Objective:To investigate the role of angiotensin Ⅱ(AngⅡ)and the effects of treatment with astragalus(AGI) on the expression of plasminogen activator inhibitor-1(PAI-1)on rat peritoneal mesothelial cells(RPMCs) Methods:The RPMCs were cultured to the second generation in vitro

and were randomly assigned to the control group(groupA)

the AngⅡ(10-7 mol/L)group(groupB)

the AngⅡ+AGI(2 g/ml) Group(groupC) and the AngⅡ+AGI(1 g/ml) group(groupD).Group B:RPMCs were stimulated with Ang Ⅱ(10-7 mol/L)

RT-PCR was employed to detect the mRNA expression at 0

2

4

8

12

24 h;group C and group D cells were pretreated with AGI 2 g/ml and 1g/ml respectively before adding AngⅡ

and the mRNA expression and protein expression were detected at 4h and 24 h respectively.Results:①AngⅡstimulated PAI-1 mRNA expression in a time-dependent manner from 2 h up to 12 h and peaked at 4h

compared with 0 h group(P< 0.05)

at the same time

PAI-1 protein expression were also upregulated by Ang Ⅱ in RPMCS and peaked at 24 h compared with 0 h(P<0.05).②Treatment with AGI effectively downregulated Ang Ⅱ-induced PAI-1 mRNA and protein overexpression.Ang Ⅱ-induced PAI-1 mRNA overexpression were significantly downregulated by 39.43% and 37.28% with 2 g/ml and 1g/ml AGI treatment respectively after 4 h(P<0.05)

while its protein overexpression were downregulated by 29.41% and 24.12% respectively after 24 h(P<0.05)

and there were no differences of PAI-I expression between the treatment of different AGI concentration(P>0.05).Conclusion:AGI can inhibit the expression of PAI-1

to reduce the accumulation of extracellular matrix in RPMCs and prevent the progression of peritoneal fibrosis.