Objective    To investigate the effect of thrombin on the proliferation and apoptosis of human hepatocellular carcinoma cell line HepG

2

.     Methods    HepG

2

cells were treated with thrombin at the doses of 0

25

50

100

150

or 200 U/ml for 24

48 and 72 h respectively. The proliferation of the cells in each groups was measured by MTT assay. Cell apoptosis was analyzed with TUNEL assay.     Results    Higher doses of thrombin had obvious inhibitory effect on the proliferation. When the dose was increased to 100 U/ml and treated for 48 h

the inhibitory ratio of the HepG

2

cells was raised to (39.08±2.32)%

wh

ich were not further elevated with the increase of dose or elapse of treatment time. HepG

2

cells apoptosis was induced by thrombin.in a dose- and time-dependent manner when the dose was between 25 to 100 U/ml. However

there was no significant difference in the apoptosis of different groups when the dose was higher than 100 U/ml and the time exceed 48 h.     Conclusion    Higher doses of thrombin can inhibit the proliferation of HepG

2

cells

and lead to cell apoptosis. The both effects are increased in a dose- and time-dependent manner when the dose is 100 U/ml and treatment time is within 48 h.