Objective:

2

To investigate the effects of Shengmai Injection (生脉注射液

SMI) on the proliferation

apoptosis and N-myc downstream-regulated gene 2 (NDRG2

a tumour suppressor gene) expression in varying densities of human hepatic stellate cells LX-2.

Methods:

2

LX-2 cells were cultured

in vitro

. Then

cells were plated in 96-well plates at an approximate density of 2.5×10

4

cells/mL and cultured for 48

72

96 or 120 h followed by the application of different concentrations of SMI (0.6

1.2

2.4

4.8 or 6 μL/mL). Cell proliferation was measured after an additional 24 or 48 h using the 3(4

5-dimethylthiazol-2-yl)-2

5-diphenyltetrazolium bromide (MTT) assay. The effects of SMI on different cell growth states (cultured for 48

72

96

or 120 h) were observed by light microscopy at 24 h after treatment. When the cells reached 80% confluence

apoptosis was detected by flow cytometry after 24 h. Lastly

LX-2 cells were treated with different concentrations of SMI and extracted with protein lysis buffer. The levels of NDRG2 were measured by Western blot.

Results:

2

When the LX-2 cells grew for 48

72

96 and 120 h

4.8 and 6 μL/mL of SMI significantly inhibited cell proliferation at 24 and 48 h after treatment (

P

<

0.05). And 2.4 μL/mL of SMI also inhibited cell proliferation at 24 h after treatment when cell growth for 48 h (

P

<

0.05) and at 48 h after treatment when cell growth for 72

96 and 120 h (

P

<

0.05). The NDRG2 expression level in the LX-2 cell was significantly increased when treated with SMI at concentrations of 1.2

2.4

4.8 or 6 μL/mL (

P

<

0.05).

Conclusions:

2

The inhibitory effects of SMI on the proliferation of LX-2 cells were related to not only concentration dependent but also cell density. In addition

SMI (2.4

4.8 and 6 μL/mL) could accelerate apoptosis in LX-2 cells

and the mechanism might be associated with NDRG2 over-expression.