Table 2. Inhibitory effects of ICA with different concentrations on PDGF-BB-stimulated proliferation of RPE cells.

Group	24 h		48 h		72 h
	Absorbance	Inhibition (%)	Absorbance	Inhibition (%)	Absorbance	Inhibition (%)
Control	0.38 ± 0.01		0.53 ± 0.02		0.69 ± 0.01
PDGF-BB	0.48 ± 0.01###		0.78 ± 0.01###		0.94 ± 0.02###
PDGF-BB + ICA (10 µM)	0.45 ± 0.01*	28.53	0.67 ± 0.01***	43.88	0.77 ± 0.01***	64.26
PDGF-BB + ICA (20 µM)	0.44 ± 0.01*	40.28	0.63 ± 0.01***,ΔΔ	60.62	0.72 ± 0.01***,ΔΔΔ	86.40
PDGF-BB + ICA (40 µM)	0.43 ± 0.01**,Δ	55.93	0.59 ± 0.01***,ΔΔΔ,◊◊	76.37	0.68 ± 0.01***,ΔΔΔ,◊	99.97

Notes:

^*P < 0.05 vs. PDGF-BB group.

^**P < 0.01 vs. PDGF-BB group.

^***P < 0.001 vs. PDGF-BB group.

^###P < 0.001 vs. control group.

^ΔP < 0.05 vs. 20 ng/ml PDGF-BB + 10 µM ICA group.

^ΔΔP < 0.01 vs. 20 ng/ml PDGF-BB + 10 µM ICA group.

^ΔΔΔP < 0.001 vs. 20 ng/ml PDGF-BB + 10 µM ICA group.

^◊P < 0.05 vs. 20 ng/ml PDGF-BB + 20 µM ICA group.

^◊◊P < 0.01 vs. 20 ng/ml PDGF-BB + 20 µM ICA group.

RPE cells proliferation was determined with MTS assay at 24, 48 and 72 h after ICA treatment. Absorbance at 490 nm shows that ICA obviously inhibited PDGF-BB-stimulated proliferation of RPE cells in a concentration dependent manner. The IC50 values of ICA in RPE cells were 30.13 μM at 24 h and 12.53 μM at 48 h. Control: blank control group without PDGF-BB; PDGF-BB: 20 ng/ml PDGF-BB; PDGF-BB + ICA (10 µM): 20 ng/ml PDGF-BB + 10 µM ICA; PDGF-BB + ICA (20 µM): 20 ng/ml PDGF-BB + 20 µM ICA; PDGF-BB + ICA (40 µM): 20 ng/ml PDGF-BB + 40 µM ICA. Data are expressed as mean ± SD.