Inhibitory effect of tetramethylpyrazine on tissue factor expression and procoagulant activity induced by lipopolysaccharide in monocytes

The present study was aim to investigate the effects of tetramethylpyrazine(TMP) on lipopolysaccharide(LPS)-induced tissue factor(TF) expression and procoagulant activity in rat monocytes,which might provide some clues in the therapy of thrombotic disease.Freshly isolated peripheral blood monocytes were cultured in media containing LPS and/or TMP.TF procoagulant activity was measured by chromogenic substrate assay,and TF mRNA expression was determined by reverse transcription polymerase chain reaction(RT-PCR).It was found that TF procoagulant activity of rat monocytes was significantly increased under LPS stimulation(100 ng/mL, 5 h),and that TMP remarkedly inhibited the TF procoagulant activity in the concentration range from 0.01 μmol/L to 100 μmol/L,whose IC₅₀was estimated to be 0.29 μmol/L.Furthermore,TMP (10μmol/L）also inhibited the expression of LPS-induced expression of TF mRNA in rat monocytes.Hence TMP significantly inhibits both LPS-induced TF procoagulant activity and TF mRNA expression in monocytes.