Objective   To observe the effect of oxymatrine (OM) on the expressions of p-STAT1 and PIAS1 signaling molecules at protein and mRNA levels in the proliferation of the human mesangial cells (HMC) induced by lipopolysaccharide (LPS) and explore the relationship between them.    Methods   HMCs were primarily cultured from a 4-month-old aborted human fetus (with informed consent and approved by the Ethics Com

mittee of Lanzhou University)

and then divided into 3 groups

that is

control group

LPS group (10 ng/ml) and OM group (LPS 10 ng/ml and OM 320 mg/L). After cultured for 12

24 and 48 h respectively

HMC proliferation were analyzed by methyl thiazolyl tetrazolium (MTT) assay and type   Ⅳ  collagen in the supernatants were detected by ELISA. At the same time points

the cells lysates were collected for the mRNA and protein expressions of p-STAT1 and PIAS1 by real-time quantitative RT-PCR and Western blot analysis.    Results   The cell proliferation of LPS group was faster and the type   Ⅳ  collagen protein was increased more than the control group (

P

<

0.01)

but decreased in OM treatment group (

P

<

0.01); The protein expression of p-STAT1 and its mRNA in LPS group were upregulated compared with the control group (

P

<

0.01)

but decreased in OM treatment group at the same time points (

P

<

0.01); the expression of protein and mRNA of PIAS1 were lower than control group significantly (

P

<

0.01)

but become higher level in OM treatment group (

P

<

0.01).    Conclusion   OM downregulated the increased expressions of p-STAT1/PIAS1 in the process of LPS-induced HMC proliferation

probably through the JAK/STAT signal pathway.