Expression of Angiotensin II Type 1 Receptor and Type 2 Receptor in Angiotensin II-Induced Mice Vascular Smooth Muscle Cells

Aim To investigate the effects of rosiglitazone on the expression of angiotensin Ⅱ(AngⅡ)type 1 receptor(AT1R)and AngⅡ type 2 receptor(AT2R)in AngⅡ-induced vascular smooth muscle cells(VSMC)and possible molecular mechanisms of anti-atherosclerosis.Methods VSMC of mice were cultured by the explant-attachment method.Using semi-quantitative reverse transcription polymerase-chain reaction(RT-PCR)and immunochemistry,we measured the dose and time dependent effects of rosiglitazone on AT1R and AT2R mRNA and protein in AngⅡ-induced mice VSMC.Results Slight expressions of AT1R and AT2R were observed in cultured VSMC in vitro.AngⅡmarkedly upregulated the expression of AT1R mRNA and protein(P0.01).Meanwhile,AngⅡdownregulated the expression of AT2R mRNA and protein(P0.01 and 0.05).Twelve hours post different concentration rosiglitazone(20,30,50 μmol/L)treatment,the expression of AT1R mRNA and protein of VSMC were significantly attenuated(P0.01,vs AngⅡ group).However,the expression of AT2R mRNA and protein of VSMC were markedly upregulated(P0.01,vs AngⅡ group).At 6 hours post 30 μmol/L rosiglitazone treatment,the expression of AT1R mRNA and protein decreased,and then the expression of AT2R mRNA and protein increased,reaching a maximum at 24 h post treatment(P0.01).Conclusions Rosiglitazone can not only downregulate the expression of AT1R mRNA and protein,but also upregulate the expression of AT2R mRNA and protein in AngⅡ-induced VSMC in concentration-dependent and time-dependent manners.Above effects may be crucial mechanisms of the anti-inflammation and anti-atherosclerosis of peroxisome proliferator-activated receptor-γ agonists.